Theses and Dissertations Collection

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Population genetics of greater cane rat (thryonomys swinderiunus) across its range areas in Africa
(SOKOINE UNIVERSITY OF AGRICULTURE,, 2023) Kilwanila S. I
The African Greater Cane rat (AGC) (Thryonomys Swinderiunus) is a wild rodent species that belongs to the Family Thryonomydae and is historically endemic to Africa. The species is widely distributed in different parts of Africa and is considered a delicacy in some societies inhabiting the continent. Despite its food value, the rodent species is also a pest of crops and a potential host of bacteria and worms that can impair human health. There is a growing body of literature about cane rat species (Thronomys spp.) but most of the published work is patchy. Currently, the spatial population distribution across suitable habitats within its range areas in Africa, and the species' biology, particularly in the wild, are unknown. These gaps limit broader species use for example, for commercial game farming, for developing the potential strategies for controlling the species’ destructive impacts on crops, and the measures to advocate for the species conservation in the wild. This Ph.D. study was conceived to fill in these gaps and to advance knowledge on the genetics of this species that is critical to the management and conservation of the cane rat population in the wild. The research aimed specifically to answer four objectives; first, to review the state of knowledge that is currently available about the cane rat species, second; to assess the genetic diversity and population demography of the cane rat populations inhabiting two mountains within the Eastern Arc Mountains range, third, to assess the morphometrics of the cane rat skull to improve evolutionally knowledge of the cane rat species and fourth, to assess the genetic relatedness of the cane rat populations inhabiting the East and West African regions.To understand the breadth of knowledge about the cane rat species, I conducted a systematic review of 56 years (1964 - 2020) of cane rat research published in various outlets including theses and peer-reviewed journal articles accessed from credible literature archives such as Web of Science, Scopus and Google scholar. I found that the available literature on the cane rat was mostly biased towards the West African region, and no single study published from East and Southern Africa was available. I also found that most of the published literature was based on captive cane rat individuals and that substantial knowledge gaps were remaining in various topics including genetics and species biogeography, food biology, and conservation. The knowledge generated in this systematic assessment, helped me to focus on the identified gaps in the next chapters. Further, to answer the question of genetic diversity and population demography of the cane rat species in the Eastern Arc Mountains, I conducted field surveys to collect cane rat samples from traps set in four localities in the Udzungwa south, Udzungwa north, Uluguru rural, and Uluguru urban areas all located in the Udzungwa and Uluguru mountains respectively. I used DNA sequencing of the D-loop region of MtDNA (515 bp) from 46 cane rat samples and various molecular techniques to analyze these data. I found that there were high genetic differences between than within these four populations. I also found that these four AGC populations in Eastern Arc Mountains (EAMs) have experienced a recent population expansion, especially among the urban population due perhaps to the influence of the urbanization process that may have favored and/or assisted species movements across the rural-urban landscapes. To understand the evolutionary information on the greater cane rats in the Eastern and Southern African regions, I studied T. swinderiunus populations in Tanzania to link molecular and geometric-morphological evidence to characterize these populations’ diversity using tissue samples and skulls. I found that both molecular and geomorphometric evidence were aligning T. swinderiunus into three clades based on the location where samples were collected. This suggested that genetic and morphometric methods could complement each other in understanding the evolutionary biology and within-species diversity of vertebrate species that do not exhibit strong intra- species differentiation.Further, to assess the maternal origin of the African Greater cane rats populations found in the spatially isolated localities in Africa, I compared mt-DNA D- loop sequences from samples collected from two Eastern Arc Mountains, Tanzania, and three agro-ecological zones in Ghana. I found a high genetic differentiation between AGC populations from Tanzania and Ghana with high variation coming from between while low variation was within the AGC populations. I also found that the