Browsing by Author "Nonga, H. E."

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Anthrax outbreaks in the humans - livestock and wildlife interface areas of Northern Tanzania: A retrospective record review 2006–2016
(BMC, 2018-02-15) Mwakapeje, E. R.; Høgset, S.; Fyumagwa, R.; Nonga, H. E.; Mdegela, R. H.; Skjerve, E.
Background: Anthrax outbreaks in Tanzania have been reported from the human, livestock and wildlife sectors over several years, and is among the notifiable diseases. Despite frequent anthrax outbreaks, there is no comprehensive dataset indicating the magnitude and distribution of the disease in susceptible species. This study is a retrospective review of anthrax outbreaks from the human, livestock, and wildlife surveillance systems from 2006 to 2016. The objectives were to identify hotspot districts, describe anthrax epidemiology in the hotspot areas, evaluate the efficiency of the anthrax response systems and identify potential areas for further observational studies. Methods: We prepared a spreadsheet template for a retrospective comprehensive record review at different surveillance levels in Tanzania. We captured data elements including demographic characteristics of different species, the name of health facility, and date of anthrax diagnosis. Also, we collected data on the date of specimen collection, species screened, type of laboratory test, laboratory results and the outcome recorded at the end of treatment in humans. After establishing the database, we produced maps in Quantum GIS software and transferred cleaned data to Stata software for supportive statistical analysis. Results: Anthrax reported incidences over 4 years in humans were much higher in the Arusha region (7.88/100,000) followed by Kilimanjaro region (6.64/100,000) than other regions of Tanzania Mainland. The health facility based review from hotspot districts in parts of Arusha and Kilimanjaro regions from 2006 to 2016, identified 330 human anthrax cases from the selected health facilities in the two regions. Out of 161 livestock and 57 wildlife specimen tested, 103 and 18 respectively, were positive for anthrax. Conclusion: This study revealed that there is gross under-reporting in the existing surveillance systems which is an obstacle for estimating a true burden of anthrax in the hotspot districts. Repeated occurrences of anthrax in livestock, wildlife and humans in the same locations at the same time calls for the need to strengthen links and promote inter–disciplinary and multi-sectoral collaboration to enhance prevention and control measures under a One Health approach.
Antibiotic susceptibilities of indicator bacteria Escherichia coli and Enterococci spp. isolated from ducks in Morogoro municipality, Tanzania
(BMC Research Notes, 2018) Kissinga, H. D.; Mwombeki, F.; Said, K.; Katakweba, A. A. S.; Nonga, H. E.; Muhairwa, A. P.
To estimate the prevalence of antibiotic resistance in indicator bacteria Escherichia coli and Enterococci isolated from duck faeces in Morogoro Municipality, Tanzania. Results: Escherichia coli and Enterococcus isolation rates from ducks faeces were 91 and 100% respectively. The prevalence of antibiotic resistance of E. coli and Enterococcus was 70.3 and 42%, respectively. E. coli resistant to four antibiotics were 28 (30.8%) and showed high resistance to ampicillin (81.3), tetracycline (75.8) and trimethoprim–sulphamethoxine (62.3). Multiple antibiotic resistance of Enterococcus were more than 65%. High resistance rates shown by Enterococcus were observed in rifampin (62%), ampicillin (62%) and tetracycline (42%). Almost all farmers (92.3%) left their ducks to scavenge for food around their houses. Antibiotics used in animal treatments were oxytetracyclines, sulfonamides, penicillin dihydrostreptomycin while in humans were tetracycline, ampicillin, and amoxicillin.
Assessment of Antimicrobial Usage and Residues in Commercial Chicken Eggs from Smallholder Poultry Keepers in Morogoro Municipality, Tanzania
(2009) Nonga, H. E.; Simon, C.; Karimuribo, E. D.; Mdegela, R. H.
