May 01, 2010

 

 Veterinarian helped control threat of cattle plague

 
 

Late Walter Plowright instrumental in expected eradication of rinderpest

 
 posted April 18, 2010
 


British veterinarian Dr. Walter Plowright (center) became the 1999 World Food Prize Laureate for his work developing a cattle-use rinderpest vaccine, which is credited with substantially helping eradicate the disease worldwide.

Dr. Walter Plowright, the British veterinarian who developed an inexpensive vaccine that contributed to global efforts to wipe out a disease responsible for millions of cattle deaths, died Feb. 19. He was 86.

In 1999, Dr. Plowright became the first veterinarian named as a World Food Prize Laureate, an honor given because of the impact of his rinderpest vaccine. The prize is awarded to individuals for outstanding achievements that improve the quality, quantity, or availability of food.

Officials with the Food and Agri-culture Organization of the United Nations, or FAO, credit Dr. Plowright with greatly helping to eradicate rinderpest by developing the vaccine during his time in Kenya in the 1950s. The organization nominated him for the World Food Prize.

"After more than 15 years of FAO Global Rinderpest Eradication Programme (GREP), there is now growing confidence that the whole of Asia has been free from rinderpest since the year 2000," FAO information states. "The same is true for Africa with the last known outbreak recorded in 2001."

Rinderpest is expected to be eradicated worldwide this year.

Rinderpest, or cattle plague, is a serious, contagious viral disease of cattle, Asian buffaloes, yaks, swine, African buffaloes, giraffes, and lesser kudus, with infected animals typically dying about a week after developing clinical signs of the disease.

A World Food Prize Foundation biography of Dr. Plowright states: "Dr. Plowright's contributions to developing and perfecting the vaccine for rinderpest have made its eradication, for the first time in human history, a practical objective."

Dr. Plowright traveled to Kenya and Nigeria to conduct research starting in 1950, the biography states. He and colleagues developed an attenuated live virus vaccine, and field tests showed it could be safely used in all cattle without causing adverse clinical effects.

In the past decade, rinderpest eradication efforts have moved away from mass vaccination in favor of targeted vaccination of cattle reservoirs in which the virus has survived, FAO information states. Activities since the mid-2000s have focused on surveillance, and the last known vaccine use occurred in 2006.

"Rinderpest epidemics preceded the fall of the Roman empire, the conquest of Christian Europe by Charlemagne, the French revolution, and the impoverishment of Russia," FAO information states. "The resulting epidemic, which occurred when rinderpest was introduced into sub-Saharan Africa, at the end of the 19th century, weakened livestock dependent communities, caused extensive famines, and opened the way for the colonization of Africa."

Dr. Alfonso Torres, a professor and associate dean for public policy in the Cornell University College of Veterinary Medicine and a former director of the Plum Island Animal Disease Center, said rinderpest may become the first animal disease eradicated worldwide, and it would not have been possible without the vaccine Dr. Plowright developed.

"Rinderpest is probably the most serious disease to have affected cattle in history," Dr. Torres said. "It has a morbidity of 100 percent and a mortality that approaches that same number."

The disease caused such severe harm in France in the 1740s and 1750s that authorities recognized a need for trained individuals who could respond to rural outbreaks of animal disease. The country's comptroller general of finances supported a proposal by Claude Bourgelat to found the world's first veterinary school, according to the book "Virus Diseases of Food Animals."

The school was founded in Lyon in 1761.

The book also states that Africa's first veterinary school was started in 1827 in Egypt in response to a rinderpest epidemic among cattle, and the first civilian veterinary school in Asia was formed in 1872 to train Indians as veterinary inspectors and prevent the disease's spread.

Dr. Christopher Groocock worked with Dr. Plowright in the 1960s. Dr. Groocock was the officer in charge of veterinary research in northern Tanzania starting in 1962 and said the vaccine had been in use for a few years when he first arrived in Tanzania, but he heard reports and saw photographs of the disease's devastation.

"It went through Africa like wildfire at the turn of the last century," Dr. Groocock said. "I once saw photographs in South Africa of scores of animals laying dead as if someone had taken a machine gun to them."

Dr. Groocock said it was initially unclear whether the virus would survive and continue circulating in Serengeti wildlife, such as wildebeest and Cape buffalo. But the disease disappeared as long as it was controlled in the surrounding pastoral cattle population.

"If you had a good vaccine and applied it properly, it appeared you could eradicate the disease, even in countries which had somewhat restricted veterinary services, like many of those in Africa at the time," Dr. Groocock said. "But in a way, it was fortunate that rinderpest appeared to have no effective carrier state in African wildlife and that it was so easily controlled by vaccination of cattle."

Dr. Torres said training at Plum Island for federal, state, military, university, and foreign veterinarians has long included demonstrations of rinderpest to show the clinical signs and lesions.

"Last year we stopped demonstrating rinderpest, because there's no point to continue to do that when the disease is practically gone from the planet," Dr. Torres said.