# Presentation: 193965

## Summary of West Nile Virus Activity in Canada

- Peter A. Buck  BSc DVM MSc
- Manager, Zoonoses Section
- Public Health Agency of Canada
*Acknowledgements: H. Artsob, I.K. Barker, M. Drebot, R.Lindsay, and P. Sockett*

**Notes:**
Good morning,
I would like to thank the organizing committee and, in particular, Dr. Theresa Smith, for inviting me to speak at this conference. 
By way of background information, as you all know, Canada is a very large country, however the total population is just a little over 30 million people.  We have 10 provinces, 3 territories, and hundreds of First nations communities. 

## Surveillance in Canada:  2000 - 2005

- Monitoring activities include surveillance in:
- Birds
- Dead birds
- Sentinel Chickens
- Mosquitoes
- Horses
- Humans

**Notes:**
In late summer and autumn 1999, we watched the NYC, and environs, experience with WNV very closely.
We identified and assembled a multidisciplinary and multi-jurisdictional team, and met to discuss the issue in February 2000.  At this inaugural meeting, we included several keynote speakers that were involved in the original outbreak: Dr. Marci Layton of NYC, Dr. Bob McLean, who was at the time with the National Wildlife Health Centre; and Dr. Duane Gubler, the former director of DVBID, CDC in Fort Collins.
Finally, after months of discussions, teleconferences and more teleconferences, we had put in place the prototypes for surveillance activities for dead birds, mosquitoes, horses and humans.
From 2000 to present, there have been constant, ongoing modifications to the systems. For example, from 2000 to 2002 inclusive, surveillance for WNV was only conducted in provinces from SK (approx N. Dakota) eastward to the Atlantic Ocean. This all changed after the 2002  surveillance season.

## National Surveillance for WN virus: Submission of Specimens

**Laboratory**

**Avian**

**National Surveillance for WN virus: ****Submission of Specimens**

**Public**

**Local **
**Health Unit/Natural Resources/**
**Conservation/Animal Control**

**CCWHC/Provincial **
**Veterinary Laboratories**

**Notes:**
I will now describe, in general terms, the surveillance systems that have been put in place. Please forgive me, for as you can imagine, there is variation both within and between provinces and territories, and certainly there have been changes to the systems each year since 2000.  These changes can be attributed to a variety of pressures/influences including : perceived risk, real risk, resources available; capacity; public pressure; media pressure; political pressure, etc.

Avian:
Since 2000, dead bird surveillance has been coordinated by the Canadian Cooperative Wildlife Health Centre (or CCWHC). The CCWHC is a virtual centre, based in Canada’s four Veterinary Colleges, with a network that covers much of the country.
Generally speaking, the process is as follows: READ SLIDE. 
The primary focus has been on corvids (e.g., crows, blue jays, grey jays , magpies, ravens).

## National Surveillance for WN virus: Submission of Specimens

**Laboratory**

**Mosquitoes**

**Local Health Unit/Mosquito Contractor**

**Mosquito Contractor/University-based Contractor**

**National Surveillance for WN virus: ****Submission of Specimens**

**Notes:**
Mosquitoes:
Mosquito surveillance is conducted in a large number of health regions in Canada. As you would expect, the amount /intensity of surveillance, the type of surveillance, the location/site selection for surveillance, the species of interest for surveillance varies tremendously from region to region.
In early 2000, there was little capacity for mosquito surveillance in most health regions, in most provinces/territories. A few of the larger cities had “nuisance” mosquito control programs. Since 2000, capacity and capability have built up in quite a number of regions. 
Generally speaking, the process is as follows:  READ SLIDE.

## National Surveillance for WN virus: Submission of Specimens

**Owner**

**Local **
**Veterinarian**

**Commercial Laboratory**

**Provincial Laboratory**

**CFIA**

**National Surveillance for WN virus: ****Submission of Specimens**

**Notes:**
Horses:
Surveillance data in horses, to a large degree, has been collected by the Canadian Food Inspection Agency (CFIA), an organization that is similar in some aspects to the USDA.
Collection of horse laboratory test data was facilitated in 2003 when the CFIA made WNV an Immediately Notifiable disease for animals.
Generally speaking the process is as follows READ SLIDE.
With the availability of vaccine for horses, and increasing uptake, this component of the surveillance program has become less important from a public health perspective. 

## National Surveillance for WN virus: Submission of Specimens

**Laboratory**

**Human**

**Health Care Provider**

**Provincial Laboratory**

**National Surveillance for WN virus: ****Submission of Specimens**

**Notes:**
Humans:
In 2000 and 2001, case definitions and focus was on cases that may present with meningitis/meningoencephalitis or encephalitis.
This shifted through 2002 towards considering case-patients with more of a “WNF” presentation. 
So generally speaking the process is as follows: READ SLIDE.

