Theses and Dissertations Collection

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Development and rapid assessment of community based health educational package for control of taenia solium cysticercocis/taeniasis in Tanzania
(Sokoine University of Agriculture, 2024-05) Nyangi, Chacha Joseph
aenia solium taeniasis/cysticercosis is a neglected parasitic zoonosis with significant economic and public health impacts worldwide. Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization ranked it first on the global scale of food-borne parasites. Taenia solium cysticercosis/taeniasis (TSCT) impacts is more in developing countries, including Tanzania, where social, economic, and cultural conditions favour its endemicity. Community knowledge is central in successful disease control in endemic areas. For control intervention to be effective and sustainable it should engage the community from planning stage. The study addressed the gap on knowledge, attitude and practices related to the disease, developed and conducted rapid assessment of a community-based health educational package (CHEP) for the prevention and control of TSCT in Tanzania. The study employed a community-based mixed methods approach involving different qualitative and quantitative approaches, using questionnaire for the household survey from 483 selected households, in addition, household infrastructure observations were conducted to the same 483 randomly selected households, Focused Group Discussions (FGD) and Key Informants Interviews (KII) were also conducted in Mbulu, Rungwe, Mbinga and Mpwapwa districts. The information collected led to the formulation of key messages for the development of a health education package, which comprises four components including; a training manual for the training of trainers (TOTs), a booklet with illustrations and instructions on how to perform small doable actions, brochure with key messages and poster with a tapeworm life cycle indicating the areas which can be targeted to interrupt the transmission. The formative research method was used in the development of the package. It is expected that the CHEP will be sustainable as it is development engaged the community in all stages of development. The CHEP developed was assessed in Babati district. This was done to assess the effectiveness of the package towards improvement of community knowledge attitude and practices towards control of TSCT. Qualitative data were analysed using thematic analysis. Descriptive statistics and chi-square test were used to analyse quantitative data including data on knowledge, attitude, and practices. Binary logistic regression was used to examine factors influencing socio demographic factors on knowledge and related practices, both independent and dependent variables were used. Socio demographic factors assessed were sex, age, district/location, education level, age group, main source of income, period of residence in years, and Savings and Credit Cooperative Society. The results revealed good knowledge about porcine cysticercosis, particularly among pig keepers across the districts. Majority of participants (48%) had heard about the pork tapeworm and the knowledge about clinical signs/symptoms and treatment was fair, but the means of transmission and prevention measures were often unknown. The risk perception of the infection with the pork tapeworm was low too and a similar trend is reflected in the attitudes toward the low-risk perception of cysticercosis infection. Hand washing practices was also low, many participants reported not washing their hands before eating or after using the oilet which highlights potential risks for the transmission of human cysticercosis. Almost all participants reported using the toilet always, however, household observations revealed that toilets were either lacking or had no complete walls, with others showing the sign of not being used for some time. Generally, household observations revealed a discrepancy between responses to the questionnaire on one hand and the availability of toilet and handwashing facilities, and the confinement of pigs on the other hand. This highlights the importance of including household observation during data collection. Respondents with tertiary education were more likely to have heard of tapeworm, be aware of T. solium transmission, be aware of T. solium health effects, and be aware of human cysticercosis transmission. Male respondents were more likely to be knowledgeable about porcine cysticercosis transmission. Lack of standardised education materials about the disease might influence the quality of health education in different infected communities. Using the gathered information, the health education package on knowledge, attitude, and practices reported a statistically significant improvement in knowledge regarding the link between epilepsy and cysticercosis and in the practice of washing fruits and vegetables, however, the long-term effect of the health educational package on knowledge, attitude, and practices and the disease parameter need to be evaluated. This study has revealed poor knowledge of T. solium Cysticercosis/Taeniasis with generally better knowledge about its effects on porcine than on human health. The limited overall knowledge, together with negative attitudes and practices may represent an important barrier to TSCT control and elimination efforts. It is therefore recommended to scale up the efforts of knowledge sharing with the general population on transmission, TSCT clinical signs/symptoms, control, treatment, and prevention in Tanzania, preferably adopting one health approach, to improve favourable knowledge, attitude for control and eventual eradication of TSCT. The study shows that socio-demographic factors have a direct influence on knowledge and practices related to TSCT. Education was the most important factor among the others and contributed significantly to the overall models that determined knowledge and practices related to TSCT. It is therefore, recommended that studies that include health education interventions also consider socio-demographic factors. Another area covered by this study was the development and rapid assessment of the health educational package which revealed an improvement in knowledge regarding tapeworm treatment from 61 (81.3%) pre-intervention to 76 (95.0%) post- intervention, while the knowledge regarding condemnation of infected pork increases from 65 (83.3%) pre-intervention to 73 (90.1%) post-intervention. Practices about washing vegetables and fruits significantly improved (P=0.025), while, that of pigs’ confinement increased from 45 (77.6%) pre- intervention to 54 (88.5%) post-intervention. It is recommended that to achieve the maximum impact of the intervention, the educational package should be combined with other existing control strategies as well as other intervention methods such as video, cartoons for school children, and a computer-based health-education tool such as the vicious worm. It is also recommended that the interventions preventing TSCT reinfection, such as improvements in hygiene achieved through health education, are urgently required to augment the effect of other control strategies as part of an integrated approach.
Crop storage practices and occurrence of fungi with public health importance from rodents’ trapped inside and outside the storage facilities in Mbeya, Tanzania
(Sokoine University of Agriculture, 2024-04) Mollel, Anna Peria
Animals play an important role in the dispersal of seeds and fungal spores. Several species that consume fruiting bodies of fungi play a primary role in dispersal networks. Through the rodent-mycorrhizal dispersal relationship, the study was conducted in selected wards of urban and peri-urban areas of Mbeya-Tanzania to discover whether rodents could act as the network for the dispersal of other fungi related to public health. As well as assessment of knowledge, awareness, and practices based on storage conditions, that may influence rodent infestation: implication to fungal contamination in storage facilities. A total of 210 rodents were trapped in and outside the storage facilities in selected wards in Mbeya city of which Rattus rattus (51.0%) was a dominant species, Praomys 40(19.0%), Lophuromys 29(13.8%), Mastomys natalensis 19(9.0%), Mus musculus 9(4.2%), and Lemnicomys spp 4(1.9%). Fresh fecal samples from the rectum were collected. The second form of samples were 77 pellets collected from the ground making a total number of 288 fecal pellets. Both samples were preserved at -20 0C at Mbeya National Research Institute (NIMR) for further laboratory analysis. Colony morphology obtained through Microbiological analysis and identification in selective media. A total number of 6 different fungal isolates were observed and Aspergillus fumigatus was the dominant fungal species from the cultured samples, with a prevalence of 26% (76/288) showing the potential for aspergillosis in humans followed by Aspergillus niger and Fusarium species with a prevalence of 9% (27/288), Aspergillus flavus 3% (10/288) and Aspergillus ochraceus 1% (4/288). Nested PCR confirmed the presence of aflR gene from suspected isolates of Aspergillus flavus, bands observed at 800kb for the first round and 400kb for the second round. Indirect Competitive ELISA performed on 10 maize samples that infected with A. flavus isolates, 10 maize samples free from isolates contamination, and 4 pure isolates of A. flavus. The aim was to check whether the isolates were capable of producing toxins and their respective concentrations (ug/ul) were calculated. To confirm the findings a cross-sectional survey was conducted and a total number of 50 facility storage owners were questioned based on grains storage practices, factors for rodent infestation, facility- building conditions, type of material used for storage of grains, Storage facilities owners’ knowledge based on the effects of rodent infestation and ways to reduce the effects. Poor storage practices, types of storage sacks, facility maintenance and longevity of the facility, and poor knowledge of controlling pests and losses due to rodents and moulds were the major findings. The 74% of respondents indicated that they stored only maize, while 26% stored maize along with other grains such as rice and beans. Among the respondents, 28% agreed that storing maize with other products facilitated rodent infestation, 22% disagreed with this opinion, and the remaining participants were unsure. The 58% of the participants expressed confidence in their understanding of the factors that influence rodent infestation, while 42% did not. Regarding major maintenance of their storage facilities, 38% of the storage keepers performed it annually, while 20% did it whenever they deemed it necessary. In terms of rodenticide application within the storage premises, 54% of the respondents indicated its use.