Occurrence of antimicrobial residues in commercial chicken eggs was determined in Morogoro municipality between January and February 2007. Twenty smallholder farmers were interviewed on the types of antimicrobials, reasons of use and their awareness on antimicrobial withdrawal period. Seventy egg samples were collected for qualitative antimicrobial drug residues analysis by use of agar well diffusion and Delvotest SP assays. It was found that farmers use antimicrobial drugs as prophylaxis and treatment of common chicken diseases namely fowl typhoid (85%), infectious bursa disease (Gumboro) (65%) infectious coryza (65%), collibacilosis (55%), coccidiosis (54%), Newcastle disease (50%), helminthosis (20%) and fowl pox (15%). Antimicrobials accounted for 85% of the drugs commonly used. It was also found that 65% of the farmers treat their chicken themselves. The common drugs were oxytetracycline (75%), egg booster (50%), amprolium (35%), sulphamethoxypyridazine (35%), sulphanilamide (25%), chlortetracyclines (10%), chloramphenicol (10%), sulphadiazine– trimethoprim (20%), duoxycycline (20%), sulphadiazine (25%) and flumequine (10%). Eighty per cent of the farmers had knowledge on antimicrobial withdrawal period sold eggs before withdrawal period and almost 85% were unaware of possible effects of antimicrobial residues in humans. All 70 eggs were positive to antimicrobial residues by Delvotest kit, but 21.4% positive with agar well diffusion test. It was concluded that the presence of antimicrobial residues in table eggs could be of public health significance to the egg consumers in Morogoro municipality.
Assessment of beef microbial contamination at abattoir and retail meat shops in Morogoro Municipality, Tanzania
(African Journal Online, 2014-11-19) Ntanga, P. D.; Mdegela, R. H.; Nonga, H. E.
A cross section study was conducted in Morogoro Municipality to assess microbial contamination in beef production chain from abattoir to retail meat shops during February to May, 2012. Questionnaire on abattoir and meat shop hygiene was administered to 60 respondents. Meat, meat in-contact surface swab and water samples at the abattoir (n=36) and 14 meat shops (n=56) were analyzed for Total Viable Counts (TVC), Total Coliform Counts (TCC) and Total Faecal Coliform Counts (TFC). It was found that the respondents had not attended to any training on meat hygiene, had no protective gears and do not perform regular health examination. The infrastructure appeared obsolete. Carcasses and meat handling environment at abattoir and retail meat shops were in unhygienic condition. Water was scarce in the abattoir and meat shops. Water analysis showed heavy microbial contamination (mean TVC log 5.2±0.3). All the meat and meat in-contact surfaces were at different levels of microbial contamination and were beyond FAO recommendations. The mean TVC in meat was Log 7.2±1 cfu/g with the highest count (Log 7.24±1.3 cfu/g) recorded in samples from meat shops. The mean TVC on meat in-contact surfaces was Log 6±1.3 cfu/cm2 while mean TCC and TFC in meat were Log 6.1±1.6 and 5.9±1.7 cfu/g respectively. High microbiological loads in meat indicate gross contaminations along the whole meat value chain and pose potential risks for public health. Results obtained in this study provide information to the local government authorities and all stakeholders in the meat industry for proper management of the abattoir, retail meat shops and personnel; outlines key aspects for interventions and suggests future developments to prevent health risks associated with handling and consumption of contaminated meat.
Assessment of causes of organ condemnations, financial losses and foetal wastage in cattle slaughtered at Bukoba Municipal abattoir, Kagera, Tanzania
(African Journal Online, 2014-09-03) Msafiri, P. A.; Nonga, H. E.; Kassuku, A.
Retrospective and prospective studies were carried out at Bukoba Municipal abattoir, Tanzania to identify causes of cattle organs condemnation and assess financial implications and magnitude of slaughter of pregnant cows and heifers. A retrospective study used data from 2011 to 2013 found that a total of 13,970 cattle were slaughtered and inspected. The prevalence of liver fasciolosis was 28.5%, lung congestion 10.2%, emphysema 5.1%, kidney haemorrhages 7.7% and hydronephrosis 4.3%. During a prospective study carried out in January 2014, post-mortem inspection of 692 cattle was done. The prevalence of liver fasciolosis was 37.6%, flabby heart 11.3%, emphysema 11.0% and lung congestion (6.6%). Value of condemned organs in one month of January 2014 was estimated to be Tanzanian shillings (TZS) 7,351 000 equivalent to US$ 4,595. Estimated total of TZS 6,174 600 (US$ 3,860) resulted from liver condemnations and TZS 6,092 400 (US$ 3,808) from liver fasciolosis which is 82.9% of the total financial losses. Of all the 480 cows and heifers slaughtered, 75 (15.6%) were found to be pregnant. The high condemnation rates led to financial losses and some of the conditions are of zoonotic importance. The indiscriminate slaughter of pregnant animals is against animal welfare. Therefore, diseases surveillance and control measures need to be strengthened, and enforcement of legislation governing animal welfare to curb the slaughter of pregnant animals.
