The disease surveillance program serves as an early warning system in the detection of mosquito-borne viruses that can infect people and animals.

The District uses the following factors to assess health risk in your community:

  • Higher-than-average daily temperatures
  • Mosquito Population Monitoring – Using traps set up in every community
  • Mosquito Testing for Diseases
  • Dead Birds – A CA state program: Dead birds help determine spread of West Nile virus
  • Sentinel Chickens – Chickens develop antibodies to West Nile virus, which can be detected by testing.

Using these measurements, the District is able to protect your health by responding appropriately to mosquito-borne disease threats.


Yearly Summary (2008-2019)

Note: Human cases reported by Los Angeles County Department of Public Health


Year-to-Date Statistics for 2020


2020 WNV+ Mosquito Samples
City/Community Date First Detected #WNV Positive Mosquito Sample to Date this Year
Arleta 8/06/2020 4
Artesia 8/12/2020 4
Atwater Village 10/15/2020 2
Bell 8/11/2020 5
Bell Gardens 7/14/2020 5
Bellflower 7/14/2020 8
Burbank 7/14/2020 9
Canoga Park 7/22/2020 6
Carson 9/16/2020 4
Cerritos 8/12/2020 5
Commerce 7/30/2020 3
Diamond Bar 9/4/2020 1
Downey 7/14/2020 8
East Los Angeles 7/30/2020 7
Encino 7/15/2020 15
Gardena 9/16/2020 3
Glendale 8/25/2020 3
Granada Hills 8/13/2020 3
Florence-Firestone 8/14/2020 2
Hacienda Heights 5/20/2020 4
Harbor City 10/22/2020 1
Hawaiian Gardens 9/3/2020 3
Hollywood Hills 9/10/2020 2
Huntington Park 8/25/2020 4
La Habra Heights 8/21/2020 2
La Mirada 7/15/2020 4
Lakewood 7/23/2020 9
Long Beach 8/06/2020 5
Los Feliz 7/29/2020 3
Lynwood 8/11/2020 4
Maywood 8/25/2020 2
Montebello 7/29/2020 10
Northridge 7/21/2020 6
Norwalk 8/26/2020 4
North Hills 7/15/2020 5
North Hollywood 6/18/2020 14
Pacoima 9/4/2020 2
Pico Rivera 6/15/2020 13
Panorama City 7/15/2020 6
Paramount 9/9/2020 1
Porter Ranch 7/21/2020 3
Rowland Heights 7/10/2020 2
Santa Fe Springs 7/15/2020 6
Sherman Oaks 6/11/2020 10
Signal Hill 7/09/2020 5
South El Monte 10/8/2020 2
South Gate 7/28/2020 2
Studio City 6/18/2020 10
Sunland 7/24/2020 2
Sylmar 8/21/2020 2
Tarzana 7/21/2020 5
Toluca Lake 6/18/2020 10
Valley Glen 6/18/2020 5
Valley Village 6/18/2020 13
Van Nuys 7/02/2020 12
West Hills 8/05/2020 3
Whittier 7/15/2020 7
Wilmington 8/05/2020 2
Winnetka 7/07/2020 7
Woodland Hills 6/17/2020 3
Total #WNV Positive Mosquito Sample to Date this Year 313

2020 WNV+ Dead Birds
City Positives Date of 1st Detection
Artesia 2 7/29/2020
Bell Gardens 1 10/2/2020
Burbank 4 7/12/2020
Cerritos 14 8/3/2020
Chatsworth 1 8/21/2020
Downey 1 8/25/2020
La Crescenta 1 8/5/2020
Lakewood 3 7/29/2020
Long Beach 17 7/30/2020
North Hollywood 4 6/30/2020
Northridge 2 8/5/2020
Porter Ranch 1 7/22/2020
Sunland Tujunga 1 10/2/2020
Sun Valley 1 8/19/2020
Valley Glen 3 6/23/2020
Valley Village 2 8/18/2020
Van Nuys 4 6/21/2020
Westlake Village 1 6/1/2020
Woodland Hills 1 6/1/2020