Since the Zika virus outbreak in Brazil last spring, the story of Zika has slowly emerged. The April 2016 Green Journal provides an excellent summary (here) of what OBGYNs need to know about the virus. For those of us who prefer our data in infographic form, I've illustrated all the most salient facts from the article, brought to us by doctors from the CDC.
The most shocking statistics come from the current impact of the disease in Brazil. In 2015, the Brazilian Ministry of Health estimated that Zika virus had infected between 440 thousand and 1.3 million people. In 2015, there were 3,500 cases of infants born with microcephaly in Brazil. The country had not previously tracked cases of microcephaly, but this is a significant increase. In the United States, the baseline incidence of microcephaly is 2 to 12 cases per 10,000 live births.
How did all this start? The first case of Zika dates all the way back to 1947 when it was detected in a monkey in Uganda. Since that time, there were two major outbreaks in humans, the first was in Yap, an island in the Pacific in 2007. Many of the earliest reports of the effects of the virus come from the large outbreak in French Polynesia in 2013-2014, which affected 28,000 people.
How are all these people getting infected with Zika? The culprit is the Aedes mosquito. It also transmits other viruses in the same family as Zika, including yellow fever, dengue, and chikungunya. It bites during the daytime, so the CDC recommends wearing long sleeves and pants, using approved/registered insect repellants (like DEET), and wearing permethrin-treated clothing. Ideally, individuals who do not live in affected areas should avoid travel to those areas. The mosquito lives near homes and breeds in water containers, so dump out any stagnant water at your house!
Anyone can become infected with Zika. Symptoms typically start a few days to 2 weeks after infection and last a few days to 1 week. Symptoms are variable, but often include rash, fever, and joint pain. Less commonly they can include muscle pain, headache, eye pain, itching, and vomiting. Rarely, it has been linked to Guillain-Barre syndrome, which involves paralysis.
The reason people are most concerned with infection in pregnant women is that Zika has been linked to developmental problems in infants. The most recognized abnormality is "microcephaly" which simply means the infant's head is smaller than expected. Microcephaly can have lasting effects on the infant for the rest of his or her life.
What should doctors do if they encounter a possible case of Zika infection? A blood test known as reverse-transcriptase polymerase chain reaction (RT-PCR) can detect Zika if done within 1 week of symptoms starting. The body can clear the virus in a week, so timing is important. The article's authors also point out that fevers can have ill effects on pregnancies, so tylenol can be used as a fever-reducer. If a pregnant woman has a positive Zika test, consultation with a high-risk OB is recommended.
Most importantly, we can all stay up to date with the latest recommendations and news about Zika through the CDC website.