populations from Tanzania had higher haplotype diversity indicating that they are healthier demographically than those of Ghana. I also found that the populations from Ghana do not share common maternal lineage with those of Tanzania suggesting that the species has evolved as distant populations that lacked connectivity.This study has important implications for the conservation, taxonomy, farming and ranching of African Greater Canerats (AGCs) in Tanzania. The genotype data can help to inform policy and decision-makers on conservation priorities and potential conservation measures including the need for the establishment of germ-plasm banks in vivo and in vitro for maintaining the genetic pool through selection processes. Also, the results can be useful in selecting parental stocks for establishing cane rat farming and ranching to provide farmers with viable stocks. The study will enable the resolution of taxonomic uncertainties which is mandatory for understanding species biology. The study has provided genetic sequences which have been deposited in the NCBI gene bank and are available for public use. The species is presently not endangered but if the needs arises these data can be accessed without going back to the field and used for further research. Keywords: African Greater Canerat (Thryonomys swinderiunus), Eastern Arc Mountains, geometric-morphology, Genetic diversity, martenal lineage, conservation
The prevalence, distribution and risk of viral haemorrhagic fevers in Tanzania
(SOKOINE UNIVERSITY OF AGRICULTURE,, 2023) Rugarabamu. S
Viral haemorrhagic fevers (VHFs) are a group of infectious diseases caused by viruses belonging to the Flaviviridae, Phenuiviridae, Arenaviridae, and Filoviridae families. They are characterized by fever, a constellation of initially nonspecific signs and symptoms, and a propensity for bleeding and shock. The VHFs reported in Sub-Saharan Africa include Crimean-Congo haemorrhagic fever (CCHF), Ebola virus disease (EVD), Lassa fever (LF), Lujo haemorrhagic fever (LUHF), Marburg virus disease (MVD), Rift Valley fever (RVF), and yellow fever (YF). Knowledge surrounding the distribution and risk of VHFs in Tanzania is limited. Accurate epidemiological information of VHFs is critical to implementing appropriate control and prevention strategies. This study aimed to determine the prevalence, risk of introduction, and factors associated with VHF in Tanzania. The findings provided in this thesis consolidate our knowledge of the diseases in Tanzania and the need for improved surveillance, early detection, and prompt response. The thesis is divided into two major approaches, namely systematic review and research studies. A systematic review was undertaken to analyse EVD outbreak reports, identify challenges and opportunities in detection and response in sub-Saharan Africa and propose effective control approaches. A research study was conducted to estimate the probability of introducing EVD from DRC to Tanzania. This study involved collection of national data for flights, boats, and car transport schedules from DRC to Tanzania covering a period between May 2018 to June 2019. A population study was carried out in all ecological zones of Tanzania to determine the seroprevalence and associated risk of selected five VHFs. In this epidemiological study, blood samples were collected from households and healthcare facilities in Buhigwe, Kalambo, Kilindi, Kinondoni, Kondoa, Kyela, Mvomero, and Ukerewe districts of Tanzania. The samples were screened for immunoglobulin G (IgG) and M (IgM) antibodies against CCHF, EVD, MVD, RVF, and YF. The prevalence of VHF and malaria co-infections was also determined among participants seeking care from health care facilities. Malaria infections were investigated using rapid diagnostics tests (RDT). In addition, Community knowledge, awareness and practices regarding VHF was assessed in eight districts of Tanzania. Archived sera that tested positive for immunoglobulin IgG antibodies to EBOV and RVFV using a commercially available ELISA were reanalysed using the in-house EBOV whole antigen (WAg) and RVFV inhibition enzyme-linked immunosorbent assay. The findings of the systematic review indicate that between 1979 and 2020 a total of 34 EVD outbreaks affecting 34,356 cases and causing 14,823 deaths were reported in 11 countries in Sub-Saharan Africa. The overall case fatality rate (95% CI) was 66% (62 to 71) and this did not change substantially over time (OR in 2019 versus 1976=1.6 (95% CI 1.5 to 1.8), p<0.001). The challenges to control EVD outbreaks are related to epidemiological, sociocultural and health system factors. As regards to the risk of introduction of EVD from DRC to Tanzania, the findings indicate that the most likely pathways were the entry of infected humans through air, land, and water travels. The land border crossings were considered the most frequently