The Utah Department of Health is investigating a "unique" case of Zika in Utah whereby a person reportedly became infected with the virus without a clear means of transmission.
The case was discovered in a caregiver of an elderly individual with the virus who died in late June. However, the caregiver is not believed to have traveled to an area with Zika or to have had sex with someone who had the virus.
As there is currently no evidence that the Aedes mosquito capable of spreading Zika is in Utah, the investigation is seeking to discover how the caregiver became infected.
According to a statement from the Centers for Disease Control and Prevention (CDC), the deceased patient had traveled to an area with Zika and tests revealed he had "uniquely high" amounts - over 100,000 times higher than seen in other samples of infected people - in his blood.
"...There is a lot we don't know about the Zika virus. We are still doing a lot of investigation to understand whether Zika can be spread from person to person through contact of a sick person. That's under investigation," Satish Pillai, deputy incident manager with the CDC's Zika response, said in a press conference.
As of July 13, 2016, 1,306 cases of Zika have been reported in the continental United States and Hawaii, though none of these have been the result of local spread by mosquitoes, according to the CDC.
"The new case in Utah is a surprise, showing that we still have more to learn about Zika," Erin Staples, MD, PhD, the CDC's medical epidemiologist on the ground in Utah, said.
Public health officials are interviewing the caregiver and others to learn about about their interaction with the deceased person.
Additionally, officials are collecting samples from those who had contact with the patient and are trapping and testing mosquitoes in the communities where both patients fell ill.
"We don't have evidence right now that the Zika can be passed to one person or another person by sneezing or coughing or touching or hugging or sharing utensils...," Pillai said.
"While we still don't know exactly how this family contact became sick and we are actively investigating it, what we do know is that the primary mechanism in transmission are mosquito borne. We feel that should provide some levels of reassurance to the public."
Following the report of the Utah case, the Florida Department of Health announced on Wednesday that it was also investigating a possible non-travel related case of Zika in Miami-Dade County.
The Zika virus has been found to cause serious birth defects including microcephaly, which results in babies born with abnormally small heads and incomplete brain development.
It is also linked to increased reports of Guillan-Barré syndrome, which can result in nerve cell damage, muscle weakness and paralysis.