Assessment of farming practices and uses of agrochemicals in Lake Manyara basin, Tanzania
(2011-05-18) Nonga, H. E.; Mdegela, R. H.; Lie, E.; Sandvik, M.; Skaare, J. J.
This study was conducted to assess farming practices, agrochemical usage and environmental pollution in Manyara basin, Tanzania. Field surveys, interviews, questionnaires and Lake Manyara nutrient analysis were used in data collection. The highest number (95%) of households grew crops, namely, maize, rice, banana and vegetables with median farm size of 3 ha. Irrigated farming was common (75%) which enhanced cultivation on same piece of land up to 6 times a year. Farmers indiscriminately used pesticides, namely, insecticides (50%), fungicides (37.5%) and herbicides (12.5%). Uses of endosulfan in vegetable farms poses public health threats to consumers. Most respondents (85%) applied insecticides in vegetables up to 4 times per cropping season. Excessive use of pesticides and haphazard disposal of pesticide remnants and containers caused environmental pollution. The average amount of acaricides used was 1109±915 ml (mean ± SD) per livestock keeper per month per. Most farmers (78%) used inorganic fertilizers and animal manure (43.4%). Low levels of ammonium (3.6±3.1 μg/L), nitrate (1±0.8μg/L) and phosphate (36.1±42 μg/L) were recorded in the lake. Easy access to agrochemicals, limited knowledge of pesticide on environmental health and limited extension services were factors for indiscriminate uses of agrochemicals. Increasing farmers awareness and training aimed at sustainable agriculture, agrochemical uses and integrated pest management is suggested.
Assessment of human-snake interaction and its outcomes in Monduli district, northern Tanzania
(Tanzania Journal of Health Research, 2015-01) Nonga, H. E.; Haruna, A.
Human-snake interactions has always been associated with different outcomes. This crosssectional study was conducted to assess the human-snake interaction and its outcomes in Monduli District, northern Tanzania. Data collection was done through questionnaires, key informants interviews and record review of snake bite cases at Meserani Snake Park Clinic. Most respondents (97%) in the study area had ever encountered snakes mostly in livestock grazing areas (41.5%) especially at noon hours. The common types of snakes were the black ones (44.6%) and most of these (58%) were non-poisonous species. Twelve species of snakes were reported to be found in the area while 22 species dominated by Psammophis s. subtaeniatus and Eryx colubrinus loveridgei were under zoo environment. Fifty seven people were bitten by snakes in the study area in 2012 and majority of the cases were recorded between February and April. It was further reported that many respondents (92.3%) feel worried whenever they encounter snakes and the reaction is to kill it as a means of control. This was because snakes were regarded as dangerous creatures and were not used in any traditional practices (81.5%). There was a hostile interactions between human and snakes and always humans hated snakes and, killed them whenever were encountered. Basic educations on snake conservation have to be provided to the community to avoid unnecessary killing of snakes.
Assessment of hygienic practices and faecal contamination of beef at Vingunguti slaughterhouse in Dar es salaam, Tanzania
(African Journal Online, 2013-05-15) Ndalama, E.; Mdegela, R. H.; Nonga, H. E.
An investigation was conducted between January to February 2013 to assess the hygienic practices and faecal contamination of beef at Vingunguti slaughterhouse using Escherichia coli as an indicator organism. Hygienic practices were assessed using a questionnaire survey to 40 slaughterhouse workers. Faecal sampling was done to 75 slaughter cattle and after slaughter swab samples from neck, shoulder, pelvis and thigh muscles of dressed carcasses were collected and were subjected to standard bacteriological analysis for E. coli O157 isolation. The findings revealed poor hygienic practices, lack of adequate knowledge on the existence of enteropathogens and meat contamination, and a negative perception on improving sanitary conditions and practices by workers. There were no essential basic facilities for a slaughterhouse such as potable running water, separated clean and dirty areas, stunning and bleeding facilities, area for inspection of carcasses, properly working drainages, cold room, changing room, protective clothing for the workers and proper working tools. Animals were slaughtered, dressed and meat handled in dirty environment that caused gross contamination of meat. The drainage system was dilapidated and there were no defined means of waste disposal. E. coli Escherichia coli was isolated in all the samples analysed. However, E. coli O157 strain was not isolated in all the samples analysed. It is concluded that the hygienic practices, slaughterhouse facilities and conditions at Vingunguti slaughterhouse are poor predisposing carcasses to faecal contamination. Measures to improve the sanitary situation are recommended particularly the water supply and drainage, slaughter methods, meat handling practices and standard abattoir equipment.
