More West Nile Infected Mosquitoes, Birds Found In Contra Costa County

September 1, 2018 19:00 pm · 5 comments

The Contra Costa Mosquito & Vector Control District is reporting mosquitoes from Brentwood and Quimby Island, and dead birds from Martinez and Discovery Bay have tested positive for West Nile virus.

This is the first dead bird from Martinez to test positive this year.

So far this year, 15 groups of mosquitoes, 10 dead birds, and 13 chickens from Contra Costa County have tested positive for the virus.

According to the District’s Scientific Programs Manager Steve Schutz, Ph.D., “West Nile virus season is still very active as we head into Labor Day weekend, and so it’s very important as county residents plan outdoor activities, that they remember to prevent mosquito bites by wearing repellent and by avoiding areas where mosquitoes are present.”

Report dead birds to the state hotline: 1-877-968-2473. Birds are often the first sign of disease transmission in a particular area. Ravens, jays, crows, and magpies can be susceptible to the virus, and may die if infected.

Even if the birds are not tested, the reports alone yield crucial information to protect public health.

Citizen September 1, 2018 at 7:17 PM

Can you imagine how awful it would be to have West Nile Virus? Follow the precautions please.

Citizen September 1, 2018 at 8:11 PM
WC Resident September 2, 2018 at 10:24 AM

When reading the Wikipedia article about the West Nile virus I spotted “They also question the effectiveness of insecticide spraying, as they believe mosquitoes that are resting or flying above the level of spraying will not be killed; the most common vector in the northeastern United States, Culex pipiens, is a canopy feeder.” I wondered about the recent spraying in Martinez.

The mention of Culex pipiens rang a bell as seven of the 15 mosquitoes that have tested positive for West Nile virus in Contra Costa county this year were Culex pipiens which is also known as the common house mosquito.

The other eight WNV positive mosquitoes were Culex tarsalis. Wikipedia does not have an article about that one but I found this web page which is useful. I knew that only female mosquitoes are the the ones to watch for, not that we can easily tell the guys from gals as they fly around us. I swat them all and if I get a red splash I knew I got a gal.

I also learned that a mosquito’s main source of food is nectar from flowers and other plant juices. Males only feed from plants but females need a little extra protein to make eggs and are the blood suckers.

The county’s 2018 West Nile Virus Activity has a map that can be zoomed/scrolled. If you make it full screen on a desktop then it’s more useful as the left sidebar has notes about each sighting. The web page also details the sightings.

No Excuses September 3, 2018 at 4:54 AM

The Red markers stand for one thing. The Blue for another. And the lone Green is for a third something-or-other. 🙂 Happy Labor Day!

WC Resident September 3, 2018 at 10:26 AM

See for an explanation of what the pin colors mean. One confusing aspect is that the legend also has yellow but there are no yellow pins on the map.

They do not have pins for humans despite that says “There were 11 new WNV human cases reported in California last week from the following counties: … Contra Costa (1) …” and “These are the first WNV human cases from Contra Costa, Glenn, and Orange counties this year.”

That page also reports for Contra Costa county this past week:
2 WNV positive dead birds.
2 WNV positive mosquito samples.

As expected, Sacramento county is the hotbed of WNV hedonism.

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