used means of travel (highest), while water and air travel were deemed less often (high). High probabilities of introducing EVD from DRC to Tanzania were associated with the viability of the pathogen and low detection capacity at the ports of entry. The epidemiological survey indicated that the overall, CCHF, EVD, MVD, RVF, and YF seroprevalence were 2.0%, 3.4%, 1.2%, 4.8%, and 1.4, respectively. The highest VHF antibody seroprevalence was recorded in western Tanzania (6.0%), characterized by unimodal rainfall pattern and altitude below 2,300m. The lowest seroprevalence (0.4%) was observed in the semi-arid central Tanzania, characterized by moderate precipitation and a unimodal rainfall pattern. The association between seroprevalence of VHFs and geographical location was found to be significant (P= 0.001). Contact with wild animals (OR = 1.2, CI = 1.3–1.6) and keeping goats (OR = 1.3, CI = 1.5–1.9) were significantly associated with RVF while contact with bats (OR = 1.2, CI = 1.1–1.5) was associated with MVD. The prevalence of VHF and malaria co-infections was 1.9%. The age group 46-60 years had the highest malaria co-infection p < 0.05. Over half (57%) of malaria and VHF- infected individuals reported headaches, while over one-third (37%) reported muscle, bone, back, and joint pains (p= 0.001). All EBOV positive sera turned out to be negative by In-House WAg EBOV ELISA. Two of the nine positive IgG RVF commercial ELISA samples were reactive to the RVF Inhouse ELISA, with inhibitory rates ranging from 66% to 99.6%. A slight agreement was observed between the RVF in-house and the commercial ELISA (kappa value, 0.08; 28%, 11/40 in disagreement). As regards to community, knowledge, attitudes and practice, slightly over a quarter (29.4%) of the respondents was knowledgeable, 25% had a positive attitude, and 17.9% had unfavourable practice habits. There were increased odds of having poor practice among participants aged 36–45 years (AOR: 3.566, 95% CI: 1.593– 7.821) and those living in Buhigwe, Kilindi and Ukerewe areas (AOR: 2.529, 95% CI: 1.071–6.657; AOR: 2.639, 95% CI: 1.130–7.580 AOR: 2.248, 95% CI: 1.073–3.844) than their peers. In conclusion, Sub-Saharan Africa faces considerable challenges in EVD control, whereby there are no significant changes in case fatality rates observed during the past four decades. Socioeconomic and cultural factors need to be critically considered to shape the community behaviours that lead to EVD outbreaks. The risk of introducing EVD from DRC to Tanzania is high. Infected humans arriving via land are the most likely pathway of EVD entry, and therefore, mitigation strategies should be directed towards this pathway. Although, CCHF, EVD, MVD, and YF outbreaks have not been reported in Tanzania, the viruses are prevalent and vary from one ecological zone to another, with the western part of the country at the highest risk. Co-infections of malaria and viral haemorrhagic fevers are frequent in Tanzania. The rate was higher in the age group 46-60 years. Both malaria and VHF presented with similar symptoms. There were increased odds of having poor practice among participants aged 36–45 years (AOR: 3.566, 95% CI: 1.593– 7.821) and those who reside in Buhigwe, Kilindi and Ukerewe areas (AOR: 2.529, 95% CI: 1.071– 6.657; AOR: 2.639, 95% CI: 1.130–7.580 AOR: 2.248, 95% CI: 1.073–3.844) than their peers. According to the study, 29.4% of respondents were knowledgeable, 25% had a positive mindset, and 17.9% had unfavourable practice habits. We found poor agreement between in-house and commercial ELISA tests for EBOV and fair agreement between in-house and commercial ELISA tests for RVFV, with the commercial ELISA detecting more cases than the validated in-house ELISA. The current study emphasizes the difficulties in diagnosing viral hemorrhagic fever in Tanzania. Frequent EVD outbreaks in DRC urge the need to intensify the surveillance system, including laboratory screening of suspects, thermal screening of all arrivals from endemic areas, and registering travellers within all the border entry points to prevent disease importation. Equally important, there is a need for strengthening the sensitization and awareness campaigns focusing on cross-border communities. The border healthcare facilities need to be well equipped to ensure a high disease containment capacity. The findings that VHFs are prevalent in Tanzania call for the need to strengthen the surveillance system and management of febrile illnesses in Tanzania. The discrepancy was observed between validated in-house and commercial ELISA tests. Hence, the serological results should be interpreted with caution and this emphasizes the challenges related to the diagnosis of VHFs. Overall, broad-based, one-health approach, effective communication, social mobilisation, and strengthening of the health systems need to be addressed to prevent future outbreaks.