## National Surveillance 2003 - 2005: Case Classification

|  | Suspect | Possible | Probable | Confirmed |
| --- | --- | --- | --- | --- |
| WNV Neurological Syndromes (WNNS) | 
 |  |  |  |
| WNV Non-Neurological Syndrome (WN Non-NS) |  |  |  |  |
| WNV Asymptomatic Infection (WNAI) |  |  |  |  |

**Notes:**
A)  So in 2002,
Human surveillance, in Canada, focussed more on identifying cases with 
 Meningitis,
M/E, or
Encephalitis 
However, based on the evolving epidemiological picture by the end of the 2002 season,    with the recognition of cases of AFP with and without fever or encephalitis, case definitions were re-visited.
WNv M/E became WNNS, in order to include acute flaccid paralysis (AFP) and any other potentially serious syndromes that may be recorded.

B) Largely based on the US CDC draft case definition for WN Fever, we developed our own version, with a slight Canadian – flavour to it.

C) Because of the requirement to screen donor blood beginning in the 2003 season, and the realization that this may provide some novel surveillance information, we created a category called WNAI.

All 3 categories, for both probable and confirmed cases, became Nationally Notifiable on June 1, 2003.
Modifications to case definitions occurred again during 2004 and 2005, including a change from the use of the term “WNF” to “WN Non-NS”

## Canada to the last week of December 2002-2005

|  | 2002 | 2003 | 2004 | 2005 |
| --- | --- | --- | --- | --- |
| Provinces with WN virus activity | NS, QC, ON, MB, SK | NS, NB, QC, ON, MB, SK, AB | QC, ON, MB, SK, AB | QC, ON, MB, SK, AB |
| Human cases 1 | 426 (20) | 14944 (10) | 264 (0) |  2294 (12) |
| Dead birds 2 | 556 | 1631 (11287) | 416 (6208) | 447 (3960) |
| Domestic Animals3 | 356 | 4455 | 145 | 35 |
| Mosquito Pools 2 | 305 | 570 | 176 | 695 |

- 1 probable and confirmed (number of deaths in brackets)
- 2 confirmed positive (number tested in brackets)
- 3  presumed or confirmed
- 4 Several cases are related to travel outside Canada
- 5 These figures represent the number of positive results reported to the CFIA as per the Immediately Notifiable Disease
-  Regulations

**Notes:**
Despite lots of effort, evidence of WNV activity was not found in 2000 in Canada. In 2000, surveillance methods also included sentinel chickens, placed at a dozen or so locations in southwestern, south central and southeastern Ontario, and several other locations in Canada. It is worth noting that sentinel chicken surveillance for WEE has been a regular program activity in Manitoba and SK for years. Both provinces added testing for WNV to their respective program activities.
During 2001, the first confirmed positive dead bird was collected in Windsor, Ontario on August 8.  Windsor is across the river from Detroit, Michigan.
Over the next 2 months WNV was confirmed in 128 dead birds from 12 health jurisdictions in southern Ontario.
The virus was also confirmed in nine mosquito pools from some of the same jurisdictions.
On a particularly interesting note, WNV was confirmed in a pool of over-wintering mosquitoes, collected January 2002 in the Windsor area.
During 2002, things began to get really interesting.
The first confirmed positive dead bird was found on May 19, in southern Ontario
Over the next several months, the provinces listed in the column for 2002 (NS, QC, ON, MB, SK) recorded WNV activity in at least one surveillance indicator.
At the end of August 2002, Ontario announced their first probable WNV cases of human illness.  The first in Canada.

Read slide
Comment on relative WNv activity in various species 
There are of course limitations/caveats with the numbers related to: 
Surveillance issues and intensity
Limits or caps on number tested
Testing and reporting in horses
.....and others
2002:
So, in the end, the human case count was 426, including 20 deaths.
Human cases were confined to southern Ontario, and southwestern Quebec in 2002.
Activity that was observed in these areas was quite consistent with that observed in neighbouring States, in the USA.
Obviously 2003 saw a dramatic rise in human case numbers.  While much of this activity was along the leading edge of the expanding range of the virus, many areas saw considerable activity for the 2nd or 3rd season.
Most of these cases occurred in the Prairie Provinces, with large Culex tarsalis populations.

