Every year, 55,000 people, or about one person every 10 minutes, die due to rabies, even though such deaths are preventable. Like many diseases, rabies’ mortality burden falls disproportionately on the developing world, where a lack of infrastructure, awareness and access to health services and treatments means that a vaccine-preventable disease continues to pose a serious threat.

While rabies is no longer a considerable public health threat in the United States and other developed nations, it is being described as a re-emerging disease in other parts of the world, with researchers acknowledging that its death toll is probably much higher than today’s accepted estimates. Rabies is found in carnivores and bats, and is transmitted to humans through close contact with an infected animal’s saliva. Without immediate post-exposure treatment, rabies is fatal once its symptoms begin to arise.

"It’s one of the oldest diseases with one of the oldest vaccines that can prevent it, and yet it’s still killing people," said Sergio Recuenco, MD, an epidemiologist with the Centers for Disease Control and Prevention’s Rabies Team. "That means we’re not reaching people and that’s really unacceptable."

A worker vaccinates a dog against rabies in Jordan as part of World Rabies Day activities held around the globe in 2007. Photo courtesy Society for the Protection of Animals Abroad

CDC’s Recuenco, who focuses his work mainly in Latin American countries, said the human rabies burden is probably much higher than current estimates, pointing to developing nations’ poor public health reporting and surveillance systems as well as the high potential to misdiagnose human rabies, such as in countries where malaria is endemic. Recuenco described rabies as a re-emerging global health threat, stating that the virus is changing faster than officials might realize. With six new rabies strains discovered in the last five years, Recuenco stressed that new reservoirs of rabies viruses must be recognized and researchers must continually look for new strains, noting that the "speed of discovery indicates that the virus might be evolving more rapidly than we expected."

"However, elimination is possible; the problem is how to reach that point," Recuenco told The Nation’s Health. "At this point, it’s about vaccination plus education. Vaccinating dogs is probably the most effective way to counter rabies in (developing nations)."

Increasing canine vaccination rates is one of the many goals of World Rabies Day, which took place Sept. 28. First launched in 2007, the day had an initial goal of engaging 55,000 people in rabies awareness activities — one person for every recorded rabies death, said Peter Costa, MPH, global communications coordinator for the Global Alliance for Rabies Control, which created the annual observance. Hoping to bring all the major stakeholders together to raise awareness about the "neglected disease," Costa said organizers were surprised at the initial response: during the first World Rabies Day, more than 400,000 people in 74 countries participated in events, and in 2007, 85 countries reported hosting World Rabies Day activities, from media campaigns to canine vaccination clinics. The response is a "clear indicator that people are hungry for this information," Costa said.

"Incredibly, despite all the new emerging diseases that we hear about, rabies still has the highest mortality rate, even though there’s no reason anybody should die from rabies," Costa told The Nation’s Health.

Residents line up for animal vaccinations at a rabies immunization clinic in Serengeti, Tanzania, in 2008. Photo courtesy Tendeka Maiaiu/Suzanne McNabb

Not surprisingly, the affordability and accessibility of rabies vaccines play a significant role in its control, though health workers stress that thoroughly washing a wound immediately after being bitten can reduce a person’s rabies risk. Last year, a global shortage in rabies vaccine led to restrictions on who could receive the vaccine, with U.S. public health officials limiting the vaccine’s use to those at highest risk for rabies exposure. With vaccine production on the mend, CDC lifted such limitations this summer; however, the vaccine remains out of reach for many in the developing world, Costa said.

For people living in rural areas, the nearest health clinic can be a two-day trip — a problem compounded by the fact that the rabies vaccine is given in multiple doses over many weeks, he said. Beyond vaccines, effective rabies control is difficult because it relies heavily on widespread community and government involvement. In CDC’s Emerging Infectious Diseases journal in August, researchers described rabies as a re-emerging disease in China, listing the many familiar community, policy and treatment factors contributing to the situation: undocumented rabies transmission from wildlife to dogs, counterfeit vaccines, low vaccination coverage of dogs, poor diagnostic confirmation of human rabies and poor surveillance of animal rabies.

"In the United States, we’ve done a tremendous job vaccinating our animals and controlling rabies in wildlife," Costa said. "These efforts can be duplicated in other countries…and public health workers are the foundation for spreading the word and raising awareness."

In 2007, CDC declared that canine-strain rabies had been eliminated in the United States, though U.S. residents and domestic pets still face risks from wildlife rabies as well as the movement of infected animals across U.S. borders. Today, most rabies cases reported to CDC occur in wildlife, with wild carnivores and bats serving as the principal hosts. In Florida, immunizing wild animals such as raccoons using oral rabies vaccine baits has garnered success, though such wildlife efforts can be expensive and difficult, said public health veterinarian and APHA member Lisa Conti, DVM, MPH, director of the Florida Department of Health’s Division of Environmental Health.

A rabies vaccination is administered in 2008 in Ghana. Photo courtesy David Nyoagbe

"Rabies is a classic one-health issue, where controlling the disease in domestic animals has greatly reduced the cases in people, though we still have a ways to go on the wildlife issue," she said. "This is an ancient disease and we still have a lot of work to do."

For more information on rabies, visit www.worldrabiesday.org or www.who.int/rabies.  

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