Species abundance and diversity of rodents and shrews in different habitats and seasons in the northern sector of Selous game reserve, Tanzania
(Sokoine University of Agriculture, 2015) Saanya, Aenea Eliphas
Species abundance and diversity of rodents and shrews were investigated in three different habitats and seasons in the Northern sector of Selous Game Reserve from September 2014 to May 2015. A total of 163 individuals from eight genera (5 of rodents and 3 of shrews) were captured in 1 323 trap nights using three different live traps. The abundance and diversity varied significantly between habitats (pO.OOOOl and />=0.00007) and within seasons-habitat interactions (p<0.00001 and p=0.0 1941) respectively. Riverine habitat had the highest species abundance and diversity in dry and transition period, while wooded grassland showed the least abundance and diversity. Seasonality had no major influence on species abundance and diversity. Acomys sp. and Paraxerus flavovittis showed no major fluctuations in abundance compared to other species. Acomys sp. breeding patterns were not influenced by seasonal (rainfall) variation. Riverine forest and woodland had higher community similarity of 55% while riverine forest and wooded grassland had 22% dissimilarity. Therefore, this study concludes that, species abundance and diversity is highly influenced by habitat type and seasonal variations especially associated with or without rainfall. It is recommended that, a more intensive study in Selous Game Reserve to cover an extensive area and habitats to get a greater representation on the abundance and diversity of rodents and shrews found in the area.
Assessment of maize (zea mays l.) damage and yield loss due to rodents in the field
(Sokoine University of Agriculture, 200) Mulungu, Loth Sikwese
Assessment of damage and yield Joss due to rodents was carried out in maize fields in Morogoro. Tanzania. The most abundant rodents in these fields were the multimammate rats. Mastomys nalalensis. Spatial distribution of damage in maize fields was random for experimental fields planted with maize, located between other maize fields owned by farmers. Four sampling techniques viz: non stratified systematic row sampling, non stratified systematic z-sampling. stratified random square sampling, and non stratified simple random sampling for estimation of maize damage and yield losses due to rodents were compared in terms of precision and accuracy, and time spent for damage and yield loss estimations. The actual rodent damage in 15 maize fields was determined by counting damaged and undamaged maize plants at seedling stage and the actual yield loss was calculated. The actual damage varied from 17.3% to 82% during the period of study. The results showed clearly that non-stratified systematic row sampling is the most robust technique for assessing maize damage and yield loss due to rodents. A standard curve for sampling using this technique is provided. The relationship between rodent density and maize damage at seedling was determined. The best model for the data was determined using Akaike Information Criterium. The best model for the relationship is Sigmoid (r - 0.74; n = 44; p = 0.001). Variations occurred between the observed and predicted line. Damage was low or high depending on the amount of rainfall after planting. Maize seed planting followed by heavy rainfall suffered lower damage than when rainfall was poor, due to inability by rodents to locate the planted seeds. Rodent damage and the resultant yield loss are positively correlated, but only in years with well distributed rainfall. Results from model simulations showed that it is more profitable to control rodents in the fields in February and November or February and October than any other month combinations. This calendar approach for rodent control seems to be most appropriate for the Tanzanian maize growers.
