First US Zika death reported in Puerto Rico

After months of warnings about the disease, health officials on Friday announced the first official Zika-related death in the U.S.

Puerto Rico's health secretary, Ana Rius, said a 70-year-old man infected with the mosquito-borne illness died in February in the territory from severe thrombocytopenia — a low blood platelet count that can lead to internal bleeding.

The CDC also reported Friday that there were 683 laboratory-confirmed current or recent Zika cases in Puerto Rico between November 1 and April 15. Of those patients, 74 percent reported rash, 69 percent myalgia (muscle pain), 65 percent fever and 65 percent arthralgia (joint pain).

At least 49 confirmed Zika patients were symptomatic pregnant women, the CDC said.

Only 16 patients required hospitalization, and 6 were suspected of having Guillain-Barre syndrome — when the immune system attacks a body's nerves.

The CDC said the public health response has seen increased laboratory capacity for Zika infection tests, stepped up surveillance, and prevention activities directed toward pregnant women.

In order to control the disease transmission to that population, the CDC said authorities have conducted spraying and sought to reduce mosquito breeding environments "especially around pregnant women's houses."

"Residents of and travelers to Puerto Rico should continue to avoid mosquito bites, take precautions to reduce the risk of sexual transmission, and seek medical care for any acute illness with rash or fever," the CDC said.

Health officials have been warning about Zika for months, with some issuing travel notices for the Caribbean, Central America and South America.

"We are learning more about Zika literally every day, and we're doing more about Zika every day, but there's still much more that needs to get done," Centers for Disease Control and Prevention Director Thomas Frieden told CNBC earlier this month.

As authorities step up their monitoring of the disease, Quest Diagnostics said Thursday that it had received emergency authorization from the U.S. Food and Drug Administration to sell the first commercially developed diagnostic test for Zika in the United States.

Currently, the only laboratory that will use the new Zika test is at Quest's reference laboratory in San Juan Capistrano, California, where the test was developed and validated. But the Emergency Use Authorization may allow for testing at other qualified laboratories, including one in Puerto Rico, Quest said in a statement.

—The Associated Press and Reuters contributed to this report.