The Zika virus outbreak in Puerto Rico has continued to expand in both number of persons infected and geographic extent and residents. Travelers to Puerto Rico should employ mosquito bite avoidance behaviors, take precautions to reduce the risk for sexual transmission, and seek medical care for any acute illness with rash or fever. This according to an update from the CDC that determined:

• Of 16,522 patients with suspected Zika virus disease in Puerto Rico during November 1, 2015 to July 7, 2016, 5,351 (32%) had laboratory evidence of current or recent Zika virus infection.

• The percentage of persons with confirmed or presumptive Zika virus infection among symptomatic pregnant females increased from 8% in February 2016 to 41% in June 2016.

• During the same time period, the percentage of persons with confirmed or presumptive Zika virus infection among symptomatic males and nonpregnant females increased from 14% to 64%.

• Clinicians who suspect Zika virus disease in patients who reside in or have recently returned from areas with ongoing Zika virus transmission should consider testing for Zika virus and report cases to public health officials.

Citation: Adams L, Bello-Pagan M, Lozier M, et al. Update: Ongoing Zika virus transmission — Puerto Rico, November 1, 2015–July 7, 2016. [Published online ahead of print August 5, 2016]. MMWR Morb Mortal Wkly Rep. 2016;65:774–779. doi:10.15585/mmwr.mm6530e1.

Commentary: The increase in the incidence of Zika virus infections in Puerto Rico is startling and of great concern. From February to June, the incidence of Zika virus infections has increased by approximately eightfold. The CDC is working with the Puerto Rico Health department, implementing a three-prong strategy: protecting pregnant women, controlling the mosquito vector, and expanding access to the full range of voluntary contraceptive options for women and men. This information is also important, of course, for patients contemplating travel to Puerto Rico, a popular vacation destination. —Neil Skolnik, MD