Dengue Fever, West Nile Virus Threats Being Battled In RivCo

RIVERSIDE COUNTY, CA—Riverside County's vector control officials urged residents to be cautious around mosquitoes and illness after mosquito bites with rising West Nile Virus and Dengue Fever cases in Southern California.

Though nine cases of Dengue fever were identified in Riverside County as of Oct. 1, none of those infections were locally acquired, according to the California Department of Public Health Division of Communicable Disease Control. That agency confirmed that four cases of West Nile Virus—one of those a fatality—have been contracted within Riverside County this year.

This week, the Northwest Mosquito & Vector Control District officials are spraying multiple areas to combat mosquito larvae in areas that are thought to have a heavy concentration of mosquito activity that could lead to WNV. These scheduled "ultra-low volume" insecticide spraying events will take place between 3 and 6 a.m. Thursday and Friday within the area bounded by Archibald Avenue to the west, Hamner Avenue to the east, Riverwalk Park to the north and the Santa Ana River bottom to the south, they said.

This is the second spraying operation planned for the same area as was sprayed last month. According to the district, mosquito concentrations there have raised concerns about the potential propagation of WNV.

"Our primary focus of control is to target the immature mosquito in the larval stage of its life cycle before it matures into a flying adult," the agency said in a statement.

The district's jurisdiction encompasses Eastvale, Corona, Jurupa Valley, Norco, most of Riverside, Temescal Valley and Woodcrest.

Anti-mosquito spraying involves the use of chemicals approved by the U.S. Environmental Protection Agency. Pesticides are emitted as a mist dispersed from machines anchored in the backs of pickup trucks. Officials recommended that during operations, residents stay indoors and keep windows closed until at least 15 minutes after the trucks have departed.

Four human WNV infections have been documented in Riverside County so far this year, and one of those patients suffering from complications died, according to the county Department of Public Health.

According to the California Department of Public Health, 89 infections, including four in Riverside County, have been recorded nationwide so far in 2024.

Along with West Nile Virus, Dengue fever in Southern California remains a vector control concern.

Dengue is primarily carried and transmitted by infected Aedes aegypti, a mosquito species common to the Riverside County area. The Northwest Mosquito and Vector Control District released a statement Tuesday saying that seven cases of Dengue likely involved people traveling elsewhere.

Read also: LA Sees 'Unprecedented' Spread Of Dengue Fever Spread By Mosquitoes

In Riverside County, Coachella Valley's Mosquito and Vector Control District General Manager Jeremy Wittie discussed why vigilance against mosquitoes remains important.

"With fall temperatures, we often spend more time outdoors," Wittie said, adding that mosquitoes are more active in the fall and emphasized that wearing repellent is essential to staying healthy.

The district urged residents to take several steps to help control the spread of Aedes aegypti, including eliminating standing water sources where mosquitoes lay eggs.

For those planning on traveling to active transmission areas, officials recommended applying repellents with EPA-registered ingredients and wearing long-sleeved shirts, long pants, socks, and shoes.

What Are Dengue Symptoms:

The symptoms of dengue include:

• aches and pains (such as eye pain, typically behind the eyes, muscle, joint, or bone pain),
• nausea,
• vomiting,
• rash.

The district urged anyone with these symptoms to avoid mosquito bites and contact a medical provider.

City News Service contributed to this report.

Related:

LA County Health Confirms 4th Case Of Locally Acquired Dengue

LA Sees 'Unprecedented' Spread Of Dengue Fever Spread By Mosquitoes