No United States athletes at Rio 2016 concocted Zika virus ©Getty Images

Research of United States athletes and staff who attended last year's Olympic and Paralympic Games in Rio de Janeiro has found no cases of Zika virus but did find evidence of other tropical infections.

Analysis of 457 athletes and staff undertaken in a University of Utah-led study found 32 cases of mosquito-borne infections. 

Twenty-seven had West Nile virus, while three had chikungunya and two had dengue fever. 

None of these developed into serious illnesses. 

"Everyone was concentrating on Zika and ignoring that there could be other infections caused by mosquito bites," said the University of Utah's infectious disease specialist Krow Ampofo.

"We did not expect to find so many with these other infections.

"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."

Zika virus caused huge concerns before last year's Games after it was linked with a condition in which babies are born with small heads and underdeveloped brains.

It spread through the Americas earlier in the year and, in May, 150 leading international scientists, doctors and medical experts claimed the disease made it "unethical" for Rio 2016 to go ahead as planned.

Mosquito-borne viruses besides from Zika were contracted at Rio 2016 ©Getty Images
Mosquito-borne viruses besides from Zika were contracted at Rio 2016 ©Getty Images

But the World Health Organization rejected a call for the Games to be moved or postponed due to the outbreak, saying it would "not significantly alter" the spread of the virus.

It did not stop a handful of athletes withdrawing from Rio 2016 and citing Zika as the reason.

"We were thrilled that there were no cases of Zika," added lead investigator Carrie Byington, who is now based 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."

Most of those found to be infected with the other tropical diseases either had mild symptoms or none at all.

Twelve of those tested filled out post-travel surveys in which only three - two with chikungunya and one with West Nile virus - reported having symptoms that can include body aches and rashes. 

These emerged within two weeks after travel and were resolved shortly thereafter.

Chikungunya can cause sudden onset fever along with debilitating joint and muscle pain, rash, headache, nausea, and fatigue while dengue fever can, in extreme cases, cause hemorrhagic fever, internal bleeding and breathing difficulty.

West Nile virus has less obvious symptoms but can cause vomiting, diarrhea, and rash which, in a worst case scenario, can last for weeks or months.