Emergencies

Zika situation report

25 August 2016

Zika virus, Microcephaly and Guillain-Barré syndrome

Key updates

  • Countries and territories reporting mosquito-borne Zika virus infections for the first time in the past week:
    • None
  • Countries and territories reporting microcephaly and other central nervous system (CNS) malformations potentially associated with Zika virus infection for the first time in the past week:
    • Costa Rica, Dominican Republic and Haiti
  • Countries and territories reporting Guillain-Barré syndrome (GBS) cases associated with Zika virus infection for the first time in the past week:
    • None
  • The 2016 Summer Olympics held in Rio de Janeiro ended on 21 August. From the reports WHO received from national health authorities, there have so far been no laboratory confirmed cases of Zika virus in anyone associated with the Olympics.
  • Operational measures updates from the WHO Regional Office for the Americas:
    • WHO provided technical advice on integrated vector management in Puerto Rico, molecular diagnosis of Zika in the Bahamas, and clinical management of GBS in the context of the Zika emergency in Chile.

Summary

  • 70 countries and territories (Fig. 1, Table 1) have reported evidence of mosquito-borne Zika virus transmission since 2007 (67 with reports from 2015):
    • 53 with a first reported outbreak from 2015 onward.
    • 4 with having possible endemic transmission or evidence of local mosquito-borne Zika infections in 2016.
    • 13 with evidence of local mosquito-borne Zika infections in or before 2015, but without documentation of cases in 2016, or with the outbreak terminated.
  • Since February 2016, 11 countries have reported evidence of person-to-person transmission of Zika virus.
  • 20 countries or territories have reported microcephaly and other CNS malformations potentially associated with Zika virus infection or suggestive of congenital infection. 4 of the 20 countries reported microcephalic babies born from mothers in countries with no endemic Zika virus transmission but who reported recent travel history to Zika affected countries.
  • Outcomes of pregnancies with laboratory evidence of possible Zika virus in the United States of America:
    • 16 total liveborn infants with birth defects
    • 5 total pregnancy losses with birth defects
  • Outcomes of pregnancies with laboratory evidence of possible Zika virus in territories of the United States of America:
    • 1 total liveborn infant with birth defects
    • 1 total pregnancy loss with birth defects
  • 18 countries and territories have reported an increased incidence of GBS and/or laboratory confirmation of a Zika virus infection among GBS cases.
  • In Guinea-Bissau, the gene sequencing results of the four confirmed Zika cases sent on 1 July are still pending. The investigation of the 5 cases of microcephaly detected since April 2016 is ongoing. Additional WHO deployments in entomology, epidemiology and laboratory are being planned.
  • The 2016 Summer Olympics held in Rio de Janeiro ended on 21 August. From the reports WHO received from national health authorities, there have so far been no laboratory confirmed cases of Zika virus in spectators, athletes or anyone associated with the Olympics. The situation is being closely monitored; a few cases may still occur, especially given the approximately one-week incubation period of the virus.
  • WHO has developed advice and information on diverse topics in the context of Zika virus.

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