Deadly deer mouse?: The main vector for hantavirus is the deer mouse, which lives in many states in the U.S.
Image: Wikimedia Commons/James Gathany
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Earlier this week the World Health Organization issued a global warning to travelers who might have come into contact with the deadly hantavirus while staying in Yosemite National Park in California. So far, three* people have died and at least half a dozen more have been sickened by the virus, which causes pulmonary distress. The outbreak is unusual in that cases of the virus are usually solitary and most have come from the high desert areas in or near New Mexico.
Most victims likely picked up the infection while staying in insulated tent cabins that were infested with mice, which carry the disease. The U.S. National Park Service estimates that as many as 10,000 people might be at risk of having been exposed to the disease since early June. And it has urged anyone who stayed in the "Signature Tent Cabins" in Yosemite’s Curry Village to be vigilant about looking for flulike symptoms, which can signal the onset of the illness. The virus can take as long as six weeks to incubate.
The infection was initially described in New Mexico about 20 years ago. It is exceedingly rare, with only about 600 documented cases in the U.S. But it is extremely deadly, killing more than one in three people who contract it.
The deer mice (Peromyscus) and other rodents that have been known to carry the disease, however, are by no means limited to high desert or mountainous areas and can be found throughout North America. So does that mean hantavirus could spread to other parts of the country?
To find out, we spoke with Charles Chiu, director of the Abbott Viral Diagnostics and Discovery Center and an associate professor of medicine and infectious diseases at the University of California, San Francisco. He explains what we know about hantavirus and what he and his colleagues are rushing to figure out in light of this latest outbreak.
[An edited transcript of the interview follows.]
What, exactly, is hantavirus?
Hantavirus is a very rare virus that's spread through contact with rodents. In the western U.S., it causes hantavirus pulmonary syndrome, a devastating pneumonia. There is also another disease associated with hantavirus, which is rarely found in the U.S. but is more often found in Central and South America: hantavirus hemorrhagic fever with renal syndrome.
How is the respiratory form of hantavirus spread?
It is acquired through contact with rodents, most commonly by inhaling dust that's contaminated with rodent droppings or urine. Less often, it can occur from a bite from a rodent. The main rodent that spreads this is the deer mouse.
Was hantavirus likely around before its formal description in the early 1990s?
The evolutionary data suggest that it's been around for hundreds or thousands of years. This is not a common infection, and probably a large factor in this is that there are no documented cases of human-to-human infection, so it's not contagious.
Hantavirus is usually thought of as an illness from desert areas of the Southwest, like New Mexico. Is this the first time it has sickened people in another region?
It was originally described in the Four Corners region of New Mexico in the high desert. But more than half of the states have reported cases. The cases have all been associated with wild rodents, which have been detected in every state.
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14 Comments
Add CommentThere have been 3 confirmed deaths by venomous snakes in the US since 2010, 2 of whom were intentionally handling the snakes. In this small example we have 2 people dying from exposure to deer mice infesting 1 location. I wonder which animal, snake or mice, is more of a threat to humans?
Reply | Report Abuse | Link to thisThanks Ungolythe.
Reply | Report Abuse | Link to thisThe answer is neither. The virus wants to live, is trying desparetly to live, has evolved a mechanism whereby it can evolve "faster". This means in real terms it can compensate for any changes to a system so that it can survive. You will not be able to remove it.
Now lets go for the revolutionary... as being smart is so boring. Viruses are actually apart of a pre-cursor of life and is how we evolved as bacteria. We needed to interchange ourselves with other selves. We evolved the virus to transmit codes, no matter what the hardship so that our fitness grew ever higher.
This means virus are us, we made them so we could evolve, we have evolved to be the complex life form among others so the viruses today are the most complex life form of its type.
Which also means we still have good viruses in our body and yes of course evolution is not random but specific. I have never believed in random evolution except from the very primordial soup where mutation was paramount, since then been usurped by "managed" evolution.
We CANNOT stop viruses or their effects, which arent meant to kill its just an evolutionary misfire when it does kill.
Im aware of using a virus to fight another virus, eg aids vs cancer. Which has a limited endless life, quite nice if individualistic but perhaps the perfect way to go.
Reply | Report Abuse | Link to thisA person submits a blood test, you find the disease and then you target it. Simple, effective, nice.
How then to make it target...easy because you make it target the one just in that person...
You must not make a version that targets different types...even if you can. We mustnt learn any harsh lessons before its too late...
Considering all the diseases associated with mice and/or the parasites that live on them - including (but not limited to) Salmonellosis, Lyme disease, Rickettsial pox, typhus and bubonic plague - I'd say mice. Snakes are generally not a threat if you leave them alone; mice leave nasty presents behind.
Reply | Report Abuse | Link to this"Viruses are actually apart of a pre-cursor of life and is how we evolved as bacteria."
Reply | Report Abuse | Link to thisIncorrect. All known viruses are obligate intracellular parasites. This means they NEED cellular organisms in order to reproduce. As such, they could not have evolved until AFTER cellular organisms (such as bacteria) already existed.
"We evolved the virus to transmit codes..."
No. The viruses evolved on their own to parasitize humans hosts and propagate themselves. That's all. Any genetic transfer from one host to the next is purely coincidental.
"This means virus are us, we made them so we could evolve, we have evolved to be the complex life form among others so the viruses today are the most complex life form of its type."
Wrong again. We did not make the viruses & they don't care about our evolution. In fact, it would be better for the viruse if we DIDN'T evolve, because then they wouldn't have to evolve themselves in order to adapt to our changing defenses. And viruses are the SIMPLEST "life form" on the planet, just a nucleic acid blueprint and a protein coat. So simple in fact, that they're not truly alive unless they're infecting a host.
"Im aware of using a virus to fight another virus, eg aids vs cancer."
