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Toppage > Infectious Disease > Hantavirus pulmonary syndrome > risk-assessment > Hantavirus Infection Cases on a Cruise Ship During International Voyage

Hantavirus Infection Cases on a Cruise Ship During International Voyage

This document contains information based on official documents released by domestic and international health organizations and research institutions. Accordingly, information disclosed through press conferences or similar public briefings is not included. Information may have largely evolved since the time of publication, as investigations by domestic and international health agencies and researchers are ongoing. Readers are advised to verify the most recent official information.


Japan Institute for Health Security

May 6, 2026

About Hantavirus

Hantavirus is a collective term for viruses belonging to the genus Orthohantavirus, family Hantaviridae. Hantaviruses present in the Eurasian continent are known to cause hemorrhagic fever with renal syndrome (HFRS), whereas hantaviruses present in Americas are known to cause hantavirus pulmonary syndrome (HPS). HFRS cases associated with laboratory rats were reported in Japan during the 1970s and 1980s, but no domestic cases have been reported since 1999, when the Japan's Act on the Prevention of Infectious Diseases and Medical Care for Patients with Infectious Diseases (Infectious Diseases Control Law) was enacted. No cases of HPS have been reported in Japan to date.

Hantaviruses naturally infect rodents, and human infection primarily occurs through direct contact with droppings, or saliva of infected rodents, inhalation of contaminated aerosolized particles, or exposure to environments contaminated with feces. In general, hantaviruses are not transmitted from person to person. Exceptionally, limited instances of human-to-human transmission involving specific hantavirus species, Andes virus, have been reported in Argentina and Chile. However, these cases were reported to have involved transmission through droplets or direct contact resulting from close and prolonged exposure, and transmission was successfully prevented through appropriate isolation and contact management.

The Current Event

On 2 May 2026, an outbreak of hantavirus infection associated with a cruise ship sailing in the South Atlantic Ocean was reported to the World Health Organization (WHO). The ship had traveled through South America and the Antarctic region in April and, as of 6 May, it was reported to be anchored off the coast of Africa, proceeding to Canary Islands. According to WHO, as of 4 May, a total of seven cases (two laboratory confirmed cases of hantavirus and five suspected cases) had been reported, including three deaths. All identified cases to date have been limited to individuals associated with the cruise ship.

Further epidemiological investigation, including identification of the source of infection and investigation of contacts, will be required. However, if appropriate management of passengers and crew members, including infection prevention and control measures, contact tracing, and health monitoring, is implemented, the risk of further transmission is considered to be limited.

Potential for Transmission in Japan

Each species of hantavirus associated with a specific rodent reservoir species. Therefore, even if a hantavirus is introduced into an area where its natural reservoir host is absent, sustained transmission in the natural environment is unlikely to be established. In the Americas, deer mice in North America and long-tailed pygmy rice rats in South America are recognized as reservoir hosts, but these rodent species are not known to inhabit Japan. Although the causative virus involved in the current event is still under investigation, given that the ship departed from South America, the likelihood of infection in Japan with the hantavirus responsible for this event is considered to be extremely low. In addition, human-to-human transmission of hantavirus has not been reported except for Andes virus. Even in previously reported cases involving Andes virus, reports suggest that further transmission was successfully prevented through appropriate public health measures. Therefore, the likelihood of sustained transmission through human-to-human spread in Japan is considered to be low. 

Relevant information

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