Metagenomics analysis of pathogens in rodents in selected human-wildlife Interfaces in Tanzania
(Sokoine University of Agriculture, 2024-05) Abel, Agnes
Rodents belongs to the order Rodentia, which comprise the largest proportions of all of the terrestrial mammals in the world. In Africa, rodents occur in 14 families, 89 genera and 290 species, East African region contains 14 families, 62 genera and 161 species of rodents. Over decades, rodents have been reported to harbor more than 60% of emerging zoonotic pathogens including viruses, bacteria and a number of parasites. Several human diseases including the most devastating in the history of mankind Plague‖ have been reported to have originated from rodents. Rodent borne diseases are transmitted either directly (Hantavirus, Lassa fever, Lymphocytic choriomeningitis) or indirectly through consumption of foods and water contaminated with rodent feces and urine (Leptospirosis, tularemia) or through ectoparasites carried by rodents (leishmaniasis, Lyme disease). Risks of human infection is linked to the possibility of contact between rodents, humans and animals, along with the closeness between rodent and human lives. Since there is constant interaction between humans, animals and rodents; it is therefore, essential to understand patterns of pathogen diversity and focusing surveillance in rodents in order to identify zoonotic potential pathogens prior to spill over to humans. Rodents were captured in Kibondo, Kyerwa and Uvinza in 2018. Trapping of rodents was done in peri-domestic areas by using Sherman box and Tomahawk traps added with peanut butter mixed with maize bran as baits. They were anaesthetized by using Isoflurane, and species identification was done by using morphological identification keys. In metagenomics sequencing a total of 116 rodents archived oral- pharyngeal and rectal swabs were subjected to RNA extraction and the products were pooled into twelve pools based on species of rodents, locations and swab types. There were eleven pools of oral- pharyngeal swabs and a single pool of rectal swabs. Pooled samples were sequenced on oxford Nanopore MinIon sequencing platform. This study employed 16S rRNA metagenomics sequencing analysis. Sequences were analyzed by using Kraken 2 classification and Kaiju software. A total of 5263 small mammals were trapped from Kibondo, Uvinza and Kyerwa during the three years of data collection. Majority (87.6%, n=4613) were rodents and 650 (12.4%) were shrews. Among the rodents, rats were the majority (70.0%; n=3683) while mice were 873 (16.6%) and squirrels were only 44 (0.8%). The dominant species in the group of rodents were Mastomys natalensis which constituted 63.6% (n=3346). Among the mice, Arvicanthis spp. were the majority as they constituted 7.1% (n=373) of all small mammals trapped. A total of 13 (0.3%) small mammals identified as rodents their genus was not established. In a metagenomics analysis, 44 bacteria species of public health, veterinary and environmental health importance were identified. They were detected in eight pools, while there was no detection in four pools. A total of 10 (22.7%) bacteria species including H. pylori were detected in the rectal swabs pool and the remaining 34 (77.3%) were distributed among the pools of oral-pharyngeal swabs. A total of 15 potentially pathogenic, zoonotic and bacteria of unknown zoonotic potential including Mycobacterium tuberculosis, Helicobacter pylori, Vibrio cholerae, Vibrio parahaemolyticus, Haemophilus influenzae, Klebsiella pneumonae, Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Chlamydia psittaci, Campylobacter sputorum, Acinetobacter baumannii and Acinetobacter pitti were identified in this study. The findings of this study are in line with several previous studies that have reported a number of rodent species in western Tanzania; also, citing rodents as reservoirs of disease-causing agents; and has the potential to spread and maintain transmission cycles of human and livestock diseases. This study presents the first reports of natural infection of rodents with Helicobacter pylori and Mycobacterium tuberculosis. These findings provide baseline information to inform surveillance systems and the public in general on potential health risks that are associated with interaction between rodents, humans and livestock. Furthermore, it gives insight on the potential of using a unified approach One Health‖ between sectors in order to achieve better health and a safer community. However, since the findings of this study do not explain pathogen transmission from rodents to humansand vice versa, we recommend further studies to characterize them and understand their transmission dynamics.
Merging the gap between formal and informal training: a case study of mobile phone repairers in Morogoro Municipality, Tanzania
(Sokoine University of Agriculture, 2023) Kabelinde Joram
The development of science and technology has led to the emergence of mobile phone technology which has gained tremendous popularity as the ideal device for communication in modern times. In relation to the emergence of mobile phones, there is the need for a new field of profession which ensures mobile phone repair and maintenance. In response to the need, there have emerged a lot of entrepreneurs across the country offering mobile phone repair and maintenance services. Hence, the study aimed to assess the state of mobile phone repairers’ skill development and compare the phone repairers' demands with the coverage of Vocational Education Training Authority (VETA)-Kipawa and Dar es Salaam Institute of Technology (DIT) curricula. The case study design under qualitative approach employed interview, observation and documentary review to gather the data from 15 mobile phone repairers, 20 customers of the repairers and 5 VETA trainers. The findings revealed that most mobile phone repairers joined the industry as a result of both intrinsic and extrinsic motivation. Additionally, the study found that most mobile phone repairers acquired skills through observing experienced mobile phone repairers and short courses organised by VETA. It was discovered that some of the mobile phone repairers lack formal or non-formal trainings relating to mobile phone repair. The researcher reports on the need of the government through training institutions to avail easily accessible and affordable formal and non-formal mobile phone repair trainings. The results also show that the existing curriculum used at VETA to offer trainings to mobile phone repairers does not wholly match their needs. The study based on the findings, it recommends that mobile phone repairers should not only learn informally, especially from more knowledgeable and experienced mobile phone repairers, but also should attend training institutions. It is also recommended that the government should facilitate mobile phone repair training institutions in providing specialized skills relating to mobile phone repair in order to meet the demands of mobile phone repairers.
Phytoconstituents utility in ethiopian kale and african cabbage orphan leafy vegetables and potential cultivation of the vegetables as functional foods
(Sokoine University of Agriculture, 2023) Maina S.W
Various studies have recently highlighted the importance of African leafy vegetables (ALVs), which refer to plants whose leaves are accepted and utilized as vegetables by communities through tradition. Due to their higher concentrations of nutritious and non- nutritive compounds than widely cultivated and consumed "exotic" vegetable species, ALVs constitute an important part of people's diets. Orphan ALVs, such as Cleome gynandra (African cabbage) and Brassica carinata (Ethiopian kale), are indigenous, native species that were introduced centuries ago but are still used locally or regionally, having lots of untapped potential to improve nutritional security. Due to their local benefits, occurrence as wild plants, weeds, or volunteer crops, these vegetables are typically characterized as minor, neglected, underutilized, and/or unimproved; and they are almost entirely ignored by farmers, researchers, crop breeders, and even policymakers. Consumers have recently placed a high value on vegetables as functional foods in their diets, with reports indicating that they are not only nutritionally dense, but also contain high levels of some health-beneficial phytochemicals when compared to commonly consumed staple crops, and that they have a high potential to contribute not only to food security, but also to nutritional security. In this thesis, an extensive study was conducted in order to understand the secondary metabolites present in African cabbage and Ethiopian kale vegetables, their utility in promoting human health, possible strategies to improve the vegetables, and the potential application of these vegetables as functional foods and as a source of natural bioactive compounds in the food and pharmaceutical industries. Firstly, this study involved a systematic review to determine the composition and health beneficial compounds obtainable from leafy vegetables and the possible strategies for improving such compounds during vegetable growth. Then using seeds supplied from a gene bank in Kenya, the Centre for Biodiversity in Kenya Resources Centre for Indigenous Knowledge, National Museums of Kenya (eight accessions for African cabbage and one accession for Ethiopian kale), the vegetables were cultivated in the greenhouse of KIST. Plant materials were collected at different stages and separated into several organs for bioactive component profiling. Target chemicals such as glucosinolates (GLs) and phenolics were detected in the vegetables using chromatographic techniques combined with mass spectrometry, based on their fragmentation patterns and mass to charge ratio. The identified compounds were quantified with commercial pure standards or relative response factors of the compounds using High performance liquid chromatography (HPLC) techniques. Upon identification and quantification of the compounds in the different vegetable parts and accessions, the adaptation of the vegetables for application in a vertical smart farming system was determined by checking the agronomic characteristics/desired traits. Furthermore, the possibility of improving vegetables by accumulating the bioactive secondary metabolites and their associated biological properties was evaluated using elicitors treatment. Different types and concentrations of elicitors and their applicability to vegetables grown in vertical farming system were chosen. In the findings from the review, I obtained crucial data on the major composition of leafy vegetables which include GLs and polyphenols, the type of biological activities associated with these compounds such as anticancer, anti-inflammatory, antioxidant activities as well as the different strategies that can be used to improve vegetables at different stages of growth. For the compositional data, I observed variable components and concentrations of the identified compounds in each vegetable, the accessions under study and the vegetable parts used. During the evaluation of the well adapted vegetable to be used in the vertical farming system, Ethiopian kale vegetables were best suited for this type of farming and the cultivation had positive results in improving not only yield but also the quality of the vegetables and the inherent biological activities attributed to them. This vegetable was the choice for further objectives and analysis in this research and the target development stages were chosen depending on their ability to accumulate the bioactive compounds. Ethiopian kale’s samples extracts were subjected to various chemical and in vitro biological assays including antioxidant and anti-inflammatory potential, chosen depending on the identified compounds and effective activities were attributed to these compounds based on the literature review. The findings on elicitation demonstrate how elicitors could be used as a simple strategy to obtain quality plant functional foods with increased quantities of the health promoting compounds. This study shows the utility of both the edible and non-edible parts of the orphan leafy vegetables. It reduces the gap of unknown compounds in the vegetables and the identification of new compounds and provides a future reference for further studies. The evaluation of potential smart farming techniques to improve both yield and content of essential phytochemicals in the vegetables creates a good opportunity to venture and apply this emerging farming techniques for the production of high-quality functional foods and vegetables with accumulated drug target compounds for use in the pharmaceutical industry. The identification of superior accessions provides potential research targets to be used breeding programs for improving available vegetable varieties while the strategies used in production of quality vegetables are useful in the food industry for the production and processing of functional foods from the orphan leafy vegetables.
