With summer now upon us, the heat is not the only irritant that's starting to pop up.
We're talking, of course, about mosquitoes. These little biting insects aren't just an annoyance, they could also harbor dangerous diseases.
Just this week, West Nile virus was detected in mosquitoes in Dunnigan, a rural town in Yolo County, according to officials with the Sacramento-Yolo Mosquito and Vector Control District.
Earlier this month, dead birds with the virus were found in both Woodland and in Sacramento County, near Land Park. More dead birds found near Land Park tested positive for the virus this week, the district added.
“This is a clear sign that West Nile virus activity is spreading,” said Gary Goodman, district manager. “With the warmer temperatures we’ve seen recently, West Nile virus activity is steadily rising.”
The 2023 season was “the most intense and long West Nile virus seasons that we have seen in years,” according to Luz Maria Robles with the district: California saw 433 cases of WNV, 19 of those being fatal.
“I've been with the district for almost 17 years and it was definitely one of the busiest in terms of the amount of West Nile virus activity and sadly the amount of human cases,” she said. “Last year, we had 53 human cases in Sacramento County alone, 39 in Yolo County, and eight deaths total.”
Ahead of another season, Robles spoke with CapRadio’s Chris Nichols about what can be done to lower the level of mosquito — and West Nile virus — activity in the region.
This interview has been edited for length and clarity.
Interview highlights
What exactly is the Sacramento-Yolo Mosquito and Vector Control District, and what does it do?
Definitely a long name, right? We’re an agency that's charged with protecting residents because mosquitoes pose a lot of threatening, debilitating diseases. It's our job as an agency to make sure that we're doing everything that we can to protect public health and those residents within Sacramento [and Yolo] counties against mosquitoes.
What exactly are those diseases?
I know to most people, a mosquito’s a mosquito. But in our area we have about 27 different mosquitoes and out of those 27, two of those can transmit West Nile virus, which is the most prevalent disease that we have here in our area. The disease is unfortunately here to stay — it came to California in 2003 and ever since then we've seen it year after year.
We also have some possibility of other diseases with the introduction of invasive mosquitoes. Diseases such as Zika, Dengue and Chikungunya, which are not very popular within our area, but definitely in other parts of the world.
What are the symptoms of West Nile virus, and just how dangerous is it?
Eighty percent of people who get West Nile virus don't have any symptoms, your body just kind of gets rid of it on its own. But 20% of people develop what we call West Nile virus fever, [with symptoms] such as headaches, fever, fatigue, nausea, vomiting, swollen lymph nodes. One in 150 people developed the very severe form of the disease that leads to encephalitis, meningitis, and those are the cases that typically lead to death. The people that are most at risk for West Nile virus would be the elderly, the young, or people with a compromised immune system.
I understand that the first case of West Nile for this year was found in Sacramento County in early June, and that the disease was also detected in Yolo County in Woodland just two weeks ago. Is this early to be detecting it here in our region?
It's actually not, we're right on track to what we see almost every other year. And actually we're a little far behind in comparison to last year. So every season can definitely be a little bit different.
As for 2024, you are correct, we already have started detecting West Nile virus in birds and then also in mosquito populations. Thankfully, no human cases yet. Usually West Nile virus peaks during the months of July and August. So it is very likely that we’ll continue to see West Nile virus in both birds and mosquitoes, and eventually human cases typically develop thereafter.
What is the vector control district doing to halt the spread of diseases like West Nile?
We take what we call an integrated mosquito management approach to controlling mosquitoes and that includes a variety of elements. First of all, public education: You'll see a lot of our “Fight the Bite” campaign messages either on our billboards or on television.
And we have a very robust surveillance program that's in charge of tracking and monitoring West Nile virus activity. They collect the dead birds, they set out traps in areas where those birds were found. They collect the mosquitoes and they test them and if those mosquitoes test positive then we do additional trapping. Based on the results from the laboratory, then that would dictate where we conduct our spraying.
Once we pick up a lot of West Nile virus activity in a specific area, we call that a hotspot and then we respond by doing truck spraying, backpack spraying, because our goal is to make sure that we're bringing down those mosquito populations to levels where they're not going to pose a threat.
Are there some steps that people can take? What's the best way to control the spread of mosquitoes, say, around your house?
Absolutely. Mosquito control is what we call a collaborative effort, and especially for residents. Our district knows where the creeks are, where the pastures are, where the rice fields are, and we can address those. But what we really want and need is people to do their part at home.
At least once a week, looking around your yard and making sure that you don't have any stagnant water in flower pots, the dog dish, a bird bath, a fountain, reducing those mosquito sources now will go a long way later in the summer. So please, that's one of our biggest asks. Do your part and help us out by draining those sources of stagnant water, and reporting, say, a neglected pool.
Personal protection is one that is always key. As the days are getting longer, people are spending more time outdoors, and it’s very important that we prevent mosquito bites by wearing a good mosquito repellent because obviously if we’re not bitten by mosquitoes it’d reduce the risks of getting sick.
Where can you learn more tips for keeping safe and also for the spraying schedules?
People can sign up for our spraying notifications, if you want to know where and when that’s going to be taking place, visit us at FightTheBite.net. You can register there for spraying notifications, to see a map of West Nile virus activity taking place and just to get more on the different services we provide.
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