FILE - Puerto Rico Health Department workers monitor social media for Zika related issues at the department's headquarters in San Juan, Puerto Rico.
FILE - Puerto Rico Health Department workers monitor social media for Zika related issues at the department's headquarters in San Juan, Puerto Rico.

The first death on U.S. territory related to the mosquito-borne Zika virus has been reported.

The U.S. Centers for Disease Control and Prevention said Friday that a Puerto Rican man in his 70s died from internal bleeding related to a rare immune reaction to a Zika virus infection in late February.

Officials said the man, who was not identified, recovered from the initial Zika symptoms but then developed a condition in which antibodies that formed in reaction to the infection started attacking blood platelets.

Three similar Zika-related deaths have been reported in Colombia.

Puerto Rico has been facing a widespread Zika outbreak for several months. The CDC reported that there were 683 lab-confirmed current or recent Zika infections between November 1 and April 15. At least 65 of those infected were pregnant women. Seventeen patients required hospitalization

Zika-related deaths in adults are considered extremely rare. The virus causes only a mild, brief illness at worst in most people. But infections in pregnant women have been linked to a brain defect and fetal deaths and have become an international public health concern.