Hantavirus explained: how does it spread and who is most at risk?

Three people have died after an outbreak of hantavirus onboard a cruise ship travelling from Argentina to Cape Verde. The World Health Organization says a total of seven cases – two confirmed by laboratory testing and five suspected – have been identified on the cruise ship so far. It is also investigating whether rare human-to-human transmission of the virus could be behind the cases. Madeleine Finlay talks to Prof Jonathan Ball from Liverpool School of Tropical Medicine to find out where the virus comes from, how it is transmitted to humans, and what health agencies will be doing to try to contain it