What Is Hantavirus? Symptoms, Transmission and What Patients Need to Know

A suspected hantavirus outbreak aboard the MV Hondius, a cruise ship traveling from Argentina through remote parts of the Atlantic Ocean, has killed at least three people and left one other critically ill this week, with nearly 150 people stranded off the coast of Cape Verde after the ship was refused permission to dock. The World Health Organization has confirmed cases and is actively investigating, but has been clear that the risk to the general public is low and there is no need for panic.

Still, the outbreak has many people asking a reasonable question: What exactly is hantavirus?

What Is Hantavirus?

Hantaviruses are a family of viruses that can cause serious illness and death. They cause two main diseases: hantavirus pulmonary syndrome (HPS), which predominantly affects the lungs, and hemorrhagic fever with renal syndrome (HFRS), which affects the kidneys. HPS is the form most commonly seen in North and South America, while HFRS is more prevalent in Europe and Asia.

From 1993 to 2023, only 890 cases of hantavirus disease had been reported in the United States, most of them in Western states, making this a genuinely rare condition — though one that can be severe when it does occur.

How Does It Spread?

People get hantavirus from contact with rodents, such as rats and mice, especially when exposed to their urine, droppings, or saliva. The most common route of infection is inhaling particles that become airborne when contaminated droppings or nesting materials are disturbed — for example, when cleaning out a shed, cabin or other enclosed space where rodents have been active.

The vast majority of hantavirus strains do not spread from person to person. Person-to-person transmission has only been recorded with the Andes virus, a strain found in South America. Given that the MV Hondius departed from Argentina, investigators are actively examining whether the Andes virus may be involved in the current outbreak.

What Are the Symptoms?

Early symptoms of HPS usually appear one to eight weeks after contact with an infected rodent and include fever, fatigue, muscle aches (especially in the thighs, hips and back), GI symptoms, nausea and headache — symptoms that are easily confused with influenza.

What makes hantavirus particularly dangerous is what comes next. Four to 10 days after the initial phase of illness, late symptoms appear, including coughing and shortness of breath, as the lungs begin to fill with fluid. HPS can be deadly, with roughly 38% of people who develop respiratory symptoms dying from the disease.

Hantaviruses found in Europe and Asia that cause HFRS follow a slightly different pattern, beginning with headaches, abdominal pain and nausea before potentially developing into low blood pressure, internal bleeding and acute kidney failure, with a fatality rate of 5% to 15%, depending on the strain.

Is There a Treatment?

There is no specific treatment for hantavirus infection. Patients receive supportive care including rest, hydration and management of symptoms. Those with severe breathing difficulties may need intubation and breathing support. Early medical attention is critical — the sooner a patient is seen, the better their chances of survival.

If you have had potential rodent exposure and develop any of the early symptoms described above, see a physician immediately and tell them about your exposure history.

How Can You Protect Yourself?

Prevention is straightforward and centers on reducing contact with rodents and their waste. The CDC recommends sealing holes and gaps in your home or garage, placing traps in and around your home and cleaning up any food sources that might attract rodents. When cleaning areas where rodents may have been active, always wear gloves, use a bleach solution to wet down droppings before wiping them up and avoid sweeping or vacuuming dry waste, which can send virus particles into the air.

For hikers, campers and anyone spending time in rural or wilderness settings, avoid sleeping near rodent burrows or nesting areas and store all food in sealed, rodent-proof containers.