#19,181
Although the hantavirus outbreak among the passengers and crew of the m/v Hondius has slowed, 3 new cases have been reported over the past 2 weeks, and the isolation, quarantine, and/or monitoring of exposed individuals continues.
While additional hantavirus cases are still possible, a much larger threat has since emerged in Central Africa with the rapidly expanding Bundibugyo virus outbreak in the DRC and Uganda.
Yesterday the WHO released their first formal DON update on the Andes Hantavirus outbreak since May 13th, which adds the 3 latest cases, and reiterates that the global risk level from this outbreak remains low.
Due to its length, I've only posted some excerpts. Follow the link to read it in its entirety.
Hantavirus outbreak linked to cruise ship travel, Multi-locations
28 May 2026
Situation at a glance
This is the fourth Disease Outbreak News report on the Andes hantavirus outbreak linked to cruise ship travel, following the notification to the World Health Organization (WHO) on 2 May 2026 of severe respiratory illness cases aboard M/V Hondius, a cruise ship. Since the last DON was published on 13 May, three additional confirmed cases were reported, from Canada, the Netherlands, and Spain. The previously reported inconclusive case from the United States of America was subsequently determined to be negative following further laboratory testing and has been removed from the total case count. All cases to date have been passengers or crew members on the ship.
As of 27 May, a total of 13 cases, including three deaths, have been reported (case fatality ratio 23%). Eleven cases have been laboratory-confirmed for Andes virus (ANDV) infection, and two are probable cases. Given the long incubation period of up to six weeks, it is not unexpected that cases continue to be reported until the end of the six weeks since last exposure. Through the International Health Regulations (2005) (IHR) channels, National IHR Focal Points (NFPs) have all been informed and are supporting international contact tracing and monitoring efforts. WHO has assessed the risk posed by this event to the global population as low and will continue to monitor the epidemiological situation and update the risk assessment as needed.
(SNIP)
High-risk contacts are being quarantined and monitored by local health authorities either in their respective countries or in the ship’s flag country, the Netherlands, or third countries (Table 1). As of 22 May 2026, more than 600 contacts, including 53% high-risk and 47% low-risk contacts, have been identified across 32 countries, territories and areas, and are either under close monitoring or self-monitoring in line with the updated guidance on management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship published on 17 May.
WHO risk assessment
WHO continues to assess the risk for passengers and crew who were onboard the cruise ship as moderate, as individuals exposed prior to the implementation of control measures may still develop illness during the incubation period and should therefore be closely monitored.
The risk at the global level is assessed as low for the following reasons:
- Andes virus has demonstrated limited human-to-human transmission in previous outbreaks, typically occurring among close contacts and within household settings, generally requiring prolonged close exposure. Transmission can be contained through early detection, isolation of cases, clinical management, and contact management. However, the ship environment presented an increased risk due to close living quarters, shared indoor spaces, prolonged exposure, and frequent interpersonal interactions, all of which likely facilitated transmission.
- Human Pulmonary Syndrome caused by hantaviruses in the Americas, including Andes virus, can have a high case fatality ratio, reaching 40-50%, particularly among elderly individuals and those with co-morbidities. The average age of passengers on board the ship was 65 years old.
- Investigations on the travel history and potential exposures of the first case in the Southern Cone subregion of the Americas are ongoing and suggest possible exposure to rodents during recreational activities. Viral sequencing analyses are also ongoing and are comparing the ANDV strain associated with this outbreak with strains circulating in Argentina and Chile, where the disease is enzootic. The preliminary sequencing analysis for the cases indicates a high degree of genetic similarity amongst sequenced cases —showing no more than one single nucleotide polymorphisms difference per individual – which strongly indicates that the outbreak likely arose from a single zoonotic spillover event, or from a very small number of closely related spillover events.[1]
- Additional cases may occur among individuals exposed before implementation of containment measures. However, the current response, including quarantine for those who have left the ship and rapid isolation of any new suspect cases and the monitoring of contacts, is expected to limit the risk of further spread.
- As there is no specific antiviral treatment for HPS, suspected cases require prompt transfer to an adequately equipped emergency department or intensive care unit, where available, for close monitoring and supportive management to improve chances of recovery. Consequently, for remote areas, rapid transfer to a well-resourced healthcare facility is required, which may be challenging under the current conditions.
For the general public, including people not exposed on board the ship or through close contact with a confirmed case, the overall probability of infection remains low. Current evidence indicates that human-to-human transmission occurs through close and prolonged contact, and can be effectively limited through early detection, isolation of cases, and contact tracing.