Isolation and identification of Listeria species along the milk value chain in one region of Tanzania

Milk is an important source of nutrients in the diet. However, due to its nutritional nature it also serves as an ideal medium for growth and development of various microorganisms under suitable conditions. It is a staple food, which is linked to zoonotic pathogens. This study was carried out in two districts (one region namely Tanga) of Tanzania to evaluate the awareness of farmers on milk contamination and to estimate microbial load along the milk value chain. In total 114 respondents were visited to conducted interviews on awareness as well as strategies for solving the problem of milk contamination. Subsequently milk samples were aseptically collected from each of the 114 respondents for laboratory analyses using the standard ISO procedures for food microbial analyses in particular the horizontal methods. We have showed that there are poor hygienic practices by the majority of actors along the milk value chain in Tanga region. Concerning microbial level, our results revealed that above 90 percent of all samples collected showed total plate count (TPC) above standard acceptable in the Eastern Africa countries (EAC) of 2.0x105 CFU/ml. It was also shown that there was more contamination in milk samples obtained from the household farms compared to those which were collected from the milk suppliers and in the extensive farming system than in the intensive system (P < 0.05). Moreover, three Listeria species namely L. innocua, L. ivanovii and L. monocytogenes were identified. L. monocytogenes were isolated and identified as the common contaminants in milk along the value chain in the study region

Occurrence of Eimeria species parasites on small-scale commercial chicken farms in Africa and indication of economic profitability.

Small-scale commercial poultry production is emerging as an important form of livestock production in Africa, providing sources of income and animal protein to many poor households, yet the occurrence and impact of coccidiosis on this relatively new production system remains unknown. The primary objective of this study was to examine Eimeria parasite occurrence on small-scale commercial poultry farms in Ghana, Tanzania and Zambia. Additionally, farm economic viability was measured by calculating the farm gross margin and enterprise budget. Using these economic measures as global assessments of farm productivity, encompassing the diversity present in regional husbandry systems with a measure of fundamental local relevance, we investigated the detection of specific Eimeria species as indicators of farm profitability. Faecal samples and data on production parameters were collected from small-scale (less than 2,000 birds per batch) intensive broiler and layer farms in peri-urban Ghana, Tanzania and Zambia. All seven Eimeria species recognised to infect the chicken were detected in each country. Furthermore, two of the three genetic variants (operational taxonomic units) identified previously in Australia have been described outside of Australia for the first time. Detection of the most pathogenic Eimeria species associated with decreased farm profitability and may be considered as an indicator of likely farm performance. While a causal link remains to be demonstrated, the presence of highly pathogenic enteric parasites may pose a threat to profitable, sustainable small-scale poultry enterprises in Africa

Spatial and Temporal Pattern of Rift Valley Fever Outbreaks in Tanzania; 1930 to 2007

Rift Valley fever (RVF)-like disease was first reported in Tanzania more than eight decades ago and the last large outbreak of the disease occurred in 2006–07. This study investigates the spatial and temporal pattern of RVF outbreaks in Tanzania over the past 80 years in order to guide prevention and control strategies. A retrospective study was carried out based on disease reporting data from Tanzania at district or village level. The data were sourced from the Ministries responsible for livestock and human health, Tanzania Meteorological Agency and research institutions involved in RVF surveillance and diagnosis. The spatial distribution of outbreaks was mapped using ArcGIS 10. The space-time permutation model was applied to identify clusters of cases, and a multivariable logistic regression model was used to identify risk factors associated with the occurrence of outbreaks in the district. RVF outbreaks were reported between December and June in 1930, 1947, 1957, 1960, 1963, 1968, 1977– 79, 1989, 1997–98 and 2006–07 in 39.2% of the districts in Tanzania. There was statistically significant spatio-temporal clustering of outbreaks. RVF occurrence was associated with the eastern Rift Valley ecosystem (OR = 6.14, CI: 1.96, 19.28), total amount of rainfall of .405.4 mm (OR = 12.36, CI: 3.06, 49.88), soil texture (clay [OR = 8.76, CI: 2.52, 30.50], and loam [OR = 8.79, CI: 2.04, 37.82]). RVF outbreaks were found to be distributed heterogeneously and transmission dynamics appeared to vary between areas. The sequence of outbreak waves, continuously cover more parts of the country. Whenever infection has been introduced into an area, it is likely to be involved in future outbreaks. The cases were more likely to be reported from the eastern Rift Valley than from the western Rift Valley ecosystem and from areas with clay and loam rather than sandy soil texture

