Guest post by David Miller
The hantaviruses make up a relatively new genus of viruses. It was first recognized by Western Medicine during the Korean War. In 1993, a new species of hantavirus was found to be behind that was then called Hantavirus Cardiopulmonary Syndrome (HCPS) caused by the Sin Nombre Virus in New Mexico and other Four Corners states. In addition to Hantaan virus and Sin Nombre virus, several other hantaviruses have more recently been implicated as agents.
Hantavirus Pulmonary Syndrome (HPS) is a deadly disease transmitted by infected rodents through urine, droppings, or saliva. Humans can contact the disease when they breathe in the aerosolized virus. HPS was first recognized in 1993 as noted above, and has since been identified throughout the United States. Although uncommon, HPS is potentially deadly. American’s had no reason to fear hantavirus until mid-May of 1993, when several healthy young Navajo died within a short period of time. As a result of their death, research lead to the accurate diagnosis of the disease and determined what the host was. This outbreak occurred because of a combination of unusual environmental conditions. El Nino in 1992 &1993 lead to a warm winter and a wet spring, this contributed to an explosion of growth of vegetation, providing food & cover for a burgeoning rodent population (tenfold increase in deer mice). This population explosion, in turn, exacerbated the spread of the disease. The disease had several names such as “unexplained adult respiratory distress syndrome (ARDS)” during the discovery phases until it ended as HSP.
Currently known carriers in the U.S. are the deer mouse (the primary carrier) along with the cotton and rice rats (in the Southeast) and the white footed mouse in the Northeast, also other carriers may exist. Infected rodents shed the virus through urine, droppings, and saliva. HPS is transmitted to humans through a process called aerosolization. Aerosolization occurs when dried materials contaminated by rodent excreta or saliva are disturbed. Humans become infected by breathing in these infected aerosols. Any activity that puts you in contact with fresh rodent urine, droppings, saliva, or nesting materials can place you at risk. Transmission can also occur when these materials are directly introduced into broken skin, the nose or the mouth. Eating or drinking water exposed to it, or if an infected rodent bites someone may also transmit the virus. The hantaviruses are viable in the environment for up to 3 or 4 days at normal room temperatures. Freezing temperatures will actually INCEASE the time that the virus remains viable. Ultraviolet rays in sunlight kill the viruses. The use of bleach solutions (1 ½ cup per gal. of water) or household disinfectant effectively deactivates hantaviruses when cleaning rodent infestations.
The overall human mortality rate is about 50%, so even immediate medical attention will not guarantee recovery. The primary cause of death is excessive pertinacious fluid in the lungs. The fluid essentially plasma, is leaked from capillaries into the lungs air sacs. Autopsies of HPS victims have found that their lungs were severely fluid-filled. However death is frequently associated with shock and heart failure instead of drowning as a result of the trauma to the lungs. If someone survives the cardiopulmonary phase, they usually recover rapidly. They may have kidney difficulties at first, and then may experience minor respiratory difficulties after recovery.
Cases contacted in the U.S. and Canada in general have been associated with the following activities:
* Sweeping out a barn or other farm/ranch buildings.
* Trapping & studying of mice.
* Using compressed air and dry sweeping in sawmills.
* Handling grain contaminated with rodent droppings & urine.
* Entering a barn infested with rodents.
* Planting/harvesting field crops.
* Occupying previously vacant buildings.
* Disturbing rodent-infested areas while hiking or camping.
* Living in dwellings with a sizable indoor rodent population.
If you have been exposed to rodents or rodent infestations and have symptoms of fever, deep muscle aches, and severe shortness of breath. Other symptoms may include headaches, dizziness, chills, and abdominal discomfort (such as vomiting, nausea and or diarrhea). See your doctor immediately. Inform you doctor of possible rodent exposure so that they are alerted to the possibility of rodent-borne disease such as HPS.
We as trappers are exposed to a lot of rodent waste at cabins, storage sheds, using rodents for bait & lure making, and using their nest materials for making sets. Also, the cold weather during trapping seasons allows the virus a longer life time. The fact that we are handling potential sources, eating on the run and staying in cabins that are infrequently occupied greatly increases our potential for exposure.
I stayed in an old cabin for several nights up by #9 Lake in Aroostook County, Maine two years ago that was a disgusting mess with rodent droppings and odor. I was accompanying a friend who had gotten permission to use the cabin sight unseen. In the past I had used a tent when I went up there, but because I was with him and he had access to a cabin I had left it home. We cleaned up the place as well as possible, but it was so bad that at night when the critters were running around droppings would fall off the rafters. I didn’t like it at the time, and had I known of HPS, I would have not stayed there. I have stayed in old hunting, trapping, and line cabins from Labrador to Florida and from southern California up to Utah and a lot of places in between including overseas. I will say it was by far the worst of anything previous.
If you find yourself with what you think are flu like symptoms within a short period of time after exposure to rodent waste and you are experiencing breathing difficulties., you may want to expedite getting to a doctor really fast. If you do have HPS, you don’t have much time before you’re critical.
Also this sure does give new meaning to Washing Off The Tops of Food and Beverage Cans before opening.
Dave Miller
Lexington TWP.
Dave Miller is a Maine resident, an outdoor writer and a member of the Carrabassett Valley Trappers Association.
