The National Institute for Health Crisis Management (JIHS) has assessed that the risk of hantavirus spreading from person to person in Japan is low [1, 2].

This evaluation comes as health authorities monitor the potential for zoonotic diseases to enter the country through international travel. Because hantavirus typically jumps from animals to humans, understanding the domestic environment is critical to preventing a public health emergency.

According to the JIHS, the primary rodent hosts that carry the virus are not present within Japan [1, 2]. This absence of a natural reservoir significantly reduces the likelihood of a sustained outbreak within the country's borders.

Health officials said that human-to-human transmission of hantavirus is extremely rare. Such events have only been reported in the past with the Andes virus strain [1, 2]. In those specific instances, the spread was contained through the implementation of appropriate isolation measures [1, 2].

The assessment follows reports of suspected hantavirus infections on a cruise ship. Reports indicate that three people died on the vessel [2]. There are conflicting accounts regarding the location of the ship; the World Health Organization said the ship was anchored off Cape Verde, while South Africa's health minister said that the Andes virus was identified from samples of patients on the ship [2].

JIHS said that the combination of a lack of local host animals and the historical rarity of person-to-person transmission makes a widespread domestic outbreak unlikely [1, 2].

“The risk of hantavirus spreading from person to person in Japan is low.”

The JIHS assessment underscores that while international travel can introduce rare viral strains—such as the Andes virus—the lack of a local animal reservoir in Japan prevents the virus from establishing a permanent foothold. The focus remains on containment and isolation of imported cases rather than the mitigation of a domestic animal-borne epidemic.