Assessment of microbiological quality of raw fruit juice vended in Dar es Salaam city, Tanzania
(Elsevier, 2015-05-01) Simforian, E.; Nonga, H. E.; Ndabikunze, B. K.
Fresh fruit juices are highly nutritious food for human but the hygiene involved during preparation, packaging and storage make fresh juices prone to microbial contamination. This study was conducted to assess bacterial quality and establish the risk factors for contamination of raw fruit juices vended in Dar es Salaam city, Tanzania. Ninety fruit juice vendors were assessed for possible factors of microbial contamination in fruit juices. One juice sample per vendor was collected for microbial analysis using standard laboratory protocols of International Standards Organisation (ISO), Tanzania Bureau of Standards and Codex specifications. The results showed that the total plate counts (TPC) ranged between 2.32 and 8.54 (Log cfu/ml). About 72.2% of juice samples had TPC above Codex recommended maximum levels (3.7e4.7 Log cfu/ml). The prevalence of Escherichia coli in the juices was 80% with a range between 0.0 and 5.0 (Log MPN/ml) suggesting of direct faecal contamination or contamination from the environment. All samples were negative for Salmonella species. Risk factors for high TPC and E. coli counts which were statistically significant (P < 0.05) included type of juice, extraction methods, vending sites, storage containers and sex of the vendors. Generally, 78.9% of preparation and vending premises were unhygienic and encouraged contamination of the juices. It is concluded that, the overall handling, preparation practices and bacterial quality of unpasteurized fruit juices vended in Dare es Salaam city are poor. The government should educate the vendors on food safety and hygiene as well as enforcing regular monitoring of the quality of street fruit juices.
Assessment of physicochemical characteristics and hygienic practices along the value chain of raw fruit juice vended in Dar es Salaam city, Tanzania
(Tanzania Journal of Health Research, 2014-10) Nonga, H. E.; Simforian, E. A.; Ndabikunze, B. K.
Fresh fruit juice is an essential component of human diet and there is considerable evidence of health and nutritional benefits. However, nature of the fruits used in juicing and unhygienic processes in the value chain may cause poor quality of juice. This cross-sectional study was conducted to assess physicochemical characteristics and hygienic practices along the value chain of raw fruit juice vended in Dar es Salaam, Tanzania. A total of 90 juice vendors were interviewed. Ninety juice samples were collected and analysed for physicochemical quality. The pH of juices ranged between 2.7 and 6.4, acidity 0.01% and 1.3% and, total soluble solids ranged between -1.5 and 18.04 ⁰Brix. Most juices (67.8%) had ⁰Brix levels below Codex recommended values classified as weak and watery. Juices were made of mango, passion, tamarind, sugar cane and mixture of these fruits sourced from open markets in the city. Water for washing of fruits and dilution of juices was from deep wells (53.3%) and taps (46.7%). About one third (37.8%) of the juice vendors didn’t wash the fruits before juicing and 44.4% didn’t boil water for juice dilution. Juice extraction was done by kitchen blenders, boiling in water and squeezing by simple machines. Juice pasteurization was not done. The majority of vendors (78.9%) stored juices in plastic buckets and juice was sold in glass cups, reused plastic bottles and disposable cups. Vending sites were restaurants, bus stands and along roadsides. The majority of premises (78.9%) were in unhygienic condition that likely encouraged or introduced contaminants to the juices. It is concluded that, the overall handling, preparation practices and physicochemical quality of raw fruit juices vended in Dare es Salaam City are poor. The government should educate the vendors on food safety and hygiene as well as enforcing regular monitoring of the quality of street fruit juices.
Assessment of raw cow milk quality in smallholder dairy farms in Pemba Island Zanzibar, Tanzania
(Hindawi, 2018-03-12) Gwandu, S. H.; Nonga, H. E.; Mdegela, R. H.; Katakweba, A. S.; Suleiman, T. S.; Ryoba, R.