A Qualitative Assessment of the Risk of Introducing Peste des Petits Ruminants into Northern Zambia from Tanzania

A qualitative risk assessment was performed to evaluate the risk of introducing Peste des petits ruminants virus into northern Zambia from Tanzania via live goat trade. Data was collected during a mission to Tanzania and northern Zambia and also from literature and interviews with experts. The risk of PPRV introduction was evaluated as a function of the probability of hazard (PPRV) release, exposure of susceptible hosts, and the consequences of spread using the following parameters: prevalence of infection, volume of trade, C-ELISA and quarantine screening missing an infected animal, PPRV viability (remaining infective) in transit, and the virus potential for infection. The magnitude of the consequences was derived from the probability of transmission and spread and the impact of PPRV introduction and establishment. Accordingly, the probability of occurrence of PPRV in northern Zambia from Tanzania was rated as “high” and the economic consequences were also rated as “high.” Finally, the overall risk of introducing PPRV into northern Zambia from Tanzania at the time of the assessment was rated “high.” It was concluded that import of goats and sheep be prohibited until efficient and adequate measures to reduce the risk have been put in place

Food safety risk assessment in beef in Arusha municipality, Tanzania

BACKGROUND: Thermophilic Campylobacter is one of the most important pathogen causing food borne illness in the world. In Tanzania, the risks of campylobacteriosis had not been studied yet and the risks especially from informally marketed foods are in a great need for assessment. A study on risk assessment for Thermophilic Campylobacter infection through consumption of ready to eat beef in Arusha was therefore carried out from January to March 2010. METHODS: A total of 160 samples were collected from beef carcasses (swabs) in butcher (n=73) and roast beef (nyama choma in Swahili language) (n=45; one gram pieces) and skewer beef (mishikaki) (n=42, one gram pieces) sold in beer bars. All the samples were served for isolation of thermophilic Campylobacter spp. The number of customers per hour was recorded in nine nyama choma and nine mishikaki centres for seven consecutive days. A risk model for assessing risk of campylobacteriosis due to the consumption of ready-to-eat beef was developed in @Risk (Palisade) and these data were fed into it. Dose-Response relationship was modeled using reported variables in literatures. Immunity against thermophilic Campylobacter for adults was modeled using the diarrhoeal data in a hospital reported in a separate study. Monte Carlo simulation was run for 10,000 iterations and sensitivity analysis was run for 63 simulations in 1000 iterations. RESULTS: The overall contamination rate of ready-to-eat beef with thermophilic Campylobacter was 24%. The probability of consuming contaminated meat with thermophilic Campylobacter at nyama choma pubs was 15.5% and at mishikaki shops was 34.7%. The total amount of beef sold at nyama choma pubs in Arusha municipality per day was 3,595 kg (90% CI: 1,745-6,173) and that sold as mishikaki per day was 165 kg (90% CI: 57-328). The probability that a naturally immunized person develops illness when he/she ingests enough dose of thermophilic Campylobacter causing illness to a susceptible person was 13.1% by point estimate. Risk characterization showed that the incidence rate of campylobacteriosis in Arusha per day was estimated as 6.43 people (90%CI:3.4-10.4) per 1000 people. Sensitivity analysis found that the most sensitive risk input was initial population of Campylobacter in ready-to-eat beef which we did not study in the present study. SUMMARY: Contamination of carcasses with Campylobacter spp has indicated the need of applying good hygienic standards at all levels from farm to table in order to ensure food wholesomeness and safety in beef. Public education programmes, consumer awareness and training of food handlers on general food hygiene are recommended to reduce potential health risks to the public. Additional studies on the concentration of Campylobacter in different stages of value chain especially on the surfaces of ready-to-eat beef is required to update the present study for the more reliable risk characterization

Exploring local knowledge and perceptions on zoonoses among pastoralists in northern and eastern Tanzania

