90-Second Read: Hantavirus: Of mice, men and cruise ships

A cluster eight of cases of severe respiratory illness was reported to the World Health Organization (WHO) on May 2, 2026 and confirmed to be caused by a particular Hantavirus known as Andes Virus. The Andes Virus is one of the few Hantaviruses capable of limited person-to-person transmission but WHO assessed the risk of further epidemics or a pandemic from this event to be low with the risk for passengers and crew on the ship being moderate. The detection of Hantaviruses, particularly Andes virus, have highlighted the vulnerability of cruise ships to emerging zoonotic diseases more generally. Cruise ships are small self-contained floating cities, capable of transporting thousands of passengers across oceans, but they also present a closed community setting with an underappreciated infectious disease threat.

Rats and mice were central to the spread of plague through infected fleas in the 1300s and while modern cruise ships maintain strict sanitation systems, rodents still occasionally infest food storage areas, cargo compartments, wharfs and waste-handling facilities. However, there are about 200 000 human cases of Hantavirus infections reported annually. The likelihood of acquiring Hantavirus while on a cruise ship is extremely low as Hantaviruses do not spread efficiently through casual social contact. On May 2 the Andes Hantavirus was confirmed by reverse transcription polymerase chain reaction (RT-PCR).

Hantavirus infections in humans present as two distinct, severe, and potentially fatal syndromes; Hantavirus Pulmonary Syndrome (HPS) dominating in the Americas and Haemorrhagic Fever with Renal Syndrome (HFRS) dominating in Europe and Asia. The incubation period for Hantavirus infections ranges from 1-8 weeks with early symptoms resembling an influenza-like illness, and can include abdominal pain, nausea and vomiting. Hantavirus infections from human-to-human spread are rare as is asymptomatic infection. Although overall risk to passengers is low, the severity of Hantavirus infections and other emerging zoonotic diseases demands vigilance.

Available diagnostic tests for Hantavirus include serologic testing for Hantavirus-specific IgM and IgG antibodies, RT-PCR and immunohistochemistry. Australia is the only continent where no confirmed human cases of Hantavirus infection have been recorded; however, antibodies to Hantavirus have been detected in some Australian rodents. Hantaviruses are maintained in nature by chronically infected rodents and some small mammals, which shed the virus in urine, faeces and saliva.