Milk quality depends on the physicochemical characteristics, hygienic standards, and nutritional quality; however, animal husbandry practices, unhygienic harvesting and processing, may affect its quality. A cross-sectional study was conducted between August 2010 and July 2011 to assess the hygiene of cow milk production environment, raw cow milk physicochemical characteristics, and microbial quality and estimate the prevalence of antimicrobial residues using standard methods in Pemba Island. A total of 98 raw cow milk samples from selected smallholder dairy farms were analyzed, and the judgement on the quality used the East African Standards. Generally, the milk production chain was done under the unhygienic condition, and dirty plastic containers were used for collection and storage of milk under room temperature. Some milk samples had abnormal colour (2.1%), abnormal smell (7.1%), and pH below normal (35.7%), clotted on alcohol test (9.2%), and had the specific gravity below normal (13.3%). All the milk samples had mineral contents within the recommended range. Milk samples with butterfat below normal were 29.6%, while 14.3% had total solids below recommended values. The mean total viable count (TVC) of milk container surfaces was log CFU/100 cm2, while total coliform count (TCC) was log CFU/100 cm2. Up to 55.1% of milk had TVC beyond the recommended levels. The milk mean TVC was log CFU/ml and TCC was log CFU/ml. Up to 26.5% of milk samples had the TCC beyond levels. Results on physicochemical characteristics and nutritional analysis show that the raw cow milk in Pemba Island is of inferior quality. Microbiological results of this study imply heavy contaminations of milk. Antimicrobial residues were detected in 83% of the samples and most of them were from Wete District. Unhygienic milk production chain accelerates microbial contaminations, and antimicrobial residues in milk are a big problem that needs urgent attention from the responsible authority.
Assessment of raw milk quality and stakeholders’ awareness on milk-borne health risks in Arusha city and Meru district, Tanzania
(Springer, 2015-03-30) Ngasala, B. N.; Nonga, H. E.; Mtambo, M. M. A.
A cross-sectional study was conducted to assess the quality of raw milk and stakeholders’ awareness on milk borne health risks and factors for poor milk hygiene in Arusha City and Meru District, Tanzania between October and December 2012. A total of 105 smallholder dairy farmers, milk vendors and milk retailers were interviewed, and milk samples were collected for physical, microbial and antibiotic residue analysis using standard procedures. Questionnaire results indicated high level of awareness (94 %) that drinking raw milk can predispose consumers to milk-borne diseases; nevertheless, 65 % of respondents consumed raw milk. Physicochemical analyses showed some of the milk had sediments (20 %), bad smell (21 %) and had clotted on alcohol test (27 %). About 36 % of milk samples had pH below 6.6, and 25 % had specific gravity below 1.028 g/ml. The mean total viable count (TVC) of milk from vendors is significantly (P<0.05) higher than that from retailers and smallholder dairy farmers. Generally, 65 % of milk samples assessed had a higher TVC than the level recommended (2.0×105 cfu/ml) by the East African Community (EAC) standards. Up to 91 % of the milk samples had bacterial growth that included Eschericia coli (66 %), Staphylococcus aureus (33 %), Corynebacterium (11 %) and Pseudomonas (10 %). All smallholder dairy farmers were aware of drug residues, but majority (57 %) were unaware of human health effects caused by veterinary drug residues in milk. Up to 97 % of respondents reported to comply with drug withdrawal periods. This possibly led to all milk samples analysed to be negative from detectable levels of antibiotic residues. It is concluded that the level of awareness on milk quality is high, although practices associated with milking and post-harvest handling predispose milk to bacterial contamination which is a public health risk to milk consumers.
Assessment of veterinary drug use and determination of antimicrobial residues in broiler chicken meat in Urban district, Zanzibar, Tanzania
(African Journal Online, 2013-05-15) Nonga, H. E.; Sungura, K. H.; Ngowi, H. A.
A cross-sectional study was conducted between October 2009 and January 2010 to assess veterinary drug usage by broiler chicken farmers and to determine antimicrobial residues in broiler meat in Urban district, Zanzibar, Tanzania. Fifty five smallholder farmers were interviewed on types of antimicrobials, reasons for use, their awareness on antimicrobial withdrawal periods and effects of antimicrobial residues in humans. Interviews with key informants were used to supplement the information from farmers. Up to 66% of the respondents were aware of drug withdrawal periods, however, only 45.5% reported to comply in fear of losses and limited awareness of health effect associated with antibiotic residues. Key informants reported that there was no inspection of chicken meat for residues and the indiscriminate use of veterinary drugs was fueled by trade liberalization. To determine antibiotic residues, 72 broiler meat samples were analysed by agar well diffusion and Delvo tests. Laboratory results indicated that 76.4% of the broiler meat samples contained antimicrobial residues. High proportion of positive samples in this study suggests that there is high risk of public exposure to antimicrobial residues through consumption of chicken meat in Urban district. Poultry farmers should be educated on the importance of drug withdrawal periods and the possible human health effects associated with consumption of foods with antimicrobial residues. It is further stressed that there is a need for stricter regulation regarding the use of veterinary drugs in particular antimicrobials in the poultry industry as well as the inspection of meat for residues prior to marketing
Association of long-term pesticide exposure and biologic parameters in female farm workers in Tanzania: A cross sectional study
(Toxics, 2016-09-29) Manyilizu, W. B.; Mdegela, R. H.; Kazwala, R. R.; Nonga, H. E.; Müller, M. B.; Lie, E.; Skjerve, E.; Lyche, J. L.
