It's been a while since cases have been reported in West Virginia, but the recent death of a Washington state woman has triggered a word of caution about a microbe related to the virus that infected her.
The hantavirus -- a pathogen carried by deer mice and spread to humans by tiny particles kicked into the air -- often asserts itself in spring, particularly during a dry spell that follows a period of heavy rainfall, said Hector Aguilar-Carreno, virus researcher and assistant professor at WSU's school for Global Animal Health and the Department of Veterinary Microbiology and Pathology.
In July 2004, two cases of hantavirus pulmonary syndrome were identified in Randolph County. One was a wildlife science graduate student trapping small mammals and the other was a cabin owner who removed mice from his cabin.
"People are at greatest risk when they enter sheds and other closed-in structures with poor air circulation that have been infested with deer mice. It's important to take precautions to prevent infection," said Aguilar-Carreno, who has spent most of his career researching zoonotic viral diseases (those that spread from animals to humans).
In this case, the animal is the deer mouse that harbors the hantavirus but doesn't get sick. People become sick after breathing in virus-laced dust stirred up from the mouse's dried saliva, droppings or urine.
"It's not that people should be alarmed, but they should be watchful," he said.
Hantavirus has become a household word since it was identified in the U.S. during a 1993 cluster in the Southwest. But how to prevent contracting it isn't yet common knowledge, said Aguilar-Carreno. Precautions range from sealing holes and gaps in buildings to spraying disinfectant on dead rodents and rodent droppings or nests, he said.
There is no vaccine and no cure for hantavirus pulmonary syndrome. Medical treatment must be given before the infected person becomes gravely ill.
Once a person is infected, it takes one to five weeks for symptoms to develop, according to the U.S. Centers for Disease Control and Prevention, which monitors the disease nationwide: "We do know that if infected individuals are recognized early and receive medical care in an intensive care unit, they may do better," says the agency website.
Diagnosis is tricky. Muscle aches, fatigue and fever make it hard to distinguish from influenza, according to the CDC. But four to 10 days after those symptoms surface, the infection becomes full-blown as fluid leaks into the lungs and patients struggle to breathe. Fortunately, if people suspect they've been exposed, a blood test can be done to confirm it before they move into the critical stage.
Not all deer mice carry the hantavirus, and the number that do seems to vary each year based on environmental conditions, said Aguilar-Carreno.
For example, more rain produces bumper crops of vegetation that the mice eat. This results in higher populations of babies, increasing the likelihood that more mice are spreading the virus.
Which means people are more likely to encounter the hantavirus, said Aguilar-Carreno. During a dry spell, "someone sweeping or moving boxes in a space inhabited by deer mice can stir the contaminated particles into the air," he said.
"Because hantavirus cases tend to increase when the weather warms up, people should take precautions," he said. "While the disease isn't common, it is serious, if not lethal."
For information, contact Hector Aguilar-Carreno, WSU Paul G. Allen School for Global Animal Health, 509-335-4410, hagui...@vetmed.wsu.edu.
Reach Sara Busse at sara.bu...@wvgazette.com or 304-348-1249.