Assessment of milk handling practices and bacterial contaminations along the dairy value chain in Lushoto and Handeni districts, Tanzania

Contaminated milk is responsible for up to 90% of all dairy-related diseases of humans. A cross sectional study was carried out in Lushoto and Handeni districts of Tanga, Tanzania to determine the milk handling practices, bacterial contamination and selected milk-borne zoonotic pathogens along the dairy value chain. A total of 93 respondents were interviewed and 184 milk and milk product samples were collected. Laboratory analysis of total and coliform plate counts, detection of Escherichia coli O157:H7 and Brucella abortus using polymerase chain reaction (PCR) were done. Results showed that, most farmers (57 %) milked their cows under unhygienic conditions. More than 60% of farmers did not clean their hands, wash cow teats and clean animal houses before milking. The majority (92.1%) of farmers were not trained on livestock keeping and milk handling. Although the mean TPC was within the East African Community (EAC) standards, general counts ranged between 3.3 to 5.8 log10. Eighty seven and 93% of milk from farmers and vendors, respectively, did not meet the TPC EAC standards. All the collected milk did not meet the CPC EAC standards, indicating contamination of milk with coliforms. PCR analyses did not detect E. coli O157:H7 in all the tested samples while B. abortus was detected in 37 out of 87 samples tested. It was concluded that unhygienic practices of milking and post-harvest handling along the dairy value chain possibly contributed to microbial contamination of milk. Detection of B. abortus in milk is of public health significance due to its zoonotic potential. It is recommended that veterinary/extension services be provided to livestock farmers on proper animal husbandry and control of zoonotic animal diseases. Public education should be given to all stakeholders in dairy industry on milking and post harvest handling of milk to curtail the likely losses due to rejection of spoiled milk and milk-borne pathogens resulting from contamination of milk

Determination of risk factors contributing to microbial contamination in milk and identification of presence of selected pathogenic bacteria along dairy value chain in Tanga

Contaminated milk is responsible for up to 90% of all dairy-related diseases of humans. A cross sectional study was carried out in Lushoto and Handeni districts of Tanga region to determine handling practices, bacterial contaminations and selected milk-borne zoonotic pathogens along the dairy value chain. A total of 93 respondents were interviewed and subsequently 184 samples of milk and its product were collected for laboratory analysis of total plate count (TPC), coliform plate count (CPC), and detection of Escherichia coli O157:H7 and Brucella abortus using polymerase chain reaction (PCR). Results showed 57% of famers milked their cows under unhygienic conditions and plastic containers were used for storage. Although the mean total plate count was exactly within the East African Standards (EAS, 5.3 log10 cfu/ml) the counts ranged between 3.3 log10 to,5.8 log10 where 87% and 93% of milk from farmers and vendors, respectively, were above the acceptable EAS standards. Meanwhile, 100 % of milk samples were above CPC EAS standards. PCR analyses did not detect E.coli O157:H7 in all the tested milk samples while B. abortus was detected in 37 out of 87 samples tested (42.5%). It was concluded that limited veterinary/extension services, unhygienic practices of milking and post-harvest handling along the dairy value chain possibly contributed to microbial contamination of milk. Detection of B. abortus in milk is of public health significancy due to its zoonotic potential. It is recommended that veterinary/extension services should be provided to livestock farmers on proper animal husbandry and control of diseases

Historical environmental change in Africa drives divergence and admixture of Aedes aegypti mosquitoes: a precursor to successful worldwide colonization?

Article PurchasedIncreasing globalization has promoted the spread of exotic species, including disease vectors. Understanding the evolutionary processes involved in such colonizations is both of intrinsic biological interest and important to predict and mitigate future disease risks. The Aedes aegypti mosquito is a major vector of dengue, chikungunya and Zika, the worldwide spread of which has been facilitated by Ae. aegypti's adaption to human-modified environments. Understanding the evolutionary processes involved in this invasion requires characterization of the genetic make-up of the source population(s). The application of approximate Bayesian computation (ABC) to sequence data from four nuclear and one mitochondrial marker revealed that African populations of Ae. aegypti best fit a demographic model of lineage diversification, historical admixture and recent population structuring. As ancestral Ae. aegypti were dependent on forests, this population history is consistent with the effects of forest fragmentation and expansion driven by Pleistocene climatic change. Alternatively, or additionally, historical human movement across the continent may have facilitated their recent spread and mixing. ABC analysis and haplotype networks support earlier inferences of a single out-of-Africa colonization event, while a cline of decreasing genetic diversity indicates that Ae. aegypti moved first from Africa to the Americas and then to Asia. ABC analysis was unable to verify this colonization route, possibly because the genetic signal of admixture obscures the true colonization pathway. By increasing genetic diversity and forming novel allelic combinations, divergence and historical admixture within Africa could have provided the adaptive potential needed for the successful worldwide spread of Ae. aegypti

Malaria elimination in Zanzibar: where next?

