In May 2015, the World Health Organization reported the first local transmission of Zika virus in the Western Hemisphere, with autochthonous (locally acquired) cases identified in Brazil. As of January 15, 2016, local transmission had been identified in at least 14 countries or territories in the Americas, including Puerto Rico. Further spread to other countries in the region is likely.
Local transmission of Zika virus has not been documented in the continental United States; however, Zika virus infections have been reported in travelers returning to the United States. With the recent outbreaks in the Americas, the number of Zika virus disease cases among travelers visiting or returning to the United States likely will increase. These imported cases may result in local spread of the virus in some areas of the continental United States, meaning these imported cases may result in human-to-mosquito-to-human spread of the virus.
Zika virus is a mosquito-borne flavivirus transmitted primarily by Aedes aegypti. Aedes albopictus mosquitoes might also transmit the virus. Outbreaks of Zika virus disease have been reported previously in Africa, Asia, and islands in the Pacific.
About one in five people infected with Zika virus become symptomatic. Characteristic clinical findings include acute onset of fever, maculopapular rash, arthralgia, or conjunctivitis. Clinical illness usually is mild with symptoms lasting for several days to a week. Severe disease requiring hospitalization is uncommon and fatalities are rare. During the current outbreak in Brazil, Zika virus RNA has been identified in tissues from several infants with microcephaly and from fetal losses in women infected during pregnancy. The Brazil Ministry of Health has reported a marked increase in the number of babies born with microcephaly. However, it is not known how many of the microcephaly cases are associated with Zika virus infection and what factors increase risk to the fetus. Guillain-Barre syndrome also has been reported in patients following suspected Zika virus infection.
The CDC has issued a Travel Alert for pregnant travelers to areas affected by Zika virus. The latest CDC Morbidity and Mortality Weekly Report (MMWR) also discusses guidelines for evaluating pregnant travelers for Zika virus.
Implications for College Health:
- Pregnant travelers to areas with Zika virus transmission should postpone their travel, if at all possible.
- Discuss with students traveling to Central and South America and the Caribbean the possibility of mosquito borne viral infections, including Zika, Chikungunya, and Dengue.
- Review with travelers the importance of mosquito bite prevention. Aedes species mosquitos can bite during the daytime as well as at dawn and dusk.
- Clinicians should consider Zika virus, as well as Dengue and Chikungunya virus, in the differential diagnosis in returning travelers who present with fever, maculopapular rash, and conjunctivitis.
For More Information
- General information about Zika virus and disease
- Zika virus information for clinicians
- Protection against mosquitoes
- Travel notices related to Zika virus
- Information about Zika virus for travelers and travel health providers
- Pan American Health Organization (PAHO)
- Information on microcephaly
- Approximate distribution of Aedes aegypti and Aedes albopictus mosquitoes in the United States
The ACHA National Office is sending out this information on behalf of Tim Moody, chair of the Emerging Public Health Threats and Emergency Response Coalition.