Zoonoses are diseases of animals that can be transmitted to people. Examples include anthrax, bovine tuberculosis, brucellosis, fascioliasis, hydatid disease and rabies. Collectively they are significant causes of sickness and death in humans, particularly in poor communities, but very little funding is devoted to research or control programmes that focus on zoonotic diseases. Most infections are undiagnosed.

Explosive human population growth and environmental changes have resulted in increased numbers of people living in close contact with wild and domestic animals and there is growing concern that such people face a high risk of zoonoses.

An article in PLoS Medicine describes a pilot project conducted in Tanzania to test the feasibility of a new approach to “reducing risks of infectious diseases at the animal–human–ecosystems interface”. Details of this approach, known as One Health, are available in a UN document published earlier this year. Essentially One Health involves integrated and multidisciplinary interventions that address multiple and interacting causes of poor human health, including unsafe and scarce water, lack of sanitation, food insecurity, and close proximity between animals and humans.

Tanzania’s Health for Animals and Livelihood Improvement (HALI) project was launched in 2006 to test the feasibility of the approach in a rural area notable for the abundance and diversity of its wildlife. Activities included: testing of wildlife, livestock, and their water sources for zoonotic pathogens and disease; environmental monitoring of water quality, availability, and use; assessing wildlife population health and demography; evaluating livestock and human disease impacts on livelihoods of pastoralist households; examining land and water use impacts on daily workloads and village economies; introducing new diagnostic techniques for disease detection; training people of all education levels about zoonotic diseases; and developing new health and environmental policy interventions to mitigate the impacts of zoonotic diseases.

The authors of the article identify three lessons that can be learned from the progress of HALI so far:
- First, it is crucial to recognize that zoonotic pathogens are present and emerging in rural communities and that their emergence is spatially and temporally variable within. Nevertheless, most people living in high-risk areas are not aware of the danger or what can be done to reduce it.
- Second, the role of water in disease transmission and zoonosis emergence requires particular attention and more research is called for.
- Thirdly, effective surveillance, assessments, and interventions are possible only by bridging the organizational gaps among institutions studying and managing wildlife, livestock, water, and public health.