SAN JUAN, P.R. — On an inexorable march across the hemisphere, the Zika virus has begun spreading through Puerto Rico, now the United States’ front line in a looming epidemic.
The outbreak is expected to be worse here than anywhere else in the country. The island, a warm, wet paradise veined with gritty poverty, is the ideal environment for the mosquitoes carrying the virus. The landscape is littered with abandoned houses and discarded tires that are perfect breeding grounds for the insects. Some homes and schools lack window screens and air-conditioning, exposing residents to almost constant bites.
The economy is in shambles, and thousands of civic workers needed to fight mosquitoes have been laid off. The chemical most often used against the adult pests no longer works, and the one needed to control their larvae has been pulled from the market by regulators.
A quarter of the island’s 3.5 million people will probably get the Zika virus within a year, according to the Centers for Disease Control and Prevention, and eventually 80 percent or more may be infected.