Antimicrobial use, prevalence of extended spectrum beta-lactamase producing escherichia coli and economic effects on cattle and poultry in Dar es salaam Tanzania
(SOKOINE UNIVERSITY OF AGRICULTURE, 2023) Azabo R.R
Antimicrobial usage (AMU) in livestock production provides a basis for improving animal health and productivity. However, it is evident that the over-dependence of animal production on antimicrobial agents is one of the major factors driving the emergence of antimicrobial resistance (AMR) in bacteria that can be transmitted via the food chain or environment to humans. This thesis aims to assess antimicrobial use in cattle and poultry production in relation to resistance in Extended Spectrum Beta-Lactamase (ESBL) producing Escherichia coli (E. coli) and also gain insight into economic effects (cost and benefit) of antimicrobial use reduction in animal production inIlala, Kinondoni and Ubungo districts which form part of the Dar es Salaam region, Tanzania with the following objectives.(i) To conduct a systematic review on the methods and metrics used to quantify and assess MU in cattle and poultry production in Sub-Saharan Africa, (ii) To determine the quantity, quality and pattern of antimicrobial use in cattle and poultry production in Dar es Salaam, Tanzania, (iii) To assess antimicrobial consumption in food-producing animals in Dar es Salaam, Tanzania, (iv) To determine the prevalence and antimicrobial resistance pattern of ESBL producing E.coli isolates from cattle and poultry production, and (v) To estimate the economic effects (costs and benefits) of antimicrobial use reduction in cattle and poultry production. In view of these objectives, the findings of this thesis are presented in five scientific papers. Paper 1: A systematic literature review was conducted to provide an overview of methods of measuring AMU and metrics used, reviewing existing data on AMU in cattle and poultry production in order to identify gaps in Sub-Saharan Africa. The study revealed a deficit of studies on estimate of quantity and quality of antimicrobials used in food-producing animals in Sub-Saharan Africa. Paper 2: A cross-sectional study was conducted on 116 farms (51 poultry and 65 small-scale dairy cattle) in Ilala, Kinondoni and Ubungo Districts of Dar-es-Salaam region, Eastern Tanzania from 15th August to 30th September 2019 to investigate the level of antimicrobial use practice, type and quantity (amount) of antimicrobials consumed. The study revealed that 23 (19.8%) of the farms visited had records while 93 (80.2%) relied on recall, 58.6% of the livestock farmers had adequate level of practices (favorable) in accordance to antimicrobial use based on their responses, the most commonly used class of antimicrobials in poultry production were: Fluoroquinolones (25.5%), sulphonamides (21.6%), tetracycline (11.8%) while in the small-scale dairy farms, tetracycline (20.0%), beta-lactams (18.5%), sulphonamides (12.3%) were most commonly used. Quantitatively, in the poultry farms, the frequently used antimicrobial class sulphonamides (46.1%), tetracycline (19%) and Macrolides (14.2%). In the small-scale dairy farms, the use beta-lactams (36.4%), sulphonamides (22.3%), tetracycline (14.3%) were predominant. For Paper 3: a cross-sectional study, using data extraction form to collate antimicrobial use data from sales records (three consecutive years) of five established licensed veterinary pharmaceutical wholesales/outlets which were purposively selected in Ilala, Kinondoni and Ubungo. The study revealed that 178.4 tonnes of antimicrobials (by weight of active ingredients) were consumed during the 3 year study period (2016-2018), with an average of 59.5 ± 3.8 tonnes/year. The commonly sold antimicrobials were tetracycline (44.4%), sulphonamides (20.3%) and aminoglycosides (10.3%). Regarding veterinary antimicrobial use importance to human medicine, 34.4% were critically important antimicrobials; 4.1% were reserve and 51% were watch groups according to AWaRe categorization of WHO. Overall, a mean of 7.44 ± 0.81 mg/PCU (population correction unit) was consumed by food-producing animals during the three-year study period. Paper 4: A cross-sectional study was conducted in 54 of the previously visited farms where a pre-tested questionnaire on antimicrobial (antibiotics) usage was completed. A total of 121 E. coli isolates were obtained from 201 sampled small-scale dairy cattle rectal swabs. Looped rectal swab specimens from Stuart transport medium, were streaked directly onto plain MacConkey agar (Oxoid, Basingstoke, UK) and aerobically incubated at 370C for 24 hours. Presumptive E. coli colonies were Gram stained and then subjected to biochemical tests (Indole test, Methyl red test, Voges-Proskauer test and Citrate Utilisation test; IMViC test) for identification. E. coli strain ATCC 29522 was used as a reference organism. Antimicrobial susceptibility testing (AST) was performed against eight types of antimicrobials: (Tetracycline, (TE) (30 μg), Ampicillin, (AMP) (10 μg), Gentamicin, (CN) (10 μg), Ciprofloxacin,(CIP) (5 μg), Cefotaxime,(CTX) (30 μg), Nalidixic Acid, (NA) (30 μg), Trimethoprim/Sulfamethoxazole, (SXT) (1.25/23.75μg) and Chloramphenicol,(C) (30 μg)). The highest prevalence of AMR was against AMP (96.7%), CTX (95.0%), TE (50.4%) and SXT (42.1%). The 121 isolates of E. coli belong to 41 different phenotypes showing a variation of resistance. The most frequently observed phenotypes were AMP-SXT-CTX with a prevalence of 12.4%, followed by the combination AMP-CTX with 10.7% and TE-AMP-CTX and NA+TE+AMP+CTX with 8.3% each. Fifteen different phenotypes that produce Extended Spectrum Beta-Lactamases (ESBLs) were detected with a prevalence of 42.9% and 74.4% of E.coli isolates exhibited multidrug resistance (MDR). This probably confirms that antimicrobial use is unregulated and thus inappropriate use which led to the emergence and development of resistance. Paper 5: A cross-sectional study was conducted on randomly sampled broiler farms which were in production for one year in Kinondoni and Ubungo Districts in Dar es Salaam region of Tanzania from February to March 2021. A pre-tested questionnaire was used to capture data required to complete the model for the estimation of the economic effects (costs and benefits) on reduction of antimicrobial use. Data collected included: number of chicks bought and dead on the farm (mortality), observed clinical signs; signs of respiratory infections (coughing, wheezing, sneezing and nasal discharge), enteric infection (diarrhea) and lameness (locomotive signs) (morbidity). A Mclnerney model built on biological and economic parameters of disease effects on livestock production was used to analyze the data. The net costs and benefits were estimated within a partial budgeting framework in the model. The results of this study showed that antimicrobial use reduction will have an effect on mortality and morbidity and thus increase the cost of production due to changes in additional management changes (animal health management and technical management). Findings from this thesis recommend that rational AMU should be emphasized by targeting cattle and poultry production in Tanzania in general and Dar es Salaam in particular.
