90-Second Read: Hantavirus can persist in semen for years, but that doesn’t mean it remains contagious

At a press conference on Friday, World Health Organization (WHO) officials said numerous studies are in progress on the Andes type of the Hantavirus, which began spreading among passengers and crew onboard the MV Hondius in April. Many viruses can persist in semen for years, says Steven Bradfute, an immunologist at the University of New Mexico, and whether the pathogen remains infectious can vary from virus to virus. Bradfute says there have been no documented cases of someone being infected by a person who was discharged from a health care facility after they recovered from a case of Andes type Hantavirus.

At least one case study indicates that viral RNA can persist in human bodily fluids for years after infection. In this case, a 55-year-old Swiss man who traveled from Ecuador to Chile in 2016 began showing symptoms of the Hantavirus after he returned home; he tested positive for the Andes type. Based on previous outbreaks of the Andes type, Hantavirus is believed to require extended close contact to be transmitted from one person to another-the kind of closeness that might come from living in close proximity or having sex.

But some outbreaks, such as the current cruise ship conflagration, suggest the virus may not require such prolonged close contact to spread in some cases. In the case of the cruise ship passengers, many won't leave quarantine until at least 42 days after their last exposure to the virus. The WHO is setting up a natural history study that will examine the virus's "life cycle" in human hosts, she said-that knowledge is particularly important, given there are no Hantavirus-specific treatments yet available.