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Microcephaly cases linked to Zika virus nearly triple in Brazil

Brazilian officials have updated the number of cases of microcephaly connected to Zika virus infection among infants in the country’s northeastern region to nearly triple the previously reported figure, according to a WHO news release.

The Brazilian Ministry of Health notified the Pan American Health Organization (PAHO) and WHO of the updated number of microcephaly cases. According to WHO, 1,761 cases of microcephaly, a rare neurological condition, have been reported, including 19 deaths. The cases are spread across 422 municipalities of 14 federal units, including six new Brazilian states. States with the greatest number of cases are Pernambuco (n = 804) and Paraiba (n = 316).

The press release also said that Brazilian officials have revised their definition of microcephaly for inclusion in the ongoing investigation. The head circumference of an infant with microcephaly has been reduced from no larger than 33 cm to 32 cm or smaller. Microcephaly among newborns is diagnosed when the occipitofrontal circumference is two standard deviations below the mean compared with similarly aged children, WHO said. Genetic and environmental factors, leading to developmental problems, are the cause of microcephaly. The condition is untreatable; however, early detection can boost quality of life.

Brazilian health officials previously reported that the increase in microcephaly cases is linked to Zika virus infections. The relationship between Zika virus and microcephaly was based on test results that revealed the presence of Zika virus in blood and tissue samples from an infant born with microcephaly who died. An initial analysis suggested that the risk for Zika virus infection is associated with the first 3 months of pregnancy, according to Brazil’s Ministry of Health.

Due to the unprecedented scientific relevance of the association between Zika virus and microcephaly, the release said, the Ministry of Health is pledging to undertake studies to expand the understanding of this relationship.

WHO has yet to confirm Zika virus as a cause of microcephaly.