Seroprevalence of leptospira among rodents and shrews in public markets and hospitalized febrile patients in Unguja Island
(Sokoine University of Agriculture, 2023-05) Ally Abdullah Ally
Leptospirosis is a neglected infectious zoonotic disease of public health significance caused by spirochete pathogenic bacteria of the genus Leptospira. This disease occurs mainly in tropical and subtropical countries and affects animals and humans, of which rodents and shrews are considered significant reservoirs of infection. Human might be infected by Leptospira pathogen through a contact mode of transmission, either direct or indirect, with the urine of infected animal’s host or a urine-polluted environment such as water or soil. However, infected humans develop a range of symptoms undifferentiated from other tropical diseases, such as malaria, particularly in regions with high malaria prevalence. A cross-sectional study was carried out between January and April 2022 in Unguja Island (i) to determine the seroprevalence of Leptospira infection among rodents and shrews in public markets and (ii) to determine the seroprevalence of leptospirosis among hospitalized febrile patients. Blood samples were collected from 210 live captured rodents and shrews in the five purposively selected markets including Darajani, Mombasa, Jumbi, Kwerekwe C and Mkokotoni. Likewise, 402 human blood samples were collected from febrile patients who were attended to the selected hospitals namely Mnazi Mmoja referral hospital, Kivunge district hospital and Makunduchi district hospital. The Leptospira antibodies of rodents, shrews and humans were tested against five serovars namely Sokoine, Lora, Pomona, Grippotyphosa and Hebdomadis using the Microscopic Agglutination Test (MAT). The results indicated that out of 210 rodents and shrews captured in public markets, 16 were seropositive for Leptospira serovars. Thus, the overall seroprevalence of Leptospira infection was 7.6% (95% CI =4.4−12.1), with a prevalence of 6.6% (14/210) in rodents and 1.0% (2/210) in shrews. The Leptospira serovars circulating among rodents and shrews antibodies were Sokoine 11 (5.2%), Lora 4 (1.9%), Pomona 2 (1.0%), and Grippotyphosa 1 (0.5%). Rattus rattus were shown to have high seroprevalence of Leptospira infection (4.2%), followed by Rattus norvegicus (1.4%), Mus spp (1.0%) and Crocidura spp (1.0%). Furthermore, out of 402 human sera collected from three hospitals, 31 human samples were seropositive for Leptospira serovars, and thus, the overall seroprevalence of human leptospirosis was 7.7% (95% CI = 5.3−10.8). Females 20 (5.0%) were shown to have high seroprevalence of disease compared to males 11 (2.7%). The major Leptospira serovars circulating in humans were Sokoine 44 (10.9%), Lora 25 (6.2%), Grippotyphosa 20 (5.0%), Pomona 10 (2.5%), and Hebdomadis 9 (2.2%). The findings of this study have indicated that several Leptospira serovars are common to rodents, shrews and humans. Likewise, market features and practices, including a poor drainage system, the presence of stagnant water, unhygienic conditions, and wet soil, favor rodent population and pose a risk of environmental contamination and perpetuation rodent-environment-human infection cycle. This report call for consideration and inclusion of this disease in the differential diagnosis of acute febrile syndromes in humans.
Effects of food insecurity among pastoralist families in the changing climate of Iringa rural District, Tanzania
(Sokoine University of Agriculture, 2014) Mdachi, Mary
Dietary intake measures are useful for assessing nutritional status of an individual. Dietary intake depends on the availability of healthy foods, as well as on resources available to an individual, allowing them to purchase or access foods. This study was carried out in 20 villages in Iringa Rural District, between July and September 2013 to assess effects of food insecurity among pastoralist women and their infants. Interviews were used to gather information on food insecurity and food frequency in pastoralist households. Anthropometric measurements and haemoglobin (Hb) concentrations of the participants were also collected. A total of 200 women and 30 infants were included in the study. The results indicated that majority (75.8%) of women’s diet was of plant origin. Approximately 75% of women had food shortages, defined as having at least one meal per day composed of limited food groups and quantities. All children were given meals mainly composed of carbohydrates (40%) once a day with no consistent pattern of types of foods or feeding times. Data on the nutritional status of children indicated that 6.6% of the Barbaig children experienced wasting while 10% of the Sukuma children were stunted. For women, 28% were underweight, while 7% were obese. Haemoglobin data indicate that 87.5% of children were anaemic while 42% of women were anaemic. It is concluded that most women and children had food insecurity and poor nutritional status which partly would be caused by climate change. It is recommended that nutritional education programs should be introduced in health facilities and in schools so as to improve the knowledge on nutrition. Also education should be given to the heads of households on how to utilize livestock in improving their livelihood/income and strategies to climate change adaptations.
Effects of food insecurity among pastoralist families in the changing climate of Iringa Rural District, Tanzania
(Sokoine University of Agriculture, 2014) Mdachi, Mary
Dietary intake measures are useful for assessing nutritional status of an individual. Dietary intake depends on the availability of healthy foods, as well as on resources available to an individual, allowing them to purchase or access foods. This study was carried out in 20 villages in Iringa Rural District, between July and September 2013 to assess effects of food insecurity among pastoralist women and their infants. Interviews were used to gather information on food insecurity and food frequency in pastoralist households. Anthropometric measurements and haemoglobin (Hb) concentrations of the participants were also collected. A total of 200 women and 30 infants were included in the study. The results indicated that majority (75.8%) of women’s diet was of plant origin. Approximately 75% of women had food shortages, defined as having at least one meal per day composed of limited food groups and quantities. All children were given meals mainly composed of carbohydrates (40%) once a day with no consistent pattern of types of foods or feeding times. Data on the nutritional status of children indicated that 6.6% of the Barbaig children experienced wasting while 10% of the Sukuma children were stunted. For women, 28% were underweight, while 7% were obese. Haemoglobin data indicate that 87.5% of children were anaemic while 42% of women were anaemic. It is concluded that most women and children had food insecurity and poor nutritional status which partly would be caused by climate change. It is recommended that nutritional education programs should be introduced in health facilities and in schools so as to improve the knowledge on nutrition. Also education should be given to the heads of households on how to utilize livestock in improving their livelihood/income and strategies to climate change adaptations.
Prevalence, mean intensity and pathology of ectoparasite infections in nile tilapia (oreochromis niloticus) in aquaculture production systems in Morogoro urban and rural areas, Tanzania
(Sokoine University of Agriculture, 2008) Mtenga, Coletha Mathew
A cross sectional study was carried out between September 2007 to September 2008 in order to investigate the prevalence, mean intensities and pathology of ectoparasite infections on the gills and skin of Nile tilapia (Qreochromis niloticns) in selected ponds in urban and rural areas of Morogoro, Tanzania. Pond area, fish size and water quality were also determined. On-farm oral interviews using structured questionnaire were carried out on each farm involved in the study to establish management practices. Two types of ectoparasite namely: Trichodina species and Monogeneans were identified. Trichodina spp were more prevalent (P < 0.001) than Monogeneans. Gills were the most affected organs than skins with a high number of parasites as well as pathological damage to the tissues (P < 0.001). Main pathological lesions observed on the gills were hyperplasia, sloughing and necrosis of the lamellar epithelium, clubbing and fusion of secondary lamellae. The physico-chemical parameters of water in the ponds and management practices were different from one another in the study area; however, there was no strong correlation between water quality and parasite prevalence and mean intensities of the parasites. Prevalence and mean intensities of parasites in fish varied in different ponds with some ponds having very high prevalence and mean intensity and others with very low. This might be explained by the different management systems based on the knowledge the farmers had on fish husbandry and different weather conditions in the study area. There were significantly higher parasite infections in fish in the urban than in the rural areas (P< 0.05). The overall prevalence in the study area was 68% and on average the mean intensity was 5.3. The ectoparasites seem to pose a threat to the aquaculture industry in Morogoro urban and rural areas as observed in this study. To rescue the situation, educational intervention and further research on tilapia parasitic diseases is needed. Farmers have to be trained on proper husbandry and good management practices of fish farming. There is also a need for the government to promote aquaculture as the country has a great potential for it.