**Peak season 50% of cases**

## Human West Nile Virus Cases by Clinical Classification in Canada 2003-2005

| Year | N | N-(WNAI+U) | WNNS |  |  | WN-NonNS |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |  |  | Median Age | Age Range | N | Median Age | Age Range | N |
| 2003 | 1494 | 1462 | 54 | 0-92 | 217 | 47 | 3-92 | 1245 |
| 2004 | 26 | 25 | 50 | 3-88 | 13 | 46 | 16-83 | 12 |
| 2005 | 229 | 215 | 60 | 14-87 | 49 | 47 | 6-92 | 166 |

**Notes:**
Age profile of human cases of West Nile virus by classification in Canada

## Slide 12

**Notes:**
Seasonal distribution of cases

The line graph shows rate per 100,000, by age group, for both classifications.

Peak rates per 100,000:
WN Non-NS:_________
WNNS:_________

## Slide 13

**Notes:**
Canada, in particular Toronto, lived thru SARS in 2003. READ SLIDE. I used this cartoon a lot after June 2003, and would add on to it...” and being chased by a Prairie Dog with Monkey Pox!”. Thankfully, though, monkey pox was never detected in Canada....yet!!

## Slide 14

**Notes:**
I have a few maps that I hope will help to see just where activity was detected in 2005. They show the birds positive for WNV at the end of each month through the season.
(read out the months for each slide)

## Slide 15

## Slide 16

## Slide 17

## Slide 18

## Slide 19

**Notes:**
N = 447 positive birds by the end of the 2005 season

## Slide 20

## Slide 21

**Notes:**
Seasonal distribution of cases

The line graph shows rate per 100,000, by age group, for both classifications.

Peak rates per 100,000:
WN Non-NS:_________
WNNS:_________

## Slide 22

## Slide 23

**Notes:**

The big questions for 2006 are how much activity will we see, and will surveillance idicators and human cases be detected in British Columbia and other new jurisdictions?

## Slide 24

## Blood Screening for WNV in Canada

**Blood Agencies**
- Hema-Quebec (1 province)
- Canadian Blood Services (9 provinces, 3 territories)
- Both use Roche platform
- Both have developed close working relationships with public health partners

**Notes:**
2002 was an interesting year for other reasons also, as you will all recall. Recall the traffic accident victim in Atlanta, and the large investigation that followed, that looked at blood and tissue transplants.
After 2002 revelation that WNV could be transmitted via blood and blood products, regulators, industry and blood operators worked  diligently and cooperatively to develop and obtain an Investigational Test Approval for a nucleic acid test (NAT) for donor blood. This donor blood screening test was in place by July 2, 2003.  Since this time, all donor blood has been tested for the presence of WNV either in minipools of 6 donations, or via single unit testing (S.U.T.).

Testing during the summer of 2005
Hema-Quebec
Donations routinely tested in minipools of 6
Single-donor testing introduced in a region as soon as a confirmed positive (by alternate PCR) donation is detected
Single-donor testing stopped if no positives after 2 weeks 

Canadian Blood Services
Strategy for Single Unit Testing 2005
SUT initiated in a health region when one WNV positive donor is identified
                          or 
The number of new confirmed community cases reported in a health region reaches the level of 1/1,000 (rural areas) or 1/2,500 (urban) for the past 2 consecutive weeks.

SUT only triggered in 2005 by a positive donor

SUT discontinued in a health region when no new positive donors were reported in that health region for two consecutive weeks
                          or 
The number of new confirmed community cases reported in a health region falls below 1/1,000 (rural areas) or 1/2,500 (urban) for 2 consecutive weeks.

Aside: Hema-Quebec seasonal testing
Seasonal testing introduced in mid-April 2005
From June 1 to November 30, all donations are tested
From December 1 to May 31, only donations from individuals having travelled outside of Canada in the past 56 days are tested
8% of donations tested in April and May 2005
5% of donations tested in December 2005

## WNV Infection Detected through Donor Blood Screening

|  | 2003 |  | 2004 |  | 2005 |  |
| --- | --- | --- | --- | --- | --- | --- |
| Province | # Samples Tested | # Positive | # Samples Tested | # Positive | # Samples Tested | # Positive |
| NL |  |  |  |  | n/a | 0 |
| NS |  |  |  |  | n/a | 0 |
| NB |  |  |  |  | n/a | 0 |
| QC | 146,513 | 0 | 206,058 | 0 | n/a | 1 |
| ON | 423,250 | 0 | 137,741 | 0 | n/a | 8* |
| MB | 67,772 | 1 | 22,638 | 0 | n/a | 3 |
| SK | 51,472 | 10 | 16,310 | 0 | n/a | 3* |
| AB | 152,530 | 3 | 49,932 | 0 | n/a | 1 |
| BC/YK |  |  |  |  | n/a | 0 |
| Total | 841,537 | 14 | 432,679 | 0 | 417,810 | 16 |

- * One was not positive by alternate NAT

**Notes:**
During 2002: One suspected and one confirmed transfusion transmission, and one scalpel/needle stick transmission were recorded
For 2003, 14 donor bloods were positive. There were no transfusion-associated transmissions.
For 2005, 16 donor bloods were positive.  Two (2) were not positive by alternative NAT testing.