The study aimed to assess the association of long-term pesticide exposure (5 years) with hematological, serum biochemical parameters and acetylcholinesterase activity in farm workers. These pesticides included organophosphorus pesticides, carbamates, pyrethroids, dithiocarbamates, and other pesticides such as endosulfan. Applying a cross-sectional study design, 69 females from a pesticide-exposed farm population and 30 females from a district not using pesticides (reference group) were studied. The mean red cell corpuscular volume and hematocrit values were significantly lower (74.7 9.1 fl; 95% CI 72.5–76.9 and 32.0% 4.6%; 95% CI 30.9–33.1, respectively) in the exposed compared to the reference group, whereas mean corpuscular hemoglobin concentration and platelets were significantly higher (37.4 3.8 g/dL; 95% CI 36.5–38.3 and 374.1 95.3/L; 95% CI 351.2–396.9, respectively) in the exposed compared to the reference group. Mean serum glutamic oxaloacetate transaminase (20.7 8.9 U/L; 95% CI 18.5–22.9) and creatinine (83.9 6.6 mol/L; 95% CI 82.3–85.5) were significantly higher in the exposed compared to the reference group. A higher mean esterase activity (AChE 0.6 0.2 mM/min/mg protein; 95% CI 0.56–0.7; BChE 0.9 0.4 mM/min/mg protein; 95% CI 0.9–1.1) was noted in the exposed group. Regression models suggest that occupational exposure (p < 0.001) could be a predictor of esterase (AChE and BChE) activity and biochemical changes (= 0.4, 95% CI: 0.3–0.5; = 0.7, 95% CI: 0.6–0.9, respectively). Long-term pesticide exposure affects the hemato-biochemical and esterase responses, establishing the need for further studies.
Bacteriological assessment of chlorinated and non-chlorinated water in Morogoro Municipality, Tanzania
(Tanzania Veterinary Association, 2017-12-07) Katto, T. M.; Nonga, H. E.
This cross sectional study was conducted to assess the bacterial contamination in chlorinated and non- chlorinated water in Morogoro Municipality from October 2013 – January 2014. Fifty two samples were collected from selected taps (chlorinated samples) and directly from the water sources (non -chlorinated samples). The total viable count (TVC) was performed on nutrient agar while the total coliform count (TCC) was done by Most Probable Number (MPN) using MacConkey broth. It was found that the TVC ranged between 530 CFU/100 mL and 600 CFU/100 mL during dry season and the same range during rainy season. The TVC ranged between 530 CFU/100 mL and 600 CFU/100 mL during dry season and 600 CFU/100 mL to 650 CFU/100 mL during rainy season. The results for TCC positive chlorinated samples during dry season ranged between 3.6/100 mL and 150/100 mL while during the rainy season it ranged between 15/100 mL and 150/100 mL. The highest TCC were found at Department of Animal Science and Production in both season for chlorinated water and 41% of non- chlorinated water during dry season while all the samples of non- chlorinated water during rainy season had high TCC count. Also the results further showed that TCC for positive non- chlorinated samples during dry season ranged between 210/100 mL and >1100/100 mL while it was >1100/100 mL during rainy season. In chlorinated water, significant difference (p=0.332) was observed when TVC during dry season was compared with that of rainy season. Based on the results of this study, it is concluded that chlorinated and non- chlorinated water show high number of TCC than that recommended by WHO and Tanzania Bureau of Standards (TBS). However, there was low TVC which was within recommended standards. The high TCC observed in treated water in this study may pose a risk of acquiring water-borne diseases to the Morogoro community
Brominated flame retardants (BFRs) in breast milk and associated health risks to nursing infants in Northern Tanzania
(Elsevier, 2015-12-23) Müller, M. B.; Polder, A.; Brynildsrud, O. B.; Lie, E.; Løken, K. B.; Manyilizu, W. B.; Mdegela, R. H.; Mokiti, F.; Murtadha, M.; Nonga, H. E.; Skaare, J. U.; Lyche, J. L.
