In a world where people can cross borders in minutes, an infectious disease event – such as the cluster of hantavirus cases on the MV Hondius cruise ship – can quickly become a multi-country challenge.
The International Health Regulations (2005) (IHR) are the legally binding global framework that obligates countries to prevent, prepare for, detect, report and respond to public health threats that cross borders.
When the United Kingdom notified WHO on 2 May 2026 of a cluster of severe respiratory illness cases aboard a Netherlands-flagged cruise ship in the Atlantic, passengers from 23 countries were on board. Within days, cases of hantavirus (Andes strain) had been confirmed in the Netherlands, South Africa and Switzerland. The ship was still at sea.
What followed was one of the most complex multi-country outbreak responses in recent years – and a direct test of the IHR.