Health officials in Florida are analyzing a new Zika infection in the Miami area that they think may be the nation's first transmission of Zika from a mosquito bite.
The U.S. Centers for Disease Control and Florida's Department of Health said this week that the Zika case had been confirmed, but that there were no links to transmission through travel. It has not been made clear whether the case could have originated from sexual contact with an infected person.
Earlier this week, the CDC announced that the caregiver for an elderly Utah man who died of a Zika infection also had contracted the infection, although for the caregiver the case was not serious. The caregiver was not believed to have traveled to any areas that are affected by Zika, nor had sex with any infected person.
The CDC said the elderly patient had "uniquely high amounts of virus" in his blood — more than 100,000 times higher than seen in blood samples from other infected people. Health authorities are investigating how the caregiver might have contracted the infection from the older victim.
Zika has been detected in bodily fluids including semen, blood, urine and breast milk.
The man who died caught the virus while traveling abroad. He was the first person in the United States to die after becoming infected. Officials said the exact cause of his death was not clear because the man was elderly and had an underlying heath condition.
Zika is spread primarily through mosquito bites. Experts are especially concerned about infected mosquitoes biting pregnant women. They say this can cause microcephaly, a birth defect characterized by smaller-than-average head size and possible deficiency in brain development.