Knowledge, control practices, transmission risk factors and cases trend for malaria among students of selected higher education institutions in eastern Tanzania
(Sokoine University of Agricurture, 2022) Kija, Mbogo Ng'wisabila
In Tanzania malaria accounts for over 30% of the national disease burden and over 95% of the total population is at risk of getting malaria infection. Higher education institutions (HEIs) do form clusters with different malaria transmission dynamics, but no study conducted in such clusters. This study was conducted to assess Knowledge, control practices, transmission risk factors and cases trend on malaria among students of selected higher education institutions within Morogoro Municipality, eastern Tanzania. A cross sectional and repeated cross sectional survey was conducted in four major Universities; a face to face semi structured questionnaire was administered to 398 undergraduates and supplemented with direct observation. A One Way ANOVA (p .000) at 95% CL demonstrated a prevailing low knowledge level on malaria (58.8%) among respondents. A repeated cross-sectional survey for six months regarding seasonal data (wet and dry season) revealed a total of 181 possible breeding sites. As per study breeding sites; wet season had 11072 and 3620 Anopheline and Culecine larva respectively; dry season had 1436 and 880 Anopheline and Culecine larva respectively. Also a ten-year (2011 – 2020) data on malaria cases from catchment health facilities in each institution were analyzed, a binary logistic regression (p. <0.05) at 95% CL shown that; males were positive by 3.3 percent less than females, dry season had 2.6 percent less as compared to wet season. Jordan had positive malaria cases by 2.3 times more and Mzumbe by 17.8% less as compared to SUA. The total positive cases were 65969 (34.1%) out of 193243. This study has indicated the prevailing low knowledge level and control practices on malaria among respondents with high exposure and transmission risk. This may impede the efforts towards malaria control and elimination. Therefore, there is an urgent need for control strategies that are most appropriate to higher education institutions and similar clusters.
On-farm evaluation of production performance of sasso and kuroiler chickens in Mvomero district, Morogoro
(Sokoine University of Agriculture, 2022) Lyahama, Onesmo Jackson
Improved breeds of chickens such as Kuroiler and Sasso are currently the most favourable chickens in developing countries. In African countries, these breeds have been tested for suitability under smallholder environment in Nigeria, Ghana, Ethiopia, Uganda and Tanzania. The breeds are dual purpose with higher body weight and lay more eggs than the local chickens. They are more resistant to diseases and are able to scavenge on locally available feeds than the commercial birds. These breeds have good potential to improve the economies and health of smallholder farmers in Tanzania. However, knowledge related with management practices of these breeds such as housing, feeds and feeding and health care (disease awareness, control and prevention) is crucial to optimise their genetic potentials. This study was aimed at evaluating on-farm production performance of Sasso and Kuroiler chickens reared under farmer’s management conditions in Mvomero District. Two villages namely, Luhindo and Sokoine were involved in this study. Thirty one (31) farmers, 16 from Luhindo and 15 from Sokoine were included in this study. Chickens were purchased and reared for the first 7 weeks at Sokoine University of Agriculture and then distributed to the farmers. Each farmer received 18 chickens of mixed sex. The assessment of farmers' management practices such as housing, feeds and feeding and health care was carried out using a structured questionnaire. The assessment of poultry housing was carried out through observation of features required for a poultry house including the quality of materials used for construction. Feeds and feeding practices were assessed based on the feeding program, the type of feeds and the number of feed ingredients used during feed formulation. In addition, health care, bio security issues such as overall cleanness and disease awareness were also assessed. Data collection started the day the chickens were distributed to the farmers and the recording was carried out four times at four weeks interval except for mortality, which was recorded when it occurred during the period of study. Data on poultry performance (weight measurement) and mortality were collected through well designed forms where by trained expert from ACGG Project and farmers participated in record keeping. Data related to management practices were analysed using SPSS whereby, descriptive statistics such as