On a sunny Sunday morning in September, I was on my way to piano lessons at Patrick’s Music School when I happened to spot a public health advisory sign on Woods Avenue. Looking closer, the sign read, “West Nile virus activity has been detected in this area.” I thought it was time to contact the Orange County Mosquito and Vector Control District (OCMVCD). Based in Garden Grove, the organization’s primary objective is to protect the people of Orange County from the dangers of vector-borne disease as well as educate the public about the shared responsibility of vector control. Connecting with Lora Young, the OC Mosquito and Vector Control District’s Director of Communications, I was able to schedule an interview with Laboratory Director, Bob Cummings, who was kind enough to meet me at a site in Fullerton to show me the traps that the District uses as part of their mosquito surveillance.
According to their pamphlet, “since 1947, the District has provided an effective county-wide mosquito control program to eliminate pest and pathogen carrying mosquitoes.” The mosquito control program, still in operation, consists of spraying accessible mosquito sources, such as man hole chambers, street gutters, catch basins, and flood control channels, with environmentally safe pesticides.
West Nile Virus (WNV) has spread across the United States since 1999, according to the District’s website. By 2004, evidence of transmission was detected in birds in Orange County. There have been hundreds of reported West Nile virus cases; many of which resulted in fatalities. West Nile virus is primarily found in birds, and is transmitted between birds and people by mosquito bites. A mosquito acquires the virus by biting an infected bird. The virus then multiplies in the mosquito. It is transmitted to a new host when it bites a person or animal.
To find out more about mosquitoes carrying West Nile Virus, I met with Mr. Cummings at a mosquito breeding site on the southern end of Craig Park next to an Army Corps of Engineers maintenance building just north of the corner of Bastanchury and Associated Road. As I stepped out of my car with my camera and hand-held shoulder rig, I noticed a sticker on the side of the District’s vehicle warning passersby that the van was a poison storage area. Mr. Cummings greeted me warmly while taking off a blue glove from his hand.
“We set mosquito traps at eight routine locations every week in Fullerton,” said Mr. Cummings as we walked over to a mosquito trap behind Craig Park’s tennis courts. “Mosquito control inspectors working in the city will set traps as well based on need when they investigate mosquito calls from the public. Altogether for 2019, mosquito traps have been set at 45 locations in Fullerton, 8 of which are the weekly routine sites. Each week during the summer season, we set almost 200 traps in the county. We reduce trapping a lot during winter months since mosquitoes and disease are not much of a concern then.”
Mr. Cummings showed me two types of mosquito traps. He started with the Gravid trap, a trap designed to catch the mosquitoes when they try to lay eggs. I learned that mosquitoes were attracted to the trap by the stagnant water placed under a battery-powered fan which blows the mosquitoes into a collection container. “It sucks up air and blows air out,” he said. “In between the entrance and exit is a net that catches mosquitoes.” The water sat in a black container with a solution of organic material, like grass or alfalfa, that was left out to sit for several days or longer and served as an attractant by imitating the naturally occurring stagnant water, where the mosquitoes often prefer to lay their eggs.
“We’ll lay one for the location and test it later to see if it’s carrying viruses,” said Mr. Cummings as he held a plastic container with quite a few mosquitoes trapped in it. “We count the number of mosquitoes and identify the species in the net. It gives us a profile or idea of the mosquitoes in the area, the disease potential and whether or not there’s disease in the area. And we have been finding mosquitoes with West Nile virus at this particular site.”
Once he picked up the mosquitoes and put them safely away in a box, he dumped out the container of water before showing me another type of trap. “Parts of Orange County, especially the City of Fullerton, have been invaded by this particular type of mosquito; ankle-biter mosquitoes we call them, Aedes Aegypti.” They’re a real aggressive biter. They love to bite people and they breed around backyards, front yards and people’s homes. The District uses a different technique to catch this particular ankle-biter mosquito.
One part of the trap involved a bucket filled up with dry ice or frozen carbon dioxide chained to a wire-linked fence behind Craig Park’s tennis courts. He said, “The dry ice acts as an attractant.” It mimics mammals who inhale oxygen and release carbon dioxide. The mosquito can see the vapor coming out of the bucket and thinks that the vapor could be an animal or a person. They come into proximity of the other part of the trap, which was a larger black container with a white top. On the white covering, there was a hole for suction and an attractant right next to the suction. “It smells like dirty socks,” said Mr. Cummings. “It has lactic acid which is a component in our sweat. So the combination of CO2 and the smell of the lactic acid is really attractive to these mosquitoes. They also like a white/black combination. So as a mosquito comes up close to the trap, it gets sucked into a net. There’s a fan spinning in there that creates the suction.”
Crossing a bridge that ran over a creek, Mr. Cummings led me to a back-up trap. People typically think the mosquitoes are coming from the creek, but the OCMVCD knows about these breeding sites and they treat them regularly by releasing mosquito fish. These fish aren’t native to California and they’re only used in water sources that do not connect or drain to natural water bodies. “It’s a non-pesticide solution to the problem,” he said. “It’s really what we call biological control and we don’t have to spend that much effort except for an occasional check-up to see if the fish are doing alright.”
The OCMVCD has collected West Nile positive mosquitoes in 16 batches at 10 locations in Fullerton beginning in mid-August. “Some of the locations have produced positive mosquitoes more than once over the course of the summer,” said Mr. Cummings. Infected mosquitoes were still being found in the city and elsewhere in the county as of October 4th. “We expect this trend will end once the temperatures start to cool.”
So how can we protect ourselves and our families from West Nile Virus? Well, I found out that residents can do a variety of things to help reduce the risk from mosquitoes. We can start by dumping and draining standing water. It’s recommended to eliminate standing water around the home or office at least once a week. We can also keep mosquitoes out with tight-fitting screens on all windows and doors. Avoid outdoor activities between dusk and dawn during the mosquito season and dress properly. Wear loose-fitting long pants and long sleeve shirts when outdoors and opt for light colored clothing. Mr. Cummings said, “Use approved mosquito repellents containing DEET, Picaridin, IR 3535, or Oil of Lemon Eucalyptus.”
If you are bothered by mosquitoes, a Certified Vector Control Technician will investigate and lend assistance. If you have or are aware of an ornamental pond, unused swimming pool, or an animal drinking trough, the District will provide you with free mosquito fish. You can call the Orange County Mosquito and Vector Control District at (714) 971-2421 or (949) 654-2421 for more info.
To see my full interview with Laboratory Director Bob Cummings, visit the Observer website and click the tab labeled “Local.” Underneath that tab, click on “Emerson Little YouTube Channel,” which should take you directly to my page.