Understanding Hantavirus During a Suspected Outbreak on a Cruise Ship

(SeaPRwire) –   Two Dutch citizens and a German national have died following a suspected hantavirus outbreak aboard the MV Hondius, a cruise vessel operated by Oceanwide Expeditions, according to the World Health Organization (WHO). The global health agency is currently investigating three additional individuals—including two crew members—who fell ill while onboard, with the ship now anchored off the coast of Cape Verde in Africa.

Among those affected, only one case has been confirmed as hantavirus: a British passenger receiving treatment in Johannesburg, South Africa. The remaining five are considered probable cases. The two crew members who became ill reported experiencing breathing difficulties.

How could a disease primarily transmitted by rodents manifest on a cruise ship far at sea? “There are two possible explanations,” Dr. Amesh Adalja, senior scholar at the Johns Hopkins Center for Health Security and adjunct professor at the Johns Bloomberg School of Public Health, tells TIME. “Either there are rodents on board the vessel, or passengers contracted the virus during an excursion in a region where it is endemic.” The ship departed from Argentina—a country where hantavirus is known to circulate—several weeks prior; however, Argentine health authorities reported no documented cases in the area at the time of departure, as noted by the New York Times.

Below is essential information about hantavirus and the ongoing investigation into the suspected outbreak on the cruise ship.

What is hantavirus?

Hantavirus is a group of viruses transmitted mainly through the urine, feces, or saliva of infected rodents such as rats or mice, explains the U.S. Centers for Disease Control and Prevention (CDC). Each strain within the Hantaviridae family typically associates with a specific rodent host, which carries the virus without showing symptoms.

In the United States, hantavirus infections have been most frequently reported in the Southwest, particularly around the Four Corners area where Utah, Colorado, Arizona, and New Mexico converge. U.S. public health officials began monitoring hantavirus cases in 1993 after a notable outbreak in that region. Since then, nearly 900 laboratory-confirmed cases have been recorded. Among patients diagnosed with hantavirus pulmonary syndrome in the U.S., approximately 35% have died.

People can become infected by inhaling aerosolized particles from rodent droppings, urine, or nests; by consuming food or touching objects contaminated by infected rodents; or through bites or scratches from rodents.

Is hantavirus contagious between people?

Generally, hantavirus does not spread easily from person to person, states Adalja. However, one exception exists: Andes virus, part of the hantavirus family, may be transmitted via respiratory droplets among close household contacts, adds Kartik Chandran, professor of microbiology and immunology at Albert Einstein College of Medicine. It remains unclear whether this particular virus is responsible for the current cluster—whether confirmed or suspected—onboard the cruise ship. A spokesperson for the WHO noted that “detailed investigations are ongoing, including further laboratory testing and epidemiological tracing. Viral sequencing is also underway.”

What are the symptoms of hantavirus infection?

The virus primarily affects the lungs and kidneys, per the Mayo Clinic, causing fatigue, fever, headaches, chills, nausea, and vomiting. Approximately ten days after exposure, individuals typically begin experiencing shortness of breath as fluid accumulates in the lungs.

Some patients may also develop kidney complications one to two weeks post-infection. These often start with fever, nausea, and pain in the back or abdomen and can progress to low blood pressure and internal bleeding if kidney function deteriorates significantly.

How is hantavirus diagnosed?

A diagnostic test for hantavirus exists, but its accuracy decreases during the first 72 hours after exposure. Medical professionals advise that if infection is suspected, a second test should be administered at least 72 hours after symptom onset.

Are there treatments available for hantavirus?

“There is currently no standardized antiviral therapy for hantaviruses,” says Adalja. The CDC recommends rest, adequate hydration, and medications to reduce fever. Supplemental oxygen may help manage more severe respiratory symptoms.

Researchers have developed antibody-based therapies and vaccines that prove effective in preventing or mitigating disease in animal models. However, Chandran emphasizes that “the real barrier is funding, not scientific capability or medical innovation.” Despite promising results in preclinical studies, these interventions have yet to undergo human trials due to limited financial support and pharmaceutical industry disinterest.