frequencies and percentages were computed. Data on the overall management practices of the two villages and within individual villages were collected and analysed to determine whether there were any differences that existed. In addition, a combination of village management factors that led to optimum growth performance of chickens were determined by analysing the data from farmers having chickens with large body weight performance. Data of body weight performance and mortality rate were analysed using SAS version 20 and Chi-square respectively to evaluate the birds’ performance and mortality in relation to breed, village, sex and management practices. Housing as one of the management practices was assessed and shown to be in an adequate condition except for the type of floor, whereby 79 percent of poultry house floor were made on earth. Fifty-five (54.8) percent fed their chicken using homemade feed (mixture of three and above feed ingredients) and 45.2 percent used supplementary feeds like maize corn, maize bran, food left overs and other scavengable feeds. About 50% of the farmers used maize bran, sunflower seed cake and fish meal to compound the diets. Most of farmers were providing feed (48.4%) and water (58.1%) twice per day. Also, the findings showed that 51.6 percent of farmers had modern drinkers and feeders and 48.4 percent had local made feeders and drinkers. In case of health care, Newcastle was the most common disease (100%) followed by Infectious coryza (93.6%), Fowl typhoid (87.1%) and Fowl pox (54.8%). Few farmers could identify diseases such as Coccidiosis (29%) and Gumboro (19.4%). Newcastle, fowl typhoid, Fowl pox and Infectious coryza were reported to occur more frequently than other diseases. Disease control and prevention were the biggest challenge to farmers as only 32.3 percent of farmers were able to treat and isolate their chickens after disease eruption while the majority of them (67.7) did treatment only. In addition, 87.1, 12.9 and 12.9 percent of farmers knew how to prevent chickens against Newcastle, Gumboro and Fowl pox diseases respectively. Few farmers (41.9%) dewormed their chickens. Also, for those farmers preventing and controlling their chickens against diseases they do upon their understanding of the specific disease. Drugs used for poultry treatment by most of the farmers depended on their preference and their availability in the area. Regarding the adequacy of housing management practice 48.4 percent scored good, 45.2 percent medium and 6.5 percent scored low. However, on feeds and feeding practice in both villages, many farmers fell into medium level (58%) followed by good level (35.5%) and then low level (6.5%). With regards to health care, 54.8 percent of farmers were in the medium level, 29 percent were in the low level and 16.1 percent had good health care practices. Comparison between management practices levels in the two villages showed that Luhindo village scored higher on feed and feeding practices (Good level – 48.3%, Medium level – 50% and Low level 6.2) compared to Sokoine village (Good level - 26.7%, Medium level – 66.7% and low level – 6.6%). Moreover, Sokoine scored better in terms of housing (Good level – 53.3% and Medium - 46.7%) and health care (Good level - 13.3%, Medium level – 66.7% and Low level 20%) compared to Luhindo village which scored 43.8% - good, Medium - 43.8% and 12.4 – low level for housing and for health care were 13.3% - Good, 66.7% - Medium and 20% - Low level. In the prediction of management practices, levels required for optimum performance of these breeds under village conditions the results showed that, good or medium level housing, better feeding (good) and health care (good or medium) were associated with better bird’s performance. The average growth rate of these breeds of chickens for 12 weeks of study was 13.8±0.4g/d and 10.2±0.4g/d for Kuroiler and Sasso respectively. The body weight at 20 weeks of age of birds in Luhindo village was significantly higher (p≤ 0.05) (1895.4±54.3g) compared to Sokoine village (1717.2±60.5g). Breed-wise Kuroiler, had significantly higher (p≤ 0.05) body weight (1937.2±60.4g) than Sasso (1687.4±54.5g) up to week twenty. The mean body weight for the three management levels were 2086.3±57.2g, 1805.2 ±25.8g and 1527.4±144.9g for good, medium and low level respectively. The overall mortality was 18.8% which was contributed mostly by diseases (90.5%). Mortality rate was generally associated with management levels and there were no significant differences between breeds and villages. Correlation analysis showed a strong positive relationship between growth performance and feeds and feeding (r = .893) compared to growth performance and health care (r = .415) as well as growth performance and housing (r = .093).
