West Nile, Hantavirus, Plague-
A zoonosis is an infectious disease transmitted between species, especially from animals to humans and vice versa. New strains of influenza are usually a zoonosis having emerged from DNA mixing in geese, pigs, birds and the like, but The Wildlife News is generally concerned with zooneses like Rocky Mountain spotted fever and Lyme disease in they that come from wildlife.
West Nile Virus, Echinococcosis, Giardia, Hantavirus, Bubonic Plague, Brucellosis, Toxoplasmosis, Rocky Mountain spotted fever, and Lyme disease. It it interesting how there is a politics of these diseases with anti-wolf folks worrying about echinococcosis; ranchers ginning up fear about brucellosis; and outdoor enthusiasts worrying about the rest of the diseases listed above. Folks in these groups try to play up fear or downgrade it in order to accomplish other political objectives.
It is doubtful this year that anyone has been infected by Echinococcosis or brucellosis from wildlife, but it has been a record year for West Nile Virus. It has killed 43 in Texas, and 87 nationwide with at least 1,069 neuroinvasive West Nile cases and 924 non-neuroinvasive West Nile cases. You get it from mosquitoes. The risk overall depends on the number of mosquitoes and the percentage of them that are infected.
In terms of the likelihood of getting seriously ill or dying if you contract the disease, hantavirus is more dangerous (36% mortality) of the two, but there are fewer cases of it. However, this summer has seen an unprecedented level of exposure to hantavirus. It came at Yosemite National Park where the structure of rented, already erected tents (Signature tent cabins) facilitated the tents becoming inhabited by the prime host of hantavirus, the “cute” deer mouse (Peromyscus). So far only 3 people have died, but as many as 6000 (some say 12,000) persons might have stayed or entered the Signature tent cabins where the mice found refuge. The disease does not always develop quickly after exposure. Five others are currently sick from it, but there could be more. Story: Yosemite extends hantavirus warning; death toll rises. Reuters.
Overall, since the hantavirus pulmonary syndrome (HPS) was identified (1993), there have been 556 cases reported in the U.S.. The mortality rate was 36%. The most cases have been in Arizona, New Mexico and Colorado. California, Washington, and Montana follow. The secret of staying safe is to keep away from deer mouse droppings, and if you clean droppings up, do not sweep them. This makes the virus airborne. The droppings can instead be disinfected by spraying down the area with bleach.
Every year about 10 or 20 people in the U.S. get the notorious “Black Death” (plague). Mortality is about 15%. The Plague is caused by the pathogen Yersinia pestis which seems to have lost some of its “ummphf” since the says when it killed a quarter or so of the population of Europe.
This summer an Oregon man barely survived an infection he got when his cat bite him while it was choking on an infected mouse. He was trying to save the cat. Oregon man recovering from case of the plague. Posted by Cathy McLain. Seattle Times. Meanwhile a Colorado 7-year old girl is recovering from The Plague transmitted to her by fleas that were on a dead squirrel she examined near Pagosa Springs. Fortunately the physician quickly put her symptoms together with the dead squirrel to make the uncommon, but correct diagnosis. Story. Rare Colorado plague case had Girl Scout near death. By Michael Booth. The Denver Post.
In Missouri a new zoonosis has been identified. So far it has infected two men. They barely survived. Named the “Heartland Virus” it is an addition to the long list of diseases passed to humans and other animals by ticks. This time the tick is the Lone Star tick. Other tick borne diseases are Q-fever, Colorado tick fever, Rocky Mountain Spotted Fever, Lyme Disease, babesiosis , and ehrlichiosis. Story from the New York Times. New Virus Tied to Ticks Poses Puzzle for Doctors. By Denise Grady.
Of course, Lyme Disease is the most common zoonosis in the United States. Lyme Disease has been increasing over time, though not in a strictly linear trend. Soon (maybe 2012), we will see at least 50,000 cases reported in a year.
Zoonoses have always been with us. On the other hand the number of new ones seems to be growing. One hypothesis is that environmental disruptions and population migrations play a key role in animal organisms becoming pathogens in new species. Dengue fever has been spreading north due to climate change. Back at the time of the Black Death (peak in Europe 1348-50) the great kill was set in motion by the opening of new trade routes and the infected fleas were carried to and from ships by fleas on black rats. Famine also helped create a population more susceptible.
With so many changes taking place in our environment and that of all the organisms on the planet, surveillance for upswings of zoonoses is critical, hardly the sort of activity that should be scaled back to save relatively small amounts of money. Nevertheless budgets for the U. S. Center for Disease Control have been cut and are proposed for more cutting. See, US disease agency in fiscal peril. Proposed budget changes threaten disease prevention and surveillance programmes. Nature.
By Michele Simon. Feds Playing Politics With Food Safety Is Enough to Make You Sick. Huffington Post.
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Update: Lyme disease is associated with the small deer tick, and most people assume that an illness after a tick bite is Lyme disease. It turns out now that other ticks, especially in the Southeast are most likely not deer ticks and the illness not Lyme Disease. Research just published in the journal Zoonoses and Public Health indicates the illness is much more likely to be spotted fever rickettsiosis or ehrlichiosis. Even that is not certain, however, because climate change is driving Lyme Disease southward while Lone Star ticks which harbor perhaps as many as ten or so tick borne diseases are moving north. Folks should read this article in Science Daily. Precautions for Tick-Borne Disease Extend ‘Beyond Lyme’. This confusion, of course, makes treating Lyme disease with antibiotics, which is already controversial, more so.
