Dengue strikes United States

From Toronto, at a meeting of the Infectious Diseases

Society of America

Texas has been hit with the first-ever outbreak of dengue hemorrhagic fever in the continental United States. Sixteen people in Brownsville contracted this severe form of dengue fever late in 2005, and another nine people had a less severe form of dengue infection at that time, says physician Bryan K. Kapella of the Centers for Disease Control and Prevention in Atlanta, who presented these findings.

Dengue is a viral disease, carried by mosquitoes, that causes a high fever, headache, vomiting, muscle and joint aches, and rashes. Dengue hemorrhagic fever includes those symptoms plus small–blood vessel leakage, which can lead to shock, internal bleeding, circulatory failure, and death. There is no vaccine for dengue and no direct treatment.

In the U.S. outbreak, none of the patients died.

Dengue is most common in tropical regions. It’s caused by four distinct—but related—viruses. A person can’t be re-infected with the same type of dengue. However, dengue hemorrhagic fever seems to strike people who have been infected with one virus type and then later become infected with another.

Therefore, some Brownsville patients may have been previously exposed to a dengue virus. Indeed, authorities had recorded five earlier instances in which verifiable dengue fever had crossed from Mexico, but none had caused hemorrhagic illness.

The dengue virus is carried by Aedes aegypti, a day-biting mosquito that is partial to humans. The mosquitoes breed in open water containers and pools, Kapella says. He recommends stepped-up dengue surveillance along the border.

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