George Warimwe: Rift Valley Fever
In both livestock and humans, Rift Valley Fever is caused by a virus that was first isolated in Kenya in 1930, but has since spread throughout Africa and parts of the Middle East. There are fears that it might spread to Europe as the mosquitoes which transmit the disease are widespread. Although it mainly affects livestock, it can also cause infection in humans.
Q: What is Rift Valley Fever?
GW: Rift Valley Fever is a disease of livestock. It is transmitted by mosquitoes and caused by a virus called the Rift Valley Fever virus. It primarily infects sheep, goats and cattle, although the disease also affects humans so it is a zoonosis. In sheep, which is the species that bears the brunt of the disease, you get very high mortalities in young lambs, and in pregnant sheep you get abortions - which are a hallmark of the disease. In humans you get a febrile illness that tends to resemble flu, although a proportion of individuals do get severe complications such as blindness or even death.
Q: Is it widespread and do we have a vaccine?
GW: The virus was originally isolated in Kenya in 1930 and since then there has been a spread of the disease throughout much of Africa and much of Africa now actually has the disease, so it is endemic in Africa. Although in the last decade the disease has popped up in part of the Middle East and there are growing concerns that the virus will spread to Europe and other parts of the world, particularly because the mosquitoes that transmit the virus are widespread globally. So that is of course a worry. But we do not have a vaccine, which again adds to the worry and that is why there are many programmes trying to develop a vaccine against Rift Valley Fever.
Q: Can you tell us about your work with the International Livestock Research Institute?
GW: The International Livestock Research Institute, which I will call ILRI, is a Centre of Excellence in Africa. They develop disease control interventions against diseases most prevalent in Africa, for instance East Coast Fever and Rift Valley Fever. It is one of very few Institutes in Africa that actually have that capacity and expertise of livestock vaccine development. So building on that experience and together with the experience here at the Jenner Institute, I am going to exploit the synergies between the livestock vaccine development and human vaccine development which is done here at the Jenner Institute to develop a vaccine against Rift Valley Fever which might be useful for both livestock and humans.
Q: What are the most important lines of research that have developed over the past five to ten years?
GW: Over the last decade there has been a lot of information coming through about the biology of the virus, and this has been very useful in terms of working out what are the best targets for a vaccine, or any other intervention. The other development has been in a better understanding of the epidemiology of the disease so now we know more about the risk factors that leads to Rift Valley Fever. One of the really stand out points has been that because Rift Valley Fever tends to occur as outbreaks that are preceded by unusually heavy rainfall, there has been development of models that can predict when Rift Valley Fever will occur, just based on precipitation. So that is really useful as a tool that can be used together with vaccination programmes and other disease control strategies.
Q: Why does your line of research matter, why should we put money into it?
GW: Rift Valley Fever, like a disease such as malaria, is a disease that disproportionally affects people in Africa, and in this case farmers. It restricts trade because there are trade barriers if the country has got Rift Valley Fever endemic. It also has an impact on human health.
Q: How does your research fit into translation medicine within the department?
GW: A strategic objective of the Jenner Institute is to prioritise vaccine development for pathogens that are widespread and most prevalent in Africa, and this includes things like malaria, HIV, TB, and Rift Valley Fever is one that fits such a profile. The ultimate aim of my work is to develop a vaccine that can be used for humans; however because the virus that causes human Rift Valley Fever is the same that causes the disease in sheep and other livestock, a vaccine for human use would also be useful potentially for livestock - which we think is really very translational.
This interview was recorded in March 2012.