Elora Ontario, Canada
Elora Ontario, Canada

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Falzon L.C.,University of Guelph | Falzon L.C.,University of Bern | Van Leeuwen J.,University of Prince Edward Island | Menzies P.I.,University of Guelph | And 4 more authors.
Parasitology Research | Year: 2014

This study compared results obtained with five different fecal egg count reduction (FECR) calculation methods for defining resistance to ivermectin, fenbendazole, and levamisole in gastrointestinal nematodes of sheep in a temperate continental climate: FECR1 and FECR2 used pre- and posttreatment fecal egg count (FEC) means from both treated and control animals, but FECR1 used arithmetic means, whereas FECR2 used geometric means; FECR3 used arithmetic means for pre- and posttreatment FECs from treated animals only; FECR4 was calculated using only arithmetic means for posttreatment FECs from treated and control animals; and FECR5 was calculated using mean FEC estimates from a general linear mixed model. The classification of farm anthelmintic resistance (AR) status varied, depending on which FECR calculation method was used and whether a bias correction term (BCT, i.e., half the minimum detection limit) was added to the zeroes or not. Overall, agreement between all methods was higher when a BCT was used, particularly when levels of resistance were low. FECR 4 showed the highest agreement with all the other FECR methods. We therefore recommend that small ruminant clinicians use the FECR4 formula with a BCT for AR determination, as this would reduce the cost of the FECRT, while still minimizing bias and allowing for comparisons between different farms. For researchers, we recommend the use of FECR1 or FECR2, as the inclusion of both pre- and posttreatment FECs and use of randomly allocated animals in treatment and control groups makes these methods mathematically more likely to estimate the true anthelmintic efficacy. © 2014 Springer-Verlag.


Meadows S.,University of Guelph | Jones-Bitton A.,University of Guelph | McEwen S.A.,University of Guelph | Jansen J.,Veterinary Science and Policy | And 4 more authors.
Vector-Borne and Zoonotic Diseases | Year: 2016

Coxiella burnetii is a zoonotic bacterium that causes Q fever, a potentially severe disease of humans. The objectives of this study were to determine the seroprevalence and risk factors for C. burnetii exposure in sheep and goat farm workers in Ontario, Canada. Between August 2010 and March 2012, 172 farm workers from 78 sheep and goat farms were surveyed regarding demographics, lifestyle, farm practices, and medical history. Sera from these people were collected and analyzed for Q fever titers using the immunofluorescence assay. A mixed multivariable logistic regression model was constructed to identify risk factors for seropositivity. Individual-level and farm-level seroprevalence for C. burnetii were 64.5% (111/172, 95% CI = 57.2-71.4) and 74.4% (58/78, 95% CI = 63.2-83.6), respectively. Farm worker seropositivity was positively associated with an increasing proportion of seropositivity of sheep/goats on farm (odds ratio [OR] = 1.04; 95% CI 1.02-1.07). A higher odds of seropositivity was also observed for people working on dairy goat farms compared to the odds on dairy sheep (OR = 0.04; 95% CI 0.003-0.53) or meat goat (OR = 0.09; 95% CI 0.01-0.67) farms. Coxiella burnetii seropositivity was common in workers on sheep and goat farms in Ontario. Given the significant risk of morbidity associated with this infection, early recognition and treatment of Q fever are important. The risk factors identified provide insight into disease transmission between animals and people, which is particularly important for farmers, researchers, medical doctors, veterinarians, and public health professionals. Physicians practicing in rural areas should consider Q fever infection when patients present with atypical pneumonia and suggestive risk factors. © Copyright 2016, Mary Ann Liebert, Inc. 2016.


Falzon L.C.,University of Guelph | Menzies P.I.,University of Guelph | Vanleeuwen J.,University of Prince Edward Island | Jones-Bitton A.,University of Guelph | And 4 more authors.
Small Ruminant Research | Year: 2013

To describe parasite control and farm management practices commonly used by Ontario sheep farmers, and to determine whether any of these practices were associated with the level of anthelmintic resistance (AR) to ivermectin, fenbendazole or levamisole, we conducted fecal egg count reduction (FECR) tests in Ontario sheep flocks, and administered a questionnaire pertaining to farm practices that were considered putative risk factors for AR. In the previous 5 years, most of the producers had used ivermectin and fenbendazole drenches (95% and 68%, respectively), while only 11% had used levamisole drench. Producers treated their animals a mean of 2.6 times per year. Routine treatment was practiced by 82% of the producers; most ewes were treated either at lambing (55%) and/or at the beginning of winter housing (48%). The majority of the producers (82%) also used targeted or targeted selective treatment; however, it was often in addition to, rather than in lieu of, routine treatment. Twenty-five producers (66%) brought in new animals in the previous year. Many producers (45%) did not calibrate the drench gun before use. The mean FECR percentages following treatment with ivermectin, fenbendazole, and levamisole were 23.7%, 28.6% and 99.1%, respectively. Although univariable analyses identified several marginally significant risk factors (0.10 > p > 0.05), none were significant in the final model for ivermectin FECR percentage. In contrast, use of benzimidazoles in the previous 5 years was associated (p = 0.01) with increased resistance (lower mean FECR percentage) to fenbendazole. Levamisole resistance could not be modeled due to the very low levels of resistance on the farms surveyed. This study: (1) provided a picture of management practices employed by Ontario sheep producers who were experiencing AR to one or more anthelmintic drugs on their farms; and (2) allowed us to identify areas for further AR risk factor research. © 2013 Elsevier B.V.


