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A survey of wild carnivores in Canada was conducted over a 10-year period to determine the prevalence and genotypes of Trichinella. Muscle samples collected from 1409 animals representing 15 hosts species were enzymatically digested to recover Trichinella larvae. Larvae were recovered from a total of 287 (20.4%) animals and PCR identified four genotypes of Trichinella. Trichinella nativa was found in 5 host species and was the most commonly found genotype. Trichinella T6 was present in 7 species of carnivores, and coyote and badger are new host records for this genotype. The recovery of T. pseudospiralis and T. murrelli from cougars is the first documentation of these species in Canada and in cougars. The cougar was also the only host species in which all four genotypes of Trichinella were identified. Black bears and walruses had the highest tissue levels of larvae in this study and are also the species most frequently associated with human trichinellosis in Canada. This work identifies additional host species and expanded geographic ranges for 4 genotypes of Trichinella in North America. Failure to demonstrate T. spiralis in wildlife and continued negative results from ongoing surveillance activities in swine provide additional evidence that T. spiralis is not present in Canada.

Serological and clinical evidence of human toxoplasmosis in the Canadian Arctic indicates a food safety risk associated with the consumption of wild game meat. Such meat often is eaten raw or partially cooked in locally prepared traditional (country) foods, but no data have been collected to describe survival of Toxoplasma gondii forms in these foods. The muscle of grey seals (Halichoerus grypus) experimentally infected with T. gondii oocysts was used to prepare three country foods: igunaq, a fermented product; nikku, a dried product; and sausage, a salted and spiced product. Igunaq and nikku were stored at 4 degrees C and bioassayed in cats at 49, 95, and 140 days postpreparation (DPP) and 41, 84, and 132 DPP, respectively. Raw and cooked sausages were stored at -20 degrees C and bioassayed at 50, 92, and 141 DPP. The source seal meat was infective for cats, but none of the foods prepared with this meat were infective for cats. Some cooked sausages did not reach internal temperatures considered lethal for T. gondii. Data from studies in domestic animals suggested that the negative results in this experiment were due to temperature and duration of storage. Because of the possibility that T. gondii of arctic origin might be more freeze tolerant than the swine-origin isolate used in this experiment, additional studies are necessary to clarify the risks of toxoplasmosis associated with consumption of arctic country foods.

The Canadian Food Inspection Agency (CFIA) has developed a program to accredit external laboratories to conduct Trichinella digestion assays for export purposes. Accredited laboratories are responsible for staffing, equipment and operating test facilities under the auspices and guidance of the CFIA. The CFIA's Centre for Animal Parasitology provides training, proficiency samples, audits and other support for the accreditation process. The program has also been adapted for use in laboratories conducting Trichinella digestion tests for surveillance and food safety purposes and provides a useful template for others wishing to develop similar systems.

The infectivity of Trichinella nativa larvae in three traditional northern (country) foods was assessed. Foods were prepared with meat from seals experimentally infected with Trichinella nativa and evaluated over a 317-day period during which this food was fed directly to cats while mice were orally inoculated with larvae recovered following the digestion of the food in a solution containing 1% pepsin and 1% HCl at 37 degrees C. Foods examined were igunaq (meat and blubber placed in a seal skin bag and allowed to ferment), nikku (air-dried meat), and sausage (meat, fillers, salt, and spices). Sausage was examined both in a raw state and after partial cooking. Infective T. nativa larvae survived in igunaq, nikku, raw frozen sausage, and poorly cooked sausage for at least 5 months under controlled laboratory conditions. Core temperatures of partially cooked sausage never exceeded 50 degrees C. Caution should be exercised in using these data to establish guidelines for the consumption of raw products, since the survival of infective larvae could be unpredictably extended under field conditions. These data indicate significant food safety risks associated with igunaq, nikku, and sausage prepared with Trichinella-infected meat and provide information for use in risk management and in directing future research.

Sera from 14,408 market sows from the Canadian domestic swine herd were tested for trichinellosis using an indirect-ELISA as a screening test and a competitive ELISA for confirmatory testing. Three sera (0.02%) gave low level reactions on the competitive ELISA. These reactions were considered nonspecific, and this designation was supported by data from previous and subsequent national surveys, in which serologic, trichinoscopic, and digestion test methodologies was used. This study provides additional evidence that Canada is free of trichinellosis in domestic swine.

A novel Brucella sp. was isolated from lymph nodes of four ringed seals (Phoca hispida) collected near Pangnirtung (Baffin Island, Canada) in January and February 1995 and in one harp seal (Phoca groenlandica) collected near the Magdalen Islands (Gulf of St. Lawrence, Canada) in March 1996. Bacteriological characteristics were the same for all five isolates. The colonies were typical of Brucella spp., but took 2 to 5 days longer than the traditional species to appear on primary isolation media. Biotyping results did not match any of the known biovars of Brucella, but were similar to isolates of the genus Brucella previously reported from marine mammals inhabiting other areas of the northern hemisphere. This is the first confirmed report of brucellosis in marine mammals from Canada, and the first report of this organism in ringed and harp seals.

A total of 41 Brucella isolates, examined by standard biotyping procedures, were found to be similar to Brucella abortus biovar 2 in dye sensitivity but had a dominant M antigen. Oxidative metabolic tests performed on 39 of the isolates confirmed them as B. abortus. Additional biochemical and bacteriophage susceptibility studies were performed on 35 of the isolates. The isolates had identical reactions in the various tests, except for one isolate which was resistant to lysis by all phage strains used. Two isolates were injected into guinea pigs and shown to be virulent. The isolates described in this study appear similar to atypical Brucella isolates previously reported in the United Kingdom and the United States and may form the basis of a new biovar, B. abortus biovar 10.

Six agglutination and two complement fixation tests were compared with respect to specificity, sensitivity and relative sensitivity for the serodiagnosis of bovine brucellosis. Based on 1051 sera from brucellosis free herds, the specificity of the tests was 98.9% for the buffered plate antigen test (BPAT), 99.2% and 99.3% for the standard tube and plate agglutination tests (STAT and SPAT), respectively, and 99.8% for the 2-mercaptoethanol test (2MET). On this small sample, the rose bengal plate test (RBPT), card test (CARD) and the complement fixation test (CFT) correctly classed all sera as negative. On a sample of 167 culture positive cattle, the sensitivities of the tests were CFT: 79.0%, BPAT: 75.4, RBPT: 74.9%, CARD: 74.3%, SPAT: 73.1%, STAT: 68.9%, and 2MET: 59.9%. All tests combined detected only 82% of these infected cattle. Analysis of the relative sensitivity of the six agglutination tests gave the following ranking: BPAT greater than RBPT greater than CARD greater than SPAT greater than STAT. The 2MET ranked between the BPAT and RBPT or between the RBPT and CARD depending on the analysis used. The use of the BPAT as a screening test is recommended provided that a test of high specificity and sensitivity such as the CFT is used to confirm screening test reactions.

Severe granulomatous nephritis caused by Brucella suis biotype 4 was found in a barren ground caribou (Rangifer tarandus groenlandicus) from Northwest Territories, Canada. A review of the distribution of human and animal cases of brucellosis in northern Canada indicated that B. suis biotype 4 is distributed widely and is probably enzootic in most Canadian caribou herds.