Temporal fluctuations in the sero-prevalence of <i>Taenia solium</i> cysticercosis in pigs in Mbeya Region, Tanzania

BACKGROUND: Porcine cysticercosis is an emerging agricultural problem in sub-Saharan Africa. This has been documented primarily through cross-sectional studies, however detailed knowledge of the transmission dynamics of this disease in sub-Saharan Africa is lacking. This study aims to describe seasonal variations in sero-prevalence of antigen ELISA positive porcine cysticercosis in an endemic area. METHODS: A longitudinal study composed of three cross-sectional surveys was carried out in Mbeya Region, Tanzania; the first two six months apart (March/April 2012 and October/November 2012) and the last eight months later (July/August 2013). Venous blood was collected from pigs in 22 villages and analysed using Ag-ELISA. RESULTS: In each survey between 800–1000 serum samples were collected. The first survey revealed a cysticercosis sero-prevalence of 15% (n = 822, 95% CI: 13-18%). The sero-prevalence had significantly increased to 24% (p < 0.001, χ2-test, n = 812, 95% CI: 21-27%) at the time of the 6 month follow-up. At 14-months the sero-prevalence had dropped to 20% (p = 0.053, χ2-test, n = 998, 95% CI: 18-23%). Overall, this was a reduction in sero-prevalence compared with a study conducted in 2007 in the same area, where 31% (186/600) of pigs were found positive. CONCLUSION: Confined pigs did not have a lower sero-prevalence compared to free roaming pigs in any of the three surveys. Several factors may have contributed to the observed fluctuations such as African swine fever or seasonal variation in local crop production practices. Also, as the Ag-ELISA assay used is not species specific, variation in transmission of Taenia hydatigena could potentially influence the results. The observed fluctuations contradict a theoretical model which predicts a stable equilibrium, which only considers a two-compartment (pig and human) model excluding the effect of the environment. Whether the disease has an endemic equilibrium, or undergoes fluctuations dependent on extrinsic and/or socio-economic factors remains to be elucidated

Smallholder Pig Marketing Systems in the Southern Highlands of Tanzania

A study using two cross-sectional and a longitudinal research designs was undertaken to assess smallholder pig marketing system to explore basic information for  improving smallholder pig production and marketing systems. The first design involved a cross-sectional survey of 300 pig farmers randomly selected in 30 villages in Mbozi and Mbeya rural districts. The second design used a cross-sectional survey of 124 pig traders randomly selected in 65 villages in Mbozi and Mbeya rural districts, and Mbeya Municipality. The third one used a longitudinal design and collected data from 40 pig farmers in 10 villages who had also participated in the first design. Results showed that, pig-marketing systems had various channels and segments moving mainly pigs and pork to farmers, traders and consumers.  Major market participants in the pig market chain were the pig farmers who played a dual role as pig producers and buyers, traders of live pigs and pork, and finally pork consumers. Most farmers (85%) bought pigs for breeding, while few (18%), bought for fattening. The mean (±SD) weight and age of pigs purchased was 18.2±12.6 kg and 6.2 ±4.7 months, respectively. Farmers sold about 70 and 30% of their pigs to pig traders and other farmers, respectively.  Pigs sold to farmers had significantly (P&lt; 0.001) lower mean age (6.1±1.5 months) and live weight (LW) (14.3± 3.6 kg) than pigs sold to traders with a mean age of 12.8± 1.5 months and LW of 40.0± 3.6kg. The study concludes that marketing systems were dominated by informal marketing channels, hence, limit the effectiveness of pig production and marketing. Marketed pigs had smaller weights compared to their ages, therefore contributing to poor returns to pig farmers and sub-optimal pork market supply. The study recommends strategic development of pig value chain for sustainable improvement of smallholder pig production and marketing systems and quality pork to consumers. Keywords: Smallholders farmers, pigs, marketing channels, price determinant

Bridging gender gaps with dairy goats and root crops

Aiming to boost household food security and nutrition in resource-constrained, semi-arid areas of Tanzania, a system of integrating dairy goats (Toggenburg and Norwegian breeds) with production of cassava and sweet potato is being studied. Women in agro-pastoral societies in Tanzania typically have low incomes, limited access to resources and are of poor nutritional status. The project methodology addresses gender roles, access, control and ownership of resources, and decision-making among smallholders. It provides a model for establishing dairy goat enterprises in semi-arid areas and has created new hope in test communities, helping alleviate low agricultural productivity and malnutrition

Taenia solium taeniosis and cysticercosis literature in Tanzania provides research evidence justification for control:A systematic scoping review

Background Despite Taenia solium taeniosis/cysticercosis (TSTC) having been put high on the global agenda of neglected tropical diseases (NTDs), which over the last years has received a lot of attention, there has been no control programmes in place in sub-Saharan Africa, a highly endemic region. This could be attributed to lack of awareness of many stakeholders on the burden and impact of T. solium. This information is essential in guiding TSTC policies, practices and research agendas as well as encouraging cross-sectoral collaboration in the control of this important zoonotic parasite using a One Health approach. National elimination of the parasite is the foundation for global eradication. This will require that substantial country-level information is provided to all key stakeholders. We have mapped out TSTC research evidence in Tanzania to inform on disease burden and potential for integrated control measures. Methodology/Principal findings A scoping review of all TSTC studies undertaken in Tanzania and published up to December 2018 was conducted. The articles were searched from PUBMED, AJOL, Google Scholar and Google in general. Fifty-one (51) articles met the inclusion criteria and were reviewed. Prevalence of taeniosis of 2.3% - 5.2% was estimated based on copro-antigen ELISA while human cysticercosis of >16% was estimated based on serum antigen ELISA (Ag-ELISA) or IgG Western Blot. Neurocysticercosis (NCC) contributed significantly to epilepsy in adults. Farm prevalence of porcine cysticercosis were 6.0% - 17.4% (lingual examination) and 1.5% - 33.3% (Ag-ELISA). Slaughter-slab prevalence were 0% - 18.2% (routine meat inspection). Lacking latrines, watering pigs with river or pond water, and feeding pigs with potato peels were associated with porcine cysticercosis prevalence. Washing hands by dipping method increased the risk of human cysticercosis. In 2012, the number of DALYs/1000 person-years for NCC-associated epilepsy was 0.7 (95% UI, 0.2–1.6), around 5 million USD (95% UI, 797,535–16,933,477) were spent due to NCC-associated epilepsy and nearly 3 million USD (95% UI, 1,095,960–5,366,038) were potentially lost due to porcine cysticercosis. Three rounds of annual treatment of school-age children with praziquantel significantly reduced prevalence of taeniosis and porcine cysticercosis. Health education was efficacious in improving knowledge and attitudes favourable for control of TSTC while a single dose of oxfendazole 30 mg/kg body weight was efficacious in eliminating T. solium cysticerci from pig musculature. Conclusions/Significance The observed high burden of TSTC and the significant contribution of NCC to epilepsy in Tanzania warrant urgent interventions. Evaluation of best control options should make use of disease transmission dynamics models such as cystiSim, taking into account findings from the field based intervention studies. In addition, locally adapted management guidelines for people suffering from NCC are urgently needed