As the Zika epidemic continues to spread, especially in South and Central America, more than a million people are believed to have been infected with the virus. And in areas with large Zika outbreaks, an increasing number of babies have been born with microcephaly, a birth defect marked by a smaller than normal head and brain and, often, severe disabilities.
Now researchers have another reason to think mosquito-borne Zika is indeed the “smoking gun” in many instances of microcephaly. The Centers for Disease Control and Prevention (CDC) has identified the Zika virus in the brain tissue of two babies with microcephaly who died. Both of the infants’ mothers were infected with the virus in Brazil.
"This is the strongest evidence to date that Zika is the cause of microcephaly,” CDC Director Tom Frieden, MD, recently told members of the U.S. House Foreign Affairs Joint Subcommittee Hearing on the global Zika epidemic.
Researchers are investigating whether the virus may cause additional birth defects. For example, new study of children with Zika-associated microcephaly found the majority had serious, vision endangering eye problems.
Although the Zika virus is primarily spread through mosquito bites, the disease is known to be sexually transmittable, too. And it now appears the virus could be contagious through sexual contact for a longer period of time than first thought.
Based on this new information, the CDC has issued revised guidelines for women who are pregnant or could become pregnant.
The CDC now recommends that pregnant women who have traveled to areas where the Zika virus is known to be transmitted be offering testing for Zika infection, whether or not they have any symptoms of the virus. Blood tests for Zika can be offered two to 12 weeks after pregnant women return from trips to areas where they could have been exposed to the virus.
If a pregnant woman does have signs of illness consistent with Zika infection — such as body aches, fever, red eyes, and fatigue — she should be tested for the virus during the first week she feels unwell.
In addition, women who live in areas where there are ongoing Zika cases and who become pregnant should be tested as soon as they begin their prenatal care, and tested again during the middle of the second trimester of pregnancy, whether or not they have any symptoms.
There are currently no vaccines or drugs that prevent or cure Zika infections. However, scientists have stepped up research to develop a vaccine as quickly as possible, and public health measures are being enacted internationally to slow down and eventually stop the spread of the virus.
In the meantime, you can take many common sense measures to help prevent infection with Zika and lower the odds your unborn baby will suffer from Zika-associated birth defects.
First and foremost, if you are pregnant, the CDC urges postponing travel to South America, Central America, and Caribbean countries such as Puerto Rico, where the virus is spreading rapidly. Women who are living in those parts of the world should take precautions to protect themselves from mosquitoes, which are the main way the disease is transmitted.
And based on evidence Zika can be transmitted through semen, CDC experts emphasize the importance of safe sex. “Given the potential for Zika virus to be spread through sex, if male partners have or are at risk for Zika virus infection, pregnant women and their male partners should consider abstaining from sexual intercourse or using condoms,” said the CDC's Frieden.
Although the Zika epidemic has not spread to the U.S., it makes sense to prepare for that possibility sooner than later.
Zika is primarily transmitted by mosquitoes in the Aedes aegypti species which are found throughout much of the Americas, including the southern U.S. These mosquitoes bite mostly during daylight hours so, as warm weather approaches, it’s important to protect yourself from mosquito bites throughout the day —especially if you are pregnant or could become pregnant. Wear long-sleeved shirts, pants, and EPA-approved insect repellants.
February 18, 2016
Christopher Nystuen, MD, MBA