Few rabies cases remain in Americas

Dog-transmitted human infections could be eliminated this year
Published on December 17, 2014
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Louise Taylor, PhD, said the effort to eliminate dog-transmitted rabies in humans in the Western Hemisphere has already saved thousands of lives.

The 30-year collaborative effort to remove such infections has been a huge success, she said, and the region’s countries could reach a Pan American Health Organization goal of eliminating dog-transmitted rabies in humans this year.

Dr. Taylor, coordinator of the Partners for Rabies Prevention expert group in the Global Alliance for Rabies Control, said the effort will have been a success even if it does not achieve the goal of eradication in 2015.

Dr. Marco Antonio Natal Vigilato, a Peru-based veterinary public health adviser for PAHO, which serves as a regional office for the World Health Organization, said human deaths in Latin America and the Caribbean declined from about 340 known cases in 1983 to 11 in 2013, even as surveillance and diagnostic testing capabilities have improved in those countries. Confirmed infections in dogs declined from about 20,000 to 400 in that same period.

By the end of 2015, he said, “We expect that the majority of the countries will reduce to very, very, very low levels of human rabies transmitted by dogs, or they won’t have any more cases of human rabies transmitted by dogs.”

This chart includes three known deaths in Haiti during 2013 but no data from Haiti in 2014. A separate World Health Organization report has stated that rabies cases in humans likely are underreported, particularly in Haiti.
Source: Dr. Marco A.N. Vigilato, Pan American Health Organization

Outside of Haiti, for which figures are not available, the region had only six known dog-transmitted infections in humans during the first 11 months of 2014—four in Bolivia and two in Guatemala—and about 200 infections in dogs, he said. He noted that those are only the reported cases, dependent on the quality of surveillance systems.

Dr. Vigilato said that Haiti has human infections but no active rabies reference laboratory. The earthquake that hit the country in 2010 wiped out much of the national infrastructure needed to perform health activities, although he noted that the PAHO is working with the U.S. Centers for Disease Control and Prevention to improve Haiti’s surveillance and diagnostics capabilities.

The 2013 report from the WHO Expert Consultation on Rabies states that rabies cases have declined, but official figures probably still underestimate circulation of canine-transmitted rabies, which the WHO estimates kills about 200 people per year in the Americas and Caribbean, most in Haiti. The WHO report includes estimates that more than 30,000 people die of rabies in Asia each year, as do an estimated 24,000 in Africa, although it notes that the reliability of both estimates is uncertain.

The article “Gains and future road map for the elimination of dog-transmitted rabies in the Americas” (Am J Trop Med Hyg 2013;89:1040-1042), which Dr. Vigilato co-authored for the December 2013 issue of the American Journal of Tropical Medicine and Hygiene, attributes much of that success to dog vaccination and cooperation among member country governments and nongovernmental organizations. Most parts of the Americas have eliminated circulation of rabies virus among canine populations, the article states, and human infections from dogs were found in only 11 of 570 administrative units of participating countries over the preceding four years.

Those cases were concentrated in the periphery of cities, neglected communities, or international border areas.

Continued political will to fight rabies is the most critical component of efforts to eliminate dog-transmitted rabies cases in the Americas, Dr. Taylor said. Strengthening rabies surveillance is important in the final stages of eradicating dog-transmitted rabies, when most of the countries that still have infections are concentrating efforts on remaining hot spots.

Dr. Vigilato said PAHO member countries have many health-related priorities, such as nutrition, heart disease, diabetes, dengue, and chikungunya. Eliminating canine rabies transmission in Latin America requires continued engagement from governments, including funding for surveillance and control.

Guatemala, the Dominican Republic, Bolivia, northeastern Brazil, and the Puno region of Peru still have rabies in dogs, and the PAHO is coordinating with national rabies control programs across the Americas and urging continued investment to maintain control, he said.

A PAHO action plan published in connection with an August 2013 meeting among directors of national rabies control programs states that it is “ethically unacceptable” that human rabies infections still occur in this decade.

“The main challenges for eliminating human rabies transmitted by dogs are not technical; they have to do with political determination and commitment by all interested parties, both public and private,” the report states.

The Global Alliance, World Medical Association, and World Veterinary Association have jointly called for all countries to implement disease surveillance systems that can help prevent rabies infections, and they urged collaboration among professionals in human and veterinary medicine toward prevention. The AVMA is a member organization of the WVA.

In a statement published by the group of three organizations two days before World Rabies Day on Sept. 28, 2014, Dr. Faouzi Kechrid, president of the WVA, said reductions in rabies cases in the Philippines, Indonesia, and Malaysia proved that interprofessional collaboration can provide sustained rabies elimination.

Dogs are the sources of 96 percent of human infections with rabies, according to the joint statement.

Dr. Vigilato said that, in the Americas, reducing wildlife-mediated rabies infections, such as those related to vampire bats, will be one of the next challenges for the PAHO. Programs to provide pre-exposure prophylaxis in some communities are providing innovative experience, and he hopes continued commitment to such projects will have a substantial impact in Amazonian regions, particularly in preventing deaths of children.  

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