During the 2009 CWD surveillance program a total of 757 white-tailed deer were collected and sampled from CWD surveillance zones 1, 2 and 14. All samples were collected between September and December of 2009. The sample size target for each zone was 460 samples; it was not met in any of the three zones. In zone 14 (Thunder Bay-Atikokan area), 110 samples were collected, in zone 1 (Cornwall-Ottawa area), 349 samples were collected, and in zone 2 (Barrie-Toronto area), 298 samples were collected. All test results proved negative for presence of CWD prions.
Chronic Wasting Disease (CWD) is a fatal disease which infects members of the cervidae family. CWD is caused by abnormally folded proteins called prions, which cause lesions on the brain and often leads to death. The disease is not known to infect any species outside the cervidae family. It has become endemic in several states in the U.S. west (i.e. Colorado and Wyoming) and has been identified in two western Canadian provinces (Alberta and Saskatchewan). More recently the disease has also gained a foothold in the U.S. east in several states (i.e. Wisconsin, West Virginia). Currently CWD is not known to exist in Ontario, but has been discovered in three bordering states; New York (2005), Minnesota (2002), and Michigan (2008). In the primary infection area of the U.S. west white-tailed deer, elk, and mule deer have been shown to be very susceptible to CWD, and more recently a small number of moose have also tested positive for CWD.
Ontario Surveillance Program background
With increasing concern about Ontario’s white-tailed deer and elk herds, an Ontario surveillance program was designed to establish whether CWD was present in our wild herd populations. In 2002 a pilot program collected deer samples from the Grey-Bruce counties area. The Ontario surveillance program generally collects its samples in the fall season by relying on volunteer participation from hunters. Small crews of MNR staff roam in a patrol area, asking hunters if they can remove a brain and lymph node sample from their hunted deer. Following a successful pilot program, the Ontario Chronic Wasting Disease Surveillance program became operational in 2003.
A sample size of 460 deer samples from each surveillance zone was determined adequate to statistically claim that we can have 99% confidence that CWD would be detected in the deer population if the disease was prevalent in 1% or greater of the population.
The province was divided into 14 different CWD surveillance zones (Figure 1) and prioritized using a formula of estimated deer populations, proximity to CWD cases in neighbouring U.S. states, elk reintroduction release sites and number of cervid ranches within the zone. In an effort to speed up the surveillance of the province, the number of CWD zones surveyed per year was increased to three annually in 2005.
Figure 1. Ontario CWD Surveillance Zones
In 2009 zones 14 (Thunder Bay-Atikokan area), 1 (Cornwall-Ottawa area), and 2 (Barrie-Toronto area) were sampled. A total of 757 samples were collected from these three zones. All samples tested negative for CWD.
A Weighted Surveillance Approach for Detecting Chronic Wasting Disease
Foci Daniel P. Walsh1,2 and Michael W. Miller1 1 Wildlife Health Program, Colorado Division of Wildlife, Wildlife Research Center, 317 West Prospect Road, Fort Collins, Colorado 80526-2097, USA 2 Corresponding author (email: firstname.lastname@example.org)
ABSTRACT: A key component of wildlife disease surveillance is determining the spread and geographic extent of pathogens by monitoring for infected individuals in regions where cases have not been previously detected. A practical challenge of such surveillance is developing reliable, yet cost-effective, approaches that remain sustainable when monitoring needs are prolonged or continuous, or when resources to support these efforts are limited. In order to improve the efficiency of chronic wasting disease (CWD) surveillance in Colorado, United States, we developed a weighted surveillance system exploiting observed differences in CWD prevalence across demographic strata within infected mule deer (Odocoileus hemionus) populations. We used field data to estimate sampling weights for individuals from eight demographic strata distinguished by differences in apparent health, sex, and age. In this system, individuals from a sample source with high prevalence and low inclusion probability (e.g., clinical CWD "suspects") received 10.3 times more weight than those from a source with low prevalence and high inclusion probability (e.g., apparently healthy, hunter-harvested individuals). We simulated use of this alternative surveillance system for a deer management unit in Colorado and evaluated the potential effects of using biased weights on the probability of failing to detect CWD and on relative surveillance costs. We found that this system should be transparent, cost-effective, and reasonably robust to the inadvertent use of biased weights. By implementing this, or a similar, weighted surveillance system, wildlife agencies should be able to maintain or improve current surveillance standards while, perhaps, collecting and examining fewer samples, thereby increasing the efficiency and cost-effectiveness of ongoing CWD surveillance programs.
A ProMED-mail post ProMED-mail is a program of the International Society for Infectious Diseases
Date: Fri 19 Mar 2010 Source: Country-Guide [edited]
While Alberta's fall  surveillance program for chronic wasting disease (CWD) in wild deer has turned up fewer cases than last year's , deer with the disease were found further south and west than previously detected.
Hunters have submitted more than 4800 wild deer heads for testing since 1 Sep 2009, the province said in a release Friday [19 Mar 2010]. Of the 12 new cases of CWD identified, 10 were detected near past positive cases.
One new case, however, was detected south of Highway 1, 25 kilometres [15.5 mi] south of Medicine Hat. Another case was found just east of Highway 884 along the Red Deer River.
The 12 new cases, along with an "emaciated" deer found in June , bring the total to 13 new cases of CWD found in 2009, down from 25 in 2008. Since the 1st case of CWD was found in the province in 2005, there have been 74 cases in Alberta's wild deer.
11 of the 12 new positive cases from the fall  program were mule deer and 9 of the hunter-killed cases were adult males, including an adult male white-tailed deer, the province said.
Current strategies for monitoring the spread of CWD include "maximizing the harvest" of deer in risk areas and continuing the testing program. The province has run ongoing surveillance in elk and wild deer since 1996.
The province's surveillance program includes testing roadkill and any wild deer that may show CWD symptoms, such as loss of co-ordination, weight loss, excessive salivating, and isolation from other deer.
The province's sustainable resource development ministry said it "continues to talk with stakeholders and landowners in the area to discuss plans for management."
According to Saskatchewan's environment ministry, CWD was unintentionally introduced into farmed elk population taken from South Dakota and has since been introduced to Saskatchewan, Alberta, and Korea. The economics of trade in live elk and their products, such as antler velvet, has been affected as a result.
Because CWD belongs to the group of transmissible spongiform encephalopathy (TSE) diseases along with BSE in cattle, scrapie in sheep, and Creutzfeldt-Jakob disease in humans, the association has led to possible public health concerns -- although there remains no scientific evidence that CWD can infect humans.
The disease can be transmitted from one animal to another, mainly through contaminated saliva or contaminated feed and water. Infectious material can survive in the environment for an unknown period -- at least 3 years, the Saskatchewan government said.
-- Communicated by: ProMED-mail and Terry S Singeltary Sr
[CWD has also been found in 3 isolated geographic areas of Saskatchewan's northeast, northwest, and southwest.
While most deer do not roam much more than a mile diameter from their "home" territory, there are other ways of translocating the disease, including predators dragging carcasses, hunters unwittingly transporting carcasses, or relocation of deer from one area to another. - Mod.TG]
[Alberta and Saskatchewan can be located on the HealthMap/ProMED-mail interactive map of Canada at . - Sr.Tech.Ed.MJ]