Foot and mouth disease in sub-Saharan Africa moves over short distances, wild buffalo are a problem

New research shows that in sub-Saharan Africa the virus responsible for foot and mouth disease (FMD) moves over relatively short distances and the African buffalo are important natural reservoirs for the infection. The study, published in mBio, the online open-access journal of the American Society for Microbiology, sheds light on how the type of FMD virus called SAT 2 emerged in sub-Saharan Africa and identifies patterns of spread in countries where SAT 2 is endemic.

"The data suggest that the common ancestor of all SAT 2 was in [African] buffalo. It's very clear that historically infections have moved from buffalo to cattle," says corresponding author Matthew Hall of the University of Edinburgh in Scotland.

Foot and mouth disease (FMD) is devastating to livestock all over the world, but it's a particular problem in Africa, where wildlife that harbor the virus are thought to pass it on to their domesticated cousins.

FMD strikes cloven-hoofed animals, presenting as a high fever, blistering in the mouth and feet, decline in milk production in females, and weight loss. Although most animals recover over the course of months, some die of complications from the disease. In wild buffalo, the disease is very rarely symptomatic and animals can be persistently infected for a period of several years. The SAT 2 serotype of the virus is endemic in sub-Saharan Africa, but it has crossed the Sahara and caused outbreaks in North Africa and the Middle East between 1990 and 2012.

In the hopes they could eventually predict future outbreaks, Hall and his colleagues wanted a better picture of the diversity of SAT 2 in sub-Saharan Africa and how they move around from one location to another. They used 250 genetic sequences of the VP1 section of the genome from SAT 2 isolates taken from all over sub-Saharan Africa and tracked the appearance of the various unique 'topotypes' over the region.

Hall says the patterns in which the topotypes appear in different places gives strong support to the idea that the virus is spread by infected hosts in land movements over relatively short distances. What's more, African buffalo are an important "maintenance host", meaning they maintain a reservoir of the virus that can re-infect domesticated animals after time and culling has ended an outbreak among livestock. The relationships between the 250 sequences also indicate that it's possible the original source of the SAT 2 viruses that are now found in wild and was African buffalo.

To Hall, these results indicate that genetic tracking of viruses has a lot of potential for making inferences about viral spread and heading off future outbreaks.

"We showed that we can demonstrate [ movement] using genetic data. It's a tool that can be used for that kind of inference. In cases where less is known, this is a valid way of going about answering the questions," says Hall.

Going forward, Hall says he plans to apply a similar approach to studying serotype O FMD viruses in Africa, Asia, and South America to identify links between different animal populations. "It's good to know the reason it spreads," says Hall. "It could be quite a contribution to eradication or control efforts."

add to favorites email to friend print save as pdf

Related Stories

No need to battle with cattle

May 31, 2013

A new study by the Wildlife Conservation Society's Animal & Human Health for the Environment And Development (AHEAD) Program, World Wildlife Fund (WWF), and regional partners finds that a new approach to ...

Recommended for you

Two expats die of MERS in Saudi commercial hub

Apr 20, 2014

Two foreigners died of MERS in the Saudi city of Jeddah, the health ministry said Saturday, as fears rise over the spreading respiratory virus in the kingdom's commercial hub.

UAE reports 12 new cases of MERS

Apr 20, 2014

Health authorities in the United Arab Emirates have announced 12 new cases of infection by the MERS coronavirus, but insisted the patients would be cured within two weeks.

Filipino tests negative for Middle East virus

Apr 19, 2014

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

User comments