The cases follow regions of the country where you're most likely to be exposed to wild rodents. Most cases are in hikers, campers and people in rural areas. There are some areas where deer mice are not found, such as Florida and some of the other states along the eastern coast, but the risk distribution map broadly covers most of North America, including areas of Canada and Mexico.
Does this mean that we should be wary of Hantavirus elsewhere in the country?
It clearly can pop up in other regions of the U.S. There have been cases in the Great Smoky Mountains and in the Sierra Nevadas. The mouse favors higher elevations. And the deer mouse prefers cool, moist forests.
How does the virus get spread to these other areas? Does it have to spread through mouse populations?
We're still figuring out how it's transmitted from mouse to mouse. The mice are reservoirs, so they can harbor the virus without any symptoms. Up to 20 percent of deer mice have evidence of hantavirus infection. In Yosemite, that level is estimated to be 18 percent.
So should people be looking out for hantavirus across the U.S.?
As opposed to watching out for hantavirus, I think it's important for people to avoid contact with rodents, which can spread other diseases, such as plague. For people who live in cabins or houses with a rodent issue, it's important that they deal with the infestation. And upon entering unused cabins, don't sweep or vacuum the dust, which can lead to aerosolization and inhalation of the dust.
This virus has such a high fatality rate—would it be lower if people were more vigilant and sought treatment for symptoms earlier?
The infection itself is quite virulent. It's not simply a matter of detecting it early. There is no vaccine or cure. The treatment we have is primarily supportive. It has been shown that patients who presentearlier in the illness tend to do better. But even patients who present early—their mortality rates are still very high.
We don't know much about how this virus causes disease. Part of the reason is that there have been so few cases. It's clear that this is a very deadly virus—especially because people getting it have been young, healthy adults. It is interesting that infections in elderly and children are not as common. Part of it might be that children and the elderly don't get the same exposure that adults do; healthy adults are the ones going out hiking and camping and doing the cleaning. We do know that when healthy children get it, the mortality rates are still high. So it's a very deadly virus. That being said, the virus is quite rare, and it really requires significant exposure to rodents.
Are there any treatments in the works for hantavirus?
There is a common antiviral that's been tried: ribavirin. It's unclear whether or not it's efficacious against the virus. It's my hope that better appreciation of this virus will help spark the development of drugs or vaccines. It would be possible to make one, but there hasn't really been a strong motivation to work on a vaccine because there have been so few cases.
Should campers be worried?
I don't think there's a reason to be alarmed. Unlike other outbreaks, this virus is not contagious.
It is unusual that there was a cluster here at Yosemite. It opens the question as to why there was a cluster. Maybe because all of the patients had the same exposure history, and as a result, it was probably by chance that they unfortunately became infected by the virus.
There is still a possibility that they were infected by a slightly different strain of the virus or that this virus has different qualities. I am working with a team now to sequence the genome of these new samples and compare them to historical strains to see: Has any change occurred in the genome of this virus to make this outbreak occur? Has the virus changed at all—has it evolved? We're actually finishing that up now, and we hope to have results in a few months.
*Update (9/7/12): A third death was confirmed shortly after this article was posted; the figure was changed from two to three.
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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>