Preliminary Report of Microcephaly Potentially Associated with Zika Virus Infection During Pregnancy - Colombia, January-November 2016

In Colombia, approximately 105,000 suspected cases of Zika virus disease (diagnosed based on clinical symptoms, regardless of laboratory confirmation) were reported during Aug 9, 2015-Nov 12, 2016, including nearly 20,000 in pregnant women. Zika virus infection during pregnancy is a known cause of microcephaly and serious congenital brain abnormalities and has been associated with other birth defects related to central nervous system damage. Colombia's Instituto Nacional de Salud (INS) maintains national surveillance for birth defects, including microcephaly and other central nervous system defects. This report provides preliminary information on cases of congenital microcephaly identified in Colombia during epidemiologic weeks 5-45 (January 31-November 12) in 2016. The temporal association between reported Zika virus infections and the occurrence of microcephaly, with the peak number of reported microcephaly cases occurring approximately 24 weeks after the peak of the Zika virus disease outbreak, provides evidence suggesting that the period of highest risk is during the first trimester of pregnancy and early in the second trimester of pregnancy.