First off, if you try to use AIDS (HIV) to fight cancer, you'll just end up dying of AIDS AND cancer. Second, only a few cancers have been linked to viruses, most are caused by spontaneous mutations. Third - and most important - viruses need a CELLULAR host and will just ignore other viruses. There has been some work using engineered viruses (usually adenoviruses) as vectores for gene therapy and recenlty some interest in using a particular class of bacteria-infecting viruses (bacteriophages) to fight bacterial disease, but viruses have not and CANNOT be used to fight other viruses.
"How then to make it target...easy because you make it target the one just in that person..."
Impossible. Viruses start infecting their hosts by latching onto protein molecules that are found on the cell surfaces of ALL members of the host species. For a virus to evolve (or for us to engineer) a mechanism that targets a specific individual would be a COLOSSAL waste of time & energy.
"You must not make a version that targets different types...even if you can. We mustnt learn any harsh lessons before its too late..."
Viruses mutate rapidly. The more that can be targeted by any given therapy, the better.
Snakes eat mice. At least some snakes eat mice; among those that do are species of rattlesnakes.
Reply | Report Abuse | Link to thisMy point exactly. There would be far more deaths of humans due to the diseases that rodents and other small critters than would be from snake deaths, no question.
Reply | Report Abuse | Link to thisI remember reading about the 1918 flu pandemic and the idea that young healthy adults were more susceptible to dying presumably because their immune response was so robust that their respiratory system was quickly destroyed by the immune response. Is there evidence that this virus causes an overly aggressive response? What, if any are the numbers on mortality rates by age?
Reply | Report Abuse | Link to thisI imagine as the planet warms these kinds of diseases could very well become common in the states.
Reply | Report Abuse | Link to thisAs we have done to the planet, so the planet will do to us.
I wonder if something like this didn't account for some of the prehistoric "abandoned" cities in that area.
Reply | Report Abuse | Link to thisKienhua68 - interesting speculation. However, I caution on the correlation/causality of measured microclimate change over time and viral morbidity rate. Not completely unfathomable, but worth research and analysis.
Reply | Report Abuse | Link to thisGlobal warming has nothing to do with this. The planet is not exacting revenge. In fact we would be in far worse shape with respect to rodent vector diseases if we were cooling (i.e. more time indoors with the little buggers which was one important factor in the black death). Hanta and other similar viruses are doing what they will. If you place the right person in an environment where they can get and adequate inoculum clinical disease can develop, fulminant disease in rare cases. Yet the vast majority of us can go into the same environment and get the same inoculum and experience little to no symptoms at all. Note the numbers quoted 10000 possible exposures with 3 deaths and a couple dozen cases. This is the norm with viral disease. Its occurrence is a reminder that biology is always at work exploiting opportunity. We just never pay attention to it until by randomness, conditions arise that provide for a concentration of cases. Then and only then does our alarmist news media pick up the story and run it as the latest armageddon that is all to soon to be forgotten.
Reply | Report Abuse | Link to thisThankfully we have PHS personeel who monitor these emergent diseases on a daily basis and can provide for us balanced view of what is really going on.
Preventative steps to avoid Hanta and other rodent vector diseases include:
1) Rodent proof your home and other environs as much as possible.
2) Isolate all food stuffs including pet food and particularly bird seed.
3) Prepare a dilute solution of bleach in a spray bottle and use it when cleaning up dusty areas where rodents may have frequented.
4) Use a good quality surgical mask and change it often. A respirator filter is even better.
5) Avoid staying in places where rodents frequent (including chipmunks and ground squirrels) they are not cute they are vermin.
6) Particular to this case don't feed the rodents in our National Parks. This practice acclimates the vermin to human presence and increases the risk for exposure.
The only way on Earth to destroy any possible viruses while they attack you and to possess The Iron Constitution and The Freedom of Life, is doing the Immunizer...
Reply | Report Abuse | Link to thisEverybody Relax! Yosemite, West Nile and any other viruses on Earth can be destroyed and everybody, kids and adults, can be absolutely untouchable for them nasty critters once and for all...
Human body can be a fortress immune against viral attack...
I believe in the very near future (depends on the governments around the world to arrange the payment) the presence of any type of viruses anywhere in the U.S., Britain, Canada, Australia and the rest of the world will not matter even in the least, because The Deadliest Virus Killer on Earth has been discovered - The Immunizer - The Most Powerful Immunity Booster on Earth. That is just a simple exercise, but is The Complete Colds/Flus/AIDS/Yosemite/West Nile/Cancers Prevention - normally done for a minute a day for kids and adults as the full prevention of the major plagues of civilization. No killer viruses on Earth got any chance against the tremendous power of the immunizer - they just die the moment they touch you...
If the 10,000 or more Yosemite visitors start doing the immunizer for 2 - 3 minutes a day, any hantavirus infection symptoms are excluded, because the dreaded virus will be killed before it takes hold... Even if symptoms are experienced, the immunizer guarantees a very fast recovery... (The same is true for any virus infection possible on Earth)...
Doing the immunizer, I stay healthy all the time. For me Cold and Flu Season does not exist. I wear my summer tees and shorts all the time, even at air temperature of -15C...
I offer my Dream Immunizer (The Deadliest Virus Killer on Earth) to the world for 2 trillion US Dollars. The sooner I am paid, the better for the Entire World... I will disclose the greatest discovery in human history (in more than 200,000 years of humankind on the planet) to everybody and all of us, kids and adults, will stay absolutely healthy all the time, all our lives, even if we are directly exposed to any possibly existing viruses on Earth - mutant, deadly and all the like...
Of course snakes eat mice!
Reply | Report Abuse | Link to this<a href="http://www.youtube.com/watch?v=5JuQfpblygc">Video Proof :)</a>