Studies on the effects of trypanosoma congolense infection on the reproductive function of the ram
(University of Glasgow, 1993-12) Mutayoba, Benezeth Mugyabuso
This thesis describes a series of studies carried out in Scottish blackface rams experimentally infected with Trypanosoma congolense stabilates 57/10 and 57/11 (originally imported from ILRAD, Kenya as ILRAD 1180) with the primary aim of determining the effects of infection on the function of the hypothalamo-pituitary-gonadal axis. The studies also investigated the possibility that pyrexia is responsible for inducing gonadal endocrine and exocrine dysfunctions in infected animals. In addition the effect of infection on the function of the hypothalamo-pituitary-adrenal (HPA) axis was assessed in order to determine whether reproductive dysfunction generally seen during trypanosomiasis is related to stress caused by the infection. Chapter I comprises an introduction and a literature review on trypanosome- induced reproductive dysfunctions with emphasis on pyrexia and changes in the HPA axis. Chapter II describes the two experiments carried out in rams infected with T. congolense and the general materials and methods used in these studies. Chapter III describes the effects of infection on semen characteristics and pathology of various reproductive organs such as the testis, cauda epididymis, prostate and pituitary gland. It was found that T. congolense induced a progressive deterioration of semen quality in terms of an increased percentage of abnormal spermatozoa in the ejaculate. Progressive non-inflammatory degenerative changes were observed in the testis and prostate gland. The cauda epididymis showed varying degrees of decreased sperm reserve. Trypanosome-induced pyrexia led to an elevation of scrotal temperature in infected rams, suggesting that the changes in the gonads could have been due to increased testicular temperature. Indeed, similar changes were observed in the semen and gonads of uninfected rams following artificial elevation of testicular temperature by scrotal insulation. The pituitary gland showed changes associated with increased basophilic degranulation in infected rams. Changes in plasma concentrations of reproductive hormones in the same rams are described in Chapter IV. It was observed that soon after the onset of parasitaemia, which occurred within 1-2 weeks of infection, plasma testosterone concentration declined and levels remained low throughout the infection period. This reduction in plasma testosterone concentration was associated with a progressive and marked decline in testosterone pulse amplitude and testosterone secretion after injection of gonadotrophin-releasing hormone (GnRH) was also depressed throughout the infection period. By four weeks after infection, declining plasma testosterone concentration was accompanied by a significant increase in plasma luteinizing hormone (LH) pulse amplitude and increased pituitary responsiveness (LH secretion) to exogenous GnRH. As the infection progressed up to 8 weeks, the plasma LH concentration declined. This could not be associated with some aspects of gonadal steroid feedback as similar LH changes were observed in infected rams which had been castrated. Neither was the decline in plasma LH concentration caused by the inability of the pituitary gland to secrete and release LH as secretion of LH in response to exogenous GnRH was not impaired throughout the infection period. It was therefore concluded that the decline in plasma LH concentration after 8 weeks of infection was possibly induced by a progressive impairment of the ability of the hypothalamus to synthesize and/or release GnRH. Gonadal steroidogenesis in infected rams was investigated in the in vitro experiments described in Chapter V. This work showed that the alteration in plasma testosterone concentration following infection was associated with a decline in Leydig cell steroidogenesis, possibly mediated by increased testicular temperature affecting testosterone biosynthetic enzymes. However, by 4 weeks after infection, reduced plasma testosterone in infected animals was exacerbated by the impaired ability of the testes to release testosterone into the circulation resulting in a significant increase in intratesticular testosterone content. A similar increase was also observed in scrotal- insulated rams and it was therefore suggested that changes in intratesticular testosterone in infected rams at 4 weeks of infection was associated with a trypanosome-induced increase in testicular temperature perhaps through an effect on testicular blood flow. The effects of T. congolense infection on the function of the HPA axis in rams and the relationship between this and the changes in the hypothalamo-pituitary-gonadal axis are described in Chapter VI. The onset of parasitaemia stimulated a significant increase in plasma cortisol concentration which was followed within 3-6 week of infection by a decline in plasma cortisol levels and a reduced ability of the pituitary to secrete adrenocorticotrophin hormone (ACTH) after injection of corticotrophin-releasing hormone (CRH). Thereafter, the activity of the HPA axis was increased in step with the fluctuating parasitaemia. CRH stimulation of the HPA axis had no effect on LH secretion but reduced the plasma concentration of testosterone indicating the possible aggravation of T. congolense-induced reproductive disorders by stress-induced cortisol. The general discussion and conclusions drawn from all the experiments are. presented in Chapter VII. It can be concluded that T. congolense causes a very profound dysfunction of the hypothalamo-pituitary-gonadal axis in rams through actions at various sites. These effects may be partly associated with trypanosome-induced pyrexia and are exacerbated by increased plasma cortisol concentrations resulting from the activation of the HPA axis.
Porcine cysticercosis in Angonia district, North-Western Mozambique: epidemiology and evaluation of the effectiveness and efficiency of oxfendazole treatment
(Sokoine University of Agriculture, 2010) Junior, Alberto Pondja
A research was conducted to investigate the epidemiology of porcine cysticercosis in Angonia district, Mozambique, and to evaluate the effectiveness and efficiency of oxfendazole (OFZ) for the treatment of porcine cysticercosis. Prevalence and risk factors associated with porcine cysticercosis were determined in a cross-sectional survey conducted in 11 randomly selected villages. Out of 661 pigs screened, porcine cysticercosis was diagnosed in 12.7% and 34.9% by lingual examination and Ag-ELISA, respectively. Increasing age (OR = 1.63; 95% CI: 1.13, 2.37) and free-range pig husbandry system (OR = 3.81; 95% CI: 2.08, 7.06) were significant risk factors associated with the disease. The incidence of porcine cysticercosis was determined in a study conducted in 4 endemic villages. A total of 108 piglets were tested repeatedly for porcine cysticercosis (by Ag-ELISA) at 4, 9 and 12 months of age. The incidence rate of porcine cysticercosis increased significantly from 3.8 cases per 100 pig-months in the first period (between 4 and 9 months of age) to 19.3 cases per 100 pig-months in the second period (between 9 and 12 months of age). The effectiveness and efficiency of 30mg/kg dose of OFZ for the treatment of porcine cysticercosis were evaluated in a randomized control trial that involved 216 piglets. Fifty four piglets were treated at 4 months of age (OFZ-T1), other 54 piglets treated at 9 months (OFZ-T2) and matched with 108 controls. Baseline prevalence (by Ag-ELISA) was similar among the study groups. At 12 months of age, infections were found in 66.7% controls, 21.4% OFZ-T1 and 9.1% of the OFZ-T2 pigs. There was a significant risk reduction for cysticercosis if pigs were treated either at 4 months (OR = 0.14; 95% CI: 0.06, 0.34) or 9 months of age (OR = 0.05; 95% CI: 0.01, 0.15). Treating pigs with OFZ resulted in positive incremental net benefits. Porcine cysticercosis is endemic in Angonia district. Oxfendazole treatment is cost-effective, and combined with health education programs would have a significant contribution to the control of Taenia solium transmission. Further studies are needed to fine-tune the use of OFZ into a more practical field control tool for porcine cysticercosis.
