Are environmental changes spreading Rift Valley and Lassa fevers?

Delia Grace in the povertymatters blog at the Guardian (UK):  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.

Although mapping work is adding to our knowledge of which zoonotic diseases are affecting whom and where this is happening, there remains little understanding of how their spread is affected by shifting environmental factors. There is strong evidence emerging, though, that such links do exist....

The Rift Valley Fever virus