Publications

childhood lymphadenitis in a harsh northern climate due to atypical mycobacteria.	between 1979 and 1983, 16 patients under 15 years of age living within 480 km of edmonton, alberta (latitude 53 degrees 34' n) were seen with cervical lymphadenitis caused by atypical mycobacteria. during this period only 4 cases of cervical lymphadenitis from mycobacterium tuberculosis occurred in the same age and geographical grouping. young children age 1-4 years accounted for most cases (14/16). the onset showed no seasonal preponderance and the nodal enlargement was either asymptomatic (8/1 ...	1987	3563428
mycobacterium paratuberculosis in dairy herds in alberta.	fifty dairy herds in alberta were tested for the presence of mycobacterium paratuberculosis by fecal culture and serum enzyme linked immunosorbent assay (elisa). individual sera (1500) were tested for antibodies to m. paratuberculosis by elisa. fecal samples were combined in pools of 3 (10 pools/herd) for a total of 500 pools that were cultured for m. paratuberculosis. thirty cultures, including all 10 pools from 1 herd, were not readable due to fungal contamination. the remaining 470 cultures, ...	2003	12677691
changing mortality rates and causes of death for hiv-infected individuals living in southern alberta, canada from 1984 to 2003.	to examine changes over a 2-year period in both the mortality rate and the causes of death in a geographically defined hiv-infected population.	2005	15807715
seroprevalence of mycobacterium avium subspecies paratuberculosis, neospora caninum, bovine leukemia virus, and bovine viral diarrhea virus infection among dairy cattle and herds in alberta and agroecological risk factors associated with seropositivity.	a province-wide, cross-sectional seroprevalence and agroecological risk factor study of mycobacterium avium subspecies paratuberculosis (map), neospora caninum (nc), bovine leukemia virus (blv), and bovine viral diarrhea virus (bvdv) genotypes 1 and 2 (bvdv1 and bvdv2) infection in dairy cattle herds in alberta was conducted. among adults, the seroprevalence of map, nc, and blv was 9.1%, 18.5%, and 26.9%, respectively. for map, based on a herd test cutpoint of 2 or more seropositive cows, 58.8% ...	2006	17078247
seroprevalence of and agroecological risk factors for mycobacterium avium subspecies paratuberculosis and neospora caninum infection among adult beef cattle in cow-calf herds in alberta, canada.	a province-wide cross-sectional seroprevalence and agroecological risk factor study of mycobacterium avium subspecies paratuberculosis (map) and neospora caninum (nc) infection among cattle in 100 cow-calf herds in alberta was conducted. the seroprevalence of map in adult cattle was 1.5% across all herds. using a widely accepted herd test cutpoint of 2 or more seropositive cows out of 30 animals tested, 7.9% of herds were estimated to be infected (95% confidence interval (ci): 2.3-23.4%). seropr ...	2007	17494367
bayesian kriging of seroprevalence to mycobacterium avium subspecies paratuberculosis and neospora caninum in alberta beef and dairy cattle.	identifying spatial patterns of risk is important in the study of diseases with ecologic causes. furthermore, relatively complex hierarchical modeling is required to determine how factors that are organized across levels interact, such as how an ecologic cause interacts with farm management and with animal characteristics. the objective of this study was to map the risk for mycobacterium avium subspecies paratuberculosis (map - the causative agent of johne's disease) and neospora caninum (nc - t ...	2007	18189052
serum biochemistry, serology, and parasitology of boreal caribou (rangifer tarandus caribou) in the northwest territories, canada.	boreal caribou (rangifer tarandus caribou) are an ecologically and culturally important wildlife species and now range almost exclusively in the boreal forests of canada, including the northwest territories, northern alberta, and british columbia. boreal caribou are threatened throughout their canadian range because of direct and indirect natural and anthropogenic factors. in the northwest territories, however, they have a continuous range that overall has not yet been subjected to the same degr ...	2010	20966261
attitudes of canadian dairy farmers toward a voluntary johne's disease control program.	the success of johne's disease (jd) control programs based on risk assessment (ra) depends on producers' compliance with suggested management practices. one objective of this study was to describe the perception of participating canadian dairy farmers of the impact of jd, the ra process, and suggested management strategies. the second objective was to describe the cost of changes in management practices following the ra. a telephone survey was conducted with 238 dairy farmers in ontario, manitob ...	2010	20338426
occurrence, diagnosis, and strain typing of mycobacterium avium subspecies paratuberculosis infection in rocky mountain bighorn sheep (ovis canadensis canadensis) in southwestern alberta.	the role that wildlife may play in the transmission of mycobacterium avium subspecies paratuberculosis (map), the causative agent of johne's disease (jd), and the potential consequences of infection in these populations are being given increasing consideration. a yearling male rocky mountain bighorn sheep (ovis canadensis canadensis) from southwestern alberta, canada, was found infected with map in august 2009. clinical signs of emaciation and diarrhea and histologic findings of diffuse granulom ...	2012	22247368
