A suspected hantavirus outbreak aboard a cruise ship has claimed three lives, prompting urgent investigations by health authorities. The World Health Organization (WHO) has launched detailed epidemiological studies and laboratory testing to understand the virus's spread, including sequencing of the virus from the current outbreak.
What is hantavirus?
Hantavirus is mainly spread by contact with rodents or their urine, saliva, or droppings, particularly when these materials become airborne and are inhaled. People are typically exposed around homes, cabins, or sheds, especially when cleaning enclosed spaces with poor ventilation or areas with mouse droppings. The virus is widespread globally but rarely spreads between humans. However, the Andean strain, suspected in this outbreak, has shown evidence of human-to-human transmission in the past.
Professor Robin May, chief scientific officer at the UK Health Security Agency (UKHSA), described hantavirus as a "such a severe disease" that global efforts are underway to develop vaccines. The US Centers for Disease Control and Prevention (CDC) began tracking the virus after a 1993 outbreak in the Four Corners region of the United States.
Symptoms of hantavirus
An infection can rapidly progress and become life-threatening. Early symptoms include:
- Fever
- Chills
- Muscle aches
- Headache
"Early in the illness, you really may not be able to tell the difference between hantavirus and having the flu," said Dr Sonja Bartolome of UT Southwestern Medical Center in Dallas. Symptoms of hantavirus pulmonary syndrome (HPS) usually appear one to eight weeks after contact with an infected rodent. As the infection progresses, patients may experience chest tightness as the lungs fill with fluid. The other syndrome caused by hantavirus — haemorrhagic fever with renal syndrome (HFRS) — typically develops within one to two weeks after exposure.
Death rates vary depending on the strain. HPS is fatal in nearly 40% of cases, while HFRS death rates range from 1% to 15%, according to the CDC.
How to prevent hantavirus
There is no specific treatment or cure, but early medical attention can improve survival chances. The best prevention is to minimize contact with rodents and their droppings. Use protective gloves and a bleach solution for cleaning, and avoid sweeping or vacuuming, which can aerosolize the virus.
Current outbreak details
Health authorities are tracing individuals from the MV Hondius cruise ship and their contacts in South America. Several passengers and crew are isolating, including two Britons who returned to the UK independently and are isolating at home. Two confirmed British cases include a 69-year-old man receiving care in Johannesburg and Martin Anstee, 56, an expedition guide being treated in the Netherlands. A third suspected case has been reported on Tristan da Cunha. The UKHSA said people may need to isolate for up to 45 days, but the risk to the public remains very low.
Professor May noted that contact tracing focuses on close contacts such as family members, roommates, and those seated nearby on long flights, but excludes transient contacts like passing in an airport due to extremely low transmission risk.
