Mystery Zika case in Utah was likely spread by virus victim to son through sweat or tears

New details are emerging about the mysterious Zika case in Utah where a son caring for his sick father became infected with the virus. The father’s death in June was the first related to Zika in the continental United States. His son’s infection was unusual because, unlike all other known adult cases, he had not traveled to a Zika-infected region or had sex with a partner who had done so.

Instead, he had remained at his father’s side in the hospital.

In a case study published Wednesday in The New England Journal of Medicine, the medical team who cared for both patients said it’s likely the younger man contracted the virus through his father’s sweat or tears. The older man had an unusually high level of virus in his blood, more than 100,000 times higher than that seen in samples of other infected people.

The son had contact with his father’s skin and wiped his eyes, “both without gloves,” said Sankar Swaminathan, an infectious disease specialist at the University of Utah’s School of Medicine who treated the two patients.

No other family members or health care workers who had contact with the 73-year-old man reported a Zika infection.

Swaminathan said the case offers critical new information for health care providers and researchers. In rare cases, when patients have severe Zika infections, “the levels of virus may very well be unprecedented, and the implication is that such cases may present increased risk for transmission through bodily fluids,” he said.

There only have been nine other Zika-related adult deaths in the Americas that have not been linked to Guillain-Barré syndrome, a rare nervous system illness that causes muscle weakness and sometimes paralysis. Some of those nine individuals had serious underlying medical conditions or very weak immune systems, Swaminathan said.

But that was not the case for the Utah man. The father had been treated for prostate cancer but did not have a severely weakened immune system when he became ill with Zika.

However, he had previously been infected with dengue, a related virus. Some research in animals has suggested that previous dengue infections may worsen a subsequent Zika infection. It’s possible that could have happened in this patient’s case, triggering his severe infection, Swaminathan said.

The father had traveled to the southwest coast of Mexico, where he got bitten by mosquitoes. After returning home, he became sick and was admitted to the hospital in shock, respiratory distress, with a sore throat and conjunctivitis, or inflammation of the eyes.

Swaminathan said most doctors treating someone with those symptoms might suspect illnesses such as pneumonia or sepsis, a complication from a life-threatening response to infection. But not Zika.

“What this case tells me is that doctors should think about Zika when they see someone who is severely ill and might have been exposed,” he said. “It now expands the spectrum of illness.”

Associated Press