The Peruvian Amazon is the area of the Amazon jungle included in the territory of Peru, and is home to indigenous groups of people, such as the Aguaruna, Cocama-Cocamilla and Urarina. Rabies infections spread by bites from vampire bats are fairly common in the Amazon region. Without treatment, rabies, which is a deadly viral disease that attacks the central nervous system (brain and spinal cord), can be fatal.
But a new study suggests that certain populations regularly exposed to vampire bat bites develop natural immunity to rabies.
The interesting finding was arrived at by researchers from the U.S. Centers for Disease Control and Prevention, who conducted a survey in two Amazon communities in Peru where outbreaks of human rabies infections caused by vampire bat bites have occurred regularly over the past two decades.
According to the researchers, 92 people in two Amazon communities in Peru were surveyed, and 50 of them reported previous bat bites. The blood samples of 63 people were analyzed and 7 were found to have rabies virus neutralizing antibodies. Although one person with antibodies reported receiving vaccine previously, the other people with antibodies did not receive medical care following prior bat bites.
Commenting on the finding, lead author of the study Amy Gilbert said, "Nearly all rabies virus exposures that proceed to clinical infections are fatal. Our results support the idea that under very unique circumstances there may be some type of enhanced immune response in certain populations regularly exposed to the virus, which could prevent onset of clinical illness."
Rodney Willoughby Jr., pediatric researcher at the Medical College of Wisconsin, is of the view that a detailed genetic analysis of the subjects in the Peruvian Amazon may provide information on which pathways in human biochemistry and physiology promote resistance to human rabies.
It is estimated that over 55,000 people around the world die of rabies each year. According to the CDC, in the United States, human deaths from rabies have declined over the past century from more than 100 annually to an average of two per year because of aggressive campaigns to vaccinate domestic animals against the disease. However, this disease is reportedly on the rise in China, the former Soviet Republics, southern Africa, and Central and South America.
by RTT Staff Writer
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