pathogens at the livestock-wildlife interface in western alberta: does transmission route matter?	in southwestern alberta, interactions between beef cattle and free-ranging elk (cervus elaphus) may provide opportunities for pathogen transmission. to assess the importance of the transmission route on the potential for interspecies transmission, we conducted a cross-sectional study on four endemic livestock pathogens with three different transmission routes: bovine viral diarrhea virus and bovine herpesvirus 1 (predominantly direct transmission), mycobacterium avium subsp. paratuberculosis (ma ...	2014	24517283
occurrence of mycobacterium avium subspecies paratuberculosis and neospora caninum in alberta cow-calf operations.	mycobacterium avium subsp. paratuberculosis (map) and neospora caninum (nc) are two pathogens causing important production limiting diseases in the cattle industry. significant impacts of map and nc have been reported on dairy cattle herds, but little is known about the importance, risk factors and transmission patterns in western canadian cow-calf herds. in this cross-sectional study, the prevalence of map and nc infection in southwest alberta cow-calf herds was estimated, risk factors for nc w ...	2014	25277685
economic evaluation of participation in a voluntary johne's disease prevention and control program from a farmer's perspective--the alberta johne's disease initiative.	the alberta johne's disease initiative (ajdi) is a johne's disease (jd) control program with the goal of reducing the spread of mycobacterium avium ssp. paratuberculosis (map) through implementation of best management practices. the objective was to estimate the economic benefit of participation in the ajdi. a decision tree was constructed in which disease prevalence, test characteristics, and probabilities for implementation of best management practices suggested by herd veterinarians were impl ...	2014	24582447
surveillance and molecular characterization of non-tuberculous mycobacteria in a hospital water distribution system over a three-year period.	a three-year surveillance of non-tuberculous mycobacteria (ntm) in a hospital water distribution system was conducted at a facility located in southern alberta. ntm was not present in any intake water samples, but was found in 106/183 (58%) of endpoint samples across 15 sites over the study period. two different species of ntm were identified, mycobacterium gordonae (88/183) and mycobacterium avium (34/183); with only one strain of each m. gordonae and m. avium found. given the sensitive nature ...	2014	24746232
high herd-level prevalence of mycobacterium avium subspecies paratuberculosis in western canadian dairy farms, based on environmental sampling.	mycobacterium avium subspecies paratuberculosis (map) causes chronic progressive enteritis in ruminants. the pathogen is present in most countries with modern dairy production, causing substantial economic losses for the industry. the objectives of this study were to estimate dairy herd prevalence of map in the western canadian provinces of alberta and saskatchewan, and to determine whether herd size and housing system (tie-stall versus freestall or loose housing) affected the risk of a herd tes ...	2014	25151881
sampling location, herd size, and season influence mycobacterium avium ssp. paratuberculosis environmental culture results.	mycobacterium avium subspecies paratuberculosis (map), the etiologic agent of johne's disease, a chronic progressive enteritis, is a common pathogen on dairy farms. environmental sampling is frequently used to detect map-infected herds, because it does not require sample collection from individual animals. the objectives were to determine (1) location-specific odds of map-positive environmental sampling results and whether season or herd size affect results; (2) whether season and herd size affe ...	2015	25465568
factors affecting management changes on farms participating in a johne's disease control program.	modern johne's disease programs aim to control mycobacterium avium ssp. paratuberculosis (map) infection through implementation of management practices that reduce the probability of map introduction and within-herd transmission on dairy farms. success of these programs depends on whether weaknesses in management are corrected through implementation of management improvements. the objectives of this study were, therefore, to (1) assess whether scores in risk-assessment (ra) questions predicted s ...	2015	26342989
short communication: herd-level prevalence of mycobacterium avium ssp. paratuberculosis is not associated with participation in a voluntary alberta johne's disease control program.	johne's disease (jd) control programs for dairy farms have the general objective of reducing both cow- and herd-level prevalence of mycobacterium avium ssp. paratuberculosis (map). an important aspect of many programs is herd testing for map to determine the infection status of participating farms. however, it is uncertain whether map herd-level prevalence on farms voluntarily participating in a jd control program is different from that on nonparticipating farms. therefore, the aim was to compar ...	2016	26778309
dairy farms testing positive for mycobacterium avium ssp. paratuberculosis have poorer hygiene practices and are less cautious when purchasing cattle than test-negative herds.	mycobacterium avium ssp. paratuberculosis (map), the causative agent of johne's disease, is present on most dairy farms in alberta, causing economic losses and presenting a potential public health concern. the objective of this cross-sectional study was to identify risk factors for alberta dairy herds being map-positive based on environmental samples (es). risk assessments were conducted and es were collected on 354 alberta dairy farms (62% of eligible producers) voluntarily participating in the ...	2016	26995127