Risk Assessment for the Importation of Farmed Elk (Cervus elaphus canadensis) to Saskatchewan from Ontario (Canada) with respect to the Nematode Parasites Elaphostrongylus cervi and Parelaphostrongylus tenuis
Executive Summary
This report presents the results of a risk assessment for the importation of Elaphostrongylus cervi and Parelaphostrongylus tenuis with live farmed elk from Ontario to Saskatchewan, under proposed import protocols. The import protocol requires, among other things, quarantine in both Ontario and Saskatchewan, and evidence of two negative Baermann beaker tests on feces collected prior to animal movement for all members of a group being proposed for import.
The range of scenarios presented, based upon a mathematical model created for a total importation of 350 animals, indicates that there is a greater than 50% chance of importing a small number (1-6) of elk that test negative but are actually infected with either E. cervi or P. tenuis. The accuracy of our estimates would improve if better information became available. At this time, a rigorous evaluation of the sensitivity of the Baermann test has not been carried out, a wide range is possible for the prevalence of the two parasites in question in Ontario elk, and the exact number of elk and number of groups of elk being imported is unknown. However, in general, importing multiple small groups would result in a greatly increased probability of importing at least one infected, false negative, elk.
It was not possible to evaluate the effectiveness of the proposed post-entry quarantine. The post-entry quarantine standards are not specifically defined, and details of molluscicide use and effectiveness are lacking. Information is limited on the presence and distribution of the gastropod intermediate hosts in Saskatchewan, although some of the known intermediate hosts for P. tenuis do exist in southern areas of the province.
The probability of establishment of E. cervi in Saskatchewan is unknown. There is no information to show whether E. cervi has or has not become established in eastern Canada. The potential negative impact of E. cervi, if it were to become established in Saskatchewan, is unknown. The probability of establishment of P. tenuis is considered low for much of Saskatchewan, but could be significantly higher in areas that meet the ecological requirements of the parasite. P. tenuis has very well documented negative effects on a variety of species, and the risk of significant negative impact, if the parasite should become established in Saskatchewan, is considered high.