Meadows S.,University of Guelph | Jones-Bitton A.,University of Guelph | McEwen S.,University of Guelph | Jansen J.,Veterinary Science and Policy | Menzies P.,University of Guelph
Preventive Veterinary Medicine | Year: 2015

Coxiella burnetii is a zoonotic bacterium that can cause abortion in sheep in late gestation, as well as the delivery of stillborn, and non-viable lambs (Rodolakis, 2006). A cross-sectional study was conducted in Ontario, Canada, to investigate C. burnetii exposure in sheep. Between August 2010 and January 2012, sera from 2363 reproductively active ewes from 72 farms were tested for C. burnetii specific antibodies using the CHEKIT Q fever ELISA Test kit (IDEXX Laboratories). Overall, exposure was common; sheep-level seroprevalence was 14.7% (347/2363, 95% CI: 13.3-16.2), and was higher in dairy sheep (24.3%, 181/744) than meat sheep (10.2%, 166/1619) (p< 0.0001). At the farm-level, 48.6% (35/72, 95% CI: 37.2-60.1) of farms had at least one seropositive sheep. A mixed multivariable logistic model that controlled for farm-level clustering, identified risk factors associated (p< 0.05) with sheep seropositivity. Increasing female flock size (logarithmic scale) was associated with increased odds of seropositivity. By way of illustration, increasing the female flock size from 100 to 200 increased the odds of seropositivity by 2.26 times (95% CI: 1.5-3.5). Sheep that lambed in an airspace separate from the flock had 11.3 times (95% CI: 2.9-43.6) the odds of seropositivity relative to other sheep. The practice of loaning sheep that returned to the farm increased odds of seropositivity by 8.1 times (95% CI: 1.8-33.6). Lambing pen hygiene practices also influenced odds of seropositivity. Relative to sheep from farms where all lambing pen hygiene measures were practiced after lambing (i.e., adding bedding, removing birth materials and disinfection), sheep from farms that only added bedding, or those that just added bedding and removed birthing materials had 5.9 times (95% CI: 1.1-32.1) and 9.0 times (95% CI: 2.2-36.9) the odds of seropositivity, respectively. These results can be used to inform prevention and control strategies with the aim of reducing C. burnetii exposure in sheep. © 2015 Elsevier B.V..


Meadows S.,University of Guelph | Jones-Bitton A.,University of Guelph | McEwen S.,University of Guelph | Jansen J.,Veterinary Science and Policy | Menzies P.,University of Guelph
Preventive Veterinary Medicine | Year: 2015

Coxiella burnetii is a zoonotic bacterium, and infection in goats with this bacterium can result in abortion, stillbirth or birth of non-viable kids. A cross-sectional study was conducted to identify the seroprevalence and risk factors for C. burnetii exposure in Ontario goats. Sera were collected between August 2010 and February 2012, and tested for C. burnetii specific antibodies using an enzyme-linked immunosorbent assay (IDEXX).Overall, 63.2% (48/76, 95% CI = 51.9-73.4) of farms had one or more seropositive goats. A higher farm-level seroprevalence of 78.6% (33/42) was found on dairy goat farms, compared to 44.1% (15/34) on meat goat farms (p<0.01). At the overall individual-animal level, 32.5% (714/2195, 95% CI = 30.6-34.5) of goats were seropositive. Similarly, a higher individual-level seroprevalence was identified for dairy goats (43.7%, 633/1447) compared to meat goats (10.8%, 81/748) (p<0.001).A mixed multivariable logistic model that controlled for farm-level clustering identified risk factors associated with seropositivity (p<0.05). Increases in the female herd size (logarithmic scale) were associated with increased odds of seropositivity, while increases in male herd size had a negative association with seropositivity. If other sheep or goat farms were located in a 5-km radius, goats had 5.6 times (95% CI = 1.01-30.8) times the odds of seropositivity compared to those that were not. Relative to goats from farms where all kidding pen hygiene was practiced (adding bedding, removing birth materials and disinfection after kidding), goats from farms which only added bedding and removed birth materials had a higher odds of seropositivity (OR = 19.3, 95% CI = 1.1-330.4), as did goats from farms which practiced none of these measures (OR = 161.0, 95% CI = 2.4-10822.2). An interaction term revealed kidding outdoors when there were no swine on farm had a protective effect on seropositivity compared to kidding indoors, or kidding outdoors with swine on the farm. These results can inform strategies to mitigate exposure to C. burnetii in Ontario. © 2015 Elsevier B.V.