Themain aim of this studywas to assess brominated flame retardants (BFRs) in breastmilk in the Northern parts of Tanzania. Ninety-five colostrum samples from healthy, primiparous mothers at Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), (2,3-dibromopropyl) (2,4,6-tribromophenyl) ether (DPTE), pentabromoethylbenzene (PBEB) and 2,3,4,5,6- pentabromotoluene (PBT). The Ʃ7PBDE (BDE 28, 47, 99, 100, 153, 154, 183) ranged from below level of detection (bLOD) to 785 ng/g lipid weight (lw). BDE 47, 99, 100 and 153 were the dominating congeners, suggesting recent and ongoing exposure to banned, commercial PentaBDE mixture. Amultiple linear regressionmodel revealed that mothers eating clay soil/Pemba during pregnancy had significantly higher levels of BDE 47, 99, 100 and 153 in their breast milk than mothers who did not eat clay soil/Pemba. Infant birth weight and birth length were significantly correlated with the levels of BDE 47, 99, 100 and 153. The estimated daily intake (ng/kg body weight/day) of BDE 47 and 99 exceeded the US EPA Reference doses (RfD) in four and eight mothers, respectively, suggesting a potential health risk to the nursing infants.
Conjugation of microcystins with thiols is reversible: Base-catalyzed deconjugation for chemical analysis
(Chemical Research in Toxicology, 2016-03-21) Miles, C. O.; Sandvik, M.; Nonga, H. E.; Ballot, A.; Wilkins, A. L.; Rise, F.; Jaabaek, J. A. H.; Loader, J. I.
Microcystins are potent cyclic heptapeptide toxins found in many freshwater cyanobacteria. Most microcystins contain an α,β-unsaturated amide that can react with thiolcontaining amino acids, peptides, and proteins in vivo and in vitro. While soluble conjugates formed from small peptides can be extracted and analyzed directly by LC−MS, microcystins conjugated to proteins are analyzed after oxidative cleavage of their Adda side chains, but information on which microcystin analogues were present is lost. Observations during the development of thiol-derivatization-based LC−MS methods for microcystin analysis indicated that the reaction of thiols with microcystins was reversible. The kinetics of deconjugation was investigated with mercaptoethanol as a model thiol to identify suitable reaction conditions. A range of microcystins conjugated to mercaptoethanol, methanethiol, cysteine, and glutathione were then successfully deconjugated, demonstrating the feasibility of releasing conjugated forms of microcystins for chemical analysis. Reagents for removing the released thiols or for trapping the released microcystins increased the reaction rate. Optimization of methodologies based on this reaction should increase the method’s utility for measuring free and conjugated microcystins. The results also indicate that thiol-conjugated microcystins slowly release free microcystins, even at neutral pH, with consequences for assessment of toxin exposure, metabolism, and trophic transfer. A range of other common natural and environmental toxins, such as deoxynivalenol and acrylamide, also contain α,β-unsaturated carbonyl groups and can be expected to behave in a similar manner.
Conjugation of microcystins with thiols is reversible: Base-catalyzed deconjugation for chemical analysis
(ACS Publications, 2016-03-21) Miles, C. O.; Sandvik, M.; Nonga, H. E.; Ballot, A.; Wilkins, A. L.; Rise, F.; Jaabaek, J. A. H.; Loader, J. I.
Microcystins are potent cyclic heptapeptide toxins found in many freshwater cyanobacteria. Most microcystins contain an α,β-unsaturated amide that can react with thiolcontaining amino acids, peptides, and proteins in vivo and in vitro. While soluble conjugates formed from small peptides can be extracted and analyzed directly by LC−MS, microcystins conjugated to proteins are analyzed after oxidative cleavage of their Adda side chains, but information on which microcystin analogues were present is lost. Observations during the development of thiol-derivatization-based LC−MS methods for microcystin analysis indicated that the reaction of thiols with microcystins was reversible. The kinetics of deconjugation was investigated with mercaptoethanol as a model thiol to identify suitable reaction conditions. A range of microcystins conjugated to mercaptoethanol, methanethiol, cysteine, and glutathione were then successfully deconjugated, demonstrating the feasibility of releasing conjugated forms of microcystins for chemical analysis. Reagents for removing the released thiols or for trapping the released microcystins increased the reaction rate. Optimization of methodologies based on this reaction should increase the method’s utility for measuring free and conjugated microcystins. The results also indicate that thiol-conjugated microcystins slowly release free microcystins, even at neutral pH, with consequences for assessment of toxin exposure, metabolism, and trophic transfer. A range of other common natural and environmental toxins, such as deoxynivalenol and acrylamide, also contain α,β-unsaturated carbonyl groups and can be expected to behave in a similar manner.
