STANISLAUS COUNTY, Calif. — Modesto’s East Side Mosquito Abatement was taken by surprise with what may be the first human case of West Nile virus reported in California this year.
“It was a little bit of a surprise to us because normally we find positive birds and positive mosquitoes prior to a human infection, but this year, that was our first indication of West Nile,” Lloyd Douglas, East Side Mosquito Abatement's District Manager, said.
The case involves a 81-year-old man in the 95357 area of Stanislaus County. One of the surprising elements was that the mosquito districts hadn’t picked up positive mosquito pools in that area before the infection.
Traps were set up in the area and caught relatively few mosquitoes, so a human infection case was a bit odd to see.
“Last year, it wouldn’t have been odd for this time of year, but, like I said, usually we find positive birds and positive pools prior – maybe as much as two or three weeks prior to a human infection and this year our positives came after the human infection,” Douglas said.
California tracks West Nile activity in the state at Westnile.ca.gov, and, according to their current tracker, no human cases have been recorded for this year. Right now, the East Side Mosquito Abatement District believes their human case of West Nile was a local transmission.
San Joaquin County recently had two mosquito samples with West Nile in Tracy and Ripon areas. Dead birds have previously been found in Orange County and San Diego County.
The discovery of the case comes at time when the mosquito district has been doing all they can to temper the population of pasture mosquitoes, which aren’t vectors of virus, but are the source of a lot the calls they receive.
What mosquito conditions are like in the area
These pasture mosquitoes are often the ones that receive the most complaints from customers, and, according to Douglas, are the ones that drive the public crazy. Since those mosquitoes like warm temperatures, the above average temperatures have been causing problems.
“The main ones we’re having problems with is the pasture mosquitoes and that is mostly temperature driven,” Douglas said. “This above average temperature is just making the numbers ridiculous.”
Pasture mosquitoes tend to be hard to target. Since they like to come out in warm weather, the adulticide used to combat them is less likely to stay on the ground when the district sprays for mosquitoes.
While a large spraying effort will likely have an effort to notify the public, there are scenarios where the district is left with little time to notify people of a spraying schedule.
“We have such a small target. If we worry about actually setting the schedule, we might miss our opportunity to do it,” said Douglas.
Protecting yourself
To avoid mosquitoes and mosquito bites, the district recommends staying indoors at dawn and dusk, due to mosquitoes being most active around these times, and wearing long-sleeved shirts and pants while outdoors.
Since mosquitoes lay eggs on water, draining any standing water is a good way to stop mosquitoes from breeding around your home. This would include bird baths, flowers pots, clogged gutters, neglected swimming pools, and discarded tires.
Repellent is also considered by the Centers for Disease Control and Prevention to be the best way to protect yourself from getting sick due to a mosquito bite, when used as directed.
If you invest in repellent, the CDC suggests making sure that it has one of these active ingredients:
- DEET
- Picaridin
- IR3535
- Oil of lemon eucalyptus
- Para-menthane-diol
- 2-undecanone
“The one thing that’s the hardest to push – and always reminds of when DOT tried to get us to wear seat belts – is that people do not like wearing repellent, but it is important if you’re going to be out in the evening that you think about that.”