Study on congenitally acquired Plasmodium Falciparum infection in neonates in Muheza district, Tanzania
(Sokoine University of Agriculture, 2006) Mwangoka, Grace Wynn
The study aimed to determine if infants diagnosed with malaria parasites in the age below three months acquire the infection congenitally from their mothers through the placenta. Placenta blood, cord blood samples and blood from infants born of mothers diagnosed with placental malaria by blood smear and presented clinical malaria below three months of age were examined by PCR amplification, PCR-RFLP and sequenced. Prevalence of Plasmodium falciparum by PCR in the placenta and cord were 9.2% and 65%, respectively and 18 (19.1%) of infants born from mothers diagnosed with placental malaria developed clinical malaria below three months of age. Placental blood and cord blood sample, and placental blood and blood samples of infants below three months that shared the same band size by PCR and fragments size by PCR-RFLP were considered to be genetically related. Though sequencing results confirm differently that, sharing band size and fragments size between samples does not confirm that the parasites are genetically related. Six pairs (40%) out of 14 pairs of placental blood and cord blood samples that shared band size and fragments size, after sequencing were genetically unrelated while eight pairs (60%) were genetically related which is an indication of transplacental transmission of malaria parasites to the cord. One pair (14.3%) of sequenced placental blood samples and blood samples of infants below three months were genetically related. This showed that the malaria parasite that crossed from the placenta to the infants through the cord caused congenital malaria. Over three-fourths (79.8%) of newborn infants delivered from mothers with placental malaria were below normal gestation age and 14.9% of newborn infants had low birth weights. Some 42.5% of primigravidae were found to be parasitized with P.falciparum in the placental. A higher proportional of infants from primigravid were frequently infected with malaria while infants from multigravid observed to acquire malaria infection early in life. Placental malaria, which leads to cord malaria, observed to significantly decrease (P <0.001) as gravid increases.
Prevalence, risk factors and genetic relatedness among thermophilic campylobacters from humans and chickens using rapd-pcr in Morogoro, Tanzania
(Sokoine University of Agriculture, 2009) Chuma, Idrissa Shomari
jejuni and 5% of C. coli were100% similar. Conclusively, zoonotic thermophilic Campylobacter infections existed between humans and chickens in Morogoro municipality. Besides chickens, the role played by other domestic and wild animals in transmitting thermophilic Campylobacter infections to humans particularly children, should be closely examined. jejuni and 5% of C. coli were
Attitudes towards animals and their welfare among cattle keepers in Morogoro and coast region in Tanzania
(Sokoine University of Agriculture, 2014) Burashi, Wilbert Vitus Joseph
Investigation of knowledge on essential needs of animals, reactions of cattle keepers towards farm and other domestic animals with the aim of determining attitudes and perceptions towards animals and their welfare in Tanzania. Comparison was done between traditional and peri-urban backyard dairy cattle keepers. Primary and secondary data was collected through questionnaires, focus group discussion and on site observation. The findings show that in both groups, awareness on animals’ welfare was recognized but they differed in aspects like disease prevention, input associated with welfare and attitudes towards handling and treatment of farm animals. However, the way cattle, dogs and cats were treated seems to differ between peri-urban and traditional cattle keepers. Poor treatment of cattle was observed in traditional group especially on aspects of dipping, vaccination, deworming and additional feeds such as concentrates, fodder and water supply. Low level of education, poor knowledge and little exposure on animal welfare were the key factors for the bad treatment of animals. Comparatively, cattle were cared more than dogs and cats in both sectors because of economic benefits. Therefore, due to the importance accumulated from the livestock sector to the economy of individual farmers and the country, the welfare of animals need to be advocated with all efforts. Good trained professionals working to reduce animal suffering should implement animal welfare laws, policies and practices. Educational campaign, seminars and workshops should be used to promote animal welfare issues. The Ministry of livestock and fisheries must take this as an important issue for good products of animals and for the benefit of the country.
Ultrastructural study of brain with experimental cowdria ruminantium infection (heartwater)
(1991) Mwamengele, George L. M.
Heartwater is an infectious, vector-borne, non-contagious disease of ruminants caused by Cowdria ruminantium. The etiologic agent is an obligate, intracellular parasite infecting phagocytic cells and, particularly, vascular endothelium. Transmission is effected by a three- host tick of the genus Amblyomma. Clinically, the disease is characterized by fever and signs of central nervous system disorder. There is general agreement on a deranged transport mechanism across the vascular wall as the basis for the development of morphologic lesions and clinical signs, but the actual mechanism of damage is poorly understood. Previous ultrastructural studies are few and have mainly been concerned with the parasite itself. The present morphologic study of the cerebral microvasculature is an attempt to elucidate the pathogenesis of the central nervous system changes. Five, clinically healthy, adult, Danish goats were used to establish the optimal procedure for perfusion fixation of the brain and, at the same time, to serve as normal controls. The animals were put under general anesthesia with pentobarbitone intravenously at 25 mg/kg and placed in dorsal recumbency. Following dissection of the ventral neck region intubation was performed and carotid arteries were isolated. Heparin (1250 i.u./kg) was injected and perfusion done through one of the carotid arteries using 3% phosphate-buffered glutaraldehy de solution at pH 7.4 and 500 mOsm. The best perfusion results were achieved with the tank placed 1.5 m above the heart. The brain was removed and 1 mm3 samples were diced from the best fixed areas of the cerebral and cerebellar cortices and further fixed i 3% glutaraldehyde solution. Some of the samples were routinely processed and stained for transmission electron microscopy. In an attempt to improve fixation and enhance demonstration of cellular membranes and other structures, other samples were subjected to alternative processing and staining regimes including reduced osmium tetroxide, ruthenium red, tannic acid, and uranyl block staining. On balance, however, these regimes did not produce entirely satisfactory results and were therefore omitted in the experimental studies. Corresponding pieces of brain tissue were post-fixed in 10% neutral, buffered formalin and routinely processed for light microscopy. A complete necropsy was performed and various tissues were taken and similarly processed for light microscopy. Fourteen Tanzanian blended goats were experimentally infected by intravenous inoculation with the Ball 3 strain of Cowdria ruminantium. Following an incubation period of about 2 weeks the animals developed temperatures up to 41.7°C. Other clinical signs included bleating, loss of appetite, loss of body condition, listlessness, abdominal respiration, stupor, head tremors and ataxia. In 2 goats, fits, opisthotonus, paddling movements and lateral recumbency were also observed. When temperatures started to drop the animals were killed and subjected to the same procedures as the controls. Necropsy revealed mild hydropericardium (2-13 ml) and splenomegaly in all 14 goats. Other, inconstant findings were urine retention in bladder, subepi- or subendocardial petechiae and flabbiness of the heart. In areas of incomplete perfusion leptomeninges appeared hyperemic. Light microscopically, Cowdria organisms were found in vascular endothelium of the brain in 8 goats. Focal perivascular mononuclear cell infiltrations, sometimes extending into the adjacent neuropil, were present in the brains of 12 animals. More extensive mononuclear cell infiltrations, occasionally with a few eosinophils, were in the leptomeninges of 11 goats. Focal mononuclear cell infiltrations were also found, although variably, in pulmonary and renal interstitium and in subepi- and subendocardial locations. All experimental animals ex hibited moderate hyperplasia of splenic lymphoid tissue. The only ultrastructural change of parasitized endothelial cells was compression and displacement of cytoplasm and organelles by membrane-bound colonies of Cowdria organisms. Perivascular accumulations of cells, consisting of macrophages, lymphocytes and occasional plasma cells, were invariably associated with non-parasitized segments of capillaries or venules. Often intravascular mononuclear cells were seen adhering to the endothelium with portions of their cytoplasm dipping into the endothelial cell membrane or interposed between the endothelial cell and the basement membrane. Large, spherical, electron-dense inclusions, often several in the same cell, were found in pericytes, both in control and experimental animals but with a notably higher incidence in the latter. Similar inclusions as well as smaller inclusions with the features of lipofuscin were seen in perivascular macrophages. An additional and unique type of cytoplasmic inclusion was encountered in perivascular macrophages. These inclusions presented as aggregations of irregularly round, membrane bound particles, 0.25-0.4 /zm in diameter, in some cases with an internal structure remini scent of partly degraded mitochondria. However, the aggregations were not convincingly enclosed within membranes as would be expected in case of autophagocytosis. Another, hypothetical, interpretation is that they represent abortive stages of Cowdria ruminantium attempting to develop extravascularly and that possibly cell-mediated immunity, developed during and after the incubation period, limits this second cycle within the host and results in the perivascular mononuclear cell infiltrations observed. The findings in this study suggest the possibility of a direct involvement of circulating monocytes in the pathogenesis of the brain lesions. Such cells may carry and shield the antigen through the vessel wall into extravascular sites since no signs of vasculitis or abnormal vascular permeability were found, making it unlikely that soluble antigens are involved. The finding of a morphologically intact endothelium and vessel wall, even under perfusion conditions, also casts doubt on a possible role of vasoactive substances in the development of the lesions. If and when permeability changes of the brain microvasculature occur, they apparently represent a later development of an inflammatory process rather than a primary mechanism in the pathogenesis of cerebral heartwater.
