Hantavirus Outbreak on Cruise Ship: What You Need to Know About the Deadly Andes Variant

The MV Hondius cruise ship, where a hantavirus outbreak was detected, docked over the weekend, allowing approximately 150 passengers to disembark. Medical repatriation flights have been arranged by most of the 23 countries with nationals aboard the vessel.

An additional 32 passengers had already disembarked at an earlier stop—the Atlantic island of St. Helena—and flew home on April 24, before the outbreak was identified. Three passengers have died from hantavirus, a disease typically contracted through exposure to rodent droppings, urine, or saliva.

All three fatalities were linked to the Andes variant, which can spread via human-to-human contact. Hantaviruses may cause either hantavirus pulmonary syndrome or hemorrhagic fever with renal syndrome; the current outbreak involves the former.

U.S. Response and Quarantine Measures

The U.S. Department of Health and Human Services (HHS) is processing all 17 American passengers at a facility in Nebraska. While details remain unclear, quarantine is likely due to the virus’s long incubation period.

One American passenger tested positive for hantavirus despite showing no symptoms, while another has developed symptoms. Both were transported on the same flight as other passengers but with additional containment measures implemented “out of an abundance of caution.”

Asymptomatic Spread and High Fatality Rate

Health experts warn that asymptomatic spread may be occurring, compounding concerns due to the virus’s two- to three-week incubation period. The case fatality rate for the Andes variant, which causes severe respiratory illness, is approximately 38%.

If the outbreak were to grow, containment could prove challenging. Long incubation periods and the difficulty of convincing asymptomatic individuals to self-isolate for extended periods may allow the virus to spread undetected.

Timeline of Transmission

An analysis suggests that Cases 2-8 may have resulted from a single human-to-human transmission from Case 1, as their incubation periods cluster around 22 days from the onset of Case 1 symptoms. As of now, 13 days have passed since the mean symptom onset date for Cases 2-8.

Expert Concerns and Unanswered Questions

Dr. Steven Quay highlighted the potential for a new wave of cases, emphasizing the need for vigilance. Meanwhile, Dr. Roger Seheult noted the implications of a positive test in an asymptomatic individual, calling for further investigation into transmission dynamics.

Health authorities are still determining the level of contact required for transmission, raising questions about their preparedness in managing this outbreak.