Hantavirus: How It Spreads, Symptoms and Prevention

Hantaviruses are a family of viruses that can cause serious illness and death in people around the world. People catch them mainly from rodents such as rats and mice, especially through contact with their urine, droppings and saliva. Much more rarely, a rodent's bite or scratch spreads the virus. Only one type, the Andes virus, is known to pass from person to person, and usually only to people in close contact with someone who is ill.

Hantaviruses cause two syndromes:

• Hantavirus pulmonary syndrome (HPS) is caused by hantaviruses of the Western Hemisphere, including the United States. The most common one behind HPS in the United States is spread by the deer mouse.
• Hemorrhagic fever with renal syndrome (HFRS) is a group of similar illnesses caused by hantaviruses found mostly in Europe and Asia. One of them, Seoul virus, is found worldwide, including in the United States.

Hantavirus pulmonary syndrome

HPS is a severe, potentially fatal lung disease. Symptoms usually begin 1 to 8 weeks after contact with an infected rodent.

• Early symptoms: fatigue, fever and muscle aches, especially in large muscle groups such as the thighs, hips, back and sometimes the shoulders. About half of patients also have headaches, dizziness, chills, and stomach problems such as nausea, vomiting, diarrhea and abdominal pain.
• Late symptoms, 4 to 10 days after the first phase: coughing and shortness of breath, and sometimes a tight chest as the lungs fill with fluid.

Thirty-eight percent of people who develop respiratory symptoms may die.

Hemorrhagic fever with renal syndrome

HFRS is a severe, sometimes fatal disease that affects the kidneys. Symptoms usually appear within 1 to 2 weeks of exposure, rarely up to 8 weeks.

• First symptoms come on suddenly: intense headache, back and abdominal pain, fever or chills, nausea and blurred vision. The face may flush, the eyes may be inflamed or red, and there may be a rash.
• Later symptoms can include low blood pressure, acute shock, internal bleeding (vascular leakage) and acute kidney failure, which can cause severe fluid overload.

How serious it is depends on the virus. Hantaan and Dobrava viruses usually cause severe illness, fatal in 5% to 15% of cases. Seoul, Saaremaa and Puumala viruses usually cause more moderate illness, with fewer than 1% dying. Full recovery can take weeks to months.

Lowering the risk

The key is to avoid or reduce contact with rodents at home, at work and at campsites:

• seal holes and gaps in the home or garage to keep rodents out;
• set traps in and around the home to reduce infestations; and
• clear away any easily reached food that might attract rodents.

Diagnosis

Hantavirus infection is hard to diagnose in the first 72 hours. If a first test comes too early to find the virus, it is often repeated 72 hours after symptoms begin. Early symptoms such as fever, headache, muscle aches, nausea and fatigue are easily mistaken for influenza. Anyone who suspects hantavirus disease should see a physician right away and mention any possible contact with rodents. State laboratories and CDC can confirm the diagnosis.

Treatment

There is no specific treatment. Patients receive supportive care: rest, fluids and treatment of their symptoms. People with HPS may need help breathing, such as intubation, in which a tube is placed through the mouth to help deliver oxygen. People with HFRS may need dialysis to clear toxins from the blood and keep fluids in balance while the kidneys are not working well.

Sources

• Centers for Disease Control and Prevention, "About Hantavirus": https://www.cdc.gov/hantavirus/about/index.html