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Epidemic vs. Endemic Zika

To protect travelers from Zika, scientists and travel experts at CDC are monitoring the status of Zika in countries around the world and making appropriate travel recommendations. These recommendations are based on a number of factors, including the historical or current presence of Zika in the country. Based on this assessment, areas with Zika are classified as epidemic or endemic.

Epidemic: These countries are currently experiencing outbreaks of Zika, and travel notices have been posted to alert travelers, particularly pregnant women, of the risk. These countries are considered epidemic because

  • The mosquito that carries Zika virus is present,
  • Zika has not been reported there in the past, and
  • Very little, if any, of the population is likely to be immune.

When Zika is first introduced into a country, it generally spreads quickly through the population. Over time, as the outbreaks decrease, these countries will change from the “epidemic” to the “endemic” classification, and travel notices will be removed.

Endemic: These countries have reported cases of Zika in the past and may report occasional new cases. A large number of local residents are likely to be immune, so occasional cases may occur but generally not in numbers large enough to be considered an outbreak. Because the risk to travelers is likely much lower in these countries than in epidemic countries, travel notices will not be posted unless the number of cases rises to the level of an outbreak. For more information, visit Questions and Answers: Zika Risk in Endemic Countries.

Special Note about Southeast Asia: Some of these countries have reported cases of Zika in the past, have reported recent variations in the number of cases, or share borders with those countries. Limited information is available to fully evaluate risk of Zika virus infection in some of these countries. This list might change as we learn more about Zika transmission in Southeast Asia.  Because of this, CDC has issued special travel considerations for these areas.

For general information on countries with endemic Zika, visit Zika Travel Information and Questions and Answers: Zika Risk in Endemic Countries.