Molecular epidemiology of bovine tuberculosis in indigenous cattle and selected wild animals in livestock wildlife interface in Mikumi-selous ecosystem, Tanzania
(Sokoine University of Agriculture, 2016) Mwakapuja, Richard Simon
Bovine tuberculosis is a chronic infectious disease that affects the health of livestock, humans and wild animals in Tanzania and worldwide. In Tanzania, the majority of livestock are indigenous and are kept under extensive management system. High number of the livestock are reared in livestock-wildlife interface areas where there is sharing of pasture and water among different animal species. Such ecological environment can easily enhance the spread of multi-species pathogens such as M. bovis. Spread of M. bovis depends on spatial-temporal variation of animals within population, population dynamics and movement of pathogens within population. The present study aimed at investigating the burden, spatial distribution, clustering and genetic relatedness of pathogenic Mycobacteria in indigenous cattle and wild animals in Mikumi-Selous ecosystem. The single intradermal comparative tuberculin test (SICTT), gamma interferon (ylFN) and BovidTB Stat-Pak assays were applied to test M. bovis infection in live animals. Tissue samples from dead animals were cultured and isolates were identified using the Mycogenus and Deletion methods. Genotypic relatedness was determined using Spoligotyping. A total of 1288 live cattle, 89 slaughtered cattle, 63 African buffaloes (Syncerus caffer) and 35 hunter-killed wild animals of 17 different species were tested. The prevalence of M. bovis infection in cattle was 3.7% and 7.8% (n=1288) using a cut- off for positivity of 4 mm and 2 mm, respectively. Significant large M. bovis infection clusters was located across Msolwa, Mfilisi, Mikumi and Msongozi villages and round Wami and Mkondoa rivers near Mikumi National Park (p=0.02) in Kilosa district. Low clusters were found in Ulanga district (p=0.03). Mycobacterium bovis was isolated from 11.2% (n—89) of cattle samples. No Mycobacteria isolate was found in wild animals samples. Three spoligotypes were identified, namely SB 1467, SB013.3 and SB2190. Spoligotype SB 1467 was the most dominant and was reported for the first time in Tanzania. Spoligotype SB2190 was novel isolate. Spoligotypes SB 1467 and SB2190 were genetically related by 96.9% while SB2190 and SBO133 were related by 59.4%. The agreement between the tests was established using Cohen’s kappa statistic to evaluate the agreement and form the basis for evaluation and comparison between S1CTT, ylFN and BovidTB Stat- Pak. Cohen’s kappa coefficient (k) agreement between ylFN and BovidTB Stat-Pak in African buffaloes was 0.14 while the agreement between SICTT and ylFN and between SICTT and BovidTB Stat-Pak in indigenous cattle was 0.5 and 0.21, respectively. The agreement between the tests ranged from poor (k=O.I4) to moderate (k=0.5). This study, for the first time established the spatial distribution of AL bovis infection and identified AL bovis infection clusters and a novel AL bovis spoligotype. A structured questionnaire was used to capture information from livestock farmers on knowledge and awareness related to tuberculosis transmission and the associated risk factors in animals and humans. About 21% (n=148) of livestock farmers were aware of existence of AL bovis infection in livestock. There was significant difference (p<0.001) between farmers with knowledge on M. bovis infection transmission in animals and humans and those without the knowledge. These findings can be applied to guide cost-effective surveillance and interventions strategies in control of bovine tuberculosis in Tanzania.
Epidemiological studies on bovine parasitic otitis
(Sokoine University of Agriculture, 1998) Shayo, Elizabeth Tabu Elikana
Experimental infection with Rhabditis bovis, Pseudomonas aeruginosa and Actinomyces pyogenes was carried out on fifty-three male weaner calves. The calves were inoculated into their ears with seven different combinations of suspensions of Rh. bovis, P. aeruginosa and A. pyogenes, the eighth group (control) was inoculated with phosphate buffered saline (PBS). Twenty-five calves (47.2%) developed mild to severe clinical manifestations in-groups inoculated with the nematode and the bacteria. Calves inoculated with the bacteria alone and the control did not develop clinical manifestations. There was significant difference (P<0.05) in responses between groups one, two, three and four which were inoculated with bacteria and nematode and those inoculated with bacteria alone and the control group. The responses were not significantly different (P>0.05) between groups five, six, and seven which were inoculated with bacteria alone and the control group. Histopathological studies revealed polymorphonuclear cell infiltration, thickening and desquamation of the epithelium of the aural canal. In this study, Rh. bovis was shown to be a primary pathogen although histologically there was no evidence of the involvement of the nematode. Bacteria exacerbated the clinical effects only in the presence of the nematode. Studies on the roles of dips and spray races in the transmission of the nematode Rh. bovis were carried out by subjecting 20 healthy cattle to dipping, 20 to spraying using Steladone®, and 20 to a topical application with Ectopor® SA 020 (Ciba - Geigy Limited Switzerland) as controls. No animal in all three groups contracted the disease. The dip wash and mud from the footbath and in the collecting pens were examined for the presence of nematodes. Nematodes were isolated from manure from night pens in only one farm and one dip and none from the footbath and collecting pens. Dip tanks were established as temporary reservoir of the nematode only during dipping and nematodes were introduced mainly through ears of infected animals. The prevalence of P. aeruginosa and A. pyogenes in the ears of clinically healthy cattle and those clinically affected with bovine parasitic otitis was established by bacteriological examination of 652 samples from diseased animals and 410 from non diseased animals. Prevalence rates of 1.5% in diseased ears and 5.1% in non-diseased ears for P. aeruginosa and 4.9% and 2.5% in diseased and non-diseased ears for A. pyogenes respectively were determined. From this study, it has been found that severe clinical disease of bovine parasitic otitis is significantly associated with A pyogenes (OR=1.27) while P. aeruginosa has a “sparing” effect (OR=0.27) Further studies on the role of flies on the transmission of bovine parasitic otitis are required.
Performance of grazing crossbred cattle supplemented with minerals: calcium, phosphorus and zinc
(Sokoine University of Agriculture, 2001) Phiri, Elliot Chikula Jailos Henderson
A study was conducted from 1997 to 1999 in Iringa region, Tanzania in order to evaluate the mineral status and performance of grazing crossbred dairy cattle as affected by season and nature of mineral supplementation. Initially concentration of calcium, (Ca), phosphorus (P) and zinc (Zn) in soil, grass pasture and blood plasma were measured. Seasonal effect was apparent (P< 0.05) in soil and pasture mineral concentration. Soil calcium (4.46 - 5.67 me /100g), was adequate during the dry and the rainy season. Soil phosphorus (P< 0.05) was low during the rainy season and high in the dry season (11.9 - 14.8 vs 28.1 - 31.8 ppm) whereas zinc (0.81 - 1.02 ppm) was deficient in both seasons. Pasture Ca (0.33 - 0.39%) and P (0.25 - 0.34%), were adequate whereas Zn (21.2 - 25.2 ppm) was inadequate for the sampled periods. Blood plasma Ca (<2.20 mmol/1), inorganic phosphate (< 1.28 mmol/1) and Zn (<12.2 pmol/1) were marginal to normal values in the sampled dairy cattle. Other minerals in the soil and grass pasture were also analysed. Sodium (Na) (0.31 - 0.37 me /100g), potassium (K) (0.36 - 0.42 me /100g), iron (Fe) (76.4 - 101 ppm) and copper (Cu) (1.38 -2.24 ppm) were adequate during the dry and the rainy seasons. However, magnesium (Mg) (0.99 - 1.57 me /100g) was deficient in both seasons. Pasture K (2.05 - 2.67%), Na (0.21- 0.23%) and Fe (154 - 190 ppm) were adequate whereas Mg (0.15 -0.17%) and Cu (2.53 - 4.57 ppm) were inadequate in the sampled periods. In an attempt to quantify the requirement for supplementation of Ca, P and Zn forty eight dairy cows in their first, second and third parity were allocated to eight groups, comprising six cows based on breed, parity, stage of lactation and milk yield. Group 1 was control group receiving no mineral supplement; group 2 (Ca) received 10 g of Ca in the form of calcium carbonate (CaCCh); group 3 (P), received 8 g of P in the form of sodium monophosphate (Na2HPC>4.2H2O) and group 4 (Zn) received 400 mg of Zn in the form of zinc oxide (ZnO). The rest of the groups received a combination of Ca and P or Zn or both. Animals were drenched with the minerals daily as of May 1997 to March 1999. Performance was evaluated in terms of cow’s health status, milk yield and reproductive performance and by measurement of blood parameters and metabolites which affect health, energy and protein balance before supplementation started and thereafter at every two month intervals. Significant differences (P< 0.05) were observed between groups in terms of performance. Low plasma Ca, Pi and Zn were more prevalent in the dry season (P < 0.05) especially in the month of July and during calving period in the month of March. None of the Ca, P and Zn formulations were able to rectify the low plasma Ca observed during these periods, however, Ca supplementation in the form of CaCCh. improved tissue P and Zn status. Diy season supplementation with concentrates, hay and fresh forage improved plasma Ca, Pi and Zn concentrations. Cows supplemented with Ca in the form of CaCOj only were superior (P< 0.05) in terms of body condition, less cases of mastitis and anaplasmosis, short calving interval (< 365 days) and high milk yield with high fat and protein content compared to the other groups. General health status, live weight gain, body condition score were affected negatively with P supplementation in the form of Na2HPO4.2H2O alone. Supplementation with Ca/Zn in dairy cows maintained copper balance, however, the other formulations resulted in reduction in copper balance. Supplementation of P/Zn maintained stable levels of blood selenium concentration during both the dry and rainy season. Calcium and Zn supplementation reduced the blood selenium concentration in the rainy season. Since incidences of low plasma Ca, Pi and Zn occurred during the dry season, supplementation with concentrate, hay and fresh forage during the dry season should be encouraged to the farmer and other farmers with similar problems for better metabolism of Ca, P and Zn. However caution should be taken with type and the amount of Ca, P and Zn fed to the animals to avoid interactions between these elements other minerals like Cu and Se. Since P requirements for tropical grazing cattle is not known with certainty, further research on P requirements in grazing crossbred cows is recommended. Magnesium and Cu were inadequate in forage, supplementation of these minerals in the diet was recommended. The effects of Ca, P and Zn supplementation on Cu and Sc balance need more research in order to quantify the effects and understand the mineral interaction mechanisms involved.