Cyanobacteria and cyanobacterial toxins in the alkaline-saline Lakes Natron and Momela, Tanzania
(African Journal Online, 2016-12-05) Nonga, H. E.; Mdegela, R. H.; Sandvik, M.; Lie, E.; Miles, C. O.; Skaare, J. U.
Physicochemical parameters, phytoplankton communities, microcystin (MC) concentrations and potential MC-producing cyanobacteria were investigated in Lakes Natron and Momela, Tanzania. In Lake Big Momela, concentrations of soluble reactive phosphorus, nitrate and ammonia were 7.1, 2.6 and 0.9 μg/L, respectively, while dissolved oxygen, salinity, conductivity and pH were 9.4 mg/L, 19‰, 30 mS/cm and 9.7, respectively. The concentrations of soluble reactive phosphorus, nitrate and ammonia in Lake Natron were 129.4, 8.1 and 58 μg/L, respectively, while dissolved oxygen, conductivity and pH were 8 mg/L, 52 mS/cm and 9.5 respectively. The phytoplankton communities in both lakes were dominated by cyanobacteria, particularly Arthrospira fusiformis. Navicula and Nitzschia diatoms, and Chlorella, Chlorococcum and Scenedesmus green algae were common in Lakes Momela and Natron. Liquid chromatography–mass spectrometry (LC-MS) analysis phytoplankton detected four microcystin variants namely MC-RR, -YR, -LR and -RY. The total MC concentrations in Lake Natron were 0.1–4.5 μg/mL of phytoplankton scum and in Lake Momela were below quantifiable levels. Polymerase chain reaction analysis of phytoplankton revealed presence of Microcystis and the Microcystis mcyB gene in some samples. Finding of potential MC-producing cyanobacteria and MCs in study lakes poses a health risk to Lesser Flamingo which feed on cyanobacteria.
Dioxins, PCBs, chlorinated pesticides and brominated flame retardants in free-range chicken eggs from peri-urban areas in Arusha, Tanzania: Levels and implications for human health
(Elsevier, 2016-02-03) Polder, A.; Müller, M. B.; Brynildsrud, O.B.; de Boer, J.; Hamers, T.; Kamstra, J. H.; Lie, E.; Mdegela, R. H.; Moberg, H.; Nonga, H. E.; Sandvik, M.; Skaare, J. U.; Lyche, J. L.
The environment in the northern part of Tanzania is influenced by rapid population growth, and increased urbanization. Urban agriculture is common and of economic value for low income families. In Arusha, many households sell eggs from free-ranging backyard chicken. In 2011, 159 eggs from different households in five different locations in Arusha were collected, homogenized, pooled into 28 composite samples and analyzed for a wide selection of POPs. Levels of POPs varied widely within and between the locations. The levels of dieldrin and ΣDDT ranged between 2 and 98,791 and 2 and 324 ng/g lipid weight (lw), respectively. EUMRLs of 0.02 mg/kg dieldrin for eggs were exceeded in 4/28 samples. PCBs, HCHs, chlordanes, toxaphenes and endosulfanes were found at lower frequency and levels. Brominated flame retardants (BFRs), e.g polybrominated diphenylethers (PBDEs), hexabromocyclododecane (HBCD) and 1,2-bis(2,4,6-tribromphenoxy)ethane (BTBPE) were present in 100%, 60% and 46% of the composite samples, respectively. Octa-and deca-BDEs were the dominating PBDEs and BDE 209 levels ranged between bLOQ (limit of quantification) – 312 ng/g lw. Dioxins were measured using the DRLUC bio-assay and found in levels of bLOQ – 20 pg bio-TEQs/g lw. Four samples (13%) exceeded the maximum level of 5 pg/g total WHO-TEQs for hen eggs set by the Commission Regulation (EU) No 1259/2011. The daily/weekly intake was calculated and risk was characterized for all compounds comparing with available toxicity reference values (TRVs) such as the provisional tolerable intake (PTDI) or Reference Doses (RfDs). In one sample dieldrin exceeded the PTDI (100 ng/kg bw/day). Correlation was found between bio-TEQs and lipid adjusted levels of ΣPBDEs, suggesting similar sources. Open fires in backyards may be one of the sources for contamination of eggs with BFRs and dioxins.