Hantavirus: Did the Ship’s Enclosed Environment Help Spread Infection?

Editorial

13:29 JST, May 12, 2026

When an infectious disease appears in an enclosed environment like a ship, cluster infections are likely to occur. As an increasing number of people enjoy traveling on cruise ships, it is important to remain vigilant regarding infectious diseases.

Multiple cases of hantavirus infection, a disease transmitted by mice and other rodents, occurred on a cruise ship sailing the Atlantic Ocean. Six cases have been confirmed and three people have died, with the latter number including a suspected infection.

Carrying about 150 people, the ship has arrived at the Spanish autonomous region of the Canary Islands. Passengers hail from over 20 countries. They have since disembarked from the ship and headed to other countries to undergo quarantine and other measures.

One Japanese national was among the passengers. This passenger is in good health and is scheduled to receive medical treatment in Britain.

A COVID-19 outbreak occurred on the Diamond Princess cruise ship in 2020.

However, unlike COVID-19, in which the virus spreads easily through droplets from coughs and sneezes, hantavirus is said to rarely spread from person to person. The World Health Organization has said that the risk of widespread infections is low in general. It is important to respond calmly at this time.

The cruise ship set sail from Argentina last month, and infections among the passengers were discovered during the voyage. Before the infections were confirmed, about 30 people got off the ship in the British territory of St. Helena late last month.

The relevant countries must track the movements of those who were on the ship and thoroughly monitor their health status, among other measures. The WHO should urgently collect and analyze information on infection routes and promptly share it with all nations.

Hantavirus infections occur through bites from infected rodents or by inhaling air contaminated with their dried feces. Symptoms include fever and difficulty breathing, and severe cases can be fatal.

Person-to-person infections do not generally occur with hantavirus. However, the people on the ship were infected with the Andes type of the hantavirus, which has been confirmed to spread from person to person in the past, although in limited instances.

People are in close proximity with each other on a ship, making them more susceptible to the virus than in a normal environment. Furthermore, the incubation period is said to be up to six weeks, so the number of infected passengers is likely to increase in the future.

According to the Japan Institute for Health Security, there are no animals carrying the hantavirus in Japan, and the likelihood of it spreading domestically is said to be low. The government should provide accurate information to prevent the public from becoming anxious.

It is important for people traveling abroad to take precautions, such as avoiding unsanitary places as much as possible and not approaching wild animals unnecessarily.

(From The Yomiuri Shimbun, May 12, 2026)