A suspected outbreak of hantavirus, a rare but deadly disease that attacks the lungs, has left three people dead and several others severely ill aboard a luxury cruise ship.

Here’s what we know about the voyage and the virus that also made headlines last year after it killed Gene Hackman’s 65-year-old wife, Betsy Arakawa.

What’s going on?

Global health officials and the cruise operator, Oceanwide Expeditions, are investigating and working to contain the illnesses suspected to have been brought on by the rodent-borne illness aboard the MV Hondius — a Dutch-flagged ship, according to the World Health Organization.

On Monday, the WHO announced that the luxury ship carrying 147 passengers and crew had two laboratory-confirmed cases and five suspected cases of hantavirus. The three deaths are included in that total.

The cruise ship, which was on a 46-day journey that traveled from Antarctica with stops in Argentina, has remained off the coast of Cape Verde in the Atlantic Ocean. During a news conference, WHO officials said they’re planning to medically evacuate two individuals with suspected infections.

The vessel departed Ushuaia, Argentina, on April 1 and traveled across the Atlantic with multiple stops in remote and ecological diverse regions, according to the WHO.

“The extent of passenger contact with local wildlife during the voyage, or prior to boarding in Ushuaia, remains undetermined,” the organization said in a statement.

What we know about hantavirus

Typically, hantavirus spreads by inhaling particles contaminated with the urine, feces or saliva of wild rodents.

“What we don’t know about this current outbreak is whether someone got onto the ship and was already sick or there were rodents on the cruise,” said Dr. Gaby Frank, director of the Johns Hopkins Special Pathogens Center.

There is, however, a strain of hantavirus that can be spread from human to human, known as the Andes virus, Frank said.

In such a case, a person would first be infected by a wild rodent’s contaminated particles and then, after becoming infected themselves, pass the infection to another person.

There are 50 species of hantavirus. The virus that’s found in the Americas tends to cause a cardiopulmonary syndrome, a condition that affects the heart and the lungs, according to Frank.

There have been 890 laboratory-confirmed cases of hantavirus disease reported in the United States since surveillance began in 1993, according to the most recent data from the U.S. Centers for Disease Control and Prevention.

The data suggest that contracting hantavirus is rare, said Dr. Afif El-Hasan, member of the American Lung Assn.’s national board of directors.

“That being said, it’s probably underdiagnosed because the symptoms are a lot like the flu or other illness,” El-Hasan said. “And a lot of people may have passed away or had hantavirus, but it was never diagnosed.”

There is no vaccine or specific antiviral medicine for hantavirius.

The ICU treatment may include intubation and oxygen therapy, fluid replacement and use of medications to lower blood pressure, according to the American Lung Assn.

Know the signs of hantavirus and next steps

Early symptoms of hantavirus are similar to the flu and include fatigue, fever and muscle aches, according to the CDC. Signs of these symptoms start to show within one to eight weeks after contact with an infected rodent.

Half of those who contract the virus also experience headaches, dizziness, chills, nausea, vomiting, diarrhea and abdominal pain.

Four to 10 days after the initial phase of the illness, another round of symptoms can develop, which include coughing, shortness of breath and possible tightness in the chest as the lungs fill with fluid.

Even though contracting hantavirus in the United States continues to be a rare event, El-Hasan said, people should take these initial symptoms seriously and promptly seek medical care.

Hantavirus can be deadly. CDC officials said 38% of people who develop respiratory symptoms may die from the disease.

How to protect yourself

Hantavirus cases can occur year-round, but the peak seasons in the United States are in the spring and summer, which coincide with the reproductive seasons for deer mice.

To lessen your risk of infection, keep wild rodents out of your home, workplace, shed, cabin, car or other enclosed spaces.

Los Angeles County public health officials offer suggestions on how you can keep rodents at bay, which include:

• Sealing up holes, the width of a pencil or larger, that mice can squeeze into.
• Place snap traps to catch any rodents. The CDC cautions against using glue or live traps because they can scare the rodents, causing them to urinate, which increases your chances of exposure to any virus they may be carrying.
• Store all food items in rodent-proof containers.

If you find evidence of mice in a space that you frequent, local and state officials advise:

• Before you clean, air out the space for 30 minutes. Equip yourself with rubber or plastic gloves, an N-95 mask and a disinfectant or mixture of bleach and water.
• While cleaning, spray the contaminated areas with your disinfectant and let it soak for at least five minutes. Do not sweep or vacuum the area, the movement could stir up the infectious materials in the air. Instead, use paper towels, a sponge or a mop to clean. When you’re done, put everything, including cleaning materials, in a bag and toss it in your trash bin.