In the early 1950s, thousands of UN troops in Korea fell ill with a mysterious fever, said Chris Smith in The Spectator. Doctors suspected that a virus might be to blame – but it wasn’t until 1978 that a Korean scientist isolated the culprit in a mouse, and named it after a nearby river, the Hantan.
He also showed that hantaviruses, which are carried by rodents, can be inhaled by humans in dust contaminated by droppings or urine. The troops had likely kicked the virus up as they dug foxholes.
Old vs. New World
Since then, numerous strains that can be transmitted to humans have been identified. They divide into two groups: Old World hantaviruses, in Europe and Asia, cause kidney dysfunction and have a mortality rate of 1% to 15%; New World ones, in the Americas, lead to severe lung infections and are fatal in around 40% of cases. It was the latter group that caused the outbreak on the cruise ship MV Hondius, and specifically the Andes strain, the only hantavirus that – in very rare cases – can pass from human to human.
It is not yet clear how this outbreak started, said Esther Addley in The Guardian, but it is thought that one, or possibly two, passengers were carrying the virus, which has an incubation period of up to 42 days, when they boarded the ship in Argentina on 1 April. A Dutch ornithologist who fell ill on 6 April and died five days later has been identified as “patient zero”. He had spent months travelling in South America with his wife – who died on 26 April. A German woman then died on 2 May. By 10 May, seven others had fallen ill.
No pandemic
This week, 20 British nationals on board flew home to the UK, and were bussed to an isolation facility on the Wirral, said Sarah Knapton in The Daily Telegraph. Described as healthy, they were assessed for 72 hours and then asked to self-isolate at home for 42 days.
Health officials have stressed that we are not facing a pandemic. The Andes strain does not spread easily: it requires intimate or very close contact. And though many passengers left the ship weeks ago, there have so far been no “third-generation” cases – among people who were not on board. Given the virus’s incubation period, clinicians say that 21 June is the date to watch: if there have been no third-generation cases by then, it means the outbreak has run its course.
As passengers from the MV Hondius quarantine, health experts do not believe the virus will cause a pandemic
