Zika situation report
24 March 2016
Zika virus, Microcephaly and Guillain-Barré syndrome
- From 1 January 2007 to 23 March 2016, Zika virus transmission was documented in a total of 61 countries and territories. Four of these countries and territories reported a Zika virus outbreak that is now over. Argentina and New Zealand are the latest countries to report sexual transmission of Zika virus. Thus, five countries have now reported locally acquired infection in the absence of any known mosquito vectors, probably through sexual transmission (Argentina, France, Italy, New Zealand and the United States of America).
- The geographical distribution of Zika virus has steadily widened since the virus was first detected in the Americas in 2014. Autochthonous Zika virus transmission has been reported in 34 countries and territories of this region.
- So far an increase in microcephaly and other fetal malformations has been reported in Brazil and French Polynesia. Two additional cases, linked to a stay in Brazil, were detected in the United States of America and Slovenia. Panama recently reported a newborn with microcephaly and occipital encephalocoele (neural tube defect) who died a few hours after birth and tested positive for Zika virus by RT-PCR.
- In the context of Zika virus circulation, 12 countries or territories have reported an increased incidence of Guillain-Barré syndrome (GBS) and/or laboratory confirmation of a Zika virus infection among GBS cases.
- The mounting evidence from observational, cohort and case-control studies indicates that Zika virus is highly likely to be a cause of microcephaly, GBS and other neurological disorders. Among the tasks ahead are to further quantify the risk of neurological disorders following Zika virus infection, and to investigate the biological mechanisms that lead to neurological disorders.
- The global prevention and control strategy launched by the World Health Organization (WHO) as a Strategic Response Framework encompasses surveillance, response activities and research, and this situation report is organized under those headings.