Ontario Ministry of Health and Long-Term Care - Health Care Providers - Program - Public Health - West Nile virus Bulletin - Volume 2 / Issue 11

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West Nile virus Bulletin : 2001 Archive
Disease Control Service Public Health Branch	Volume 2 / Issue 11 – October 30, 2001

IN THIS ISSUE

Summary of Ontario Surveillance Activities
WNv Surveillance in Ontario
Human Encephalitis Surveillance
Dead Bird Surveillance

Mosquito Surveillance
Other News
U.S. National Maps
Maps

Summary of Ontario Surveillance Activities
Human Surveillance	No confirmed cases in the year 2001.
Mosquito Surveillance	As of October 17, 2001, one pool of mosquitoes out of 606 has tested positive for WNv. The pool was collected on August 31, from Peel Region.
Dead Bird Surveillance	As of October 26, a total of 4,748 dead birds have been sighted and/or collected in Ontario. Of these, 2,608 were collected and sent to Guelph for consideration, and 1,720 were sent to Winnipeg for WNv testing. As of October 26, there were 121 confirmed WNv-positive birds. 101 birds are American Crows and 20 birds are Blue Jays. The confirmed positive birds were found in Windsor-Essex (20), Chatham-Kent (3), Lambton (1), Middlesex-London (3), Niagara (1), Hamilton (4), Waterloo (1), Halton (7), Peel (17), Toronto (41), York Region (18), and Durham (5).
Summary of surveillance activities in other jurisdictions to date
Canada
As of October 26, 2001, there have been 6,771 dead birds reported to the WNv Dead Bird Surveillance program for all Canadian provinces.
U.S.
Human Cases :
As of October 26, 2001, 44 human cases of WNv have been reported in 2001.
Birds, mosquitoes, horses and other animals :
5,900 dead birds, 737 WNv-positive mosquito pools, and 282 horses have tested positive for WNv.
Data Source: Canadian Cooperative Wildlife Health Centre and Health Canada.

WNv Surveillance in Ontario

The purpose of the WNv Bulletins is to provide a summary of the results of the various surveillance activities in Ontario for the current year. This issue will update WNv findings elsewhere in Canada and in the U.S.

WNv Activities in Ontario for the Year 2001

Human Encephalitis Surveillance

Health Canada has asked that key health care providers, including family and emergency room physicians, infectious disease specialists and neurologists, monitor their patients for symptoms of WNv in 2001. These health care professionals are being asked to promptly report any probable and confirmed cases of viral encephalitis to local/provincial public health authorities.

REMINDER

Physicians (Hospital, clinic, private practice) :
- Send blood samples from suspect WNv patients to the Central Public Health Laboratory (CPHL) in Toronto for serological testing to :
  
  Central Public Health Lab
  81 Resources Road
  Toronto, ON
  M9P 3T1
- Report suspect WNv cases immediately to the local Medical Officer of Health and fax "Patient Report Form"
Health Units :
- Report suspect WNv cases immediately by telephone to Dr. Margaret Fearon.
  
  Dr. Margaret Fearon
  416-235-5725 (pager : 416-715-4209)
  (After hours duty officer : 416-605-6113)
- Report suspect WNv cases immediately by telephone to Dr. Chuck Le Ber or Dr. Dean Middleton at the Ministry of Health and Long-Term Care (MOHLTC), Public Health Branch.
  
  Dr. Chuck Le Ber
  416-327-7421
  
  Dr. Dean Middleton
  416-327-7422
- Report suspect WNv cases in RDIS under the disease "viral meningitis/encephalitis" as outlined in the April 27, 2001 letter to all MOH and Communicable Disease Coordinators from Dr. Colin D'Cunha regarding Enhanced Passive Human Surveillance for West Nile Encephalitis.

Dead Bird Surveillance

This bulletin summarizes information up to October 26 of the 43^rd week of the Dead Bird Surveillance season (Week 43 = October 22 to 26, 2001). There have been a total of 4,748 reported dead bird sightings and/or submissions. Of these 4,748 birds, 2,608 were picked up and sent to the lab in Guelph for WNv testing ('pick-ups'), of which 1,720 were submitted for testing at the national laboratory in Winnipeg ('Submissions'). Maps stating the number of dead bird submissions to the lab will be provided weekly to health units.

Figure 1. Ontario Reported Number of WNv Surveillance Program Dead Birds
October 26, 2001 (N= 4,748*)
* Omitted from graph : Three dead birds reported prior to season

Data : Canadian Cooperative Wildlife Health Centre, Health Canada August 30, 2001

Note :

Week 16 = April 16-20, 2001
Week 43 = October 22-26, 2001

Figure 2. Types of Ontario Dead Birds Reported in 2001 Season as of October 26, 2001

Figure 3. Total Number of Dead Bird Reports in 2001 by Ontario Health Units as of October 26, 2001

Note ** 'PickUps' are health unit submissions to the lab in Guelph, whereas 'Submissions' refer to dead birds sent to the lab in Winnipeg for Federal WNv Testing.

Data Source : Canadian Cooperative Wildlife Health Centre & Health Canada (October 26, 2001)

Mosquito Surveillance in Ontario

A pilot program for mosquito surveillance was initiated in six heath units in early August. These health units include Niagara, Hamilton, Toronto, Hastings and Prince Edward and Eastern Ontario. Mosquito surveillance began in health units where birds were confirmed positive for WNv (see results below).

Week 35 - August 27-31, 2001
Week 41 - October 22-26, 2001

* identifications are still in progress
** preliminary results based on subsampling of some of the large samples. Final values are not expected to differ significantly from the values presented.

South-West Ontario Region

Central-West Ontario Region

Central-East Ontario Region

Eastern Ontario Region

Summary of WNv Mosquito Testing

As of October 17, 2001, one pool of mosquitoes out of 606 has tested positive for WNv. The pool of Culex pipiens was collected on August 31, from Peel Region.

Other News

Worldwide Geographic Distribution

WNv has been described worldwide and is no longer limited to Africa and Eurasia.

North American Geographic Distribution

The American media has paid much attention to state health departments and local units with respect to their choices regarding the spraying of chemical pesticides.

Figure 4. Number of birds, mosquito pools, horses and humans that have tested positive for WNv in the U.S., 2001.

U.S. National Maps

Maps of the United States WNv Surveillance Programs can be accessed through the United States Geological Survey : Center for Integration of Natural Disaster Information (CINDI) Web site.

Maps

Acknowledgements

The contribution of the following agencies and individuals in the publication of this year's issues of the WNv Bulletin is greatly appreciated :

Ontario Ministry of Health and Long-Term Care (MOHLTC) : Public Health Branch : Dr. Colin D'Cunha, Dr. Charles Le Ber and Dr. Dean Middleton.

Canadian Cooperative Wildlife Health Centre : Dr. Ian Barker and Ron Templeman.

Health Canada : Dr. Peter Buck and Rob Meyers.



Comments, questions and suggestions about surveillance results in this bulletin should be directed to : Dr. Dean Middleton, Veterinary Consultant, Disease Control Service, Tel: 416-327-7422, E-mail : dean.middleton@moh.gov.on.ca

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