Zika Virus Case in Utah Baffles Health Officials

In another puzzling twist to the Zika epidemic, the Utah Department of Health on has reported the diagnosis of a new case of the virus that did not appear to have been contracted through either of the known sources of transmission: a mosquito bite or sexual contact. The patient, who has fully recovered, was a “family contact” who helped care for an older man who had become infected with the virus after travelling abroad. That man, from Salt Lake County, died in June. He also had other ailments, and it was unclear whether the virus had contributed to his death. The Zika virus has caused more than 1,500 cases of birth defects, mostly in Brazil, where the epidemic began last year. In the United States and its territories, several hundred pregnant women have been infected with the Zika virus, with the largest concentration in Puerto Rico; many had travelled to countries where the virus is circulating. Zika is known to be transmitted by the Aedes aegypti mosquito and through sex, but neither seemed to be a plausible explanation for what happened in Utah. The infected caregiver, who tended to the ailing man at home and in the hospital, had not travelled to a country where Zika is circulating and had not had sex with him, officials said. Local health workers had been trapping mosquitoes since last year, but had found no Aedes aegypti. Joseph Conlon, a technical adviser to the American Mosquito Control Association, said neither Aedes aegypti nor a cousin, Aedes albopictus, is found in Salt Lake County. “We have found no evidence that mosquitoes here in Utah are transmitting the Zika virus,” said Dr. Angela Dunn, the deputy state epidemiologist at the Utah Department of Health on a call with reporters. She said that for that reason the case was not a danger to the broader public. Zika has surprised scientists with its ability to be transmitted by sex — both from men to women and, in a recent discovery in New York City, from women to men. But it is not known to be transmitted in any other way — without the help of a mosquito — so the Utah case is remarkable. Disease sleuths are sifting through clues. The Utah man who died had a very high level of virus in his body, which may have increased the risk that his bodily fluids could infect others. But while the virus has been detected in blood, semen, vaginal fluid, saliva and urine, it had not been known to infect others through nonsexual contact. “We don’t have any evidence that suggests Zika can be passed from one person to another by sneezing or coughing or kissing or sharing utensils,” said Dr. Thomas R. Frieden, the director of the Centres for Disease Control and Prevention, which has a team investigating the case. Dr. Frieden said other people who had come into contact with the Utah man were being tested. The results will take a few weeks. The continental United States has become a useful laboratory for unusual transmission of Zika. There has yet to be a local spread through mosquitoes, making sexual and other transmission easier to trace. There are more than 1,300 case of the Zika in the continental United States — all acquired through travel abroad. “This raises some interesting questions,” said Dr. William Schaffner, an infectious disease specialist in Tennessee. “Was there a needle stick or injury? Or if not, possible contact with other bodily fluid like urine or saliva?”

New York Times, 18 July 2016 ; http://www.nytimes.com/ ;