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West Nile Virus (WNV) is a vector-borne disease of public health importance in Ontario. Each week, we analyze provincial mosquito, human and weather data to produce a weekly vector surveillance report. Public health units provide us with mosquito and human data, and Environment Canada is our source for weather data. Until June 2016, weekly West Nile Virus surveillance reports were available in PDF form. This data, from 2002 year to the most recent surveillance week, is now available in the graphs below.
For more information on the graphs, maps, and health unit codes, please read the West Nile Virus surveillance glossary and data caveats. If you have any questions, please contact firstname.lastname@example.org.
Surveillance Week 42 (October 16 – October 22, 2016)
- As of week 42, all health units have stopped mosquito trapping for 2016. This will be the last update until 2017 the season.
- Human cases: Up to week 42, there has been 49 reported West Nile Virus (WNV) human cases; from City of Hamilton (1), City of Ottawa (2), Durham Region (2), Haldimand-Norfolk (1), Halton Region (1), Niagara Region (7), Peel Region (5), Simcoe Muskoka (1), Toronto (22), Windsor-Essex County (4) and York Region (3).
- Equine: Currently, there are two horses reported with WNV, one each from Toronto and Middlesex-London.
- Positive Mosquito Pools: In week 42 there were no new WNV positive mosquito pools. To date, there have been 211 positive mosquito pool reported for 2016.
- The majority of mosquitoes species were captured in low numbers across Ontario. The Coquillettidia genus is not a major vector of WNV in Ontario, and was caught in relatively low numbers, but can be a biting nuisance. The number of Cx. pipiens/restuans that are being captured is low across province.
There have been no reports of mosquitoes or horses testing positive for Eastern Equine Encephalitis (EEEV
- Culiseta melanura is an important mosquito vector in the transmission cycle of EEEV as it is responsible for amplifying the virus in the bird population. This species was not reported in is an important mosquito vector in the transmission cycle of EEEV as it is responsible for amplifying the virus in the bird population. This species was not reported in week 42.
- Although large numbers of Cq. perturbans can be identified in Ontario, this species is not considered a competent vector species in the transmission of WNV due to the presence of a substantial salivary gland barrier (Sardelis et al. 2001).
(January 1 to (January 1 to October 8, 2016):
WNV United States
- Human cases have been reported in Alberta (4), Manitoba (20), Quebec (19) and Saskatchewan (1).
- Mosquito pools have tested positive in Manitoba (39), Quebec (28) and Saskatchewan (67).
(January 1 to (January 1 to October 18, 2016):
- The Centers for Disease Control and Prevention (CDC) reports 1352 human WNV cases; with 47 states adn the District of Columbia reporting WNV activity (e.g., birds, mosquito pools, humans), for 2016 .