By Deborah Sanborn, Editor/Outpost
Vampire bats do exactly what you think they do—they feed off animal blood. Native to Latin and South America—where they hide out in caves, old wells and trees, especially in rainforests—they’re a major reservoir for rabies, a deadly virus transmitted through saliva.
Since rabies can be fatal to humans if left untreated (and most often is in fact, fatal to humans), people travelling to places with vampire bat habitats should be vaccinated, says Dr. Terill Udenberg, a B.C. veterinarian and volunteer with the Canadian Animal Assistance Team (CAAT), an organization that helps domestic animals in underdeveloped regions. (Udenberg also co-owns the Gentle Pet Clinic in Fort St. John, B.C.)
“Certainly if you are sleeping in a hammock with your toes sticking out, you are going to be exposed to rabies.”
Yet perhaps the greater threat is how bats can infect other animals, like dogs and cats, which are rarely immunized for rabies in the under-developed and developing world. And it’s quite possible this is how a dog Udenberg encountered in Guyana became rabid.
“The family brought the dog to us because she’d been acting abnormal and threatening to bite. You just needed to look at it to know—her lips peeled over, [she showed] the salivation typical of rabid dogs, she was uncoordinated.”
Etch this picture in your brain, Udenberg told his team—this is what rabies looks like. Each year, according to the World Health Organization (WHO), it’s estimated that 60,000 people die from rabies in Asia and Africa alone. As a disease of nature that can infect almost any mammal, it’s considered prevalent worldwide—though the less developed the country, the higher the incidence—and is highly endemic in China, India, Pakistan, the Philippines and sub-Saharan Africa. In Canada, four people have died from rabies since 2000—one of them a traveller bitten by a rabid dog while in the Dominican Republic.
In North America, Europe and other developed countries, widespread pet immunization has rendered rabies a low-risk disease, and provincial and territory wilderness vaccine-drop programs have helped lessen the risk of rabies from an animal in the wild. Even still, according to Canadian government, there are a number of “rabies-positive animals” reported every year, most often in bats, foxes, skunks and raccoons, which can make its way into livestock.
According to Dr. Charles Rupprecht of the Centers for Disease Control and Prevention (CDC), all bat species pose a threat for rabies since they don’t respond to the vaccine-laced bait-drop programs done in many regions to immunize animals in the wild. Compounding the containment problem, people often don’t realize they’ve been bitten and the incubation period (the time before symptoms manifest) can run from 20 to 60 days, up to months and even years.
If you’re ever bitten or even scratched by a bat anywhere in the world, immediately contact a doctor or public health authority, who may prescribe post-exposure treatment.
Rabies is a horrific way to die. As an acute, progressive encephalitis (inflammation of the brain), it begins when the virus attacks the central nervous system and travels along the spinal cord to the brain. It ends up in saliva looking for an exit route. It literally drives its victims mad—causing hallucinations, delirium, convulsions, paralysis and difficulty swallowing, and a peculiar fear of water (hydrophobia).
There’s no cure, no medicine that can kill the virus in your body once symptoms begin to appear. For travellers, rabies is both a rural and an urban hazard, since dogs and farm animals often roam free, and our sense of curiosity (and affection!) often gets the best of us. Human cases have definitely resulted, says Rupprecht, from people interacting with the unknown and exotic. And Western travellers can attract dogs, says Udenberg, since they may look or smell differently. (This reverberates so tragically now, with the recent report of a 24-year-old traveller dying from rabies weeks after returning to Norway from the Philippines, where she was scratched by a puppy she’d rescued on the side of road.)
Fortunately, travellers can get a pre-exposure vaccine, and there’s an effective (if taken in time) post-exposure treatment.
The not-so-great news is that pre-exposure doesn’t confer total immunity. You absolutely need post-bite (or scratch, or lick) treatment if there’s any chance you’ve been exposed to the virus because the chance you take with rabies is not whether you end up sick, but whether you end up dead. Here’s a few guidelines when it comes to travelling and rabies. You can also check out the Public Health Agency of Canada here.
When to Ask about Vaccination
- If you’ll be in a country identified by a public health agency as hyper-endemic for rabies; a place where dog rabies is known to occur.
- If you’ll be in a remote area where: wild rabies likely exists; animals roam free; post-exposure treatment may be an issue; repeated exposure to animals and wildlife is possible.
