It was a cold Utah morning when the man went to his old pickup truck to haul hay to animals in the field. Mice had crawled in to get out of the weather, and he shooed them out. Then he turned on the heater to warm the vehicle.
Within 72 hours, he was dead from hantavirus, an often-fatal airborne respiratory illness that comes from exposure to rodent saliva, urine and droppings, especially from deer mice. Health officials believe the heater blew out mice droppings and he got a dose so virulent he might has well have been air-bombed with it.
Utah has had 17 confirmed cases of hantavirus over the years, most from agricultural exposures, often from deep cleaning areas like crawl spaces, sheds and barns where rodents have sheltered. The victims ranged from 19 to 67. Health officer Robert Resendes of the Central Utah Public Health Department said no children have become ill, though some have tested positive for the antibodies; they were clearly exposed.
Summer is prime time for hantavirus. It is now that the danger is greatest, because people take advantage of good weather and more spare time to do the very activities that bring them in contact with hantavirus.
In the earliest known case anywhere, a Utah man became ill in 1959, more than 30 years before health officials had a name and a cause for the symptoms, which usually show up from four days to six weeks after exposure and include fever, chills, headache, muscle aches and sometimes nausea, vomiting and abdominal pain. It quickly progresses to difficulty breathing, caused by fluid buildup in the lungs. He survived.
The illness was confirmed years later from a blood sample. It was the same with a 25-year-old woman who almost died in 1991. Years later, she read about the illness and had her blood tested. Her hantavirus antibodies "were off the chart," Resendes said.
Not everyone is so lucky. Nationally, about half of the people who get hantavirus pulmonary syndrome die; in Utah, it has been closer to 30 percent, with five fatalities, including one last year. Health officials don't know the true hantavirus count; blood or tissue must be sampled to look for the disease. It was identified after an outbreak in the Four Corners region in 1993, and cases have been found in 27 states.
Utah hasn't had a case yet this year, which Resendes hopes means people are aware of precautions and are taking them. Last year, four cases were confirmed.
Wet weather and lots of food seem to promote hantavirus, because rodent populations thrive. It has been drier this year. On the other hand, infestations of Mormon crickets could have provided an abundant food source, which might boost mice populations, Resendes said.
The only sure bet is to stay away from it. The Utah Department of Health and the Centers for Disease Control and Prevention offer these tips:
Keep a clean house, especially the kitchen. Put tight-fitting lids on garbage. Throw out uneaten pet food daily.
Keep spring-loaded rodent traps near baseboards, where rodents are more apt to run. "Don't live-trap them," Resendes said. "Kill them," because live-trapping terrifies them and they salivate, urinate and defecate even more, spreading the virus. Or use EPA-approved rodenticide in covered bait stations. Be careful because the poisons are harmful to pets and people.
Last year, a man told Resendes he'd been breeding deer mice but had let them go because of the health risk. Resendes said destroying them is the only sure way to avoid hantavirus risk.
In areas with bubonic plague, spray flea killer before setting traps, since fleas leave rodents once they die and look for other food sources, including people and pets.
Seal entry holes from outdoors.
Clear brush, grass and junk where rodents may nest away from house foundations. Also elevate hay, woodpiles and garbage cans to eliminate possible nesting sites. If possible, move them away from the house.
If you're cleaning rodent-infested areas, spray with a general household disinfectant such as Lysol or a solution of three tablespoons bleach to a gallon of water. Wear latex or rubber gloves. Dead rodents should be sprayed, then placed in double garbage bags for disposal.
For heavily infested or enclosed areas, like crawl spaces or cellars, get additional guidelines from state or local health departments.