West Nile Virus Activity 2023

West Nile Virus in Los Angeles County

West Nile virus is the most common mosquito-borne disease that affects residents in Los Angeles County. Public health agencies detect West Nile virus every year in L.A. County which means it's endemic and found naturally in our city environments.

Our agency reports data related to mosquitoes. Human cases are reported by the L.A. County Department of Public Health.

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.

Year-to-Date Statistics for 2023

2023 WNV+ Mosquito Samples

City/Community	Date of First Detection	Positives
Arleta	8/11/2023	2
Artesia	8/24/2023	1
Bellflower	7/21/2023	5
Burbank	5/24/2023	12
Canoga Park	6/29/2023	10
Carson	8/31/2023	1
Cerritos	7/26/2023	9
Chatsworth	7/27/2023	7
Commerce	8/18/2023	2
Cudahy	8/16/2023	2
Diamond Bar	9/14/2023	3
Downey	9/6/2023	3
Downtown Los Angeles	9/8/2023	2
East Los Angeles	10/6/2023	2
Eagle Rock	10/4/2023	2
Encino	8/16/2023	9
Elysian Valley	9/20/2023	3
Gardena	8/11/2023	2
Glendale	9/1/2023	5
Granada Hills	9/15/2023	3
Hacienda Heights	10/27/2023	1
Harbor City	10/20/2023	1
Hawaiian Gardens	8/2/2023	2
Hollywood Hills	9/12/2023	2
Huntington Park	8/16/2023	3
La Cañada Flintridge	9/21/2023	3
La Crescenta	11/8/2023	1
La Habra Heights	10/12/2023	1
La Mirada	7/26/2023	7
Lake Balboa	7/26/2023	5
Lake View Terrace	8/25/2023	3
Lakewood	8/2/2023	5
Lincoln Heights	10/6/2023	1
Long Beach	7/19/2023	5
Los Angeles City	8/10/2023	4
Los Feliz	9/1/2023	2
Lynwood	8/3/2023	3
Mission Hills	8/25/2023	3
Montebello	9/14/2023	1
North Hills	9/6/2023	1
North Hollywood	7/25/2023	4
Northridge	8/29/2023	5
Norwalk	7/26/2023	5
Pacoima	9/22/2023	3
Panorama City	8/1/2023	2
Paramount	8/3/2023	2
Pico Rivera	8/24/2023	2
Porter Ranch	8/10/2023	6
Reseda	7/26/2023	3
Rowland Heights	7/25/2023	4
San Fernando	8/11/2023	4
San Marino	11/8/2023	1
San Pedro	8/31/2023	2
Santa Clarita	9/15/2023	5
Santa Fe Springs	8/24/2023	3
Sherman Oaks	8/1/2023	7
Signal Hill	8/2/2023	3
Silver Lake	10/5/2023	1
South El Monte	8/23/2023	5
South Los Angeles	9/15/2023	4
South Gate	7/21/2023	4
South Whittier	8/9/2023	3
Studio City	8/9/2023	14
Sunland	8/25/2023	7
Sun Valley	8/11/2023	6
Sylmar	11/15/2023	1
Tarzana	8/29/2023	4
Toluca Lake	7/12/2023	6
Tujunga	10/25/2023	1
Valley Glen	8/9/2023	4
Valley Village	8/9/2023	8
Van Nuys	9/6/2023	4
Vernon	9/6/2023	1
Watts	10/13/2023	1
West Hills	7/27/2023	9
Whittier	8/23/2023	2
Willowbrook	9/15/2023	3
Winnetka	7/27/2023	5
Woodland Hills	7/27/2023	7
	Total # of Positive Mosquito Samples This Year	291

2023 WNV+ Dead Birds

City/Community	Date of First Detection	Positives
Canoga Park	8/22/2023	2
Cerritos	8/15/2023	1
Glendale	9/12/2023	2
Lakewood	8/6/2023	4
Long Beach	6/13/2023	5
Montebello	10/6/20203	1
Northridge	7/5/2023	1
Pacoima	8/31/2023	1
Tujunga	8/25/2023	1
Whittier	8/29/2023	1
Woodland Hills	6/6/2023	1
	Total # of Positive Dead Birds this Year	20