What Is Hantavirus?

Hantavirus is a virus primarily carried by rodents. It typically spreads to humans who inhale airborne particles from mice and rat droppings, urine, and saliva.

“This hantavirus outbreak on a cruise ship is the first reported event of its kind, so it’s worth paying attention to and watching for any similar cases,” says Robert H. Hopkins, MD, medical director of the National Foundation for Infectious Diseases. “A single outbreak like this, however, doesn’t necessarily mean more outbreaks are likely.”

People usually get hantavirus in rural communities on land, not at sea, adds Peter Chin-Hong, MD, an infectious disease specialist and professor of medicine at the University of California San Francisco School of Medicine. “So this is highly unusual,” he says.

Hantavirus disease in humans is rare.

From 1993 (when public health officials began hantavirus surveillance) to the end of 2023, a total of 890 cases were reported in the United States, with the vast majority in the West and Southwest, according to the Centers for Disease Control and Prevention (CDC).

HPS Hantavirus Symptoms

HPS is most likely to occur in the Western Hemisphere. It is considered to be deadlier than HFRS and mostly attacks the lungs.

Early symptoms can include:

• Fatigue
• Fever
• Muscle aches, especially in the large muscle groups like the thighs, hips, back, and sometimes shoulders

About half of all HPS patients also experience:

• Headaches
• Dizziness
• Chills
• Abdominal problems, like nausea, vomiting, diarrhea, and abdominal pain

Later signs that appear 4 to 10 days after early symptoms include:

• Coughing
• Shortness of breath
• Tightness in chest as lungs fill with fluid

HFRS Symptoms

HFRS is more likely to occur in Europe and Asia. It mostly affects the kidneys.

Usually signs develop within one to two weeks (or, rarely, up to eight weeks) after exposure to the virus.

• Intense headaches
• Back and abdominal pain
• Fever or chills
• Nausea
• Blurred vision
• Possible flushing of the face, inflammation or redness of the eyes, or a rash

Later signs include:

• Low blood pressure
• Lack of blood flow (which causes acute shock as it deprives cells of oxygen and nutrients)
• Internal bleeding (vascular leakage)
• Acute kidney failure, which can cause severe fluid overload

For the most part, hantavirus spreads to humans who inhale airborne viral particles from mice and rat droppings, urine, and saliva.

• Infrequently used buildings, such as storage sheds
• Farm buildings
• Campers or seasonal cabins
• Camp sites or hiking shelters
• Attics or basements
• Construction sites

Hantavirus can be very difficult to diagnose because initial symptoms are similar to many common illnesses such as the flu, according to Chin-Hong.

• Abnormal lung sounds as a result of inflammation
• Signs of kidney failure
• Low blood pressure
• Low blood oxygen levels

“Clinicians need to be very astute to recognize that hantavirus is a possibility,” Chin-Hong says. “Hantavirus will not grow on a routine blood culture. It is typically diagnosed by antibody testing, which may take some time. PCR testing is faster and more sensitive but these tests are not widely available.”

Note that antibody tests look to see if the immune system is producing antibodies against the virus, while PCR tests look for the presence of the virus' genetic material.

Other possible diagnostic tests include urinalysis, and X-ray or computerized tomography (CT) scan of the chest.

Hospitalized patients with hantavirus pulmonary syndrome typically receive oxygen and may need mechanical ventilation (a breathing machine) or extracorporeal membrane oxygenation (ECMO), an advanced form of life support.

Individuals with complications such as hemorrhagic fever and renal syndrome require close monitoring of kidney function and may need dialysis.

To lower the risk of hantavirus infection, it’s important to avoid contact with contaminated dust from rodent excretions when cleaning homes, sheds, or other enclosed areas that have been empty for a long time.

• When opening an unused cabin, shed, or other building, open all the doors and windows, leave the building, and allow 30 minutes to air out.
• 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 percent solution of chlorine bleach or similar disinfectant. Allow it to sit for 30 minutes. Using rubber gloves, discard materials in plastic bags.
• Wash all potentially contaminated hard surfaces with a bleach or disinfectant solution. Vacuum only after the area is thoroughly decontaminated. Consider wearing a mask.
• Seal holes and gaps in structures.
• If you have a heavy infestation of rodents, call a pest control company.

Hantavirus is a serious infection that can worsen quickly without hospitalization and aggressive care.

“ICU treatment is key to survival for many patients, which might also explain the high fatality rate as many people in rural areas may not get to the ICU in time,” says Chin-Hong.

• Hantavirus infection is rare. It mainly occurs in humans who breathe in airborne virus particles from rodent feces and urine.
• Depending on the viral strain, hantavirus can cause a range of symptoms, from headache, fever, and muscle aches to nausea and blurred vision.
• There is no specific medication or vaccine for hantavirus infection but early diagnosis and supportive care (such as with supplemental oxygen) can help with recovery.
• Hantavirus is difficult to diagnose and has a high fatality rate.