Zika situation report

26 May 2016

Zika virus, Microcephaly and Guillain-Barré syndrome


  • As of 25 May 2016, 60 countries and territories report continuing mosquito-borne transmission of which:
    • 46 countries are experiencing a first outbreak of Zika virus since 2015, with no previous evidence of circulation, and with ongoing transmission by mosquitos.
    • 14 countries reported evidence of Zika virus transmission between 2007 and 2014, with ongoing transmission.
  • In addition, four countries or territories have reported evidence of Zika virus transmission between 2007 and 2014, without ongoing transmission: Cook Islands, French Polynesia, ISLA DE PASCUA – Chile and YAP (Federated States of Micronesia).
  • Ten countries have reported evidence of person-to-person transmission of Zika virus, probably via a sexual route.
  • In the week to 25 May 2016, no new country reported on mosquito-borne or person-to-person Zika virus transmission.
  • As of 25 May 2016, microcephaly and other central nervous system (CNS) malformations potentially associated with Zika virus infection or suggestive of congenital infection, have been reported by ten countries or territories. Infection of the mothers took place in eight different countries, for one additional case the precise country in Latin America is not determined. Spain is the latest country to report a case of microcephaly associated with Zika virus in a returning pregnant traveller.
  • Two cases of microcephaly and other neurological abnormalities are currently under verification in the Bolivarian Republic of Venezuela and Costa Rica.
  • In the context of Zika virus circulation, 13 countries and territories worldwide have reported an increased incidence of Guillain-Barré syndrome (GBS) and/or laboratory confirmation of a Zika virus infection among GBS cases. One GBS case associated with Zika virus infection in a returning traveller to the Netherlands has been reported. A case of GBS from Guadeloupe is under verification.
  • Sequencing of the virus that causes the Zika outbreak in Cabo Verde showed that the virus is of the Asian lineage and the same as the one that circulates in Brazil. The precise implication of this finding is yet to be determined.
  • Based on research to date, there is scientific consensus that Zika virus is a cause of microcephaly and GBS.
  • The global Strategic Response Framework launched by WHO in February 2016 encompasses surveillance, response activities and research. An interim report has been published on some of the key activities being undertaken jointly by WHO and international, regional and national partners in response to this public health emergency. A revised strategy for the period July 2016 to December 2017 is currently being developed with partners and will be published in mid-June.
  • WHO has developed new advice and information on diverse topics in the context of Zika virus. WHO’s latest information materials, news and resources to support corporate and programmatic risk communication, and community engagement are available online.

This page links all WHO information to its response on the Public Health Emergency of International Concern.