The Centers for Disease Control and Prevention released a Level 2 alert ("Practice Enhanced Precautions") for travel to Brazil and several other South American and Central American countries this week. The alert warns pregnant women against travel to Brazil and the other destinations where the virus has spread, due to the sudden and the unexpected effects the virus has had on unborn and newborn babies in Brazil (see below).
What is the Zika virus?
The Zika virus was first discovered in monkeys in Uganda in the 1940s. It is named for the forest where it was first discovered. The virus is not uncommon in Africa and Southeast Asia, but it has been more widely spread in Brazil as of late, perhaps as a result of increased travel to Brazil for the 2014 FIFA World Cup and recent Olympics preparations. The virus is spread to humans through the Aedes aegypti mosquito, the same type of mosquito that carries yellow fever and dengue. The virus cannot be transmitted from person to person directly.
What are the symptoms of Zika?
Until now, Zika has not caused much alarm because the symptoms of Zika are generally mild. The virus causes relatively mild symptoms for several days and is not considered life-threatening. Symptoms include a red rash, fever, mild headache, joint pain, and conjunctivitis (pink eye). The virus is typically treated with mild pain medication and rest.
In fact, many people who have Zika do not show symptoms; according to the CDC, only one in five people who have Zika will become ill.
How can Zika be prevented?
Those who are ill with Zika should avoid mosquitoes as much as possible for several days to prevent the disease from spreading to others. The best way to avoid Zika is to practice good mosquito-prevention techniques: wear long-sleeved clothing; use an effective insect repellent that contains DEET, oil of lemon eucalyptus, or Picardin; stay in places that have air conditioning and/or screens; and avoid staying outside at dawn or dusk when this type of mosquito is especially active.
However, it is important to note that the Aedes aegypti mosquito is active during the day, not at night. There is no vaccine to prevent Zika.
Why are pregnant women advised not to travel to Brazil?
The CDC announced a travel warning for pregnant women, advising them to consult their doctors and to avoid travel to Brazil and other countries where Zika has spread in Latin America. This warning follows the unexpected spike in babies born with microcephaly, a serious birth defect that causes smaller-than-normal brains, in Brazil. The effects of the condition vary depending on the severity of microcephaly in each individual baby but can include intellectual disabilities, seizures, hearing and vision loss, and motor deficiencies.
The sudden connection between Zika and microcephaly is still not completely understood. This appears to be a new effect of the virus that is perhaps the result of women being infected with dengue within a certain amount of time before becoming infected with Zika. Brazil also had an epidemic of dengue in 2015.
There have been more than 3500 cases of microcephaly in Brazil in recent months. In previous years, there are approximately 150 cases of microcephaly in Brazil annually.
It is unclear how this outbreak and the related travel warning may affect travel to Brazil for the 2016 Summer Olympic and Paralympic Games in Rio de Janeiro.