/ 13 August 2008

Tackling rabies in Africa

Pretoria-born Dr Wanda Markotter’s research takes her to some of the remotest corners of the continent to sample bat species and study their viruses to update veterinarian workers on the diagnosis of rabies in the region.

With rabies and rabies-related viruses in Africa as the focus of her research, she has a special interest in rabies-related viruses found in African bat species.

Markotter is a lecturer at the University of Pretoria and a member of the lyssavirus research group.

Markotter says rabies remains a fatal disease with little or no chance of survival after symptoms appear, but if post-exposure prophylaxis is administered directly after exposure to a potentially rabid animal the disease can be prevented.

In Africa different viruses can cause rabies. The first is a virus that most often occurs in dogs. The others are the Mokola virus, the Lagos bat virus and the Duvenhage virus and they are known as the rabies-related viruses.

As Markotter and her research group intensify their surveillance of African bats, they are finding increasing numbers of viruses associated with bat species. Insectivorous bats and fruit-eating bats may carry different genotypes or variants of rabies-related viruses, which are related to but distinct from rabies.

In her thesis entitled Molecular epidemiology and pathogenesis of Lagos bat virus, a rabies-related virus specific to Africa, she presents a comprehensive analysis of a group of viruses that are related to but distinct from the better known rabies virus.

The thesis shows that the incidence of the Lagos bat virus has been underestimated and that new virus isolates are regularly discovered in South Africa in bat species. “As a spillover may occur from bats to dogs, cats or even to mongoose, killing the animals in the process, there is a risk that it can be fatal for humans too,” she says.

It is estimated that annually 24 000 people die of rabies in Africa, but the true impact is unknown owing to the absence of proper diagnostics. It has been shown that if the disease in animals is controlled by vaccination, the number of human cases will decrease.