- If you’ll be on a longer trip, where multiple opportunities for exposure exist.
- If you’ll be doing an activity like hiking, cycling, camping or spelunking where you may be exposed to rabid animals, particularly bats.
- If you’re travelling with children, who like to pet animals and may not tell you if they’ve been scratched or bitten, and who account for the largest portion of human rabies deaths worldwide.
Rabies Risks While Travelling
- Provoking an animal to bite by petting or encouraging physical contact.
- Getting bitten, scratched or licked by an infected animal, since it’s excreted through saliva; scratches transmit rabies because animals lick paws.
- An unprovoked animal attack, especially by a dog, which can indicate rabies.
- Contact of infected animal saliva on mucous membranes of the eyes, mouth, nose (though rare).
Rabies Vaccine And Treatment
- CDC says thorough, vigorous washing of any animal bite or scratch (and licked skin) with copious amounts of soap and water for several minutes (and iodine, if possible) substantially reduces risk of getting rabies, as this physically dislodges the virus; remove any clothes you were wearing when bitten.
- Pre-travel vaccine: three weekly doses; confers some protection if you’re unknowingly exposed.
- Post-exposure treatment: five weekly doses, as soon as possible.
Q&A: Outpost talks with Dr. Charles Rupprecht, (former) Chief of the Rabies Program, Centers for Disease Control and Prevention, USA
Outpost: Why is the incubation period for rabies so variable?
Charles Rupprecht: With many things in rabies we say “it depends”—on the dynamic between agent, host and environment, on how much virus is being inoculated [introduced into the body], on where it’s being inoculated, on if the exposure is a bite or a lick. The variables are dose, route, severity, proximity [of the bite] to the central nervous system [and brain] and host susceptibility, which varies.
OP: What animals should travellers be most wary of?
CR: Most human cases are due to dogs—dogs are the global reservoir for rabies. But the two major reservoirs we’re concerned about are carnivores, particularly of the canine family—dogs, foxes, coyotes, jackals, but also raccoons and skunks—and bats, which form a reservoir for rabies all over the world. We’re more concerned about the unprovoked bite by an obviously ill animal in a hyper-endemic country than we are by a bite where rabies hasn’t been reported.
OP: Is it also true rabies can surface in livestock, such as cows?
CR: Yes, we believe all mammals are susceptible…cows, horses, sheep, goats, just about any mammal that has a risk of exposure to the reservoirs—meaning carnivores and bats. [But cows] don’t have the same kind of teeth and hence are unlikely to cause the same degree of damage—to drive the virus deep into tissue. So I’m less concerned about cows than dogs with rabies.
OP: The quality of biologicals in many countries is not always guaranteed. Is this a concern for post-exposure rabies treatment?
CR: We have three major concerns here: one, the availability of biologicals at all; two, the availability of quality biolgicals; and three, counterfeit biologicals. And we have had human deaths from counterfeit rabies biologicals. We had a situation with somebody on a [school] semester at sea, where they found a bat on the deck of the boat and made a pet of it. Then [they were] bitten. The bat died, was sent to us, where we found out it was positive [for rabies]. The poor student had to fly home from Latin America to North America just to receive rabies prophylaxis, at undue cost, ruining [their] semester. Don’t provoke exposures, and find out whether you should have pre-exposure. Have a plan of action in case you’re bitten in a country where rabies is a concern.
OP: Pre-exposure and post-exposure medication is the same, correct?
CR: Pre-exposure vaccination and post-exposure vaccination is the same. [But] the post-exposure vaccine also contains rabies immunoglobulin [antibodies], because when you’re exposed to the virus it takes a while for you to respond to the vaccine. And we want you to have a preformed response, preformed antibodies, that attack the virus immediately.
OP: If a short-term traveller is bitten, but has taken pre-exposure vaccine, should they seek treatment while abroad, or is it safe to wait until they get home?
CR: I’m never happy saying one is safe, because you’re gambling. Once you’ve given the advantage to the virus, your chances for intervention go down. Rabies [is always] a medical emergency.
- This article first appeared in Outpost magazine and has been updated. This information is a guideline only. Always get individual medical advice from a travel health doctor. For more info on rabies and travelling see Public Health Agency of Canada, www.phac-aspc.gc.ca, the CDC’s Yellow Book on International Travel and the WHO www.who.int/rabies.