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This week Puerto Rico declared a public health emergency. The territory has seen a lot more dengue cases than normal. The mosquito-borne disease has hit record levels in North and South America, with more than 3.5 million cases this year so far. NPR's Gabrielle Emanuel has more.
GABRIELLE EMANUEL, BYLINE: Grayson Brown's team has laid 5,000 traps across Puerto Rico to catch the mosquito that spreads dengue.
GRAYSON BROWN: It's completely dependent on people - abandoned pools. Or they're breeding in underground septic tanks and cisterns.
EMANUEL: Brown runs the Puerto Rico Vector Control Unit. He tests the mosquitoes for four types of dengue. One type is common here, but there are other types that are now circulating widely for the first time in a couple decades. He blames ferries and cruise ships.
BROWN: Up to 14 ships take 2 or 3,000 passengers a week out, and they take them to all throughout the Caribbean. And every single thing in the Caribbean and Central America ends up here.
EMANUEL: There have been major outbreaks in Brazil, Argentina and elsewhere. Puerto Rico's health department says it has seen more than 500 cases so far this year. That's a lot more than normal, and Brown expects the number to grow heading into the summer months.
BROWN: We'll probably end up with close to or over 10,000 by the end of this year. So it's really serious. And not only do we have a lot of cases, but the symptoms are worse.
EMANUEL: The vast majority of dengue cases are mild - fever, headache, rash. But Brown says in Puerto Rico, somewhere around 7% of cases are severe. And in rare cases, it can be deadly. Jarbas Barbosa heads the Pan American Health Organization.
JARBAS BARBOSA: So probably this would be the worst dengue fever season in the Americas.
EMANUEL: He says not only are there record numbers, but the disease is being seen in new places. He says things like climate change and urbanization are contributing to the growing number of dengue cases. Gabrielle Emanuel, NPR News.
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