By Kim Greenwood

ALAMOSA, Colorado--Hantavirus, a disease that killed 13 people in the Southwest during a 1993 outbreak, continues to be a major health concern for local officials, including Reclamation managers.

With 36 reported cases of hantavirus in New Mexico and Colorado since 1994 and the recent finding of deer mice nests at Reclamation work sites in the region, the Alamosa Field Division held a safety seminar to alert managers to the danger and recommend ways to prevent infection.

The presentation was led by Stan Kauchek, of the New Mexico State Occupational Safety and Health Department's Division of Labor in Albuquerque. He reviewed the history of the virus in the area, described the symptoms, and detailed a number of precautions that can be taken.

Reclamation managers and staffers at the Nov. 8. seminar here included Jim Canning, regional safety manager, Salt Lake City Office; Russ Fennema, safety manager, Albuquerque Office; Mark Treviño, manager, Alamosa Field Division; and employees of the Alamosa and Chama Field Divisions. Also attending were

After the 1993 outbreak of hantavirus, several health agencies worked together to identify the disease and develop possible treatments. The groups included the Center for Disease Control, Indian Health Service, University of Albuquerque, Navajo Nation, New Mexico Department of Health, and the Office of Medical Investigator. Researchers attempted to determine the symptoms of the disease at the onset of infection as well as at its advanced stage and to correlate prognoses for infected humans. They also sought to identify the carrier of the disease.

According to Kauchek, the Sin Nombre strain of hantavirus is most common in the southwestern United States. DNA tracing confirmed that the disease had caused at least one death as early as 1959. Researchers theorized that the increase in victims in 1993 was linked to the larger rodent population caused by El Nino, which provided more moisture, food, and shelter for mice.

Kauchek also reviewed case studies, including that of a young man from the Four Corners area who died of the disease shortly after attending his fiancee's funeral. Through an investigation of the couple's activities prior to contracting the disease, researchers learned that they had cleaned out a barn where they may have contracted the virus. They were both healthy, had similar symptoms, and both died untimely deaths.

DNA samples from the victims and rodents taken from their households contributed to the diagnosis. The samples matched, providing the link to the carrier of the disease in the area--deer mice. Other carriers in America are the Western Harvest Mouse, Mexican Harvest Mouse, Cotton Rat, California Meadow Mouse, and White-Footed Mouse.

Because the virus is zoonatic--transmitted from animals to humans--exposure occurs through direct contact with the rodent or other animal carrying the disease or any of its excreta (feces or urine). The virus, which can survive 48 to 72 hours after the host has died, contains a fatty envelope that attaches itself to dust particles stirred up during dry sweeping or excessive air movement caused by fans or blowers. The virus dies quickly when exposed to ultraviolet light.

The virus incubates in humans in one to five weeks. Initial symptoms resemble those of the flu: fever, fatigue, and muscle aches. In seven to ten days, intense muscle aches occur in the large muscle groups of the thighs, hips, back, and shoulders, accompanied by headache, nausea, vomiting, diarrhea, coughing, and shortness of breath. If the disease is diagnosed early and infected patients are hospitalized immediately, they have a 50 percent chance of recovery, depending on their health and immunity. If not, death quickly occurs from pulmonary or renal failure.

To minimize the risk of exposure to hantavirus in work and home environments (including garages, shops, barns, and vehicles), air out enclosed areas prior to entering, and spray or soak rodent excreta and rodent nesting sites with a disinfectant. At a minimum, clean-up activities should include the use of rubber gloves to remove any nesting material after it has been sprayed with a disinfectant. A 10:1 solution of water and bleach may also be used as a disinfectant.

In areas of rodent infestation, personal protective equipment should include a HEPA filter respirator, N100, gloves, a one-piece hooded suit with foot protection covering, a bag to place the dead rodent or feces into, and a bag in which to place the uniform and other articles upon completion of work in the infested area.