Aside:
One detected by single-unit and the other by mini-pool
Possible interpretations
False positive
Very low viral level
Virus detected by Roche assay but not alternate NAT (e.g. SLE)

## Serosurvey Results in Canada

|  | Year | Mean | 95% CI |
| --- | --- | --- | --- |
| Ontario | 2002 | 3.1% | 2.2 – 4.0% |
| Manitoba | 2003 | 3.2% |  |
| Saskatchewan | 2003 | 10% | 7 – 13% |
| Alberta | 2003 | 4.6% | 2.8 – 6.8% |
| Quebec | 2004 | 0.2% | 0.1 – 0.5% |

**Serosurvey Results in Canada**

**Notes:**
Reference in the USA:
Queens, NY: (1999) 2.6% (1.2-4.1%)
Cleveland, Ohio: (2002) 1.9% (0.8-4.6%)

## Partners in West Nile virus Surveillance and Response

**Partners in West Nile virus Surveillance and Response**

- Public Health Agency of Canada
- Pest Management Regulatory Agency
- First Nations and Inuit Health Branch
- Healthy Environments and Consumer Safety Branch
- Health Products and Food Branch
- Communications, Marketing and Consultation Directorate

- Canadian Cooperative Wildlife Health Centre

- Chief Medical Officers of Health

- Canadian Food Inspection Agency

- Provincial/Territorial Steering Committees

- Department of National Defence

- Environment Canada

- Blood Operators

- International Linkages

- Health Professional
- Organizations

- Department of Fisheries and Oceans

- Parks Canada

- Consumers’ Groups

**Notes:**
As I close my presentation, I would like to acknowledge the countless dozens of persons who are involved, from our many partner organizations.

## For more information, please consult the Public Health Agency of Canada’s WNV website at:
www.westnilevirus.gc.ca

Pour plus d’informations, consulter le site Web d’Agence de santé publique du Canada sur le virus du Nil occidental à l’adresse suivante:
www.virusduniloccidental.gc.ca

**www.westnilevirus.gc.ca**
**Pour plus d’informations, consulter le site Web d’Agence de santé publique du Canada sur le virus du Nil occidental à l’adresse suivante:**
**www.virusduniloccidental.gc.ca**

**Notes:**
Thank you for your attention this morning.
I would be happy to discuss our experiences with anyone at anytime.
STOP.

## Communications Approach

- To date
- Served as a credible source of information
- Ensured consistent messaging and reached high risk populations
- During 2005,  PHAC continued its coordinating role with regional offices, P/Ts and other federal Departments.  Key objectives were to sustain messaging while supporting provincial/territorial efforts
- Facilitate information-sharing through communications committee
- Continue public education with in-store promotion
- The First Nations and Inuit Health Branch’s public education campaign focused on personal protective measures (avoiding mosquito bites and eliminating sources of standing water)

**Notes:**
Communications in 2003 and 2004
In 2003, awareness across the country was high but only 4 in 10 took appropriate protective measures
In 2004, strategies continued to build on 2003 communications efforts

Past objectives have included the following:
To serve as a credible source for WN virus information
To ensure consistent messaging
To reach new, high-risk target audiences
For 2005
PHAC continued its coordinating role with regional offices, P/Ts and other federal Departments.  
Key objectives were: 
to sustain messaging while supporting provincial/territorial efforts
to facilitate information-sharing through communications committee
To continue public education with in-store promotion campaign
FNIHB’ s public education campaign will focus on personal protective measures (avoiding mosquito bites and eliminating sources of standing water)
A media kit containing  FNIHB WNV public service announcements was distributed to 150 Aboriginal media outlets
An article about WNV was published in the April edition of INAC Update, a newsletter distributed to First Nations households on reserve

## Communications and Public Education

- Canadians are not taking proper steps to protect themselves against WNV
- Communications and public education to get people to take action
- Focus on behaviour and attitudinal change
- Reach people in high risk target groups
- Partnerships: public and private
- Proactive communications
- Social marketing
- Ensure equal access to information for all Canadians
- Reinforce messaging on the safety of DEET

**Notes:**
Research conducted at the end of the 2004 season indicated that people aren’t concerned enough so they aren’t protecting themselves
Barriers – too hot so won’t wear long sleeves; insect repellent yucky; don’t perceive it as an issue because they don’t see it as a threat; or because of over-messaging

Approaches include:
Reinforce that it is preventable and that you have to take the appropriate measures; reach people with reinforced messagings, something to be considered; Potential public health threat that can be prevented
Reach them at the community level 
Reinforce message to protect yourself and that there are effective ways to protect yourself.