Deadly Virus Surfaces in California for First Time

The dengue virus is circulating in California for the first time, health officials warn.

An unnamed person in Pasadena, just northeast of Los Angeles, has tested positive for the virus after having no recent history of travel. This indicates that they contracted the virus locally, which has never been recorded before in the Golden State.

“Pasadena Public Health Department has been conducting surveillance and investigation of mosquito-borne diseases in Pasadena for years," Matthew Feaster, M.D., Pasadena public health epidemiologist, said in a statement. "... [we have] confidence that this was likely an isolated incident and that there is very low risk of additional dengue exposure in Pasadena."

While there is little risk of further spread within the general population, local officials are warning Southern California residents to take precautions around mosquitoes.

Dengue is a mosquito-borne illness. It can transmit to humans when an infected bug bites them. The World Health Organization estimates that it sickens up to 400,000 people each year globally, and is responsible for 40,000 annual deaths. 

It is most common in tropical, humid, environments where mosquitos thrive. Jamaica, for example, suffered a massive outbreak of the disease over summer. An extended rainy season in Bangladesh is believed to be the reason for a  severe outbreak of the virus linked to more than 1,000 deaths in the South Asian nation.

However, as the climate changes, experts fear these mosquito-borne illnesses will become more common. Florida recorded 10 domestic-borne cases of dengue in the Miami area over the summer, a staggeringly high total. The Sunshine State also recorded cases of malaria, the first domestic-borne cases of that mosquito-borne illness in more than a decade.

While South California is humid, it is not considered to be at the same risk as southern states near the Gulf of Mexico like Florida, Louisiana and Texas.

The Pasadena person who was infected with the virus is recovering from their illness.