The Ministry of Health and Long-Term Care (MOHLTC) posts data daily regarding avian surveillance for West Nile virus (dead crows are indicated as well as ravens in northern Ontario). This information is provided to the Public Health Division by the Canadian Cooperative Wildlife Health Centre (CCWHC) which carries out the WNv testing on birds (with the support of Health Canada). The reports include the date of finding the first WNv positive crow in a Health Unit, as well as the date of the lastest WNv positive one found in the Health Unit.

It is important to note that the absence of positive bird findings after the 'lastest' date does not imply that WNv is no longer in the local bird population. To interpret the data, the following further explains the purpose of the sampling and the process.

The submission of birds to the CCWHC by public health units is based on the arrival time of birds in the Spring in each area of the province as established by the experience of the naturalists of the CCWHC. Each Health Unit is allotted a fixed number of submissions per week for WNv testing to maximize the resources of the CCWHC in covering the anticipated arrival of crows.

The sole purpose of bird surveillance is to establish whether or not the WNv is present in the Health Unit. This is key information required by the medical officer of health for each local health unit for purposes of decision making. The WNv bird surveillance is not intended as an ongoing monitoring of the status of bird health with respect to WNv.

Once it is established that WNv exists in the bird population within a local health unit, it is an appropriate assumption that WNv infection exists throughout the bird flocks in that jurisdiction. With WNv conclusively determined to be in a Health Unit, further bird testing is no longer deemed a necessary activity, and the CCWHC reserves the option to re-allot testing submissions to other areas within the Province which have not demonstrated WNv in their bird populations.

It is the policy of the Ministry of Health and Long-Term Care to be as open and as timely as possible in providing all available information pertaining to WNv.

The CCWHC informs the local Health Units and the Public Health Branch (PHB) of the ministry regarding the test results from their dead bird (crows/ravens) surveillance program.

Two categories (Presumptive and Confirmed/Presumed Confirmed) are used to record dead bird surveillance. The first four WNv-positive VecTested ® birds are confirmed positive for WNv by the CCWHC, after which all birds determined positive for WNv by the VecTest ® are deemed to be confirmed without any further formal testing.

The ministry operating policy posts the respective reports below as either ”presumptive” or ”confirmed/presumed confirmed“ 24 hours after notification to the Public Health Branch from the CCWHC of bird surveillance results. After the first four birds are confirmed positive by CCWHC as indicated above, further VecTest ® WNv-positive birds will be recorded as ”presumed confirmed”.

Special requests from medical officers of health will be taken into consideration only with approval of the Chief Medical Officer of Health or his Associate.

Reports received from the Canadian Cooperative Wildlife Health Centre to December 16, 2003.

Note : As of August 25, 2003, a number of Health Units, where West Nile virus has been conclusively demonstrated, will no longer be submitting birds for testing to the CCWHC. Therefore, no change in their data will be recorded to this website.

Note : After the 4^th confirmed crow or raven reported in a health unit, only the VecTest ® will be carried out on any future submissions and no further confirmatory testing will be done. Those birds will be recorded in the confirmed/presumed confirmed column.

Most Health Units in Ontario will record reports of dead crows or ravens found by residents in their communities. The crows and ravens recorded on this listing will not have been submitted for WNv testing to the Canadian Cooperative Wildlife Health Centre. While it is understood that some of the crows or ravens reported may have died from causes other than WNv, a large number of dead crows or ravens in the area may still contribute useful information for the local medical officer of health to explore the potential for WNv activity in that community.

Starting with the week of April 14, 2003, any sightings reported by the public to the participating public health units will be received weekly and updated below each Thursday. As of August 25, 2003, a number of Health Units, where West Nile virus has been conclusively demonstrated, will no longer be submitting birds for testing to the CCWHC.

A study is being planned by Health Canada to determine the relative relationship between such sighting information and the presence of human cases of WNv illness in the community.

Surveillance statistics are current as of 5:00 p.m. EST Monday through Friday.

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