PREPARED BY
Environmental Health Department
DATE
May 19, 2022
SUBJECT
2022 Vector-borne Surveillance Program
BACKGROUND/PURPOSE
The Environmental Health Department delivers a vector-borne surveillance program to monitor West Nile Virus (WNV), Eastern Equine Encephalitis (EEE), Zika Virus and Lyme disease activity in Windsor and Essex County (WEC). The program is required under the Health Protection and Promotion Act and provides the community with an early warning system for disease transmission through ticks and mosquitoes known as vector-borne diseases. This program is made up of the following components: mosquito larval surveillance and larviciding, adult mosquito trapping, human case surveillance for WNV and Lyme disease, public education, and active tick surveillance. The tasks of mosquito larval surveillance and control, along with mosquito identification and viral testing, are performed by contracted agencies on behalf of the WECHU.
DISCUSSION
Active Tick Surveillance
Lyme disease is a vector-borne disease caused by the bacterium Borrelia burgdorferi. It is transmitted to humans through the bite of infected black-legged ticks. The WECHU's role is to measure and evaluate the risk of this tick-borne disease in our area.
Active surveillance is used to assess the local distribution and incidence of black-legged ticks in WEC. It involves the dragging of a white cloth through grassy areas whereby ticks attach themselves to the fabric and can be easily spotted and identified. Any black-legged ticks identified are sent to an accredited laboratory for testing of Lyme disease. Tick dragging is performed twice yearly in the spring and the fall.
This year tick dragging will be conducted at the following four sites during the months of May and September:
- Ojibway Prairie Nature Reserve
- Chrysler Greenway
- Gesstwood Camp and Education Centre
- Ruscome Shores Conservation Area
Mosquito Surveillance
Adult mosquito surveillance is an important component of the vector-borne disease program and involves the deployment of black-light CDC traps and BG-Sentinel 2 (BGS-2) traps at various locations throughout WEC.
The CDC traps are equipped with light and dry ice that attracts and traps the mosquitoes. These traps capture mosquitoes for testing to determine the presence of WNV and EEE in our region. BG-Sentinel 2 (BGS-2) traps are species-specific traps set up to catch invasive species of mosquitoes (Aedes albopictus and Aedes aegypti) that were identified during routine WNV surveillance in WEC in 2016. These traps use a scent lure and dry ice to attract daytime mosquitoes and are set up in high-traffic areas (such as near transport routes and industrial cargo areas) as well as in residential homes. The trapped mosquitoes are sent to an accredited laboratory for identification and testing to determine if any of the mosquitoes carry the WNV, EEE or Zika virus.
The trap deployment will start on May 25, 2022, and run until mid-October. Once a week, 50 mosquito traps (26 CDC light traps and 24 BGS 2 traps) will be set up across WEC to collect mosquitoes for identification and viral testing. The weekly mosquito surveillance data will be made available on the WECHU's Mosquito Surveillance Dashboard.
Human case Surveillance
The human case surveillance program identifies human cases of WNV and Lyme disease in WEC to determine the source of the disease. Physicians and hospitals must report all probable and confirmed cases to the WECHU.
The health unit investigates all suspected, probable and confirmed WNV and Lyme disease cases among WEC residents based on case definitions developed by the Ministry of Health (MOH). Standardized medical information, including demographics, symptoms, risk factors (such as travel history or having received blood products) and test results, are entered into the MOH's Integrated Public Health Information System (iPHIS). Through case interviews and GIS mapping, the health unit identifies clusters and geographic areas that may need targeted intervention.
Fight the Bite! Campaign
Fight the Bite! Public awareness campaign will launch in July 2022. It will focus on the prevention of mosquito breeding sites, information on tick removal, signs and symptoms of WNV and Lyme disease, and personal protection. Messages and promotional materials will be developed to reach priority populations and inform the public of hot spots identified through previous monitoring efforts. This event is done in conjunction with health unit external stakeholders such as municipalities and other health units.