Published online 2 December 2009 | Nature | doi:10.1038/news.2009.1120

News

Deadliest animal disease on the brink of eradication

Rinderpest will be only the second disease to be wiped out.

cowRinderpest: a killer disease now vanquished.FAO/F. Paladini

Rinderpest, the world's most devastating cattle disease, will be declared eradicated within 18 months, according to world health bodies.

The effort will make it only the second disease to be wiped from the globe — the first was smallpox, eradicated in 1980.

"Rinderpest tops the list of killer diseases [in animals]," says Juan Lubroth, chief veterinary officer for the Food and Agricultural Organization of the United Nations (FAO) in Rome. It not only kills cattle and other wildlife, it also causes famines when people in developing countries lose the beasts they need to plough their fields, he adds.

Eradication of the disease would be a "massive achievement for the veterinary community", says Chris Oura, head of the Non-Vesicular Disease Reference Laboratory Group at the Institute for Animal Health in Pirbright, UK.

Rinderpest, otherwise known as cattle plague, has killed many millions of cattle and other wildlife around the world since it first spread from Asia to Europe in the herds of the invading tribes, causing outbreaks during the Roman Empire in 376-386. Since then, the disease has spread throughout Europe and on to Africa, the Middle East and the Indian sub-continent. Outbreaks in Nigeria during the 1980s cost around $2 billion, according to the FAO.

The disease is caused by a virus called a morbillivirus — a group that also includes the measles virus. Clinical signs include fever, discharges from the eyes and nose, diarrhoea and dehydration and the disease kills 80-90% of infected cattle in just 7-10 days. The last outbreak in Asia was in 2000 and the last known cases of the disease were in Kenya in 2001.

Surveillance challenge

The FAO and the World Organisation for Animal Health (OIE), based in Paris, headed up an international effort to eradicate the disease, which began in 1994 with the launch of the Global Rinderpest Eradication Programme.

The programme's success depended on widespread vaccination programmes and long-term monitoring of cattle and wildlife. A breakthrough in controlling the disease came in the 1980's when a heat-stable vaccine was developed that contained the attenuated virus, allowing the vaccine to be stored and transported over long distances.

Oura says that the biggest scientific challenges in eradicating the virus is the large-scale monitoring and surveillance needed to ensure that the virus is gone. "It's a huge task when you have the virus in developing countries and war zones, such as Somalia, to carry out monitoring and surveillance," he says.

Although the vaccine can provide life-long protection, it has also caused some problems. Because it contains the live virus, diagnostic tests can't differentiate between infected and vaccinated animals, as both will test positive for antibodies against the virus. Cows also pass on antibodies to their offspring through their milk. To evaluate whether the virus has been eradicated, vaccinations must stop for a period of two years and calves less than two years old tested. "It is a difficult, long process to make sure nothing is there," says Oura.

ADVERTISEMENT

Lubroth says he is "confident" that the world is already free of the disease but that the FAO and the OIE expect to make an official declaration that rinderpest has been eradicated in 18 months. Bernard Vallat, director-general of the OIE, says that the hold-up is because 12 countries have not yet submitted their final test and surveillance results to the organization. He adds that over the next year and a half, the OIE will be drawing up an inventory of which governments and laboratories around the world are keeping a stock of the virus. 

Commenting is now closed.