West Nile Virus

West Nile Virus (WNV) is a virus of African origin that can be spread to humans and other mammals via the bite of an infected mosquito. The CDC reports that West Nile virus (WNV) is the leading cause of mosquito-borne disease in the continental United States. Cases of WNV occur during mosquito season, which starts in the summer and continues through fall. There are no vaccines to prevent or medications to treat WNV in people. Fortunately, most people infected with WNV do not feel sick. About 1 in 5 people who are infected develop a fever and other symptoms. About 1 out of 150 infected people develop a serious, sometimes fatal, illness.


The Bucks County Department of Health (BCDH), in cooperation with the PA Department of Environmental Protection (PA DEP), conducts an annual Mosquito-borne Disease Control Program to help protect the residents of Bucks County from the West Nile Virus (WNV). The program focuses on mosquito surveillance, WNV education for the public and government officials, and a mosquito habitat reduction and larval suppression campaign to reduce the adult mosquito population.


Adult mosquito surveillance is conducted from April through October to monitor mosquito numbers and the prevalence of the WNV in Bucks County. Mosquito traps, as shown, are used to capture mosquitoes, which are then shipped to the state laboratory to determine if the mosquitoes are infected with the disease. In cases where the WNV infection rate of the mosquito population exceeds certain thresholds, the BCDH conducts adult mosquito sprays to lessen the risk of disease transmission.


The Department investigates mosquito problems via written complaint (form SA-2). These complaint forms should be returned to the nearest District Office. Please see the Mosquito Control Web page for more tips on how to reduce mosquito breeding around your home or business. In addition, below are links to the Bucks County Department of Health Disease Vector Control Regulations, the PA DEP WNV Web site and the CDC WNV web site for more information.

Learn more about West Nile from PA DEP - This site is for local information. Look up current positive cases for West Nile Virus, Information on upcoming spray events, Mosquito testing data and more helpful information on the virus. 

Learn more about West Nile from the CDC - Look up information on prevention, symptoms/diagnosis/treatment, transmission, statistics & maps (state by state), for healthcare providers, mosquito control, West Nile virus/dead birds and more helpful resources.  

2023 West Nile Virus Activity by County
2022 Positive Bird/Human/Mosquitoes for West Nile
2021 Positive Bird/Human/Mosquitoes for West Nile
2020 Positive Bird/Human/Mosquitoes for West Nile
2019 Positive Bird/Human/Mosquitoes for West Nile

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