The Centers for Disease Control and Prevention (CDC) is helping the state of Utah figure out a medical mystery: how a person with no apparent exposure to the Zika virus contracted the disease.

The Utah resident is an acquaintance of an elderly man who had traveled to a Zika-ridden area. That man contracted the disease and died in late June – with what the CDC calls “uniquely high” amounts of the virus -- more than 100,000 times higher than seen in other samples of infected people—in his blood.

“The new case in Utah is a surprise, showing that we still have more to learn about Zika," said Erin Staples, MD, PhD, CDC’s Medical Epidemiologist on the ground in Utah.

A CDC Emergency Response Team (CERT) is in Utah at the request of the Utah Department of Health. The team includes experts in infection control, virology, mosquito control, disease investigation, and health communications.

Interviews, lab tests

They’ll help state and local public health disease control specialists try and determine how the second resident became infected. The investigation includes additional interviews with and laboratory testing of family members and health care workers who may have had contact with the person who died and trapping mosquitoes and assessing the risk of local spread by mosquitoes.

Sexual contact

Of the 1,306 cases of Zika reported in the continental U.S. and Hawaii as of July 13, 2016, none were the result of local spread by mosquitoes; 14 were believed to be the result of sexual transmission and one was the result of a laboratory exposure. Non-sexual spread of the virus from one person is not common.

Since early 2016, CDC has worked with state, local, and territorial public health officials to protect pregnant women from Zika infection, through these activities:

  • Alerts to pregnant women to avoid travel to an area with active Zika transmission, to women in these areas to take steps to prevent mosquito bites, and to partners of pregnant women to use a condom to prevent sexual transmission during pregnancy.
  • Development and distribution of PCR and IgM testing kits to confirm Zika virus infection.
  • Establishment of CDC Emergency Response Teams to rapidly deploy to assist with Zika-related preparedness and response activities in the United States.
  • Deployment of experts to assist in enhancement of mosquito surveillance and testing.
  • Collaboration with FDA, blood collection centers, and other entities in the public and private sectors on enhancement of surveillance of blood donations.
  • Guidance to prevent sexual transmission, particularly to women who are pregnant.
  • Guidance for clinicians on the care of pregnant women who may have been exposed to Zika.
  • Studies in collaboration with Brazil, Colombia, and other countries to better understand the link between Zika infection and birth defects, including microcephaly.

For more information about Zika: