Areas with Zika
On January 22, 2016, CDC activated its Incident Management System and, working through the Emergency Operations Center (EOC), centralized its response to the outbreaks of Zika occurring in the Americas and increased reports of birth defects and Guillain-Barré syndrome in areas affected by Zika. On February 1, 2016, the World Health Organization declared a Public Health Emergency of International Concern (PHEIC) because of clusters of microcephaly and other neurological disorders in some areas affected by Zika. On February 8, 2016, CDC elevated its response efforts to a Level 1 activation, the highest response level at the agency.
CDC is working with international public health partners and with state and local health departments to
- Alert healthcare providers and the public about Zika.
- Post travel notices and other travel-related guidance.
- Provide state health laboratories with diagnostic tests.
- Monitor and report cases of Zika, which will help improve our understanding of how and where Zika is spreading.
Areas with active mosquito-borne transmission of Zika virus
- Prior to 2015, Zika virus outbreaks occurred in areas of Africa, Southeast Asia, and the Pacific Islands.
- In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infections in Brazil.
- Currently, outbreaks are occurring in many countries and territories.
- Zika virus will continue to spread and it will be difficult to determine how and where the virus will spread over time.
- Local mosquito-borne transmission of Zika virus has been reported in the Commonwealth of Puerto Rico, the US Virgin Islands, and American Samoa.
*Territories of the United States are sub-national administrative divisions overseen by the US federal government.
- No local mosquito-borne Zika virus disease cases have been reported in US states, but there have been travel-associated cases.
- With the recent outbreaks, the number of Zika cases among travelers visiting or returning to the United States will likely increase.
- These imported cases could result in local spread of the virus in some areas of the United States.
Local mosquito-borne transmission
Local mosquito populations are infected with Zika virus and can transmit it to humans.
See “What is Local Transmission?” [PDF - 1 page]
Travel-associated transmission (imported case)
infection associated with travel to an area with local mosquito-borne transmission.
See “What is an imported case?” [PDF - 1 page]
- Page last reviewed: April 26, 2016
- Page last updated: May 26, 2016
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