Zika Mystery: Health Officials Stumped After Elderly Patient Transmits Virus to Caregiver

A caregiver of an elderly Zika patient in Utah has now been diagnosed with the disease, leaving health officials stumped about how the virus was transmitted from patient to caregiver.

The Utah Department of Health said they do not know how the caregiver could have been infected with the Zika virus after looking after the elderly patient. The original unnamed patient died while infected with the virus, but the patient had an underlying condition and it was unclear if or how the virus contributed to their death, according to the health department.

The virus has been known to spread person to person only through sexual contact or through mosquito transmission. The U.S. Centers for Disease Control and Prevention are currently investigating how the infected family member could have contracted the virus even if they had not gone to a country with ongoing Zika virus transmission and had not had sex with a person known to be infected with the virus.

The CDC has reported at least 1,133 cases of Zika infections within the U.S. Virtually all of them were cases where a person traveled outside the U.S. and became infected by mosquitoes abroad. In a small number of cases, the virus was transmitted through sexual contact within the U.S. There have been no cases of people being infected from mosquitoes within the continental U.S.