PREPARED BY:
Environmental Health
DATE:
March 21, 2024
SUBJECT:
2023 Vector Borne Disease Report
BACKGROUND/PURPOSE
Vector-borne diseases are caused by the transmission of parasites, viruses, and bacteria in humans by vectors. The most common vectors are mosquitoes and ticks and can transfer the pathogen from one host to another. Public health units in Ontario are required under the Health Protection and Promotion Act to conduct vector-borne disease surveillance to monitor trends for emerging diseases including factors that influence their occurrence. In 2023, the Environmental Health Department continued to implement 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).
DISCUSSION
Active Tick 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 and is performed twice yearly in the spring and the fall. Any black-legged ticks identified are sent to an accredited laboratory for testing for Lyme disease. In 2023, tick dragging was conducted at four sites across WEC in May and October. A total of forty-four black-legged ticks were identified, with twenty ticks carrying the infectious agent that causes Lyme disease. In 2023, there were eight human cases of Lyme disease reported in WEC.
Mosquito Surveillance Program ran for a total of 21 weeks from May 23 to Oct.13, 2023. Once a week, forty-one mosquito traps (26 CDC light traps and 15 BGS 2 traps) were set up across WEC to collect mosquitoes for identification and viral testing. In 2023, there were 11 WNV positive pools identified and one positive WNV human case was reported. There were no positive pools or human cases for EEE or Zika identified this year.
Mosquito Larviciding involves applying larvicides to catch basins, standing water sites, and lagoons that hold water where mosquitoes may breed. The WECHU and municipalities contracted a service provider to run larval surveillance beginning in May. Three rounds of roadside municipal catch basin larviciding were conducted and a total of 133,024 catch basin treatments were applied WEC. There were a few challenges identified during the larviciding season for catch basins and only one standing water complaint submitted by WEC municipalities. Prior to 2024 season, meetings will be set up with municipalities and vendor of record to look at processes as well as to address concerns from last season.