Thanks to Greg Folkers for sending the link to this CDC Travel Health Notice: Zika Virus in Puerto Rico - Watch - Level 1, Practice Usual Precautions. Excerpt:
In December 2015, a locally transmitted case of Zika virus infection was detected in Puerto Rico. This is the first case of Zika virus in Puerto Rico. Local transmission means that mosquitoes in Puerto Rico have been infected with Zika virus, spreading it to humans.
CDC recommends that travelers to affected areas in South America, Central America, the Caribbean, or Mexico protect themselves from mosquito bites. Zika outbreaks have been identified recently in several countries in Central and South America. The outbreak began in Brazil in May. Recently, the Ministry of Health in Brazil has raised concerns about a possible association between the Zika virus outbreak and increased numbers of babies born with birth defects. For this reason, pregnant women should take extra precautions to avoid mosquito bites.