Hantavirus pulmonary syndrome

Overview

Mainly occurring in the southwestern United States, but not confined to that area, Hantavirus pulmonary syndrome is a viral disease first reported in May 1993. The syndrome, which rapidly progresses from flulike symptoms to respiratory failure and, possibly, death, is known for its high mortality. The hantavirus strain that causes disease in Asia and Europe — mainly hemorrhagic fever and renal disease — is distinctly different from the one currently described in North America.

Symptoms

The early symptoms of hantavirus disease are similar to the flu and include:

  • Chills
  • Fever
  • Muscle aches

People with hantavirus may begin to feel better for a very short amount of time, but within 1-2 days, it becomes hard to breathe. The disease gets worse quickly. Symptoms include:

  • Dry cough
  • General ill feeling (malaise)
  • Headache
  • Nausea and vomiting
  • Shortness of breath

Source: National Institute of Health

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 aerosols (such as dust) contaminated by urine or feces from infected rodents, the primary reservoir for this virus. Data suggest that the deer mouse is the main source, but pinon mice, brush mice, and western chipmunks in close proximity to humans in rural areas are also sources. 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 but shed the virus in feces, urine, and saliva. Human infection may occur from inhalation, ingestion (of contaminated food or water, for example), contact with rodent excrement, or rodent bites. Transmission from person to person or by mosquitoes, fleas, or other arthropods hasn’t been reported.

Prevention

  • Avoid exposure to rodent urine and droppings.
  • When hiking and camping, pitch tents in areas where there are no rodent droppings.
  • Avoid rodent dens.
  • Drink disinfected water.
  • Sleep on a ground cover and pad.
  • Keep your home clean. Clear out potential nesting sites and clean your kitchen.

 

If you must work in an area where contact with rodent urine or feces is possible, follow these recommendations from the Centers for Disease Control and Prevention (CDC):

 

  • When opening an unused cabin, shed, or other building, open all the doors and windows, leave the building, and allow the space to air out for 30 minutes.
  • Return to the building and spray the surfaces, carpet, and other areas with a disinfectant. Leave the building for another 30 minutes.
  • Spray mouse nests and droppings with a 10% solution of chlorine bleach or similar disinfectant. Allow it to sit for 30 minutes. Using rubber gloves, place the materials in plastic bags. Seal the bags and throw them in the trash or an incinerator. Dispose of gloves and cleaning materials in the same way.
  • Wash all potentially contaminated hard surfaces with a bleach or disinfectant solution. Avoid vacuuming until the area has been thoroughly decontaminated. Then, vacuum the first few times with enough ventilation. Surgical masks may provide some protection.

 

Source: National Institute of Health

Diagnosis

Despite ongoing efforts to identify clinical and laboratory features that distinguish Hantavirus pulmonary syndrome from other infections with similar features, diagnosis currently is based on clinical suspicion along with a process of elimination developed by the Centers for Disease Control and Prevention (CDC) with the Council of State and Territorial Epidemiologists. (See Screening for Hantavirus pulmonary syndrome.) Serologic testing for hantavirus can be performed. Laboratory tests usually reveal an elevated white blood cell count with a predominance of neutrophils, myeloid precursors, and atypical lymphocytes; elevated hematocrit; decreased platelet count; elevated partial thromboplastin time; and a normal fibrinogen level. Usually, laboratory findings demonstrate only minimal abnormalities in renal function, with serum creatinine levels no higher than 2.5 mg/dl. Chest X-rays eventually show bilateral diffuse infiltrates in almost all patients (findings consistent with acute respiratory distress syndrome).

Prognosis

Hantavirus is a serious infection that gets worse quickly. Lung failure can occur and may lead to death. Even with aggressive treatment, more than half of people who have this disease in their lungs die.

 

Source: National Institute of Health

Treatment

Primarily supportive, treatment consists of maintaining adequate oxygenation, monitoring vital signs, and intervening to stabilize the patient's heart rate and blood pressure. Drug therapy includes vasopressors, such as dopamine or epinephrine, for hypotension. Fluid volume replacement may also be ordered (with precautions not to overhydrate the patient). Ribavirin in aerosol form has been used for children, but its efficacy for adults has not been proven.