West Nile virus found in East Palo Alto | News | Palo Alto Online |


West Nile virus found in East Palo Alto

Mosquito spraying ordered for some areas late Sunday into Monday

West Nile virus-carrying mosquitoes found in East Palo Alto have prompted vector-control officials to order spraying in neighborhoods near the baylands, officials announced Thursday.

San Mateo County Mosquito and Vector Control District laboratory staff detected West Nile virus in adult mosquitoes on Thursday, according to a press release. The district will conduct truck-mounted adult mosquito control treatments in the area where the infected mosquitoes were collected. The treatment will take place between 9 p.m. Sunday, Aug. 12, and 5 a.m. Monday, Aug. 13, weather permitting.

"An adult mosquito infected with West Nile virus can pass it on to any person it bites, so we want to make sure we act quickly. It's very important that residents are aware of the risk of West Nile virus and take appropriate precautions to avoid being bitten by mosquitoes," Public Health Education and Outreach Officer Megan Sebay said in the statement.

The area to be sprayed includes parts of the Pulgas Gardens, Palo Mobile Estates and Weeks Gateway. Not all areas of the neighborhoods are included in the treatment, officials noted. The treatment area is approximately bounded by Beech Street to the north, Clarke Avenue to the west, Bayshore Road to the south and the San Francisquito Creek Trail to the east.

The county will use plant-derived insecticides or synthetic versions that include pyrethrins, Synthetic pyrethroids and piperonyl butoxide. The product currently used by the San Mateo County Mosquito and Vector Control District for adult mosquito control is called Zenivex E4. It is not harmful to humans in the very low dosages that will be sprayed or to family pets, according to the district.

County staff will collect mosquitoes after the treatment is completed. If those mosquito samples are carrying West Nile virus, the county will perform additional mosquito control treatments.

West Nile virus is transmitted through the bite of an infected mosquito. Birds are the primary hosts. Humans, horses and other animals can become infected with the disease if bitten by an infected mosquito. It cannot be spread person to person. The virus can cause a host of flu-like symptoms that are often mild. Many cases go unreported.

But the disease can become much more severe in some people, particularly those older than 60 years, according to the U.S. Centers for Disease Control and Prevention. Symptoms include fever, headache, body aches, skin rash, and swollen lymph nodes. Severe symptoms might include stiff neck, sleepiness, disorientation, coma, tremors, convulsions, and paralysis.

Dead birds are an early indication that the West Nile virus is circulating in an area. Officials ask residents to report fresh bird and squirrel carcasses to the West Nile virus hotline through westnile.ca.gov or by phone through 877-WNV-BIRD (877-968-2473).

Residents can reduce their risk of mosquito bites by taking the following precautions, according to vector control officials:

• Apply insect repellents that contain DEET, picaridin, oil of lemon eucalyptus, or IR 3535. Always follow label instructions.

• Make sure that doors and windows have tight‐fitting screens to keep out mosquitoes and repair or replace screens with tears or holes.

• Eliminate standing water and containers that can hold water from around the home.

• Wear long-sleeved shirts and long pants when outdoors.

For assistance with a mosquito problem in San Mateo County, residents can contact the district at 650-344-8592. More information on West Nile virus and district services can be found at smcmvcd.org.


Follow the Palo Alto Weekly/Palo Alto Online on Twitter @PaloAltoWeekly and Facebook for breaking news, local events, photos, videos and more.

What is community worth to you?
Support local journalism.


2 people like this
Posted by Jessica F.
a resident of East Palo Alto
on Aug 12, 2018 at 10:17 pm

Can someone point me to the reasoning behind choosing to fog the neighborhood with pesticides?
(1) I just don't see how spraying certain neighborhoods would keep mosquitoes, birds, and critters carrying West Nile from re-entering the treated area over time - they would just re-populate the area right?
(2) San Mateo and nearby counties have zero reports of people getting infected with West Nile, and only 2 birds have been reported to be found with West Nile according to Web Link. How was pesticide use and exposing people involuntarily to pesticides in this area justified?
(3) Isn't there a general concern regarding pesticide use and development of resistance?
(4) It sounds like West Nile is generally mild in most people and not commonly deadly. I feel that perhaps informative measures - alerting people to screen their windows/doors, use mosquito nets, get rid of standing water etc. would be more appropriate than exposing people to a pesticide they barely were informed about - no matter how "safe" the pesticide is deemed at the concentrations used?
(5) Is there a concern of other insects and bugs also being harmed by the chemical used? Would this then effect birds/reptiles/mammals that eat those insects? Would there be negative consequences to the wildlife that inhabits that neighborhood?

1 person likes this
Posted by resident
a resident of East Palo Alto
on Aug 13, 2018 at 3:04 pm

Web Link

"Avoiding human exposure to WNV-infected mosquitoes remains the cornerstone for preventing WNV disease."

Regarding the first question, why try to kill mosquitoes if it's incomplete? It has to do with epidemiology and playing the odds. If county health strikes quickly at the most vulnerable and most easily impacted stage of the virus's lifecycle (the mosquitoes) while the numbers are still small, we may never have a human West Nile Virus (WNV) victim and can fight the disease while it's still just in the bird population.

With the mosquitoes mostly gone for this year, the last infected birds can die or recover before WNV spreads from them. When the mosquito population recovers, there's a good chance there won't be infected birds to pick up WNV again from, and locally, the risk may vanish for years. I might have started the fog zone quite a bit larger, but maybe sick birds don't fly as much. I'm glad the county gave us the warning they could within a quick response time, and am waiting to hear how testing goes this week. Changing lifestyle or the county's health response to be slower is also risky. We took a few more protective measures than usual (staying inside more, DEET bug repellent, dumping the kid's pool, and would have closed windows the night of the fog). Everyone is susceptible, but the consequences are worse for the elderly, diabetic or immunocompromised, and pregnant. And honestly, we really hate (and some of us have allergies to) mosquito bites, so are inclined to tolerance of the pesticide fog.

2 people like this
Posted by just saying
a resident of another community
on Aug 13, 2018 at 3:08 pm

[Post removed.]

1 person likes this
Posted by A Tradition of Spraying
a resident of Los Altos
on Aug 13, 2018 at 5:01 pm

>>>Can someone point me to the reasoning behind choosing to fog the neighborhood with pesticides?

Coverage. Old timers will recall the med fly spraying back in the early 1980s.

Auto parts stores sold a lot of car covers back then as the sticky spray had a way of etching into some car paints. Autobody paint insurance claims increased during the time of sparying.

The irony was that the while the spraying was implemented to protect the local fruit crops, the helicopters seemed to be covering a lot of residential areas as well.

1 person likes this
Posted by A Landlord's Perspective
a resident of Downtown North
on Aug 14, 2018 at 1:11 pm

It's not like they're spraying Agent Orange or DDT.

If the pesticide works and is relatively harmless, so be it.

Better than getting sick from out-of-town mosquitos.

Don't miss out on the discussion!
Sign up to be notified of new comments on this topic.


Sorry, but further commenting on this topic has been closed.

All your news. All in one place. Every day.

Anne Le Ziblatt, formerly of Tamarine and Bong Su, is back with a Vietnamese noodle bar in Redwood City
By Elena Kadvany | 7 comments | 3,391 views

Local Pols Debate Climate
By Sherry Listgarten | 11 comments | 2,765 views

Letting Christmas Linger
By Cheryl Bac | 5 comments | 1,452 views

The E.R.A. – no real equality yet. Why not?
By Diana Diamond | 14 comments | 923 views

Truth Matters (and so does good beer)
By Laura Stec | 2 comments | 876 views