From:
"Church, Robert Ray (UMC-Student)"
Date: 2002-07-12 18:44:34 UTC
Subject: Bob C: Vitamin A and CD-3
To: <ferrethealth@smartgroups.com>
Cc: "Church, Robert Ray (UMC-Student)" <rrc961@mizzou.edu>
Message-ID: <43C5FBB91EB9CC468627C2BCB23391D32B9CA0@TIG-MAIL2.tig.mizzou.edu>
3. Is there a danger that humans or other pets can catch distemper?
Unlike most viruses, the Morbillivirus disease complex is NOT species speci=
fic. Measles is a human disease, but it will infect gorillas, chimpanzees,=
and orangutans, as well as other primates. Canine distemper will cross sp=
ecies barriers to infect seals, ferrets and other mustelids, mongeese, all =
canids, raccoons, bears, large felids (lions, tigers, and leopards), and hy=
enas. Rinderpest, and the closely associated peste des petits ruminants, w=
ill take down just about ANY artiodactyl species, ranging from giraffe to w=
ildebeest to any number of antelope, deer and elk. At a superficial level,=
you are safe to say that measles attacks many primates, that rinderpest at=
tacks many artiodactyls, and that canine distemper attacks many carnivores,=
as long as you recognize many exceptions exist. Canine distemper infected=
and killed a Japanese macaque a few years ago. There are reports of Rinde=
rpest infecting humans. Measles infects rabbits, and lagomorphs are pretty=
far from the primate tree. There are numerous other examples, but the poi=
nt is made that Morbilliviruses easily cross species barriers given time an=
d proximity.
Can humans catch canine distemper? I guess that depends on how you look at=
it. In a way, we already have, but we just call it measles. There are se=
veral leading medical anthropologists that think canine distemper crossed i=
nto humans several times during our close association with dogs, explaining=
the many variants, or strains, of measles. I=92m not sure I would accept =
that hypothesis without better genetic evidence, but it is at least theoret=
ically possible. Still, it raises the question if we would even notice if =
canine distemper crossed into humans; because of the number of similarities=
in symptoms, most doctors would just think it was just a strange variant o=
f measles. Without genetic tests, there would be no way of knowing the str=
ain of measles present, or even if you had a species-jumping case of canine=
distemper. Since most deadly cases of measles occur in areas where advanc=
ed medical testing is at a premium, given the similarity of symptoms, it is=
likely no one would notice if canine distemper jumped the species barrier.=
These types of species barrier jumping events are sort of like winning the =
lottery; the chances are extremely small, but sooner-or-later someone ALWAY=
S wins. Given proximity and chance mutation, just about any viral disease =
of animals can cross to humans. Don=92t think so? How about rabies, a vir=
us infecting carnivores and bats, but readily infects humans and nearly any=
other mammal? Not convinced? How about HIV/AIDS, a disease that originat=
ed in small primates? The Gordian knot of influenza is still being unravel=
ed, but humans (and ferrets) contracted that modern plague from poultry and=
/or swine (more people have died of the flu than from the black death). St=
ill not convinced viruses cross species barriers? Ok, how about African gr=
een monkey (or Marburg) disease, bat salivary gland fever, California encep=
halitis, Colorado tick fever, B virus, cowpox, eastern equine encephalomyel=
itis, dengue virus, foot-and-mouth disease, feline panleukopenia, Japanese =
B encephalitis, lymphocytic choriomeningitis, West Nile fever, Yellow fever=
, Mokola, St. Louis encephalitis, Newcastle disease, infectious hepatitis, =
Hunta virus (or Hantavirus), Rift Valley fever, Lassa fever, Jinin virus, o=
r =91mad cow=92 disease? These just a few viruses infecting various animal=
s that readily cross species barriers to infect humans and other animals. =
Many medical anthropologists argue most modern viral diseases were passed t=
o humans through contact with domesticated animals (or exotic pets). The c=
hance may be a hundred billion to one that a mutant virus will pass to huma=
ns, but someone always gets to be that unlucky one if they stick around lon=
g enough.
Personally, I would worry more about a meteorite smacking me on the head be=
fore I would worry about catching canine distemper. But there are other wo=
rries; just think of what might happen to housecats or wild North American =
felids if the strain infecting lions or leopards managed to introduce itsel=
f in our hemisphere. One of the reasons I defend the practice of inoculati=
ng against canine distemper so strongly is not JUST because it protects fer=
rets, but because it also decreases the chances of the disease crossing to =
other pets. Of course, it COULD pass into humans (yet again), but then we=92=
d probably just think it was measles.
Bob