First 2019 human case of West Nile virus found near Modesto, authorities say

East Side Mosquito Abatement District’s Tom Smith explains spraying methods

Tom Smith, a technician from the East Side Mosquito Abatement District in Modesto, California, shows how they spray larvae-killing chemicals on storm drains and ponds on June 17, 2019.
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Tom Smith, a technician from the East Side Mosquito Abatement District in Modesto, California, shows how they spray larvae-killing chemicals on storm drains and ponds on June 17, 2019.

A human case of West Nile virus was confirmed this week near east Modesto, according Lloyd Douglass, manager of the East Side Mosquito Abatement District.

Douglass said the case came a bit earlier than last year for the area, and could be the first in the state. There were no reported human cases as of last Friday, according to the state’s West Nile website. Generally, the first cases are seen in the Bakersfield area and Southern California.

Mosquitoes with West Nile have been found this year, with a report of three dead birds — two in Orange County and one in San Diego County.

Warm weather coupled with plentiful water from the wet winter have created the “perfect storm” to allow mosquito populations to boom, Douglass said. With more mosquitoes comes the greater likelihood of people contracting the virus.

However, there are ways to prevent the spread. Douglass and his team work hard to control the populations in Stanislaus County, north of the Tuolumne River.

West Nile Virus can be deadly — but only one in five people who are infected by a mosquito bite will develop any symptoms, according to the South Carolina Department of Health and Environmental Control. Here's what to look for.

With an annual budget of $1.7 million, the district sprays anything from storm drains to neglected residential pools to ponds with chemicals that kill larvae and prevent others from growing in the standing water.

They spent part of Monday morning spraying near the intersection of Parker Road and Santa Fe Avenue east of Claus Road.

They also set traps in locations where a mosquito sample, person or dead bird has been found with the virus.

“The trap will help determine how many mosquitoes were in that area,” said Wakoli Wekesa, who will take over as manager of the district July 1. “If there’s one or two, we see it’s a little bit better because we know there’s not as many infected there. But we get 1,500 mosquitoes per trap, then we’re scared because we know more people could easily get the disease.”

If they find a trap with a large amount, the technicians will go out to the area and spray any standing water, Wekesa said. Many times, areas as small as a potted plant saucer with water runoff in it may be a breeding ground.

Another common breeding ground are neglected pools. When a pool turns green, that is when the owner should call the district to come out and spray, Douglass said.

“We’re not police; we don’t care about anything but mosquitoes,” Douglass said. “Let us in. We’ll help you out, get rid of your mosquitoes, and we’ll move on.”

Zika and West Nile viruses are both transmitted by mosquitoes. Officials from public health and from Sacramento-Yolo vector control explain how to protect yourself from bites.

Douglass said the No. 1 rule is to simply dump out any standing water as often as possible.

Dead birds are a sign West Nile may be present. Because they carry the disease, Douglass advises to report them as soon as possible by calling 1-800-WNV-BIRD.

“Birds are maybe our best sentinel,” he said. “And we need fresh birds, dead within 24 hours is best. We have to have fluids in the body that we can test.”

Douglass said public help in reporting any dead birds is vital.

For horse owners, Douglass said, many are regularly vaccinating their animals. With better technology, there have been fewer cases in horses recently, Douglass said.

Stanislaus County West Nile Virus confirmed positive cases.png
Mackenzie Shuman mshuman@modbee.com

There is no vaccine for humans, but about 80% of those infected do not even show symptoms from the disease. However, according to Julie Vaishampayan, public health officer of the Stanislaus County Health Services Agency, 20% of those infected may have a fever and generally feel unwell with non-specific symptoms like feeling tired and achy. About 1 in 100 will develop an infection of the brain, which can be quite serious.

The only way to protect yourself is to avoid mosquito bites:

    • Wear an effective mosquito repellent such as one with DEET, picaridin, oil of lemon eucalyptus, or IR3535.

    • Avoid being outside at dawn and dusk, when mosquitoes are most active.

    • Ensure window screens fit tightly and repair tears.

    • Drain all standing water on your property. This is where mosquitoes breed.

Douglass said there is simply no way to determine what kind of West Nile season there will be this summer. There were 18 reported human cases last year after 31 were reported in 2017.

Those infected who show serious symptoms are usually over the age of 60, and with other medical conditions that weaken the immune system such as cancer, diabetes, hypertension, kidney disease and people who have received organ transplants, according to the California Department of Public Health.

People typically develop symptoms three to 14 days after they are bitten by an infected mosquito.

To report a dead bird, call 1-800-WNV-BIRD or visit westnile.ca.gov for further information about WNV.

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Mackenzie Shuman is a summer news intern for The Modesto Bee. She originally hails from Colorado Springs, Colorado, but goes to school at Arizona State University’s Walter Cronkite School of Journalism and Mass Communication where she is studying Journalism with a minor in Political Science.
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