|MMWR Early Release|
Vol. 65, Early Release
January 22, 2016
|Zika Virus Spreads to New Areas — Region of the Americas, May 2015–January 2016|
Morgan Hennessey, DVM; Marc Fischer, MD; J. Erin Staples, MD, PhD.
MMWR Morb Mortal Wkly Rep 2016;65(Early Release):1–4
In May 2015, the World Health Organization reported the first local transmission of Zika
virus in the Americas, with autochthonous cases identified in Brazil. In December, the
Ministry of Health estimated that 440,000–1,300,000 suspected cases of Zika virus
disease had occurred in Brazil in 2015. By January 19, 2016, local transmission had
been identified in Puerto Rico and 19 other countries or territories in the Americas.
Further spread to other countries in the region is likely.
SummaryWhat is already known on this topic?
Zika virus is a mosquito-borne flavivirus transmitted primarily by Aedes aegyptimosquitoes. Most
infections are asymptomatic, and symptomatic disease generally is mild. In May 2015, the first local
transmission of Zika virus in the Region of the Americas was reported in Brazil. Following the spread
of Zika virus in Brazil, there has been a marked reported increase in the number of infants born with microcephaly; it is not known how many of these cases are associated with Zika virus infection.What is added by this report?
By mid-January 2016, local Zika virus transmission had been reported to the Pan American Health
Organization from 20 countries or territories in the Region of the Americas; spread to other countries
in the region is likely. Although local transmission of Zika virus has not been documented in the
continental United States, infections have been reported among travelers visiting or returning to the
United States, and these likely will increase. Imported cases might result in local transmission in limited
areas of the continental United States.What are the implications for public health practice?
The best way to prevent Zika virus infection is to avoid mosquito bites by avoiding exposure and
eliminating mosquito breeding areas. Until more is known, pregnant women should consider postponing
travel to any area with ongoing Zika virus transmission. Health care providers should contact their state
or local health department about testing patients with symptoms of Zika virus infection and a compatible