In January of 2016, concerns about the possibility of a recent outbreak of the Zika virus spreading to the United States prompted the Centers for Disease Control and Prevention (CDC) to release a travel alert warning advising pregnant women to avoid travel to countries with recorded cases of the virus. The first reported cases of the current outbreak were reported in Brazil in April of 2015, where it was initially mistaken for dengue fever, a disease caused by a virus closely related to the Zika virus. At the time of release of the CDC’s travel alert, the Zika outbreak had spread throughout most of South America, Mexico, and some countries in the Caribbean.
The Zika virus was originally discovered in monkeys living in the Zika forest in Uganda in 1947, with the recorded human case of infection occurring in 1954. For the next several decades, the disease was limited to Africa and Southeast Asia. Over the last ten years, however, the disease has migrated to the Americas, causing outbreaks in Micronesia, French Polynesia, and most recently, Brazil. Because the oldest outbreak of the Zika virus took place in 2007 in the Yap Islands in Micronesia, few resources have been devoted to researching a vaccine or a cure. Instead, preventive measures have been limited to stopping the spread of mosquitoes of the genus Aedes, the vectors responsible for carrying and transmitting the virus. One explanation for the swiftness spread of the outbreak from Brazil points to the climate of many Central and South American countries, where tropical climates are prone to forming standing bodies of water where mosquitoes can breed. In the absence of a medical solution to the outbreak, health officials in affected countries have begun public health education campaigns that advise the use or insect repellants and mosquito nets in order to reduce risk of infection, as well as the elimination of any sources of standing water in homes.
The true extent of the Zika virus outbreak has been difficult to measure, primarily because symptoms of the disease are mild. Only one in five patients infected with the virus develops symptoms at all, which include rash, fever, joint pain, and conjunctivitis. Because these symptoms are similar to other tropical diseases carried by Aedes mosquitoes like dengue fever and chikunguya, positive diagnoses can only be made by blood tests. Although severe symptoms and deaths due to Zika virus in adults are rare or nonexistent, pregnant women are particularly susceptible to the disease. Pregnant mothers infected with the Zika virus are especially prone to miscarriage due to abnormal development of the fetus; some that are born suffer from developmental problems even after birth. Since the beginning of the outbreak in April 2015, Brazil has reported a sharp spike in cases of microcephaly, increasing from 150 cases in 2014 to more than four thousand cases as of January 2016. Babies born with microcephaly have abnormally small heads and underdeveloped brains, as well as stunted growth and development for the rest of their lives. Although many pregnant women in the US have the option to avoid travel to areas affected by the Zika virus outbreak, however, thousands of women living in Central and South America remain at risk.