Hantavirus Outbreak on MV Hondius Cruise Ship Results in Multiple Deaths and International Quarantine Efforts

A hantavirus outbreak on the MV Hondius cruise ship has led to multiple confirmed cases, three deaths, and an international health response involving quarantine, medical evacuations, and contact tracing across 30 countries.

Outbreak and Timeline

The MV Hondius departed Ushuaia, Argentina, on April 1, carrying approximately 147 to 150 passengers and crew. The first patient, a man who had traveled in Argentina before boarding, became ill within the first week of the cruise and died shortly after. Other patients became ill approximately two weeks later.

Deaths reported in connection with the outbreak include:

• A 70-year-old Dutch man who died on board on April 11
• His 69-year-old wife who died in South Africa on April 26 after disembarking
• A German national who died on board on May 2

As of late May, the WHO reported 13 confirmed hantavirus cases linked to the cruise. At least eight cases have been laboratory-confirmed. A 12th illness was confirmed in the Netherlands on May 12. Three additional hantavirus cases have been identified in France, Spain, and Canada among individuals who had contact with passengers from the ship. More than 600 contacts are being monitored across 30 countries.

Virus and Transmission

"We do believe that there may be some human-to-human transmission that's happening among the really close contacts." — Maria Van Kerkhove, WHO epidemiologist

The hantavirus identified in two former passengers by South African authorities is the Andes strain. This strain is typically found in parts of Argentina and is the only hantavirus known to be capable of human-to-human transmission. Hantavirus is usually transmitted through contact with rodent urine, feces, or saliva.

The WHO has stated that human-to-human transmission may be occurring among close contacts, such as spouses and cabin mates. The virus is not considered highly transmissible, and transmission requires prolonged, close contact with a symptomatic individual. The Andes strain has caused person-to-person outbreaks historically, but large outbreaks have not been observed. The mortality rate for hantavirus can be up to 50% due to lung and kidney involvement.

Response and Quarantine

The WHO is coordinating an international response, including case isolation, medical evacuation, and laboratory investigations. Medical personnel on the ship are using full personal protective equipment.

The MV Hondius was denied permission to dock in Cape Verde due to health concerns. The Spanish government allowed the ship to dock in the Canary Islands, a journey expected to take three to four days. Spanish health authorities plan to conduct an epidemiological review, assess passengers, and decide on repatriation.

Three patients were evacuated from the ship and transported to the Netherlands for medical care. These individuals are German, Dutch, and British nationals, including a British crew member. One British national was in intensive care in South Africa. Two infectious disease specialists traveled from the Netherlands to the ship.

Spanish health authorities required passengers and staff who were on the ship between April 1 and May 10 or had close contact with a confirmed case to quarantine at a Madrid military hospital.

U.S. Passengers

Seventeen American passengers were transported by medical repatriation flight arranged by the U.S. government to the National Quarantine Unit (NQU) at the University of Nebraska Medical Center (UNMC) in Omaha, Nebraska. The U.S. Centers for Disease Control and Prevention (CDC) coordinated with partners and prepared medical support for American passengers. Two additional U.S. passengers were transferred to Emory University Hospital.

As of May 12, none of the American passengers were showing symptoms. The CDC issued federal quarantine orders for two passengers to prevent them from leaving the unit. Quarantine orders are a legal measure enforceable by fines and imprisonment.

Individuals are being monitored for symptoms for up to 42 days due to the incubation period of the Andes hantavirus, which can range from one to eight weeks. The CDC is determining the exact duration of quarantine for each passenger on a case-by-case basis. Some passengers may complete the monitoring period at home with daily health department check-ins.

The National Quarantine Unit is the only federally funded quarantine unit in the United States, located at UNMC. It has 20 single-occupancy rooms with negative-pressure ventilation and waste sterilization systems. The adjoining Nebraska Biocontainment Unit has a 10-bed capacity with a dedicated air-handling system. Both facilities use negative-pressure rooms and HEPA filtration to contain pathogens. The facilities have previously treated patients exposed to Ebola and COVID-19.

Quarantined individuals have access to TV, exercise equipment, high-speed internet, and can order personal items. Meals are delivered three times daily. Staff provide symptom checks twice daily.

"Traditionally, this virus has been thought to be one that would need very, very close contact most of the time to transmit. I still think that's probably the case. But all of that is really something that we're just sort of finding out about." — Dr. Angela Hewlett, medical director, Nebraska Biocontainment Unit

The quarantine is voluntary; passengers can self-monitor at home. Health authorities reported that quarantined individuals have been cooperative and no legal orders have been issued for the majority. Dr. Marty Cetron, former director of the CDC's Division of Global Migration and Quarantine, stated that voluntary agreements are typically tried first, but orders may be issued if commitments are not met.

Passenger Jake Rosmarin, who chose to stay the full 42-day incubation period, stated he wanted to keep risk to others at 0%. He is not showing symptoms and has his temperature checked daily. He described the quarantine facility as providing quick access to medical care and testing twice a week.

Dr. Stephen Kornfeld, an oncologist from Bend, Oregon, assumed medical leadership on the ship after the ship's doctor contracted hantavirus. Dr. Kornfeld initially tested positive for hantavirus via a nasal swab, but subsequent tests were negative. Dr. Angela Hewlett, medical director of the Nebraska biocontainment unit, stated that the initial test was likely a false positive, as follow-up serology tests showed no evidence of previous hantavirus infection. Dr. Kornfeld reported no symptoms and stated he felt well.

Contact Tracing

An international team is conducting contact tracing for passengers who disembarked the ship on St. Helena before the outbreak was identified. Some travelers have flown to various destinations, including the United States. Public health officials assess the risk of further spread as low.

The WHO classifies all passengers and crew as "high-risk contacts" and recommends active monitoring in designated facilities or home quarantine. The WHO Director-General urged continued monitoring of all contacts and stated that high-risk contacts are still being located.

Statements from Health Officials

• Ann Lindstrand (WHO representative in Cape Verde): Stated there is no pandemic-level threat due to low likelihood of human-to-human transmission. Quarantine could last up to eight weeks given the incubation period.
• Dr. Michael Wadman (director, quarantine unit): Stated that passengers are cooperative and each case will be evaluated individually for release.

Background

The MV Hondius departed Ushuaia, Argentina, on April 1. Argentina's health ministry is reconstructing the itinerary of a Dutch couple and conducting rodent capture and analysis in Ushuaia; no cases have been identified in Argentina. The outbreak is believed to have started after a bird-watching expedition from Argentina to Cape Verde. No rodents have been found aboard the ship.