It does not spread from person to person, but once symptoms develop there is at least a
30% death rate. Again, compare to boubonic, which was once the scourge of Europe, but
has always been extremely rare here even though it is also undeniably endemic in common
rodents. I've heard of one case in Calif this year, and we have a huge population, with a great many people in either suburban or rural areas in potential contact with ground squirrel fleas. One endemic location is right in the middle of a major city and within eyesight
of an international airport! That's why it's officially an open space an not built on. The health dept can keep an eye out on the burrows through routine testing, and if necessary
sprinkle for fleas. There are also legends among the Navajo of our SW making it highly probable that deadly hanta epidemics occurred at long intervals related to exceptional rains. If the outbreaks were common there would be anitbodies and some resistance to them among native populations. They
also have a strong taboo against mice in dwellings.
Another odd thing that comes to mind is that hanta can afflict people in their prime and skip the young and elderly - something perhaps related to metabolism. And related to another Navajo saying, that a strong warrior can only be killed by a mouse! Similar characteristics have been reported in Gobi desert hanta. Now I'm certainly no expert at this, obviously, but have had a few conversations with those who are - that is, to the
extent they aren't surmising themselves. It's a poorly-studied virus. And that three deaths
make Yosemite a "cluster" of international proportions tells you just how rare it is. That's
less than the gang war fatatilites on our city streets around here on any given day.
The term Hantavirus is derived from the Hantan River area of South Korea. The Hantaan Virus (HTNV) was isolated by Dr HO-WANG LEE in 1978? (Dr. Lee's research was prompted by viral outbreak during the Korean War which infected some 3000 UN soliders.) HTNV is one of several hantaviruses which causes Korean hemorrhagic fever (HFRS). In or around 1998 Dr. P.J. Padula et al discovered microbological evidence of person to person transmission of HTNV, during the 1997? Argentina HTNV outbreak.
There is also evidence HTNV maybe the culprit for the "sweating sickness" during the 1485 Medieval England Battle of Bosworth Field. There is also evidence HTNV was present during WWI/WWII; the American Civil War; there is documented history of HTNV being active in far east Russia for centuries; and there is anecdotal evidence HTNV existed in early man cultures.
Thanks Harrison. It's interesting (and sometimes scary) how these things get sleuthed.
The local university guys have done a lot of work on Lyme, esp the mysteries of the intermediate hosts, and it pretty remarkable what they've uncovered. Fortunately, the rate of tick infection locally is far lower than on the East Coast. When I was young I was
actually offered a key position monitoring state wildlife for disease, but it fell thru due to
the very strick state ethnic hiring guidelines back then (the specific job never was filled);
but all the state lab work is still done up the street here near the University. It's quite a
facility, possibly second only to the CDC.
In today's paper there was finally a reasonable summary of the hanta event. The year prior
was exceptionally wet and the mice had abundant natural forage well into autumn, esp pine nuts. This led to a population explosion. Then the winter was unusually mild. Combined
with the fact that the newer tent cabins were much better insulated in the old ones, and
had plenty of food scraps, meant that far fewer mice died off during winter; and they naturally concentrated in the cabins. Apparently the virus has a certain threshold before it
easily spreads among mice, always linked to population explosions following wet years with
abundant food. Although the first monitored US outbreak was in 1993, there is strong
circumstantial evidence for Southwest outbreaks in 1918, 1933, 1994, and according to
tribal tradition, even long before. Right now the next concern in Yosemite is to keep mice
out of the bear boxes, which are not currently rodent-proof (yeah, a lot of mousie poop in
There have, however, been a couple of cases of Bubonic Plague in the U.S. this year. (It's endemic among ground squirrels here, but not epidemic-- yet.)
The switches and triggers that cause a latent pathogens to become epidemic are not well understood, yet.
Yep, Ivan ... the health dept has been going around the rural areas warning folks about
rabies. My sister lives in Aromas and there's been a number of rabid animals picked up out
there. Do you live in town? Boubonic plague is very closely monitored in Calif and that's why outbreaks are almost nonexistent. They trap the squirrels in known hot areas, knock
them out with ether, comb the fleas and send them in to the state lab up the street here.
If something turns up, they move in with appropriate insecticide around the burrows. I think there was one human case in Calif last yr. Unlike hanta, it's treatable with antibiotics
if caught early.
Could be there have been animals picked up in Aromas, but surely it's not yet epidemic in Monterey County? Just nothing about it in the media and my wildlife contacts aren't talking about it, but I'll ask around. Maybe it's flying under the radar, but these things typically trend the other way, they're hugely overblown in the media, most times.
Glad to hear they're simply knocking squirrels out to collect their fleas. Keenly aware that the ground squirrels used to be subject to mass poisonings. Coated millet seed gets broadcast by helo. Buddy of mine still has a plaque commending him for his 80% kill ratio over 100,000 acres in South County. Compound 1080. All for a disease that no one much ever got. Competition for grazing in cattle country was the real point of the attempted squirrel-extirpation exercise.
San Joaquin Kit foxes that cleaned up the squirrel carcasses were very nearly extincted. Coyotes were essentially extirpated locally in Carmel Valley by 25 years ago: rarely seen...curiously non-vocal then. But numbers are coming back hereabouts, nowadays yappity as one might expect.
Ivan - you're in a tourist town and the dirty little secrets rarely come out in local news.
There's also a much higher incidence of lyme in that area than up here (still low compared
to New England). Cowboys didn't like squirrels because the horses sometimes got hurt by
the burrows. Coyotes seems more interested in gophers, and it's the badgers that really like ground squirrels (it's those huge badger holes that really scare folks riding horses). We
have a good coyote population up here, but I really miss my Sierra property where big packs would form choruses right around the house. They're smart and learned a long time
ago about poison. A lot of the old-time anti-wildlife extermination projects were pretty stupid. I lived across the road from a sheep ranch, and the coyotes never bother them.
Domestic dog packs did. The coyotes prefer rodents or rabbits, and mtn lions prefer deer.
Squirrels don't compete much with herbivores.