The following was sent out by the San Mateo County Mosquito & Vector Control District Wednesday July 23rd 2014 at 3:07 p.m.
District Trustees/County Public Health and EH/Local MVCD District Managers,
Find out what's happening in San Brunofor free with the latest updates from Patch.
The following is the current West Nile virus activity in the County.
Find out what's happening in San Brunofor free with the latest updates from Patch.
Wednesday, July 16th Two (2) dead birds were tested (RT-PCR) for West Nile virus and were positive for West Nile Virus. Western Scrub Jay from Ladera, Portola Valley and an American Crow from the City of Menlo Park. CO2 Traps (20) were set for mosquitoes in the surrounding neighborhoods which were tested (RT-PCR) for the presence of West Nile Virus.
Friday, July 18th Mosquitoes collected in CO2 traps set in City of San Mateo (94401) and Ladera, Portola Valley (94028) tested positive for West Nile Virus. City of Menlo Park mosquitos were negative.
Saturday, July 19th Press Release (attached) was submitted: “Mosquitoes carrying West Nile Virus found in City of San Mateo and Ladera, Portola Valley. Fogging is scheduled for night of July 21, 2014.” Website was updated with current press release and maps (2) showing the treatment areas.
Monday, July 21st Six (6) vehicles and nine (9) staff members conducted a mosquito fogging operation within a half mile radius around each detection site in an effort to prevent human cases of West Nile Virus. Fogging was conducted from 11:00 p.m. to 5:00 a.m.
Efficacy of the Ultra-Low Volume adulticide against caged Culex pipiens mosquitoes: City of San Mateo = 97.2% and Ladera, Portola Valley = 90.23%
Fogging agent used is a new product called Zenivex®. The active ingredient is etofenprox. This is a new active ingredient on the market that is similar to pyrethrins but has a much safer LD50 bar of >42,880. As a comparison of toxicity, caffeine has an LD50 of 335 so is much more toxic than our new mosquito adulticide, Zenivex®.
Monday, July 21st American Crow picked up from 540 El Camino Real, City of San Mateo was tested (RT-PCR) waspositive for West Nile Virus.
Wednesday, July 23rd Set 20 CO2 Traps around WNV positive bird at 540 El Camino Real, City of San Mateo. We are now waiting for the testing results for these mosquitoes.
In addition:
1. All eight (8) catch-basin right hand drive jeeps are operational with an excellent summer time staff.
2. Aedes aegypti Teams uncovered another adult mosquito in an AGO trap on Santa Cruz Ave, Menlo Park, current map attached.
Robert B. Gay
District Manager
San Mateo County MVCD
