Villagers watch on as a team restrains a small pig for blood sampling in Luang Prabang, Laos (photo credit: ILRI/Kate Blaszak).
Delia Grace, an Irish veterinary epidemiologist and public health expert at the International Livestock Research Institute (ILRI), says shifts in forest cover, agricultural practices, mining and reservoirs are thought to be affecting the transmission of diseases from animals to humans.
In an opinion piece running in The Guardian‘s Poverty Matters Blog, Grace says that ‘animals in Africa, both wild and domesticated, sustain livelihoods and promote wellbeing. They provide nutrition, labour, trade and currency, and bring millions of tourist dollars into the continent every year.
‘Yet, increasingly, they also bring disease. Since 1940, more than 60% of infectious diseases newly affecting people in Africa have been transmitted via animals. But even more important are the “classical” zoonoses such as bovine TB or pig tapeworm. Recent research shows that, globally, the top 13 zoonotic diseases are responsible for 2.2 million human deaths every year. The vast majority of these deaths are in low- and middle-income countries, where they often affect disenfranchised communities.
Even when these diseases do not kill, their effects devastate poor people’s lives and hamper development efforts. Such diseases have the potential to cross countries and continents with alarming speed—witness the spread of Sars and avian flu in recent years.
‘A handful of high-profile zoonotic diseases such as avian flu attract vast amounts of research money. But there is a large and growing number that are poorly understood and in which there has been much less investment in research or control. Zoonoses fall between the medical and veterinary sectors and are among the most underdiagnosed diseases.
‘. . . [E]nvironmental changes are thought to be affecting the emergence and spread of new infectious diseases in people. Climate change, urbanisation, forest clearance and many of the other rapid environmental shifts large parts of Africa are undergoing are also thought to be playing their part in the changing dynamics of disease transmission. Unless these dynamics are better understood, public health efforts aimed at curbing disease spread can only ever be partial.
. . . [I]t is time for some joined-up thinking on disease.
‘The process of untangling the complex links between ecosystems, health and poverty is an essential start to a more integrated and so more effective approach to disease control, and an altogether healthier future for many millions of Africans and their animals.’
Delia Grace is a partner with the Dynamic Drivers of Disease in Africa Consortium.
Read the whole opinion piece in The Guardian‘s Poverty Matters Blog: Are environmental changes spreading Rift Valley and Lassa fevers?, 23 Jul 2012.
Read an ILRI news release on a new study by Grace: New ILRI study maps hotspots of human-animal infectious diseases and emerging disease outbreaks, 5 Jul 2012.