Hantavirus Pulmonary Syndrome

Causes

A member of the Bunyaviridae family, the genus Hantavirus (first isolated in 1977) is responsible for hantavirus pulmonary syndrome. Disease transmission is associated with exposure to infected rodents, which are the primary reservoir for this virus. Data suggest that deer mice are the main source, but pinion mice, brush mice, and western chipmunks living in close proximity to humans in rural areas are also carriers. Hantavirus infections have been documented in people whose activities are associated with rodent contact, such as farming, hiking or camping in rodent-infested areas, and occupying rodent-infested dwellings.

Infected rodents manifest no apparent illness. However, they shed the virus in their stool, urine, and saliva. Human infection may occur from inhalation, ingestion (of contaminated food or water, for example), contact with rodent excrement, or rodent bites. Other means of transmission - from person to person or by mosquitoes, fleas, or other arthropods ­ haven't been reported.

Signs and symptoms

The first symptoms are flu-like and may include fever, muscle and body aches, chills, cough, headaches, nausea, vomiting, and diarrhea, or feeling tired. The lungs then begin filling with fluid, making breathing difficult. If you have been exposed to rodents and experience these symptoms, you should see your doctor immediately.

Diagnostic tests

• CBC (elevated white blood count )
• platelet count (less than 150,000 and decreasing)
• X-ray of the chest (may show interstitial infiltrates or diffuse infiltrates involving both lungs)
• liver enzymes (LDH is elevated)
• serum albumin (decreased)
• hematocrit (increased, showing hemoconcentration)
• serological testing for hantavirus

Treatment

Management during the first few hours is critical, requiring intubation and aggressive respiratory management. Treatment consists of maintaining adequate oxygenation, monitoring vital signs, and intervening to stabilize the patient's heart rate and blood pressure.

Drug therapy includes administration of vasopressors, such as dopamine or epinephrine, for hypotension. Fluid volume replacement may also be necessary, although precautions must be taken not to overhydrate the patient.

Recent investigational drug therapy involves ongoing clinical trials with ribavirin.

Prevention

The best way to prevent infection from hantavirus is to avoid contact with rodents and their droppings. The best way to prevent hantavirus infection is to control rodents in and around the home. Keep mice out of your home and learn how to clean up safely.