Sustainable interventions for an emerging livestock disease problem in Tanzania

This project has been developed in response to concerns of livestock-keeping communities who have reported major mortality losses in sheep and goats due to an emerging disease problem, known locally as Ormilo. Our preliminary studies support a growing consensus that Ormilo is the disease cerebral coenurosis, a fatal, neurological disease of sheep and goats caused by a tapeworm infection (Taenia multiceps). Sheep and goats are infected by ingesting the parasite eggs shed in the faeces of dogs (the definitive host), with clinical disease occurring when the parasite larvae migrate to the brain and form cysts. Dogs are in turn infected when they consume the brains of affected sheep and goats.

Current levels of coenurosis appear to be unprecedented and a cause of major concern among the poorest livestock-keeping families, particularly pastoralists who are increasingly dependent on sheep and goats for livelihoods and food security. Ormilo is now ranked as the highest priority disease in most pastoral communities of northern Tanzania. Several factors may be contributing to the current upsurge in cases including a shift to keeping of small ruminants in preference to cattle, a rapid increase in dog populations, and the practice of livestock-owners of feeding dogs the brains of affected animals.

This project aims to develop simple, sustainable interventions that can be adopted easily by livestock-keepers and dog-owners to prevent infection and reduce the burden of disease. The project will focus on two interventions: (a) developing and disseminating culturally-approrpriate information to livestock-keepers on the life cycle of the parasite, and the importance of not feeding brain tissue to dogs (with burning a simple alternative); (b) anthelminthic treatment of dogs with praziquantel every three months. An important additional benefit of de-worming dogs would be the effective control of Echinococcus granulosus, the cause of human hydatid disease (cystic echinococcus), a potentially fatal disease which is known to be an important but neglected human health problem in pastoral communities of East Africa. With a similar life-cycle involving dogs and small ruminants, hydatid disease may also be increasing, but cases will not become apparent for several years. An effective intervention in dogs at this stage could avert a major future human health problem.

The final output of the proposed project will be a business development plan, which charts a subsequent course of remedial Ormilo intervention. The plan will depend to a large extent on whether Ormilo is a localised or widespread/regional animal health issue and the willingness of farmers to pay for praziquantel treatment of dogs. Market research to better understand the scale of the Ormilo problem and demand for interventions will involve analysis of detailed Ormilo prevalence data being generated through other on-going studies, household econometric and wilingness-to-pay studies, as well as stakeholder workshops. Further work will involve development of materials for dissemination to livestock-keeping communities and training courses for NGOs and animal health professions. By working with project partners with experience of developing solutions for livestock interventions (GALVmed), we will explore both NGO-based delivery strategies and market-led approaches through which animal health supply chains could be developed for delivery of praziquantel to a large population of livestock-keepers, potentially extending to countries in the East African region (eg. Kenya and Ethiopia).