Dozens of mysterious deaths in the Venezuelan rainforest among indigenous peoples caused two University of California researchers to investigate. Dementia, fever, extreme hydrophobia… the results of their investigation are horrifying: man-attacks by vampire bats infected with rabies.
The cases of the 38 Warao Indian people who have died over the past three years, since June 2007, mystified scientists. Tingling in the feet. Fever, paralysis, dementia and extreme fear of water. Two researchers from the University of California investigated. What they found was horrifying: the symptoms were those of rabies, but it seems, an extremely virulent form.
Charles Briggs and Clara Mantini-Briggs are a husband and wife team from UC’s Berkeley University who looked into this mystery. The symptoms in the patients they have identified as those of rabies: fever, tingling in the feet, followed by paralysis, dementia, an extreme fear of water, convulsions and death. The victims died between two to seven days after the onset of symptoms.
Comparing these cases with the World Health Organization’s definition of rabies symptoms, there appears to be little doubt:
“The first symptoms of rabies are flu-like, including fever, headache and fatigue, and then progress to involve the respiratory, gastrointestinal and/or central nervous systems. In the critical stage, signs of hyperactivity (furious rabies) or paralysis (dumb rabies) dominate. In both furious and dumb rabies, some paralysis eventually progresses to complete paralysis, followed by coma and death in all cases, usually due to breathing failure. Without intensive care, death occurs during the first seven days of illness”.
But where did the bites come from? According to the WHO, 31,000 people per year die of rabies in Asia and a further 24,000 in Africa, all after being bitten by rabid dogs. In the case of Venezuela, the cause has been traced to bats. Vampire bats.
These bats (see photo) are endemic in the rainforest where the deaths occurred. They usually swoop down on animals during the night, when they are sleeping, make an incision with their razor-sharp teeth and inject an anticoagulant into the would with its saliva while they lap up the blood. They fly back to their roost and attack again the following night.
In this case the victims were not cattle, but humans. One village lost eight of its 80 inhabitants, all of them children and all with the same symptoms.
While laboratory analyses are still being carried out, Dr. Charles Rupprecht, Chief of the Rabies program at the US Centers for Disease Control and Prevention in Atlanta, Georgia, stated that “The clinical signs are compatible with rabies”. Pointing out that other rabies epidemics linked to vampire bats have occurred in Brazil and Peru, he explained that prevention with nets and vaccination programs are very effective in combating the outbreak of the disease.