The CDC, on January 15, 2016, issued a travel alert (Level 2-Practice Enhanced Precautions) for people traveling to regions and certain countries where Zika virus transmission is ongoing: Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela, and the Commonwealth of Puerto Rico. On January 22, 2016, the CDC added the following destinations to the Zika virus travel alerts: Barbados, Bolivia, Ecuador, Guadeloupe, Saint Martin, Guyana, Cape Verde, and Samoa. On January 26, 2016, the CDC added two more destinations to the Zika virus alerts, United States Virgin Islands and Dominican Republic.
Travelers to these areas may also be at risk of being infected with dengue or chikungunya viruses. Mosquitoes that spread Zika, chikungunya, and dengue are aggressive daytime biters, prefer to bite people, and live indoors and outdoors near people. There is no vaccine or medicine available for Zika virus. The best way to avoid Zika virus infection is to prevent mosquito bites.
The alerts follow reports in Brazil of microcephaly and other poor pregnancy outcomes in babies of mothers who were infected with Zika virus while pregnant. In early 2015, an outbreak of Zika virus, a flavivirus transmitted by Aedes mosquitoes, was identified in northeast Brazil, an area where dengue virus was also circulating.
By September, reports of an increase in the number of infants born with microcephaly in Zika virus-affected areas began to emerge, and Zika virus RNA was identified in the amniotic fluid of two women whose fetuses had been found to have microcephaly by prenatal ultrasound. The Brazil Ministry of Health (MoH) established a task force to investigate the possible association of microcephaly with Zika virus infection during pregnancy and a registry for incident microcephaly cases (head circumference ≥2 standard deviations [SD] below the mean for sex and gestational age at birth) and pregnancy outcomes among women suspected to have had Zika virus infection during pregnancy.
Among a cohort of 35 infants with microcephaly born during August–October 2015 in eight of Brazil’s 26 states and reported to the registry, the mothers of all 35 had lived in or visited Zika virus-affected areas during pregnancy, 25 (71%) infants had severe microcephaly (head circumference >3 SD below the mean for sex and gestational age), 17 (49%) had at least one neurologic abnormality, and among 27 infants who had neuroimaging studies, all had abnormalities. Additional studies are needed to further characterize this relationship. More studies are planned to learn more about the risks of Zika virus infection during pregnancy.
Until more is known, and out of an abundance of caution, the CDC recommends special precautions for pregnant women and women trying to become pregnant. Pregnant women in any trimester should consider postponing travel to the areas where Zika virus transmission is ongoing. Pregnant women who must travel to one of these areas should talk to their doctor or other healthcare provider first and strictly follow steps to avoid mosquito bites during the trip. Women trying to become pregnant should consult with their healthcare provider before traveling to these areas and strictly follow steps to prevent mosquito bites during the trip.
Some travelers to areas with ongoing Zika virus transmission will become infected while traveling but will not become sick until they return home. Four in five people who acquire Zika infection may have no symptoms. Illness from Zika is usually mild and does not require hospitalization. Travelers are strongly urged to protect themselves by preventing mosquito bites. Cover exposed skin by wearing long-sleeved shirts, long pants, and a hat. Use EPA-registered insect repellents containing DEET, picaridin, oil of lemon eucalyptus (OLE), or IR3535. Always use as directed. Insect repellents containing DEET, picaridin, and IR3535 are safe for pregnant and nursing women and children older than two months when used according to the product label. Oil of lemon eucalyptus products should not be used on children under three years of age. Use permethrin-treated clothing and gear (such as boots, pants, socks, and tents). Stay and sleep in screened-in or air-conditioned rooms.
In addition to the steps announced January 15, 2016, the CDC is working with public health experts across the U.S. Department of Health and Human Services (HHS) to take additional steps related to Zika. The CDC is developing interim guidance for pregnant women as well as sharing additional information about Zika with public health officials, clinicians and the public. In addition, efforts are underway across HHS to develop vaccines, improved diagnostics and other countermeasures for Zika.
The CDC scientists tested samples provided by Brazilian health authorities from two pregnancies that ended in miscarriage and from two infants with diagnosed microcephaly who died shortly after birth. For the two full-term infants, tests showed that Zika virus was present in the brain. Genetic sequence analysis showed that the virus in the four cases was the same as the Zika virus strain currently circulating in Brazil. All four mothers reported having experienced a fever and rash illness consistent with Zika virus disease (Zika) during their pregnancies.
According to Brazilian health authorities, more than 3,500 microcephaly cases were reported in Brazil between October 2015 and January 2016. Some of the affected infants have had a severe type of microcephaly and some have died. The full spectrum of outcomes that might be associated with infection during pregnancy and the factors that might increase risk to the fetus are not yet fully understood. Health authorities in Brazil, with assistance from the Pan American Health Organization, the CDC, and other agencies, have been investigating the possible association between Zika virus infection and microcephaly in infants. However, additional studies are needed to further characterize this relationship. More studies are planned to learn more about the risks of Zika virus infection during pregnancy.
In the past, outbreaks of Zika virus infection have occurred in Africa, Southeast Asia, and the Pacific Islands. Zika virus is transmitted to people primarily through the bite of an infected Aedes species mosquito. About one in five people infected with Zika virus will develop symptoms, which include fever, rash, joint pain, and conjunctivitis (pink eye). Other commonly reported symptoms include myalgia, headache, and pain behind the eyes. The illness is usually mild with symptoms lasting from several days to a week. Severe disease requiring hospitalization is uncommon and case fatality is low. Guillain-Barré syndrome has been reported in patients with probable Zika virus infection in French Polynesia and Brazil. Research efforts will also examine the link between Zika and GBS.
Because specific areas where Zika virus transmission is ongoing are difficult to determine and likely to change over time, the CDC will update the travel notice as information becomes available. Check the CDC travel website frequently for the most up-to-date recommendations.
See the CDC Media Statement, January 26, 2016
Also see the CDC Media Statement, January 22, 2016
See the CDC Media Statement, January 15, 2016
Also see the CDC Zika Virus Website
See also Medical Law Perspectives, August 2015 Report: Pediatrician Liability for Childhood Disease Complications
See also Medical Law Perspectives, January 2015 Report: Mothers, Infants, and Obstetrical Injuries: Labor and Delivery Liability
See the Medical Law Perspectives February 23, 2015, Blog: Florida’s No-Fault Compensation System for Severe Birth Injury Claims Fails Again