Three cases of residents contracting West Nile virus have been reported in Coronado making 2026 the most local West Nile virus infection in a decade.
According to San Diego County, Coronado will receive pesticide treatment in the coming days as the county detected at least 10 locations on the island with mosquitos infected with the mosquito-borne virus.
The treatment, AquaDuet, will be in the early mornings of Sept. 25 and 26. The pesticide is approved by the Environmental Protection Agency and does not pose a risk to people and pets, according to the county.
The treated areas will be from 2nd Street to Ocean Boulevard, F Avenue and Glorietta Boulevard.
The exact boundaries of the treatment can be found on the county’s Adult Mosquito Control Information webpage.
San Diego County conducts its routine testing of mosquitoes and birds. In the last month, almost 1,500 homes in Coronado received letters warning of infected mosquitoes.
There have been 11 reported human cases in the county as of Sept. 16.
The West Nile virus is a disease that can be transferred to humans and animals through infected mosquitos. It is the most common mosquito-borne disease in the United States, according to the county.
Most people who are infected don’t ever have any symptoms, but about 20% of those infected experience mild flu-like symptoms such as a fever or body aches, the Center for Disease Control reports.
Less than 1% of those infected develop severe central nervous system illnesses – such as encephalitis or meningitis – that require hospitalization and can lead to death. Symptoms of a severe illness include disorientation, convulsions and vision loss.
Residents can protect and prevent this disease by dumping out standing water and replacing it with fresh water and avoiding mosquito bites by wearing long sleeves and pants or using mosquito repellent.
Mosquitoes lay eggs in standing water and can grow into biting adults in less than a week, according to the county.
The most recent data showed that 95 batches of mosquitoes and 45 birds were found with the virus throughout San Diego County. Each batch contains up to 1,000 mosquitoes that were tested..
Ten of the 95 batches of mosquitos and two infected birds were found in Coronado.
The county has traps located throughout the region and vector control staff routinely check the traps as part of their monitoring program, the county’s Communications Officer, Donna Durckel, explained.
“Detections are made when mosquitoes are tested at the lab for various diseases, including West Nile virus,” Durckel said.
The county’s news center reported that one of the cases required several days in the hospital, and a second patient suffered mild symptoms. Two other cases were detected through blood-donation screening.
There were no deaths due to the virus reported this year.
Last year, San Diego had over 180 batches of infected mosquitos and 34 infected birds. But before that, it had been almost a decade since there were numerous cases discovered.
In 2016, almost 100 batches of mosquitoes were identified and over 260 birds were found with the virus. The year before that, 49 batches and over 360 birds were infected.
There was another gap of eight years with minimal cases until 2008, when more than 560 birds and 40 batches of mosquitoes were found with West Nile.