Falzon L.C.,University of Guelph | Menzies P.I.,University of Guelph | Shakya K.P.,University of Guelph | Jones-Bitton A.,University of Guelph | And 4 more authors.
Preventive Veterinary Medicine | Year: 2013

The epidemiology of the periparturient egg rise (PPER) of gastrointestinal nematodes (GINs) in sheep remains unclear, and may be influenced by the lambing season. This longitudinal study was performed to determine the effect of out-of-season lambing on the PPER in ewes in Ontario, and whether total plasma protein (TPP) and packed cell volume (PCV) were associated with the PPER. Six farms that practiced out-of-season lambing were enrolled, and sampled for three consecutive lambing seasons (winter, spring and autumn). For each lambing season, all farms were visited five times. On the first visit for each lambing season, 15-20 pregnant ewes and 15-20 non-pregnant/early gestation ewes were randomly selected. At each visit, fecal samples were collected from all selected animals and processed individually to measure GIN fecal egg counts (FECs). Blood samples were collected on three visits in each lambing period and processed to measure TPP and PCV. The ewes were classified into one of five production stages (maintenance [i.e. not pregnant], early or late gestation [<120. d and ≥120. d, respectively], and early or late lactation [<40. d and ≥40. d, respectively]) based on information collected during farm visits. Linear mixed models were developed for the TPP, PCV and logarithmic-transformed FEC (lnFEC). During the winter and spring lambing season, the FECs increased gradually over the gestation period and peaked during lactation, with these increases being larger in ewes with a low PCV (three-way interaction in the final model). In the autumn lambing season, the FECs started off higher in early gestation, and increased rapidly to peak in late gestation, particularly for animals with low PCV levels. In the TPP model, PCV and lnFEC were positively associated with TPP. During both autumn and winter lambing seasons, the TPP decreased from maintenance throughout gestation and early lactation, followed by an increase in late lactation, except for when there were high FECs. During the spring lambing season, TPP peaked at early gestation, and then decreased in late gestation, to increase more gradually over lactation. In the PCV model, PCV increased with TPP and decreased exponentially with increases in lnFEC. The PPER occurred during all three lambing seasons, and its magnitude and distribution varied with the lambing season, suggesting that the PPER in ewes depends on both environmental and animal physiological factors, an important consideration when implementing preventive parasite control strategies on sheep farms that practice out-of-season lambing. © 2012 Elsevier B.V.


Falzon L.C.,University of Guelph | Menzies P.I.,University of Guelph | Vanleeuwen J.,University of Prince Edward Island | Jones-Bitton A.,University of Guelph | And 4 more authors.
Small Ruminant Research | Year: 2014

This study was conducted to determine whether targeted anthelmintic treatment of peri-parturient ewes lambing in the winter, spring and/or autumn would suppress the peri-parturient egg rise (PPER) and improve 50-day lamb weights. Three farms in Ontario, Canada, that practiced out-of-season lambing were enrolled in 2010 and sampled for three consecutive lambing seasons (winter, spring and autumn). For each lambing season, all farms were visited three times. On the first visit, all ewes due to lamb that season were randomly allocated to treatment with ivermectin, fenbendazole or levamisole at the recommended dosage, or left untreated. Among these treated ewes, 40-60 animals (10-15 ewes per treatment group) were randomly selected for fecal sampling during the 3 sampling visits and processed individually to measure gastro-intestinal nematode (GIN) fecal egg counts (FECs). Ewe and lamb productivity data, including approximate 50-day lamb weights, were collected for all ewes lambing in each season, where available. A Fecal Egg Count Reduction Test was performed on all three farms to determine the ivermectin, fenbendazole and levamisole resistance status. Both farms A and B had fenbendazole resistance, while farm C had ivermectin and fenbendazole resistance; levamisole was effective on all three farms. The effect of targeted treatment on the subsequent PPER depended on the farm, possibly a partial surrogate variable for the different anthelmintic resistance levels on each farm, lambing season and sampling time-point. On farm A, during the winter and autumn lambing seasons, ivermectin and levamisole were more effective at reducing the FECs, compared to fenbendazole. In contrast, during the spring lambing season, treatment of ewes with ivermectin, fenbendazole or levamisole had no effect on the FECs. On farm B, all anthelmintic treatments were associated with a reduction in the FECs during the spring lambing season, while no reduction was observed during the winter and autumn lambing seasons. On farm C, the FECs decreased in ewes treated with levamisole in both the winter and spring lambing seasons, while ivermectin only reduced the FECs in ewes treated in the winter lambing season. Litter size was positively associated with FECs. Anthelmintic treatment was not associated with approximate 50-day lamb weights, although the power to detect significant difference was lower than anticipated due to only having relevant weight data from farm A. These results suggest that the efficacy of targeted treatment for the suppression of the PPER depends on the anthelmintics' efficacy and time of treatment in relation to the grazing period. © 2013 Elsevier B.V.


