5th State Reports Spread of Dengue

California logs an unwelcome first with local transmission
By Arden Dier,  Newser Staff
Posted Oct 24, 2023 1:17 PM CDT
5th State Reports Spread of Dengue
A lab technician holds a male mosquito in the World Mosquito Program's factory, in Medellin, Colombia, Thursday, Aug. 10, 2023. Scientists are breeding mosquitoes to carry the bacteria Wolbachia, which interrupts the transmission of dengue.   (AP Photo/Jaime Saldarriaga)

California has reported its first locally acquired case of dengue, a mosquito-borne virus typically associated with tropical environments—part of a trend that has seen the virus spread in new areas affected by climate change. A person living in Pasadena tested positive for dengue despite no recent travel history, indicating the virus was contracted locally for the first known time, according to public health officials. It's "an extremely rare case of local transmission in the continental United States," reads a statement from the Pasadena Public Health Department. Local transmission has previously been reported only in Hawaii, Florida, Texas, and Arizona. Of the 67 reported cases last year, 65 were in Florida and two were in Arizona, per Fox 11.

Pasadena's public health department, which has been investigating mosquito-borne diseases in the region for years, has "confidence that this was likely an isolated incident and that there is very low risk of additional dengue exposure in Pasadena," says epidemiologist Matthew Feaster, per the Messenger. "The San Gabriel Valley Mosquito and Vector Control District has deployed traps to assess the mosquito population and, importantly, testing to date has not identified any Dengue infected mosquitos," according to the statement. Still, officials are urging residents of Southern California to take precautions to prevent mosquito bites and mosquito breeding around their homes.

One modelling estimate indicates there are 390 million new dengue infections each year, "of which 96 million manifest clinically," according to the World Health Organization. Most infections are asymptomatic. In about 25% of cases, a person experiences symptoms including high fever, headache, muscle and joint pain, nausea, and rash. About 5% of cases are labeled extreme and potentially deadly, with severe abdominal pain, persistent vomiting, and other symptoms appearing after fever has resolved. The virus is most common in tropical and subtropical climates, though local transmission has been reported in new areas, including Central and Western Europe, in recent decades. As of this month, there have been 68 locally acquired cases reported this year in Florida. (Diet pills could help.)

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