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Charlie Ehlert, University of Utah Health
Krow Ampofo and Dr. Carrie Byington, who specialize in infectious diseases, helped spearhead the effort to screen for infectious diseases by administering blood tests to American Olympic athletes and U.S. Olympic Committee staff members before and after they visited Brazil in August 2016.

SALT LAKE CITY — University of Utah Health's blood testing of hundreds of U.S. Olympians who traveled to Brazil for the 2016 Summer Olympics yielded no positive indications of the Zika virus, researchers announced Saturday.

Equally surprising was the university's finding that 27 of the people tested had contracted a different mosquito-borne illness in Brazil — West Nile virus, said Krow Ampofo, infectious disease specialist for University of Utah Health.

"It was surprising to all of us because of the (publicity) on the potential of Zika and the potential exposure of the athletes," Ampofo, who is also a professor of pediatric infectious diseases at the U., told the Deseret News. "Everybody was (talking) Zika, Zika, Zika, Zika."

Last year the U.S. Olympic Committee selected infectious diseases expert Dr. Carrie Byington, then with University of Utah Health, to lead a panel that would advise the committee on how to mitigate American athletes' risk of contracting infectious diseases, including Zika.

Byington's team, which also included experts from the University of California, San Diego, and the Centers for Disease Control and Prevention, counseled Team USA on how to stay safe in Brazil. Byington, who chairs the American Academy of Pediatric Committee on Infectious Diseases, told the Deseret News at the time that the panel, under the direction of the U.S. Olympic Committee, would take "every precaution" against the virus.

“We were thrilled that there were no cases of Zika,” Byington, who is now at the Texas A&M Health Science Center, said in a statement accompanying the publishing of the findings.

She also talked about the important benefits of post-Olympics testing for the subjects themselves.

“One of the reasons we think that post-travel diagnostics is really important is because multiple things can cause a similar picture, and it’s important to know what you had,” Byington said.

In all, 457 athletes, athletes' spouses and U.S. Olympic Committee staff were tested both before and after going to Brazil for the 2016 games in Rio De Janeiro, Ampofo said. About 950 such travelers enrolled in the study before leaving, but only a little less than half followed up for testing upon returning, he said.

Combined, there were more than 2,000 athletes, staff and others who traveled to Brazil as part of the United States' Olympics contingent, said U. science writer Julie Kiefer.

What athletes had, it turns out, was a high incident rate of the West Nile virus, a separate disease spread through mosquitoes that in rare cases can cause convulsions, neck stiffness and disorientation, among other symptoms.

Of the 457 Olympic people in the Olympic traveling party who submitted blood samples after returning to the United States, 27 had West Nile virus. Three athletes tested positive for Chikungunya and two had dengue fever — two additional diseases that are spread by mosquitoes and can have severe complications.

“We all had our Hollywood sunglasses on, and they blinded us to other possibilities,” Marc Couturier, a medical director at ARUP Laboratories who was put in charge of the testing, said in a statement. “We can’t forget that West Nile virus has been around for a while, and is still here."

"We did not expect to find so many with these other infections," Ampofo said. "We were surprised as everybody else. Everybody's attention was drawn to Zika."

The spread of the Zika virus, much of it centered in Brazil, was declared a "Public Health Emergency of International Concern" by the World Health Organization in February 2016, prompting concerns from the United States and many other countries about sending athletes there to compete.

Some athletes, including golfer Rory Mcllroy of Northern Ireland, cited the Zika virus in their decision not to compete at the Olympics.

Frequently, those who are infected with Zika experience either no symptoms or only mild incidents of fever, rash, eye redness, and muscle and joint pain. However, the virus can also be spread from a pregnant mother to her unborn baby, resulting in risk of microcephaly, a condition that may impair brain development in the womb and cause the baby to be born with an abnormally small head.

Zika can also be passed via sexual intercourse, regardless of whether that occurs before, during or after the time period in which the originally infected person is experiencing symptoms, according to the Centers for Disease Control and Prevention.

The initial sample gathering was done in Houston before athletes and the U.S. Olympic Committee left there for Brazil, Ampofo said. Since the athletes and staff "don't congregate in one place" after returning, he said, the U. contracted with mobile phlebotomy providers to meet the subjects where they were and perform the blood tests.

Ampofo called it unfortunate that more athletes did not follow up for a post-Olympics tests. For those who did follow up, "we would get results back to them within a month to make sure Zika was off the table," he said. Those who were infected with the other diseases benefitted from the initial piece of knowledge they needed to protect themselves and others.

"Participants who tested positive were sent letters explaining their results and recommending they consult with their health care provider," Kiefer wrote in a release.

Also unexpected in the results were the number of subjects who carried a significant infectious disease before going to Brazil in the first place. Besides those believed to have been infected while in Brazil, there were 16 athletes or staff with such infections before going to the Olympics, Ampofo said, with most of those cases being incidents of the West Nile virus.

Of the 32 individuals who were believed to be infected in Brazil, 12 filled out surveys, with just two — one who had West Nile virus and another who had contracted Chikungunya — reporting symptoms such as a rash and body aches, Kiefer said.

"Symptoms emerged within two weeks after travel and resolved shortly thereafter," she said.

The findings from the U.'s testing will be presented this weekend at IDWeek, an infectious disease conference being held in San Diego that concludes Sunday.

In Utah, the number of West Nile virus cases in humans has caused three deaths this year, and overall human cases in 2017 — 47 of them — are at their highest level since 2007.

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Brian Houggard, manager of the South Salt Lake Valley Mosquito District, has said it's possible an excess of springtime water, arising from a large winter snowpack, may have played a role in a higher than usual number this year of the kind of mosquitoes that carry the West Nile virus. But tracking a precise cause for the unusually high number of cases is difficult, experts at the Utah Department of Health have cautioned.

Health officials in Utah have also encouraged residents to avoid mosquito exposure by draining anything near their homes that collects standing water, such as empty flower pots, buckets or children's toys.

Utahns are also encouraged to use insect repellant, avoid exposure risk around dusk and dawn, wear long pants and sleeves whenever possible and ensure door and window screens are working properly to keep mosquitos outside.