Saturday, February 25, 2017

Automobile Air System Infestation as Hantavirus Source

Mouse Infestation of Auto Cabin Air Filter

One of the future HantaSite articles will begin an analysis of risks from automobile air systems. Mouse infestations of these systems are extremely common. Toyota vehicles appear to be especially attractive to rodents.

The following is a quote from an otherwise excellent Canadian government hantavirus information website, (in the links list at right).

"Consult your health care provider as soon as possible if you have had contact with rodents and are feeling ill. The sooner you get treatment, the better your chances for recovery"

If you report to an emergency ward with flu-like symptoms, you may be asked about contact with rodents. If you answer yes you might be tested for hantavirus. But no one in Emergency or ICU will ever ask you if you were in an automobile.

The result is that the standard questioning for patients presenting with "unidentified community acquired pneumonia," a catch-all classification for incoming patients, systematically excludes any who may have acquired hantavirus by driving an infested vehicle. In general, no hantavirus test, no hantavirus diagnosis. This possible omission may only slightly affect patient care, but it can adversely impact our understanding of the epidemiology of hantavirus.

The following is a brief outline of the upcoming article.

Automobile Cabin Air Systems as a Transmission Mode
            Incidence of mouse infestation in automobile cabin air intakes
            Rapid capture, drying, and aerosolization of SNV laden mouse urine            
            Physics of electret filters, minimum efficiency particle size
            Denaturing of SNVvirions – time factors

This Youtube video shows a mouse infestation in an auto air filter system. If you google "mice cabin air filter" or anything like that you will see many, many such photographs and complaints about uncontrollable automobile mouse incursions.

The man performing this cleanup is making a critical mistake. He is wearing gloves, but NOT wearing a respirator mask. The primary risk to him is through inhaling the dust he is raising from the mouse nesting materials.

Cleaning processes like this should be done only while wearing a P100 particle mask. These masks are much more effective than the typical "surgical masks" that are more common. They are not very expensive and are a good investment for many purposes.

The following comment from a Toyota Tacoma discussion site describes a common experience.

"anyone else had this problem??? i got in my truck the other day and out of the blue there was a hint of dead animal smell, thinking that i was from outside i continued to drive, a couple miles later i turned the heat on, BAD IDEA!! i almost puked...

"when i got to work i checked my engine air filter, nothing in there... i didnt realise i had a cabin air filter til later on in the day. removed the glove box, super easy thankfully, pulled 2 tabs, there was the filter."

i started sliding it out, i wasnt moving, finally after some prying, came out a ton of chewed paper, leaves and sticks, and then 2 dead baby mice, very tiny, they were still soft, so they werent dead long. so i got a new filter, vaccumed everything and sprayed an ac duct spray for mildew etc. the next day, smells still there... i figured id take it apart again, sure enough i had missed another baby... took that out. sprayed again."

This guy didn't realize he had a cabin air filter. How would he know unless he actually read the owner's manual? These filters are relatively new and are usually incredibly well-concealed behind the glove box. Close to half of car owners are not aware that they breath through filters that are supposed to be changed about once per year.

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