For a virus that initially seemed relatively unremarkable, Zika continues to surprise us. It has made headlines again with recent reports of two cases in Brazil where the virus was transmitted through blood transfusion.
This comes after news in the United States of Zika being transmitted through sexual contact. Zika is primarily known as a “vector-borne” virus, meaning it’s usually transmitted by a mosquito. In general, you become infected with Zika by getting bitten by an infected mosquito. At least, that’s what we thought.
Now, with evidence suggesting Zika can also be transmitted via blood transfusions and sexual contact, it’s clear that Zika is becoming a subject of much more research and speculation.
Blood Transmission
The possibility of Zika being transmitted through blood transfusions has been discussed for a while. However, the two cases in Campinas, Brazil, are the first confirmed instances of infection through this method.
Countries like Britain, the United States, Hong Kong, Canada, and Australia are now deferring blood donations from individuals who have recently visited Zika-affected regions. This precaution makes transmission through blood transfusion a low risk, as blood donations are routinely screened for a range of diseases.
Sexual Transmission
Earlier, we heard of a case where a scientist contracted Zika while working in Africa. When he returned home, his wife—who hadn’t traveled to Africa—also became infected, though their children did not. The most likely explanation was sexual transmission. At the time, this seemed unusual, as there had been no previous reports of a vector-borne virus spreading this way. Many scientists were initially skeptical.
Later, during the outbreak in French Polynesia, a man was found to have Zika virus in his semen up to ten weeks after experiencing Zika-like symptoms. These findings were initially dismissed as an anomaly, as Zika hadn’t yet been seen as a major concern.
No Condom, No Sex
Some countries are taking a cautious approach regarding sexual transmission. In the United Kingdom, men returning from Zika-affected areas are advised to use condoms for 28 days if they have a female partner who is trying to conceive or is already pregnant—even if they haven’t shown symptoms of Zika.
For those who have experienced symptoms, the recommendation extends to using condoms for six months.
Although this might seem like an overreaction—considering there have only been a few confirmed cases of sexual transmission—the uncertainty surrounding the virus has led public health officials to take a cautious stance.
Should We Be Worried?
We don’t yet know how common sexual transmission of Zika is, nor do we know if someone who got the virus through sexual contact can then pass it on through sex. We don’t fully understand how long the virus can remain in semen, and while it has been found in semen, we’re not sure whether it can be transmitted by a woman during sex.
We do know that Zika can be transmitted from a mother to her fetus, and that the virus can also be found in urine. However, there haven’t been reports of Zika in breast milk, which remains an unknown.
From an evolutionary standpoint, it’s more important to know what can harm you than what might improve your harvest next season. Diseases like pandemic influenza, Ebola, and now Zika spark concern because they are new and unfamiliar.
Infectious diseases are frightening because they represent unknown threats. Throughout history, pandemics have wiped out significant portions of populations, and with each new outbreak, there’s fear that it could be the one to affect you or your loved ones. However, Zika is unlikely to become one of those deadly pandemics. Unlike some past influenza outbreaks or Ebola, Zika does not have a high fatality rate.
The good news is that there are steps you can take if you’re in an area affected by Zika. Avoid mosquito bites and practice safe sex.