Prevalence, epidemiology, and virulence of Pasteurella multocida and related organisms obtained from poultry and their animal contacts
(The Royal Veterinary and Agricultural University, 2000) Muhairwa, Amandus Pachificus
This thesis is divided into two sections. The first section presents six reviewing chapters in relation to work performed and a chapter detailing conclusions from the study. The second part contains four papers referred to as Appendix 1-1V, which detail the work in the thesis. The articles I and II present prevalence and epidemiological investigations of P. multocida in commercial poultry flocks in Denmark, and free range village chickens and their contact animals in Tanzania. Article 111 discusses phenotypic, molecular and epidemiological investigations of Pasteurella species obtained from Tanzania. The last article presents the study on correlation between serum resistance, outer-membrane proteins and virulence of P. multocida. The prevalence of P. multocida carriers in the flocks with a history of fowl cholera was shown to be significantly higher than that of the flocks without a history of fowl cholera in commercial flocks in Denmark (Appendix I). These findings underline the importance of surviving birds in the epidemiology of fowl cholera. The carriers in flocks without history of fowl cholera were also demonstrated, but their role in fowl cholera is still uncertain. All three subspecies of P. multocida, namely ssp. Multocida, ssp. septica and ssp. gallicida were demonstrated, but the subspecies gallicida was obtained exclusively from Pekin ducks from a farm with a history of fowl cholera. A single clone affected each of the investigated flocks, but some clones appealed in more than a single flock. Investigations into strains of P. multocida from one of the farms in four consecutive outbreaks demonstrated a different clone in each outbreak. This indicates that outbreaks are clonal, and the disease can be eliminated from the infected farms. Isolation of P. multocida from the cloacal mucosa of earners was reported for the first time, however, the significance of cloacal earners in spreading infection is not known. Occurrence of P. multocida and related species in free ranging chickens and ducks, dogs and pigs (Appendix II) was investigated in three subclimatic zones; hot, warm viand cool, in rural Morogoro district, Tanzania. The strains obtained included P. multocida ssp. multocida from chickens, ducks, cats and dogs, /< multocida ssp. septica from dogs and cats, gallinarum from a duck, P. canis and P. dagmatis from dogs, and P. slomatis from dogs and cats. Other strains included organisms with uncertain taxonomic affiliation named taxon 16, and unclassified strains with Pasteurella like features. P. multocida was obtained from two chickens (2%) and 11 ducks (22%) of warm zone. No isolates were obtained from poultry in the remaining zones. Cats had the highest prevalence of P. multocida ssp. multocida, while P. canis and taxon 16 were predominant in dogs. Mouse inoculation was more sensitive in etecting P. multocida ssp. multocida than blood agar and selective medium. Direct culture on blood agar recovered most of the other Pasteurella spp.. These findings demonstrated the existence of P. multocida carriers in the free ranging village poultry, cats and dogs, and underline the potential of exchange of strains between the different animal species. Surveillance of diseases in free ranging village chickens to gauge the clinical importance of fowl cholera and other diseases was recommended. One hundred and forty-three Pasteurella spp. strains and ten unclassified strains obtained from free ranging poultry, dogs and cats were investigated by extended phenotypic characterization (Appendix III). One hundred and forty-nine of these strains were selected for further studies using ribotyping and REA-typing to evaluate the role of dogs and cats in P. multocida transmission to poultry. Seven and six-type strains were included for comparison in phenotyping and genotyping, respectively. Eleven clusters and six unclustered strains were revealed by phenotyping. Ribotyping outlined twelve clusters and six unclustered strains. A correlation between clusters obtained by phenotyping and ribotyping was demonstrated which indicated that a genetic basis exists for clusters outlined by quantitative evaluation of phenotypic data. Similarities and differences in hosts, phenotype, ribotype, and zone of isolation were demonstrated among Pasteurella strains investigated. Isolates of P. multocida from ducks were shown to be clonal by both phenotyping and ribotyping. These strains were identical to one of the chicken strains. REA-typing, however, showed that the chicken strain was different underlining that exchange of clones of P. multocida viibetween avian species seems to be rarely happening under village conditions. Management practices in the villages suggest the potential for exchange of P. multocida between poultry and animals kept in contact. Tire present findings, however, did not indicate that clones of P. multocida are widely exchanged between poultry and other animal species even though close contact exists. In the present investigation, exchange of clones of P. multocida was only demonstrated among animals belonging to the same species. Caution is drawn to the use of ribotyping alone for epidemiological typing and tracing of P. multocida. The present results also underline the importance of proper phenotyping in the identification of P. multocida and related species. Serum resistance of P. multocida in the sera from chickens, turkeys, ducks and pigs was determined and correlated with in-vitro and in-vivo outer-membrane proteins expression and virulence in chickens. Eighty-seven field strains of Pastcurella and nine reference strains representing different clones were grown in sera from chickens, ducks, turkeys and pigs. Serum activity of each strain was measured by changes in the optical density of the serum after inoculation and incubation at 41 °C for chicken, turkey and duck serum and 39 "C for pig serum. The strains were classified into High serum resistant (R), moderate serum resistance (M), and serum sensitive (S) by comparing with strains of known serum activity. Strains of identical genotype by Restriction endonuclease analysis were found to have identical growth curves and the same maximum OD values, when cultured in serum from the same host species. Turkey serum was shown to be less inhibitory to a wide range of P. multocida strains than chicken, duck and pig sera. Serum resistant strains were demonstrated among avian as well as mammalian strains, with the proportion of serum resistant strains being higher in fowl cholera outbreak strains than in non-outbreak avian strains. A range of minor and major outer-membrane proteins were common among the selected serum resistant and serum sensitive strains, when cultured in BHI, in-vivo and in chicken serum. However, no specific OMP expressed in vitro or in vivo was consistent with serum resistance or sensitivity among the strains investigated. Although most severe lesions in experimentally infected chickens were produced by a serum resistant strain, lesions were also found in chickens infected by scrum sensitive strains, indicating the involvement of multiple factors in the virulence of P. multocida. Further investigations on scrum resistance should also relate other host and bacterial factors responsible development of fowl cholera.

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