Pleistocene Rabies

Viruses in the lyssavirus genus cause rabies, still a feared disease in many Third World countries.  Rabies kills over 24,000 people every year in less developed countries, but the annual death toll in the U.S. since 1900 has dropped from about 100 to 1 or 2.  Rabies viruses evolved characteristics that force physical reactions in infected organisms, and these reactions help facilitate the spread of the virus into the environment.  The rabies virus attacks the central nervous system of a vertebrate.  Eventually, the infection causes an inflammation of the brain.  Symptoms include insomnia, the inability to swallow, and a paralysis that inevitably leads to death.  An infected animal, unable to swallow, still produces saliva, and this spit foams at the mouth.  The saliva is loaded with the virus.  The insomnia causes great confusion and irritability, especially among carnivores that require lots of sleep.  (For example cats sleep 20 hours a day.)  This explains why animals infected with rabies behave oddly and more readily bite.  They become unknowing slaves to the virus, passing it in their infected saliva when they bite because they are behaving irrationally.

Studies of vampire bats determined rabies spreads in waves.  Some individual bats, unlike humans, are immune to the virus, and the population of immune individuals increases.  Rabies will disappear from the population for awhile but will return after a few generations when enough non-immune individuals are born.

Rabies viruses belong to the lyssavirus genus.

YouTube video of a raccoon infected with a rabies.  The virus attacks the brain in a way that makes the victim unable to swallow.  The virus then spreads in the foaming saliva on the mouth and is transmitted via a bite into the blood stream of another organism.  If you see an animal like this, shoot it, or call somebody else to come shoot it.

Louis Pasteur and Emile Roux invented the first rabies vaccine in 1885, and it has since been improved upon.  The widespread vaccination of pets accounts for the decline in human rabies in the U.S.  The vaccine can save people after they have been bitten by a rabid animal as well.  Modern treatment consists of thoroughly washing the wound with soap (this alone can kill the virus), followed by 5 injections in the shoulder with the vaccine.  Doctors no longer administer rabies shots deep into the stomach muscle.  Vaccinations only work if given before brain inflammation occurs.  Formerly, the mortality rate from rabies-caused brain inflammation was 100%.  But in 2004 Rodney Willoughby invented the Milwaukee Protocol.  His patient, Jeanna Giese, was suffering encephalitis after being bitten by a bat a month earlier.  (The girl and her mother didn’t realize the bite required urgent treatment.)  Dr. Willoughby hypothesized the rabies virus killed humans before the person’s own immune system had a chance to produce enough anti-bodies.  So he put Jeanna in a medically-induced coma using anesthetics and barbituates, and he also prescribed anti-viral medication.  Meanwhile, she was kept on a respirator.  After a week her body had become immune to the disease, and she survived, though she suffered some brain damage, and it took her months to learn how to walk again.  Since this case, the Milwaukee Protocol, named after the location of the hospital where it was first tried, has been used 41 times but has just an 8% survival rate, and the survivors have varying degrees of brain damage.  Do not delay treatment, if bitten by a wild animal.

ff_rabies4_f

Jeanna Giese is the first person to ever survive rabies after the disease had progressed to the brain inflammation stage.

Rabies is an ancient disease that was certainly widespread during the Pleistocene.  Rabies occurs on every continent except Antarctica and may predate the break-up of supercontinents.  Scientists don’t know where it originated.  Medical historians believe rabies occurred in the Americas before Columbus, along with other diseases such as syphilis, tularemia, giardia, dysentery, hepatitis, herpes, and staph infections.  The Spanish encountered rabies early during the conquest of South America.  It’s not likely they brought infected animals with them.  An animal infected with rabies would show symptoms before the long sea journey was over and would’ve been destroyed on board ship.

References:

Hu, W.T.; Rodney Willoughby and G.M Hoffman

“Long Term Follow Up after Treatment of Rabies by Induction of Coma”

New England Journal of Medicine 2007

Johnson, Nicholas; et. al.

“Vampire Bat Rabies: Ecology, Epidemiology, and Control”

Viruses May 2014

Martin, Debra and Alan Goodwin

“Health Conditions before Columbus: Paleopathology of North America”

Western Journal of Medicine

Vos, A; et. al.

“The Occurrence of Rabies in Pre-Columbia Central America: an historical search”

Epidemiology and Infection 39 (10) 2011

 

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