Hantavirus pulmonary syndrome

Overview

Hantavirus pulmonary syndrome (HPS) is a rare but potentially fatal respiratory disease caused by infection with hantaviruses, a group of viruses carried by rodents. First recognized in the United States in 1993, HPS typically begins with flu-like symptoms and rapidly progresses to severe respiratory distress and pulmonary edema. It primarily affects otherwise healthy individuals and requires prompt medical intervention. The disease is most prevalent in rural and semi-rural areas where contact with rodent droppings, urine, or saliva is more likely.

Causes

HPS is caused by various strains of hantaviruses, with the most common in North America being the Sin Nombre virus. These viruses are transmitted to humans through:

• Inhalation of aerosolized particles from rodent urine, droppings, or saliva

• Direct contact with rodents or contaminated materials

• Rarely, bites from infected rodents

The deer mouse (Peromyscus maniculatus) is the primary reservoir for the Sin Nombre virus in the U.S. Person-to-person transmission of HPS has not been reported in North America.

Symptoms

Symptoms of HPS develop in two distinct phases:

1. Prodromal Phase (Lasts 3–5 days):

• Fever and chills

• Muscle aches (especially in the back, hips, and thighs)

• Fatigue

• Headache and dizziness

• Nausea, vomiting, or abdominal pain

2. Cardiopulmonary Phase:

• Rapid onset of coughing and shortness of breath

• Fluid accumulation in the lungs (pulmonary edema)

• Hypotension and shock

• Respiratory failure

This second phase often progresses quickly, requiring hospitalization and intensive care.

Diagnosis

Early diagnosis of HPS is crucial due to its rapid progression. Diagnostic measures include:

• Clinical history: Noting recent exposure to rodent-infested areas or rural environments

• Blood tests: Detect hantavirus-specific IgM and IgG antibodies or viral RNA through PCR

• Chest X-ray: Reveals bilateral interstitial infiltrates and fluid buildup in the lungs

• Complete blood count: May show low platelet count, elevated white blood cells, and abnormal hematocrit levels

Treatment

There is no specific antiviral treatment or vaccine for HPS. Management is primarily supportive and may include:

• Hospitalization in an intensive care unit (ICU): For close monitoring

• Oxygen therapy: To manage respiratory distress

• Mechanical ventilation: In severe cases of respiratory failure

• Fluid and electrolyte management: To prevent shock and maintain organ function

Early recognition and hospitalization can significantly improve survival rates.

Prognosis

The prognosis of Hantavirus pulmonary syndrome depends on the speed of diagnosis and access to intensive medical care. The condition has a high mortality rate, estimated between 30% and 50%. However, patients who receive prompt, aggressive supportive treatment can recover fully. Survivors generally do not experience long-term complications, and preventive strategies, especially rodent control and avoiding exposure are critical for reducing risk.