Rabies experts on Thursday unveiled a blueprint for eliminating the pernicious disease, which almost always is caused by bites from rabid dogs and kills tens of thousands of people a year worldwide, through a program of mass dog vaccinations in targeted regions.
The viral disease is rare in developed countries thanks to routine vaccination of pet dogs, but still kills about 69,000 people globally every year, mostly in poor and rural parts of Africa and Asia. About a third of rabies-related deaths are in India alone.
Vaccines for people and dogs have long existed, but rabies has persisted in the absence of a concerted effort to wipe it out. The international team of experts, writing in the journal Science, proposed what they called a cost-effective and achievable strategy for ending canine-spread rabies.
Efforts in Latin America and pilot projects in Africa and Southeast Asia have shown that mass dog vaccination programs can prevent human rabies in low-income countries as well as wealthy ones, they said. Vaccinating 70 percent of dogs in a given region is the threshold for halting rabies, they noted.
"There is now convincing evidence that vaccination of dogs would eliminate greater than 98 percent of the rabies health burden globally," said Guy Palmer, director of Washington State University's Paul G. Allen School for Global Animal Health.
"Rabies is an ancient plague. Descriptions of human suffering and death can be seen since the earliest times of recorded history. Even today, rabies is the most consistently fatal infectious disease of humans," added Palmer, noting that virtually every person who develops symptoms dies.
Felix Lankester, director of the Serengeti Health Initiative that conducts dog vaccination campaigns in rural villages around Tanzania's Serengeti National Park, said the primary focus of the international effort would be mass dog vaccination in countries where rabies is endemic.
Multiple small- to medium-sized areas would be targeted to create disease-free zones, then the size of those zones would be increased and the various zones would coalesce into a bigger disease-free region, Lankester said.
A coordinated global effort would cost hundreds of millions of dollars and perhaps several billions, Lankester estimated, and would need international health agencies, charities, governments of rabies-endemic countries and others on board.
"We know how and we have the ammunition to do it," Lankester said. "I am optimistic that it can be done. Whether the necessary political will and funding will be harnessed is another matter."
Rabies remains a threat to half the world's people and about 40 percent of victims are children, the experts said.
The virus, present in an infected animal's saliva, is transmitted to people through a deep bite. It is one of the few diseases in which a person can be protected by a vaccine after being exposed.
Its incubation period is usually one to three months. As the virus spreads through the central nervous system, fatal inflammation of the brain and spinal cord occurs.