(CN) — A man in Puerto Rico has died of complications stemming from a Zika virus infection, health officials said Friday.
The man, in his 70s, developed a rare immune reaction to the mosquito-borne virus that led to internal bleeding, according to the Centers for Disease Control and Prevention.
The condition — immune thrombocytopenic purpura — directs antibodies against platelets, which causes the immune system to attack the host. This leads to a low platelet count and bleeding.
It is a known but rare condition associated with Zika.
Federal health officials warned Congress Thursday that the rising local transmission of Zika in Puerto Rico could lead to the virus spreading throughout the continental United States.
Obama administration officials have requested $1.9 billion in aid to battle the mosquito-borne virus.
U.S. Department of Health and Human Services Secretary Sylvia Burwell visited Puerto Rico, where 683 people have tested positive for Zika and 65 pregnant women have been affected. It is difficult to determine how many people have been infected with Zika since only about 20 percent of people with the virus demonstrate symptoms, according to the CDC.
"The trip just emphasized that in Puerto Rico and in the U.S., this problem demands our attention and continued action," Burwell said. "It also highlights why we need that $1.9 billion we requested."
The Zika virus leads to several birth defects including microcephaly, which results in babies being born with significantly smaller heads and potential brain damage.
The female Aedes aegypti mosquito is the primary carrier of Zika, West Nile virus, yellow fever and other diseases. Zika can also be transmitted sexually.
Symptoms of Zika include rashes, joint pain and fever.
About 11 percent of Puerto Ricans tested for Zika had the virus.
While Zika normally has mild symptoms, typically rare complications are becoming more common. Doctors are unsure why severe birth defects and autoimmune disorders — such as Guillain Barre syndrome — are being caused by Zika.
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