Zika Virus: CRS Experts

Summary

In late 2015, health officials in Brazil recognized a marked increase in the number of infants born with microcephaly (from Greek, meaning “small head”), a birth defect that may accompany significant, permanent brain damage. Although not conclusive, the increase in microcephaly is suspected to be related to the emergence of Zika virus infections in Brazil early in 2015.

Zika virus is related to the viruses that cause yellow fever, dengue, West Nile, and Japanese encephalitis viruses. Historically Zika virus was found in Africa. Since 2007, Zika transmission has also occurred in Southeast Asia and the Western Pacific. In the Americas, transmission was first identified in Brazil in May 2015. As of January 29, 2016, the Pan American Health Organization (PAHO) had received reports of local transmission in 25 countries and territories in the Americas, including Puerto Rico and the U.S. Virgin Islands.

Symptoms of Zika virus infection in adults are usually mild and the illness resolves quickly. However, the possible link to microcephaly has raised the level of public health concern in the Americas and elsewhere, and has spurred wide-ranging efforts to protect pregnant women from infection. Although some aspects of Zika virus infection (such as the behavior of the mosquitoes that carry it) are well understood, many other aspects of this emerging infection in the Americas are unknown. While study of the Zika virus ramps up, health officials will have to base their decisions on the best available evidence, which could have substantial gaps for the time being.

On February 1, 2016, the World Health Organization (WHO) determined that the rapid spread of Zika infections in the Americas and the suspected link to a serious birth defect constituted a “Public Health Emergency of International Concern” under the International Health Regulations. Under this designation, nations are expected to cooperate, expand monitoring, and share information in order to stem the spread of the disease.

This report discusses scientific and technical aspects of Zika virus infection, including modes of transmission, symptoms, diagnosis and treatment, and prevention. Policy concerns and official actions will be discussed in forthcoming CRS products. Unless otherwise cited, information in this report is drawn from the Zika virus information pages of the U.S. Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and PAHO.

Health system preparedness and response (domestic and global); Countries in Latin America and the Caribbean; Mosquito control; Medical product development and regulation; Women’s health; U.S. emergency management; Legal issues; FIFRA: Federal Insecticide, Fungicide, and Rodenticide Act.