The headline is How a Caribbean island became prime source of U.S. Zika cases [by Phil Galewitz, Kaiser Health News, July 23 2016], but of course it's not the island, it's the immigrants—from the Dominican Republic.

The Centers for Disease Control apparently does not break out cases by country of origin (why not?) but, Kaiser reports, it "said in June that 48 percent of the travel-associated cases for all of 2015 and through May of this year originated in the Caribbean, 26 percent in Central America and 23 percent in South America." (Link in original).

However, New York State, New York City, Florida and California, which account for more than half the cases, report that "more people who visited the Dominican Republic in 2016 returned with Zika than did U.S. residents who traveled to Puerto Rico, Colombia, Jamaica, El Salvador, Haiti, Guyana and Venezuela combined."

Reason:

In part, it reflects travel patterns between people living in the U.S. with family members in the Caribbean nation, public health officials say. “It’s not really tourists going back and forth,” said Chris Barker, a researcher in the School of Veterinary Medicine’s Department of Pathology, Microbiology and Immunology at the University of California, Davis... People who travel outside the U.S. to visit family tend to make longer visits and often stay in residential locations, instead of “more sanitized areas made for tourists,” and that may increase their chances of getting bitten by a Zika-infected mosquito, Barker said. [Emphases added]

Dominican Republic immigrants are the fifth-largest Hispanic group in the United States, numbering 960,000 in 2012, according to the Migration Policy Institute

Typically, New York City's Health Department put out a disingenuous statement to lull the American peasantry:

“Dominicans, Puerto Ricans and Guyanese do not have a higher risk of transmission for Zika infection,” the department said in a statement. “The data we have released simply reflects New York City’s demographics and travel patterns.”

Yeah—that's the point.