Background: Zoonoses account for the most commonly reported emerging and re-emerging infectious diseases in Sub-Saharan Africa. However, there is limited knowledge on how pastoral communities perceive zoonoses in relation to their livelihoods, culture and their wider ecology. This study was carried out to explore local knowledge and perceptions on zoonoses among pastoralists in Tanzania. Methodology and principal findings: This study involved pastoralists in Ngorongoro district in northern Tanzania and Kibaha and Bagamoyo districts in eastern Tanzania. Qualitative methods of focus group discussions, participatory epidemiology and interviews were used. A total of 223 people were involved in the study. Among the pastoralists, there was no specific term in their local language that describes zoonosis. Pastoralists from northern Tanzania possessed a higher understanding on the existence of a number of zoonoses than their eastern districts' counterparts. Understanding of zoonoses could be categorized into two broad groups: a local syndromic framework, whereby specific symptoms of a particular illness in humans concurred with symptoms in animals, and the biomedical framework, where a case definition is supported by diagnostic tests. Some pastoralists understand the possibility of some infections that could cross over to humans from animals but harm from these are generally tolerated and are not considered as threats. A number of social and cultural practices aimed at maintaining specific cultural functions including social cohesion and rites of passage involve animal products, which present zoonotic risk. Conclusions: These findings show how zoonoses are locally understood, and how epidemiology and biomedicine are shaping pastoralists perceptions to zoonoses. Evidence is needed to understand better the true burden and impact of zoonoses in these communities. More studies are needed that seek to clarify the common understanding of zoonoses that could be used to guide effective and locally relevant interventions. Such studies should consider in their approaches the pastoralists' wider social, cultural and economic set up

A Spatial Analysis of Rift Valley Fever Virus Seropositivity in Domestic Ruminants in Tanzania

Rift Valley fever (RVF) is an acute arthropod-borne viral zoonotic disease primarily occurring in Africa. Since RVF-like disease was reported in Tanzania in 1930, outbreaks of the disease have been reported mainly from the eastern ecosystem of the Great Rift Valley. This cross-sectional study was carried out to describe the variation in RVF virus (RVFV) seropositivity in domestic ruminants between selected villages in the eastern and western Rift Valley ecosystems in Tanzania, and identify potential risk factors. Three study villages were purposively selected from each of the two Rift Valley ecosystems. Serum samples from randomly selected domestic ruminants (n = 1,435) were tested for the presence of specific immunoglobulin G (IgG) and M (IgM), using RVF enzyme-linked immunosorbent assay methods. Mixed effects logistic regression modelling was used to investigate the association between potential risk factors and RVFV seropositivity. The overall RVFV seroprevalence (n = 1,435) in domestic ruminants was 25.8% and species specific seroprevalence was 29.7%, 27.7% and 22.0% in sheep (n = 148), cattle (n = 756) and goats (n = 531), respectively. The odds of seropositivity were significantly higher in animals sampled from the villages in the eastern than those in the western Rift Valley ecosystem (OR = 1.88, CI: 1.41, 2.51; p<0.001), in animals sampled from villages with soils of good than those with soils of poor water holding capacity (OR = 1.97; 95% CI: 1.58, 3.02; p< 0.001), and in animals which had been introduced than in animals born within the herd (OR = 5.08, CI: 2.74, 9.44; p< 0.001). Compared with animals aged 1-2 years, those aged 3 and 4-5 years had 3.40 (CI: 2.49, 4.64; p< 0.001) and 3.31 (CI: 2.27, 4.82, p< 0.001) times the odds of seropositivity. The findings confirm exposure to RVFV in all the study villages, but with a higher prevalence in the study villages from the eastern Rift Valley ecosystem

Cryptic Eimeria genotypes are common across the southern but not northern hemisphere

The phylum Apicomplexa includes parasites of medical, zoonotic and veterinary significance. Understanding the global distribution and genetic diversity of these protozoa is of fundamental importance for efficient, robust and long-lasting methods of control. Eimeria spp. cause intestinal coccidiosis in all major livestock animals and are the most important parasites of domestic chickens in terms of both economic impact and animal welfare. Despite having significant negative impacts on the efficiency of food production, many fundamental questions relating to the global distribution and genetic variation of Eimeria spp. remain largely unanswered. Here, we provide the broadest map yet of Eimeria occurrence for domestic chickens, confirming that all the known species (Eimeria acervulina, Eimeria brunetti, Eimeria maxima, Eimeria mitis, Eimeria necatrix, Eimeria praecox, Eimeria tenella) are present in all six continents where chickens are found (including 21 countries). Analysis of 248 internal transcribed spacer sequences derived from 17 countries provided evidence of possible allopatric diversity for species such as E. tenella (FST values ⩽0.34) but not E. acervulina and E. mitis, and highlighted a trend towards widespread genetic variance. We found that three genetic variants described previously only in Australia and southern Africa (operational taxonomic units x, y and z) have a wide distribution across the southern, but not the northern hemisphere. While the drivers for such a polarised distribution of these operational taxonomic unit genotypes remains unclear, the occurrence of genetically variant Eimeria may pose a risk to food security and animal welfare in Europe and North America should these parasites spread to the northern hemisphere