PubMed | University of Guelph and Veterinary Science and Policy
Type: Journal Article | Journal: Preventive veterinary medicine | Year: 2015

Coxiella burnetii is a zoonotic bacterium, and infection in goats with this bacterium can result in abortion, stillbirth or birth of non-viable kids. A cross-sectional study was conducted to identify the seroprevalence and risk factors for C. burnetii exposure in Ontario goats. Sera were collected between August 2010 and February 2012, and tested for C. burnetii specific antibodies using an enzyme-linked immunosorbent assay (IDEXX). Overall, 63.2% (48/76, 95% CI=51.9-73.4) of farms had one or more seropositive goats. A higher farm-level seroprevalence of 78.6% (33/42) was found on dairy goat farms, compared to 44.1% (15/34) on meat goat farms (p<0.01). At the overall individual-animal level, 32.5% (714/2195, 95% CI=30.6-34.5) of goats were seropositive. Similarly, a higher individual-level seroprevalence was identified for dairy goats (43.7%, 633/1447) compared to meat goats (10.8%, 81/748) (p<0.001). A mixed multivariable logistic model that controlled for farm-level clustering identified risk factors associated with seropositivity (p<0.05). Increases in the female herd size (logarithmic scale) were associated with increased odds of seropositivity, while increases in male herd size had a negative association with seropositivity. If other sheep or goat farms were located in a 5-km radius, goats had 5.6 times (95% CI=1.01-30.8) times the odds of seropositivity compared to those that were not. Relative to goats from farms where all kidding pen hygiene was practiced (adding bedding, removing birth materials and disinfection after kidding), goats from farms which only added bedding and removed birth materials had a higher odds of seropositivity (OR=19.3, 95% CI=1.1-330.4), as did goats from farms which practiced none of these measures (OR=161.0, 95% CI=2.4-10822.2). An interaction term revealed kidding outdoors when there were no swine on farm had a protective effect on seropositivity compared to kidding indoors, or kidding outdoors with swine on the farm. These results can inform strategies to mitigate exposure to C. burnetii in Ontario.


PubMed | University of Guelph and Veterinary Science and Policy
Type: Journal Article | Journal: Preventive veterinary medicine | Year: 2015

Coxiella burnetii is a zoonotic bacterium that can cause abortion in sheep in late gestation, as well as the delivery of stillborn, and non-viable lambs (Rodolakis, 2006). A cross-sectional study was conducted in Ontario, Canada, to investigate C. burnetii exposure in sheep. Between August 2010 and January 2012, sera from 2363 reproductively active ewes from 72 farms were tested for C. burnetii specific antibodies using the CHEKIT Q fever ELISA Test kit (IDEXX Laboratories). Overall, exposure was common; sheep-level seroprevalence was 14.7% (347/2363, 95% CI: 13.3-16.2), and was higher in dairy sheep (24.3%, 181/744) than meat sheep (10.2%, 166/1619) (p<0.0001). At the farm-level, 48.6% (35/72, 95% CI: 37.2-60.1) of farms had at least one seropositive sheep. A mixed multivariable logistic model that controlled for farm-level clustering, identified risk factors associated (p<0.05) with sheep seropositivity. Increasing female flock size (logarithmic scale) was associated with increased odds of seropositivity. By way of illustration, increasing the female flock size from 100 to 200 increased the odds of seropositivity by 2.26 times (95% CI: 1.5-3.5). Sheep that lambed in an airspace separate from the flock had 11.3 times (95% CI: 2.9-43.6) the odds of seropositivity relative to other sheep. The practice of loaning sheep that returned to the farm increased odds of seropositivity by 8.1 times (95% CI: 1.8-33.6). Lambing pen hygiene practices also influenced odds of seropositivity. Relative to sheep from farms where all lambing pen hygiene measures were practiced after lambing (i.e., adding bedding, removing birth materials and disinfection), sheep from farms that only added bedding, or those that just added bedding and removed birthing materials had 5.9 times (95% CI: 1.1-32.1) and 9.0 times (95% CI: 2.2-36.9) the odds of seropositivity, respectively. These results can be used to inform prevention and control strategies with the aim of reducing C. burnetii exposure in sheep.

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