Those are the primary ways the Zika virus has been transmitted, until now. The Centers for Disease Control and Prevention said Monday that health investigators are trying to figure out how an elderly Utah patient, who died earlier this summer from complications due to a Zika infection, passed the virus on to a family contact who cared for the patient before the patient’s death.
The CDC would not say if the “family contact” was a relative or caregiver, only that the transmission did not occur through sex and does not appear to have been contracted through mosquito bite. This represents a new and troubling twist to a virus that is usually stealth, but can have devastating effects especially among pregnant women who get infected.
“It’s early to make a clear statement about what could’ve happened,” said Dr. Michael Bell, a medical epidemiologist with the CDC.
To unravel the mystery, the CDC has dispatched an emergency response team to Utah after a request for help from the state’s health department. The team is similar to others the agency has sent to outbreak regions in Brazil and Puerto Rico where the virus is rampant. A virologist, infection control and mosquito control experts, investigators and health communication officers are currently in Utah. What they know so far and have released publicly is confounding.
The elderly patient visited an unspecified region with a Zika outbreak earlier this year. The patient, who was originally identified in media reports as a man, had a preexisting condition when he contracted Zika on the trip. Upon returning to Utah, his condition worsened and tests were run showing he had been exposed to Zika. Most people who get the virus never show symptoms, and those that do usually see them clear up in a week to 10 days. This man’s blood, however, showed a viral load of Zika 100,000 higher than any samples taken from other people infected with the virus. The man died in June.
A family contact, who cared for him during his illness, somehow contracted the disease, had mild symptoms but soon recovered. Mosquito transmission hasn’t been ruled out, but has been deemed highly unlikely since the two types of Aedes mosquitoes that carry Zika are not found in Utah. Robert Wirtz, a CDC microbiologist said the agency doesn’t believe other mosquitoes are spreading the disease, but the agency is collecting mosquitoes near the deceased’s home, “just to cover all the bases.” Investigators are also interviewing other family contacts, family members and those who came in contact with the original patient.
“We’re trying to figure out whether Zika can be spread from person to person through care of an infected person,” said Dr. Satish Pillai, incident manager for the CDC’s Zika response.
What this means for health care workers is an open question. At this point it does not appear that the virus is airborne, and Bell said it was “unlikely.” There’s also no evidence the virus can be spread through sneezing, coughing, kissing or common touch, he said. But health care workers dealing with anyone who has traveled to Zika-affect regions should take the same “standard precautions” they would normally take with dealing with a patient who might have an unknown or undisclosed disease such as hepatitis or HIV.
Zika continues to perplex researchers who are trying to unravel it’s secrets. Already they have proven that it causes severe birth defects and last week the CDC announced that women can give the virus to men through unprotected sex. Previously it was believed that only men gave the virus to their sexual partners.