Hantavirus has long been seen as a rodent-borne threat. But emerging evidence that some strains may pass between humans is prompting fresh concern among health experts.

A passenger aboard the m/v Hondius described fear and uncertainty as three have died and a suspected hantavirus outbreak remains under investigation.

Seven cases of hantavirus have been identified, including three deaths, one critically ill patient and three individuals reporting mild symptoms, says the World Health Organization.