In 2018, Zanzibar developed a national malaria strategic plan IV (2018-2023) to guide elimination of malaria by 2023. We assessed progress in the implementation of malaria activities as part of the end-term review of the strategic plan. The review was done between August and October 2022 following the WHO guideline to assess progress made towards malaria elimination, effectiveness of the health systems in delivering malaria case management; and malaria financing. A desk review examined available malaria data, annual work plans and implementation reports for evidence of implemented malaria activities. This was complemented by field visits to selected health facilities and communities by external experts, and interviews with health management teams and inhabitants to authenticate desk review findings. A steady increase in the annual parasite incidence (API) was observed in Zanzibar, from 2.7 (2017) to 3.6 (2021) cases per 1,000 population with marked heterogeneity between areas. However, about 68% of the detected malaria cases were imported into Zanzibar. Malaria case follow-up and investigation increased from <70% in 2017 to 94% and 96% respectively, in 2021. The review noted a 3.7-fold increase of the health allocation in the country's budget, from 31.7 million USD (2017/18) to 117.3 million USD (2022/23) but malaria allocation remained low (<1%). The varying transmission levels in the islands suggest a need for strategic re-orientation of the elimination attempts from a national-wide to a sub-national agenda. We recommend increasing malaria allocation from the health budget to ensure sustainability of malaria elimination interventions

The use of polymerase chain reaction (PCR) to confirm presence of selected pathogenic bacteria along milk value chain in Tanga region

BACKGROUND Despite the fact that foods of animal source are a minor constituent in most diets, they are responsible for incidents of food-borne illness; dairy products being implicated. Up to 90% of all dairy – related diseases are due to pathogenic bacteria found in milk. Emergence of new milk-borne bacterial pathogens with more serious challenges such as E.coli O157:H7 has been reported. OBJECTIVES The main objective was to determine milk-borne zoonotic risks associated with milk handling and storage along the dairy value chain. Specific objectives included: 1. To assess possible sources of microbial contamination of milk from farm to consumer 2. To identify practices that lead to microbial contamination along the milk value chain 3. To enumerate total number of bacteria and coliforms present in milk 4. To assess presence of E. coli and B. abortus along the milk value chain MATERIALS AND METHODS Milk samples and questionnaires from all the actors along the dairy value chains of Handeni and Lushoto districts in Tanga region were collected. The questionnaires were analyzed using Stata/IC 11 while standard microbiological cultures and polymerase chain reaction were used to identify and confirm microbial contamination in milk. RESULTS A total of 184 (118 farmers, 4 collection centres, 16 restaurants, 35 vendors, 11 consumers) milk samples were collected and a total of 81 (65 farmers, 11 restaurants, 15 vendors). A checklist of questions for four collection centres was also filled. From the sociological data, different practices that could lead to microbial contamination of milk during milking, storage and delivery were identified. Preliminary analysis showed that only 43 % of farmers cleaned the animal shed before milking, only 71 % washed hands before milking, and, only 71 % of farmers washed the cows’ teats before milking. Detailed results of the study, including laboratory results and sociological results are presented

Strong isolation by distance and evidence of population microstructure reflect ongoing Plasmodium falciparum transmission in Zanzibar

Background: The Zanzibar archipelago of Tanzania has become a low-transmission area for Plasmodium falciparum. Despite being considered an area of pre-elimination for years, achieving elimination has been difficult, likely due to a combination of imported infections from mainland Tanzania and continued local transmission. Methods: To shed light on these sources of transmission, we applied highly multiplexed genotyping utilizing molecular inversion probes to characterize the genetic relatedness of 282 P. falciparum isolates collected across Zanzibar and in Bagamoyo district on the coastal mainland from 2016 to 2018. Results: Overall, parasite populations on the coastal mainland and Zanzibar archipelago remain highly related. However, parasite isolates from Zanzibar exhibit population microstructure due to the rapid decay of parasite relatedness over very short distances. This, along with highly related pairs within shehias, suggests ongoing low-level local transmission. We also identified highly related parasites across shehias that reflect human mobility on the main island of Unguja and identified a cluster of highly related parasites, suggestive of an outbreak, in the Micheweni district on Pemba island. Parasites in asymptomatic infections demonstrated higher complexity of infection than those in symptomatic infections, but have similar core genomes. Conclusions: Our data support importation as a main source of genetic diversity and contribution to the parasite population in Zanzibar, but they also show local outbreak clusters where targeted interventions are essential to block local transmission. These results highlight the need for preventive measures against imported malaria and enhanced control measures in areas that remain receptive to malaria reemergence due to susceptible hosts and competent vectors