Zika Virus Declared a Global Public Health Emergency

The World Health Organization (WHO; Geneva, Switzerland) has declared that the current Zika virus outbreak constitutes a public health emergency of international concern.

The WHO Emergency Committee convened on February 1, 2016, to discuss the Zika outbreak, and heard and accepted (by teleconference) the recommendations of the 18 experts and advisers convened to discuss the outbreak and the recent rise in neurological disorders. The decision was made due to the strongly suspected relationship between Zika virus during pregnancy and microcephaly. Since the link has yet to be scientifically proven, the WHO recommended that research should focus on trying to determine whether or not there is a causative link between the virus and the neurological disorders.

The most important protective measures that need to be taken, according to the WHO, are the control of the Aedes aegypti mosquito populations and the prevention of mosquito bites in at-risk individuals, placing specific emphasis on pregnant women. The Committee also suggested that health services in areas affected by Zika transmission should be prepared for potential increases in the number of cases of neurological disorders such as microcephaly and Guillian-Barré Syndrome, and that surveillance of these disorders should be both standardized and enhanced.

“In their view, a coordinated international response is needed to minimize the threat in affected countries and reduce the risk of further international spread. I have accepted this advice,” said Dr. Margaret Chan, director-general of the WHO. “International response is needed to improve surveillance, the detection of infections, congenital malformations, and neurological complications, to intensify the control of mosquito populations, and to expedite the development of diagnostic tests and vaccines to protect people at risk, especially during pregnancy.”

Zika virus is a member of the Flaviviridae family, of the genus Flavivirus, and is transmitted by daytime-active Aedes mosquitoes. In humans, the virus causes a mild illness known as Zika fever, which since the 1950’s has been known to occur within a narrow equatorial belt spread across Africa and Asia. In 2014, the virus spread eastward across the Pacific Ocean to French Polynesia, then to Easter Island, and in 2015 to Mexico, Central America, the Caribbean, and South America. Locally transmitted Zika virus was first reported in Brazil in May 2015.

Since the first reported case, Brazilian health authorities have estimated that around a million suspected cases have occurred. At the same time, the authorities observed a significant increase in the number of detected cases of microcephaly and Guillain-Barré Syndrome affecting fetuses and newborns. During the outbreak in French Polynesia, a similar increase in central nervous system malformations was recorded; the similarity between this cluster of cases and those reported in Brazil was instrumental in the WHO decision.

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