Zika outbreak: Caregiver mysteriously infected from man who died

Health authorities in Utah are investigating a unique case of Zika found in a person who had been caring for a relative who had an unusually high level of the virus in his blood.

Officials say the caregiver is a 'family contact' but won't release further details

The new Zika case in Utah is a surprise but fortunately the caregiver who contracted the virus recovered quickly, said Dr. Erin Staples, a medical epidemiologist with the U.S. CDC. (Rick Bowmer/Associated Press)

Health authorities in Utah are investigating a unique case of Zika found in a person who had been caring for a relative who had an unusually high level of the virus in his blood.

Exactly how the disease was transmitted is still a mystery, though the person has since recovered.

The two people did not have sexual contact and the type of mosquito that mainly spreads the virus is not found in the high-altitude area where they live, the Salt Lake County Health Department said. The caregiver is a "family contact," but officials did not give further details, including how the virus was transmitted.

Based on what we know so far about this case, there is no evidence that there is any risk of  Zika  virus transmission among the general public in Utah.- Dr. Angela  Dunn

"Our knowledge of this virus continues to evolve and our investigation is expected to help us better understand how this individual became infected," said Dr. Angela Dunn, deputy state epidemiologist at the Utah Department of Health. "Based on what we know so far about this case, there is no evidence that there is any risk of Zika virus transmission among the general public in Utah."

The man who died in late June caught the virus while travelling abroad to an area where mosquitoes are known to spread Zika and had an unusually high level of the virus in his blood, officials said. The exact cause of the death, which was announced on July 8, was not clear. The man was elderly and also had an underlying health condition.

The man's elevated viral load is a unique situation, Dr. Satish Pillai, deputy incident manager of the U.S. Centers for Disease Control's Zika response told reporters. 

In studies, the virus can be detected in blood, saliva, semen, urine, breast milk and internal eye fluid that differs from tears.

The man had Zika symptoms — including rash, fever and pink eye — but it's unclear if or how the virus contributed to the death, the CDC said. The transmission to the caregiver was discovered after a doctor noticed Zika-like symptoms in the second person.

'More to learn' about Zika

"The new case in Utah is a surprise, showing that we still have more to learn about Zika," said Dr. Erin Staples, CDC's medical epidemiologist on the ground in Utah.

"Fortunately, the patient recovered quickly, and from what we have seen with more than 1,300 travel-associated cases of Zika in the continental United States and Hawaii, non-sexual spread from one person to another does not appear to be common," Staples added in a release.

The caregiver's mild symptoms were typical of how Zika presents, Pillai said.  

CDC experts continue to recommend standard precautions when caring for someone who might be infected.

"Make sure health-care personnel don't have any direct contact with blood or body fluids through either broken skin or a needle stick or splashes to the mucous membranes," said Dr. Mike Bell, a CDC medical epidemiologist.

It is too early in the investigation to discuss how transmission might have occurred to the caregiver, Bell said. "Certainly a high viral load is something we take very seriously."

For investigators, Bell said it's worth thinking about whether someone who is extremely ill from another disease could have a diminished immune system that doesn't fight off the Zika virus as well, or if the person could be sick from the high viral load itself. 

Dr. Amesh Adalja, a spokesman for the Infectious Diseases Society of America, said it will be important to know whether the family contact of the deceased man had any skin lacerations or skin disease that might have allowed the virus access.    

Utah authorities have refused to release additional information about the man or where he travelled, citing health privacy laws. Officials discovered the case while reviewing death certificates, and lab tests confirmed their suspicions.

The virus causes only a mild illness in most people.

But during recent outbreaks in Latin America, scientists discovered that infection during pregnancy has led to severe brain-related birth defects.

It's spread mainly through the bite of a tropical mosquito.

CDC entomologists are assisting with mosquito collections in Salt Lake City to check for West Nile Virus, as well as Zika, to cover all bases and to gather information. 

"We do not believe Zika can be spread through casual contact, through hugging or kissing, or sharing of toothbrushes or any other means of casual contact," said Dr. Denise Jamieson, a medical epidemiologist with CDC.

Canadian and U.S. health officials continue to recommend pregnant women not travel to areas with Zika, to use condoms or not have sex with partners who have travelled to or live in an area with Zika for the duration of pregnancy and to take steps to prevent mosquito bites. 

With files from CBC News and Reuters