Blood samples were drawn from US Olympic and Paralympic athletes and staff before and after the Rio Games in 2016 and tested for Zika, West Nile Virus, and other tropical infectious diseases. Courtesy of Charlie Ehlert, University of Utah Health
U.S. Olympic and Paralympic athletes and staff who traveled to Rio de Janeiro, Brazil, for the 2016 Summer Games did not become infected with Zika virus but did test positive for other tropical, mosquito-borne viral infections, including West Nile virus, dengue fever and chikungunya. Results from the University of Utah Health-led study will be reported at IDWeek, a national infectious disease conference being held in San Diego.
None of the infected travelers became seriously ill, say the study's investigators. But the findings are a reminder that amidst the frenzy over Zika, travelers were also susceptible to other, long-standing public health risks that did not receive the same level of scrutiny.
"Everyone was concentrating on Zika and ignoring that there could be other infections caused by mosquito bites. We did not expect to find so many with these other infections," says U of U Health infectious disease specialist Krow Ampofo, MBCHB., who will be presenting the study's results on Oct. 7. "That is one of the reasons why we think that being vigilant about monitoring for infectious diseases after travel to at-risk areas is so important."
Other sources have indicated that there were no Zika cases reported during the Rio Olympics. But the U of U Health investigation is the first to examine a large cohort for viruses that cause other tropical infectious diseases.
Of the 457 athletes and staff who provided blood samples after returning from Brazil, testing found that 32 (7%) had become infected with mosquito-borne viruses while abroad. Twenty-seven had West Nile Virus, three had Chikungunya, and two had Dengue. None had signs of Zika.
Twelve of the individuals who tested positive filled out post-travel surveys. From those, only three - two with Chikungunya and one with West Nile Virus - reported having symptoms that can include body aches and rash. Symptoms emerged within two weeks after travel and resolved shortly thereafter.
"We were thrilled that there were no cases of Zika," says lead investigator Carrie Byington, MD, who began the study while at U of U Health and is now at Texas A&M Health Science Center. "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."
In general, most people infected with one of the other three viruses tested in the study - West Nile Virus, Chikangunya or Dengue - either had no symptoms or, when ill, had mild symptoms. In rare cases, these infections can be severely disabling or lethal.
At the time the study began, organizers were particularly concerned about Zika, which can also spread through sexual transmission and cause debilitating birth defects in unborn babies.
The 2016 Olympic and Paralympic Summer Games were held not long after the height of the Zika epidemic. The U of U Health study was mounted as a rapid response to monitor the health of U.S. athletes and staff traveling to Brazil, the epicenter of the outbreak. Of the estimated 2,000 travelers, 950 enrolled in the study, and just under half submitted samples for testing upon return. Participants who tested positive were sent letters explaining their results and recommending they consult with their health care provider.
"We all had our Hollywood sunglasses on, and they blinded us to other possibilities," says Marc Couturier, PhD, a medical director at ARUP Laboratories who led the testing. "We can't forget that West Nile Virus has been around for a while, and is still here."
Funding was provided by the National Institutes of Health.
Source: University of Utah Health
Stay prepared and protected with Infection Control Today's newsletter, delivering essential updates, best practices, and expert insights for infection preventionists.
Reducing Hidden Risks: Why Sharps Injuries Still Go Unreported
July 18th 2025Despite being a well-known occupational hazard, sharps injuries continue to occur in health care facilities and are often underreported, underestimated, and inadequately addressed. A recent interview with sharps safety advocate Amanda Heitman, BSN, RN, CNOR, a perioperative educational consultant, reveals why change is overdue and what new tools and guidance can help.
New Study Explores Oral Vancomycin to Prevent C difficile Recurrence, But Questions Remain
July 17th 2025A new clinical trial explores the use of low-dose oral vancomycin to prevent Clostridioides difficile recurrence in high-risk patients taking antibiotics. While the data suggest a possible benefit, the findings stop short of statistical significance and raise red flags about vancomycin-resistant Enterococcus (VRE), underscoring the delicate balance between prevention and antimicrobial stewardship.
What Lies Beneath: Why Borescopes Are Essential for Verifying Surgical Instrument Cleanliness
July 16th 2025Despite their smooth, polished exteriors, surgical instruments often harbor dangerous contaminants deep inside their lumens. At the HSPA25 and APIC25 conferences, Cori L. Ofstead, MSPH, and her colleagues revealed why borescopes are an indispensable tool for sterile processing teams, offering the only reliable way to verify internal cleanliness and improve sterile processing effectiveness to prevent patient harm.
The Next Frontier in Infection Control: AI-Driven Operating Rooms
Published: July 15th 2025 | Updated: July 15th 2025Discover how AI-powered sensors, smart surveillance, and advanced analytics are revolutionizing infection prevention in the OR. Herman DeBoard, PhD, discusses how these technologies safeguard sterile fields, reduce SSIs, and help hospitals balance operational efficiency with patient safety.
Targeting Uncertainty: Why Pregnancy May Be the Best Time to Build Vaccine Confidence
July 15th 2025New national survey data reveal high uncertainty among pregnant individuals—especially first-time parents—about vaccinating their future children, underscoring the value of proactive engagement to strengthen infection prevention.