Genetic characterization and antimicrobial susceptibility patterns of proteus mirabilis isolated from domestic rats in Arusha municipaltiy, Tanzania
(Sokoine University of Agriculture, 2022) Ndakidemi, Floramanka Patrick
The aim of this study was to genetically characterize and assess antimicrobial susceptibility patterns of Proteus mirabilis isolates from rats cohabiting with human dwellings. A cross sectional survey was conducted where a total of 139 rats were trapped in houses and around peri domestic areas in selected wards in Arusha city. Following euthanization, rats were identified to Genus/species level using morphological and morphometric features. Deep intestinal swabs were ascetically obtained and pre enriched in buffered peptone water prior laboratory analysis conventional culture methods and biochemical methods were used for bacterial isolation. Molecular confirmation of the isolates was done using the 16s ribosomal RNA PCR identification method. Susceptibilities to Tetracycline (TE, 30μg), Trimethoprim sulfamethoxazole (SXT, 25 μg), Ciprofloxacin (CIP, 5μg), Cefotaxime (CTX,5μg), Ampicilin (AMP,10μg), Azithromycin (AZM, 15μg) and Gentamycin (CN,10μg) was performed and resistance genes (bla TEM, tetA, tetB, mphA, SHV, bla CTX-M, sul1 and sul2) were traced in each isolate using PCR methods. Mixed rat species Rattus rattus (55.4%; n=77) Mus musculus (15.8%; n=22) and Mastomys natalensis (28.8%; n=40) were captured. Proteus mirabilis was isolated from 4 samples (2%) from Rattus rattus. All isolates were 100% similar to P. mirabilis strains from NCBI. Constructed phylogenetic tree showed all P. mirabilis isolated from this study were closely related to Tunisia isolates. Three isolates showed MDR trait against Triomethoprim- sulfamethaxole, Azithromycin, and Ampicillin., all isolates were resistance to Azithromycin, and Ampicillin, three were resistance to Triomethoprim- sulfamethaxole, and intermediate to Tetracycline and all susceptible to Ciprofloflaxcin, Gentamicin and Cefotaxime, PCR analysis showed the presence of TetA, blaTEM, Sul1 and Sul2 resistant genes in all isolates. The study has shown that rats are potential reservoirs of Proteus mirabilis with antimicrobial resistance trait that could be transmitted to the public and it’s the first study to isolate P. mirabilis from rats in Tanzania with antimicrobial resistance trait.
Effect of cropping systems and land management practices on rodent population characteristics
(Sokoine University of Agriculture, 2003) Massawe, Apia Wilbald
A Capture Mark Release (CMR) study was carried out at the Sokoine University of Agriculture, Solomon Mahlangu Campus in Morogoro, Tanzania from April 1999 to August 2001 to investigate the effect of slash and bum versus tractor ploughing on the population of rodents in agricultural fields subjected to either monocropping (maize alone) or intercropping (maize and beans). Mastomys natalensis was the most abundant species in the different treatments (97.8%). The spatial distribution of individuals was significantly affected by land preparation methods. The coefficient of dispersion values (based on variance-to-mean ratio calculations) indicated that before land preparation, animals were randomly distributed everywhere, but after land preparation and the consequent stages of maize growth, more animals clustered around the edges in tractor ploughed fields whereas in the slash and bum fields, animals were randomly distributed. Rodent population abundance increased in slash and bum fields during the crop growth stage in the short rainy season (yuli) as a result of higher recruitment of new individuals than in the tractor ploughed fields (for both mono and intercrop) (P = 0.004) suggesting that slash and bum fields are more attractive for colonization from the surrounding fallow fields. Tractor ploughing, slash and bum, mono and intercropping systems significantly (p< 0.05) affected the home range and movements of rodents. Home range was smaller in the tractor ploughed fields (Wald stat = 57.03; df=l; p<0.001). Females occupied smaller home ranges than males (Wald stat=18; df =1 p< 0.001), but the reasons were not clear. Significant variations in rodent population density due to soil types also occurred, with lowest populations in sandy clay soils (F=(2.5)= 8.42; p=0.025). These variations could be attributed to differences in the suitability of soils for burrowing. The level and distribution of crop damage in the fields indicated higher and uniform rodent damage in the slash and bum but lower and random damage occurred in tractor ploughed fields (Variance to mean ratio calculations). This suggests that seed retrieval was easier in the slash and bum fields. The current study suggests that slash and bum practice does not affect rodent population distribution in crop fields while tractor ploughing does affect rodents, probably by reducing cover and food availability or even by killing some individuals. Yet, it seems useful as a management tool when it is practiced over a large area and the surrounding fallow lands, which act as donor habitats, are cleared. Furthermore, land preparation methods should not be assumed to be adequate and effective on their own in controlling rodents but instead, they should be integrated with other strategies to reduce crop damage.

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