As health officials continue monitoring a hantavirus outbreak tied to the Dutch expedition cruise ship MV Hondius, many people are asking the same question: Could this spread more broadly?
The outbreak involves the Andes strain, a rare form of the virus that can spread between people through close contact, though public health officials say the overall risk to the public remains low. Even so, the situation has stirred memories of the early days of COVID-19, especially as countries coordinate quarantines, monitoring and contact tracing tied to passengers aboard the ship.
To put the headlines into perspective, we turned to Stephen Waterman, M.D., MPH, a clinical professor at the Herbert Wertheim School of Public Health and Human Longevity Science at UC San Diego. Waterman is a former quarantine medical officer for the Centers for Disease Control and Prevention (CDC) with experience in cruise ship outbreaks and infectious disease response.
Could hantavirus spread like COVID-19 or become something travelers should be worried about as we head into peak travel season?
“I think the big question on people’s minds, coming out of COVID, is whether this is the start of another worldwide infectious disease problem that could spread broadly and cause a high number of deaths. This particular strain — the Andes strain found in South America — is a serious disease. It has a much higher mortality rate than COVID.
But the answer that the World Health Organization, CDC and public health experts are giving is that this is not a situation likely to lead to large worldwide spread. This disease is much harder to transmit than COVID, influenza or measles.
Hantavirus is mainly transmitted through close contact with rodents or rodent secretions, and that’s probably how the first person on the cruise ship became infected. He had spent quite a long time in South America in an area where he could have been exposed to rodents.
What’s unusual here is that the Andes strain is the only hantavirus strain known to sometimes spread person to person, and that’s likely what happened on the ship unless there was some kind of rodent exposure onboard, which seems less likely given the sanitation standards on cruise vessels.
But again, it’s nothing like the transmission you see with COVID or influenza. In South America, there are only a few dozen cases a year in countries like Argentina and Chile. It’s not a disease that typically turns into large outbreaks affecting significant portions of the population.
I think the cruise ship aspect is part of why this has captured so much attention. There are overtones of COVID and cruise ships that people remember, so naturally people are asking whether this could become something bigger.
This is the first cruise ship outbreak of hantavirus that I’m aware of, so it absolutely needs to be investigated carefully. There are still unanswered questions about person-to-person spread with this strain, and public health agencies will be following cases closely. But I think it’s likely that this will remain limited to a relatively small number of people connected to the ship.
And for people worried about summer travel or cruise vacations, I would not say this changes the overall safety of cruise travel. Cruise ships already have strong sanitation and monitoring programs because they’ve dealt with infectious disease outbreaks before, particularly norovirus.
Cruise ships do occasionally have outbreaks because there’s close contact and a lot of social interaction, but cruise ship travel is safe from an infectious disease standpoint.”
Waterman added that outbreaks like this also underscore the importance of strong international public health coordination and disease monitoring. Infectious diseases, he noted, do not respect national borders — one reason health agencies around the world continue to closely track emerging outbreaks even when the overall public risk remains low.
