Ethiopia and Tanzania 'hotspots' for animal diseases killing humans

Kenyan scientists from ILRI have released a new global study mapping the diseases humans get from animals, which presents a ‘top 20′ list of geographical hotspots, including both Ethiopia and Tanzania, and highlighting the danger of human disease from transboundary livestock trading and poor farm management.

The study, dubbed Mapping of Poverty and Likely Zoonoses Hotspots,was conducted by the International Livestock Research Institute (ILRI), the Institute of Zoology (UK) and the Hanoi School of Public Health in Vietnam.

From cyst-causing tapeworms to avian flu, zoonoses, which are diseases transmitted from animals to humans, present a major threat to human and animal health according to Delia Grace, a veterinary epidemiologist and food safety expert with ILRI in Kenya and lead author of the study. “Targeting the diseases in the hardest hit countries is crucial to protecting global health as well as to reducing severe levels of poverty and illness among the world’s one billion poor livestock keepers.”

“Exploding global demand for livestock products is likely to fuel the spread of a wide range of human-animal infectious diseases,” Grace added.

According to the study, Ethiopia, Nigeria, and Tanzania in Africa, as well as India in Asia, have the highest zoonotic disease burdens, with widespread illness and death.

Meanwhile, the northeastern United States, Western Europe (especially the United Kingdom), Brazil and parts of Southeast Asia may be hotspots of ‘emerging zoonoses’—those that are newly infecting humans, are newly virulent, or have newly become drug resistant.

The researchers initially reviewed 56 zoonoses that together are responsible for around 2.5 billion cases of human illness and 2.7 million human deaths per year. A more detailed study was made of the 13 zoonoses identified as most important, based on analysis of 1,000 surveys covering more than 10 million people, 6 million animals and 6,000 food or environment samples.

The analysis found high levels of infection with these zoonoses among livestock in poor countries. For example, 27 per cent of livestock in developing countries showed signs of current or past infection with bacterial food-borne disease—a source of food contamination and widespread illness. The researchers attribute at least one-third of global diarrheal disease to zoonotic causes, and find this disease to be the biggest zoonotic threat to public health.

Among the high-priority zoonoses studied were ‘endemic zoonoses’, such as brucellosis, which cause the vast majority of illness and death in poor countries; ‘epidemic zoonoses’, which typically occur as outbreaks, such as anthrax and Rift Valley fever; and the relatively rare ‘emerging zoonoses’, such as bird flu. While zoonoses can be transmitted to people by either wild or domesticated animals, most human infections are acquired from the world’s 24 billion livestock, including pigs, poultry, cattle, goats, sheep and camels.

Currently, nearly three-quarters of Kenyan rural families and many others in urban areas depend on livestock for their food, income, traction, manure, or other services. However, despite the danger of zoonoses, the growing global demand for meat and milk products is a big opportunity for the livestock keepers.

According to Steve Staal deputy director general-research at ILRI, this increased demand will continue over the coming decades, driven by rising populations and incomes, urbanization and changing diets in emerging economies, and greater access to global and regional meat markets. This “could move millions of poor livestock keepers out of poverty if they can effectively participate in meeting that rising demand”.

But zoonoses present a major obstacle to such returns. The study estimates, for example, that about one in eight livestock in poor countries are affected by brucellosis, or what is commonly known as lung plague, which reduces milk and meat production in cattle by around 8 per cent.

Written by Bob Koigi for African Laughter

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