What does the MV Hondius outbreak tells us about hantavirus?

For days, the hantavirus-hit cruise ship MV Hondius has made headlines worldwide, bringing a long-known yet often overlooked virus to the center of global attention. After nine cases linked to the outbreak, including three deaths, were reported by the World Health Organization (WHO), the vessel arrived last weekend in Spain's Tenerife, where more than 90 passengers were evacuated under supervised health precautions by domestic and international health authorities.

The infections were identified as the Andes virus (ANDV) – the only documented strain of hantavirus capable of human-to-human transmission. Yet despite the alarming scenes surrounding the outbreak, WHO officials stressed that the broader public health risk remains low.

Still, the outbreak has raised widespread concerns: What is hantavirus? How worried should we be about it? How could a virus carried quietly in the wild suddenly find its way onto a cruise ship? What makes ANDV different?

What should we know about hantavirus?

Hantaviruses are not new. They are a family of viruses that can cause serious illnesses and death, according to the US Centers for Disease Control and Prevention (US CDC). Humans can become infected through contact with the urine, saliva or droppings of infected rodents, or by inhaling contaminated particles in the air. In rare cases, transmission can also occur through rodent bites.

Different hantavirus strains cause different illnesses. The Chinese Center for Disease Control and Prevention (China CDC) says that some attack the lungs, triggering hantavirus pulmonary syndrome (HPS), a rare but often deadly respiratory disease with fatality rates reaching about 38% among severe cases. Others cause hemorrhagic fever with renal syndrome (HFRS), also known as epidemic hemorrhagic fever (EHF), which damages the kidneys and is more commonly seen in Europe and Asia with a fatality rate ranging from 1% to 15%.

How can hantavirus infections be treated and prevented?

Currently, there is no specific cure for hantavirus infection. The US CDC says treatment mostly relies on supportive care: rest, hydration and symptom management. Patients with HPS may require oxygen therapy or mechanical ventilation. Those suffering kidney damage from HFRS may need dialysis when the kidneys can no longer properly filter toxins from the blood.

Prevention still begins with simple steps: avoiding contact with rodents. Wang Shiwen, deputy director of the National Institute for Viral Disease Control and Prevention at the China CDC, said people working or traveling outdoors, especially in regions where hantaviruses such as the Andes strain circulate, should pay close attention to personal protective measures.

The US CDC also advises pet rat owners to test new rodents for hantavirus before bringing them home and to keep pet rodents away from wild mice and rats. Households with children under 5, pregnant women or people with weakened immune systems are also discouraged from keeping rodents as pets.

What do we know about the outbreak on MV Hondius and ANDV?

Sometimes, the most unsettling outbreaks are not the largest ones, but the ones that remind the world how thin the boundary can be between remote wilderness and modern global life.

ANDV linked to the outbreak aboard the MV Hondius stands apart because it can spread between humans. However, experts emphasize that transmission typically requires prolonged, close contact – often among family members, caregivers or healthcare workers. It is not considered highly contagious in community settings.

According to WHO reports, the first two confirmed patients aboard the ship had recently traveled through South America on a birdwatching expedition and visited areas known to harbor rodents carrying the ANDV.

"This is not the first spillover of this long-existing virus," said Dr. Zhang Wenhong, director of China's National Center for Infectious Diseases. "Only the setting has changed."

Zhang believes the next phase of the outbreak may depend largely on time, as the ANDV can incubate for as long as six weeks, which means that additional cases could still emerge among passengers returning home. 

Some countries have introduced or are preparing 42-day quarantine and monitoring measures for repatriated passengers in line with WHO recommendations. Spanish passengers will be kept in hospital for the full 42 days, while French passengers will be hospitalized for 72 hours then allowed home to self-isolate for a further 45 days, according to the respective governments, Reuters reported on Sunday.

For close contacts and medical workers, monitoring remains strict. For the broader public, however, health authorities and experts continue to urge calm rather than panic.

(Cover photo: A hantavirus sign is seen on a smartphone screen in Krakow, Poland, May 10, 2026. /VCG)