SALT LAKE CITY (AP) – Utah health officials say a man who died after being infected with Zika virus passed it to a caregiver, creating a medical mystery about how it spread between them.

The Salt Lake County Health Department said Monday that the two people didn’t have sexual contact and the type of mosquito that mainly spreads the virus is not found in the high-altitude area where they live.

Officials say the caregiver is a “family contact” but wouldn’t give further details. The man who died caught the virus while traveling abroad to an area where mosquitoes are known to spread Zika.
It marked the first time a person in the continental U.S. died after being infected with the virus.

The exact cause of the death announced July 8 wasn’t clear because the person was elderly and also had an underlying health condition.