Sunday, January 8, 2012

Big Ole Bully Mice Broadcast Hantavirus

Armed with microchips and infrared cameras, tortilla tupperware bins and 148 the best live humane mouse traps, University of Utah researchers studied the connection between Hantavirus and wild deer mice on 7.7 acres in the Western Tintic Mountains. The transmission of Sin Nombre virus, a specific Hantavirus, transmitted rodent to rodent, is also transmitted by rodent droppings to humans. A combined average of the 12 sites were used on the acreage, eleven percent of this group of mice observed were the older and larger. Any contact with the aged larger rodents led to fighting or mating with others of their species, and resulted in the spread of the deadly Hantavirus to uninfected members.

Reported in the Bristish Journal Proceedings of the Royal Society, this study proved to be contradictory to what the scientists previously thought to be true. Researchers believe that the 20-80 rule applies in transmission of Hantavirus. The 20-80 rule, a concept really, means that only 20% are responsible for transmission for that species population, this rule also applies to humans in the transmission of diseases such as AIDS, SARS, Measles, Small Pox and other diseases. The scientists presupposed that the sex of rodents, breeding age, enrivonmental surroundings and vegetation played a larger factor in transmission. And while those may also be factors, they can now add this new study to the mix of how Hantavirus is transmitted.

In the end. the study revealed that mice blood samples proved an average of 25% to 30% Hantavirus infection of that specific population. While the study pointed out that this 20-80 rule applies to the West Nile Virus transmitted by mosquitos, as well as tick borne diseases; it stands to reason that larger and older mice would contain the most ticks due to body surface, who then feed on the rodents blood and eventually transmit  to other mice, and indirectly to wildlife, pets and humans.

The study's suggestion of a risk map to identify rural areas where precautions might be taken sounds like a good idea to me (I'm rural).  Whether you could be breathing recircualted dust of rodent debris from sweeping up or cleaning up mouse droppings, it might make you think twice about wearing a filtered face mask while doing your chores; Hantavirus is transmitted to humans by mice droppings as far as researchers know now.  Thirty seven  of our states have reported cases of Hantavirus at one time or another, and most of the states are in the midwest, centering in Arizona, Colorado, New Mexico and Utah.

Some think global warming may be tied to Hantavirus and other rodent diseases, in that rodents are affected by our weather and ecosystems; the denser the vegetation, the more food available, the bigger the rodents resulting in increased Hantavirus risk versus times of drought, when vegetation and water is scarce, causing a dip in the population, smaller rodents and less Hantavirus episodes.

Recent Hantavirus outbreaks in Chula Vista, California, Canada, South Korea and Mexico are emerging to the spotlight once again. The last outbreak in 1993 was responsible for 465 cases of  the virus in the United States; of those cases and over time, 35 percents of the patients died, as recorded in 2007. The Center for Disease Control (CDC) website claims there are 60 diseases transmitted directly and indirectly by rodents, as well as rodent parasites which carry disease too. In order to get rid of mice whether they are in your walls, (ever wonder where that sudden odor came from?), you heard some noise in the attic, manybe carcasses in your hvac and then there are those awful pantry pests (sometimes those are caused by rodent infestations), its all a very nasty topic.


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