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  • P.K. Peterson

Rabies—Not In My Back Yard?

Updated: Sep 17, 2019

If rabies isn’t already at the top of your list of “most feared infections,” it probably should be. It is an especially gruesome infection of the nervous system (brain and spinal cord) that is caused by a RNA virus of the genus Lyssavirus. And, the rabies virus is one of a surprisingly small number of infectious agents that kills virtually all of its human victims. (The prion that causes Creutzfeldt Jacob Disease—the subject of a recent blog—and untreated HIV infection are also on this shortlist of killers.) There are at most three Americans who recovered from well-documented rabies. They all received extraordinary intensive care measures.


Rabies is a zoonosis, meaning that it is transmitted to humans by animals, usually by a bite. Dog bites were the main source of infection in humans in the U.S. until 1960, and they remain the source of most rabies cases throughout Asia and Africa.


Since 1960, contact with the saliva of infected bats has led the list of animal exposures resulting in human rabies cases in the U.S. As lots of bats are currently getting ready to overwinter—often in attics or outbuildings—this is a good time to review what you need to know to prevent this devastating infection.



Like many infectious diseases, the answer to who’s at risk of rabies depends on geography. If your backyard happens to be in one of a handful of countries that are considered rabies-free, like Australia or the Cayman Islands, you have nothing to worry about. But for people living or traveling in most countries of the world, Not in MY Back Yard doesn’t apply.


So it helps to know what rabies-carrying animals visit your location. For example, my backyard in the city of Minneapolis is visited occasionally by foxes. A year ago a biker and a runner were bitten by a rabid fox along a nearby lake. And in their quest for insects, bats frequently fly over my backyard. Earlier this year, several rabies-infected bats were recovered from a path around this same lake.



But the good news is that human rabies is rare in Minnesota. I’m aware of only two cases in the past 50 years—one was a trapper in northern Minnesota, who was bitten by an unprovoked cat. The second case was an elderly recluse who handled an infected bat in his cabin. Neither of these individuals sought medical attention until it was too late-when they were already sick, hospitalized, and subsequently died.


Human rabies is also uncommon in the rest of the U.S., with only between 1 and 3 reported cases per year. This low incidence contrasts sharply with rabies globally with an estimated 59,000 deaths annually in over 150 countries, occurring mainly in Africa and Asia.


As mentioned, in the U.S., most cases of human rabies come from rabies-infected bats. Contact with rabies-infected raccoons, skunks, or foxes is the source of the other human rabies cases. (Of note, small rodents, like squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats and mice and lagomorphs: rabbits and hares, are almost never infected with rabies virus and have not been known to transmit the virus to humans.)


The dramatic reduction of rabies in dogs through routine vaccination is a remarkable achievement of veterinary medicine and the public health system in the U.S. In Asia and Africa, on the other hand, 99% of rabies cases are dog-mediated, and contact with rabies-infected dogs outside the U.S. is also a risk factor for American travelers. Thus almost all of the 59,000 rabies deaths per year could be avoided if vaccination of dogs became routine world-wide.


So what should every American know about rabies, other than you don’t want to get it? If you are the victim of an animal bite—especially if it is unprovoked—first, wash the bite wound immediately. Then, call for help! (This step also applies if you’ve seen a bat flying in your home.) Your doctor is a source of reliable information regarding the next steps. Also, the Centers for Disease Control and Prevention as well as your state public health department have rabies hotlines that are manned 24 hours a day. Their phone numbers can be found on-line. If your exposure occurs while you’re traveling in a country with an inadequate public health infrastructure, I suggest calling the CDC for advice.


All considered, it’s important to know that while rabies is a frightful disease, it is 100% preventable through timely administration of rabies vaccines, called Rabies Post Exposure Treatment or PEP. Also, major health organizations including the World Health Organization, World Organization for Animal Health, and the Food and Agriculture Organization of the United Nations have pledged to eliminate human deaths from dog-transmitted rabies by 2030. This September 28 is World Rabies Day, a good time for you to pause and thank the French scientist Louis Pasteur, who in July, 1885 was the first to administer a rabies vaccine, thereby saving the life of Joseph Meister, a 9-year-old boy who had been attacked by a rabid dog.

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Main Page images courtesy of Shuxian Hu, MD. Dr. Hu is a scientist in the Neuroimmunology Research Laboratory at the University of Minnesota.

 

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