Kimberly Hatfield Freelance Writer GEN

Trying to Make Sense of an Infection that Doesn’t Play Fair

What’s becoming increasingly clear in the wake of the global Zika emergency is just how much is still unknown about the virus. Zika is linked to devastating birth defects as well as serious medical conditions such as Guillain-Barré syndrome.

Athletes, support staff, media and spectators are left to sort through conflicting advice on safety as they travel to Rio de Janeiro, epicenter of the Zika outbreak and home to the 2016 Summer Olympics.

A group of concerned scientists, now numbering 238 professionals from 40 countries, called for the Olympics to be delayed or moved in an open letter to the WHO and the IOC. The WHO stood firm. “There is no public health justification for postponing or cancelling the games,” the WHO stated. Currently the virus is reported in 65 countries and territories.

Pregnancy Complications

Heartbreaking photos of babies gave witness to an alarming trend, a rise in cases of microcephaly amidst the Zika epidemic. Data from previous outbreaks and mounting evidence linked Zika to microcephaly and other birth defects.

Concerns about heath risks led some athletes and professionals to bow out of Rio including golfers Jason Day of Australia, Lee-Anne Pace of South Africa, and Jordan Spieth of the U.S., as well as the expecting Savannah Guthrie, co-anchor at NBC. 

As the picture of Zika congenital syndrome evolves to include epilepsy, audiovisual impairment, and effects on the bones and joints according to a report by PAHO/WHO, questions remain.

News in Nature asks if Zika is only to blame. It turns out that of the 1,709 confirmed cases of microcephaly or central nervous system birth defects reported in Brazil, 90% occurred in a concentrated region of the country. This points to the possibility that other factors may have been at play in that region such as socio-economic conditions, co-infections, or rates of vaccinations for other related viruses.

Further, preliminary results from a new study just published in the New England Journal of Medicine found that in a subgroup of women in Columbia infected with Zika in the third-trimester and who had given birth, that “no infants with apparent abnormalities, including microcephaly, have been identified.” This study is ongoing.

There is a general understanding that Zika infection early in pregnancy seems to pose more of a risk to the developing fetus than later in the pregnancy, says Andrew Pekosz, an associate professor at the Johns Hopkins Bloomberg School of Public Health. “The rates of fetal abnormalities in women infected with Zika virus during pregnancy does seem to vary between countries for as yet unknown reasons, but it is clearly a risk anywhere it has been studied,” he says. 

Zika and Transmission

In light of the possible risks from Zika, a major theme for travelers to the Olympics is protection. That includes avoiding being bitten by Zika’s primary vector, infected Aedes mosquitos, which are aggressive daytime biters. It also includes preventing human transmission sexually or by an infected mother to her fetus through the placenta or at the time of delivery.

Also making headlines are transmission events that seem to be the exception to the rule. In Utah a now deceased patient who had traveled to an area with Zika was found to have unusually high amounts of the virus; what is also puzzling is that a family caregiver of that patient subsequently contracted the illness.

Further, until recently it was thought that only an infected man could spread the virus sexually. But in July a case of sexual transmission of the virus from a woman to her male partner was reported in New York.

Dr. Pekosz says these are rare examples of virus transmission. “It’s important to keep this in perspective, as the vast majority of Zika virus infections—tens of thousands of cases—are acquired by mosquito bite,” he says. He agrees that it is important for the medical community to capture and report these events, and to respond accordingly. “Right now, mosquito bites are the biggest risk and sexual transmission if the female is or is trying to get pregnant; those are the most important transmission routes that people need to be aware of,” he adds.

Safe Sex

One of the biggest stories coming out of Rio is condoms. 450,000 of them are being supplied by the IOC at an estimated rate of 42 per athlete. Health advocates are calling for safe sex or abstinence for a number of weeks or months to reduce the risk of transmission to sex partners or developing fetuses.

There is conflicting guidance on just how long safe sex should be practiced and when it could be safe to become pregnant in light of Zika infection risk.

It is already known that the virus can remain in semen longer than in other body fluids, including vaginal fluids, urine, and blood. But news in The Lancet Infectious Diseases cites a case of an unusually high Zika viral load in a semen sample and that in the semen “the virus might persist for many months.” More studies are needed, but this may present yet another challenge in managing disease transmission.

As the global community converges in Rio for the Summer games, public health experts struggle to make sense of an infection that doesn’t play by the rules.

Kimberly Hatfield is a freelance writer for GEN.


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