Physicians in Utah think they have solved the mystery of how a man who developed Zika virus infection without travel to an endemic area could acquired the pathogen: through contact with a Zika patient's tears.
The original patient was a 73-year-old man admitted to hospital with low blood pressure and abdominal pain, according to Sankar Swaminathan, MD, and colleagues at University of Utah Health Care in Salt Lake City.
He had returned from a visit to Mexico 8 days before admission, Swaminathan and colleagues reported online in the New England Journal of Medicine. He had been well until after his return, but reported being bitten by mosquitoes during the trip.
The physical exam on admission was remarkable, Swaminathan and colleagues reported, for "marked erythematous conjunctivitis with profuse tearing and soft-palate petechiae, tachypnea, and moderate, diffuse abdominal pain with mild guarding."
Although he was not systemically immune-compromised, his condition worsened, with progressive respiratory and renal failure, metabolic acidosis, and hepatitis, and he died 4 days after admission.
Testing for Zika was positive and showed a "very high viral load," the investigators reported.
The man's tears are suspected of being the transmission route for the illness of a second patient, a 38-year-old friend who had visited the original patient in hospital and later reported helping move the man without using gloves and wiping his friend's eyes. However, there was no splashing of body fluids or contact with mucosal tissues, the report indicated.
The second man presented 5 days after the first patient's death with conjunctivitis, fever, myalgia, and facial maculopapular rash, which resolved within a week.
Urine testing for Zika was positive, as was a serum IgM antibody test, Swaminathan and colleagues reported, although serum was negative on a polymerase chain reaction assay.
The second man's case, which was first reported earlier this summer, had caused considerable puzzlement. He had not travelled to a region where Zika virus is endemic and the carrier of the virus, the Aedes aegypti mosquito, has not been detected in the Salt Lake City area. Moreover, he had no sexual contact -- the only other documented means of Zika transmission, other than blood transfusion -- with the first patient or anyone else exposed to Zika.
But his symptoms developed 7 to 10 days after contact with the first patient, "which implicates direct contact" during his hospital stay.
That suggests the original patient was the source of the secondary infection, Swaminathan and colleagues argued, and also hints that the "spectrum of those at risk" for Zika infection might be wider than had been thought.
The CDC has stood by its recommendations for healthcare personnel to maintain standard precautions when dealing with Zika patients.