Additional diagnoses of Echinococcus multilocularis in eastern chipmunks (Tamias striatus) from southern Ontario - results from ongoing surveillance for E. multilocularis in intermediate hosts in Ontario, Canada

Echinococcus multilocularis, a cestode with zoonotic potential, is now known to have a high prevalence in wild canid definitive hosts of southern Ontario. The distribution of E. multilocularis across this region in red foxes (Vulpes vulpes) and coyotes (Canis latrans) is widespread yet heterogenous. In contrast, confirmed diagnoses of E. multilocularis in wild free-ranging intermediate hosts within Ontario are currently limited to a single eastern chipmunk (Tamias striatus). These findings prompted ongoing surveillance efforts in intermediate host species, primarily rodents. Our report describes the results of passive surveillance through wildlife carcass submissions to the Canadian Wildlife Health Cooperative (CWHC) and targeted active sampling of small mammal species from 2018 to 2023; a second and third eastern chipmunk were found to be infected with E. multilocularis. However, these were the only occurrences from surveillance efforts which collectively totaled 510 rodents and other small mammals. Continued surveillance for E. multilocularis in intermediate hosts is of high importance in light of the recent emergence of this parasite in Ontario.

Novel molecular diagnostic (PCR) diagnosis and outcome of intestinal Echinococcus multilocularis in a dog from western Canada

OBJECTIVE

To describe the novel PCR diagnosis and outcome of intestinal Echinococcus multilocularis in a dog.

ANIMAL

A 13-month-old female intact dog with naturally occurring intestinal E multilocularis.

CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES

The 13-month-old dog initially presented with a reduced appetite and weight loss and then developed hematochezia. The clinical history included a lack of endoparasite preventive care (fecal testing, deworming), exposure to coyotes, fox, sheep, and rodents and the dog had intermittently been fed a raw food diet. Physical examination revealed a thin dog, with a 2/9 body condition score, that was otherwise clinically unremarkable. A fecal sample was submitted for screening for gastrointestinal parasites as part of an infectious disease assessment. The fecal PCR test reported detection of E multilocularis. This result was sequenced as the European haplotype E3/E4. Centrifugal flotation (same sample) did not detect taeniid eggs.

TREATMENT AND OUTCOME

The dog was treated with metronidazole, maropitant, and milbemycin oxime/praziquantel. Clinical improvement was noted within 48 hours. No DNA of E multilocularis was detected in a fecal sample collected approximately 10 days after treatment. The dog's owner was advised to provide monthly deworming (praziquantel) for all dogs on the property and to contact their human health-care provider due to potential zoonotic exposure risk.

CLINICAL RELEVANCE

Increasing detection of E multilocularis is occurring in dogs in Canada and the US. Alveolar echinococcosis can cause severe disease in dogs and humans. Fecal PCR detection and surveillance may alert practitioners to canine intestinal cases and allow dogs to serve as sentinels for human exposure risk.

Local outbreak of spontaneous pneumothorax secondary to paragonimosis in southwestern Ontario dogs

Three dogs were diagnosed with spontaneous pneumothorax and referred to the Ontario Veterinary College Health Sciences Centre for management. The 3 dogs were diagnosed with secondary spontaneous pneumothorax due to paragonimosis. The diagnosis was made by visualization of adult trematodes during surgical exploration with histopathological confirmation in 1 dog, and detection of trematode eggs via fecal sedimentation in the other 2 dogs. Two of the dogs developed unusual additional lesions, including hemoabdomen, muscle abscess, and abdominal adhesions. These were suspected to be secondary to aberrant fluke larval migration. All 3 dogs lived within a relatively small geographical area of Ontario and were hospitalized between December 2021 and March 2022. Each dog survived to discharge with surgical or medical management of the pneumothorax and treatment with a prolonged course of fenbendazole. Key clinical message: Paragonimosis should be considered as a differential diagnosis for canine spontaneous pneumothorax in areas where Paragonimus kellicotti is, or may be, endemic, or in dogs that have travelled to endemic areas - particularly if the patient has a history of cough or potential exposure to freshwater crayfish. Routine anthelmintic treatment does not prevent infection and standard fecal floatation methods may not detect the eggs. Therefore, diagnostic testing should include a fecal sedimentation test and thoracic radiographs to screen for P. kellicotti.

Factors associated with Giardia infection in dogs in southern Ontario, Canada

Information concerning risk factors associated with Giardia infection in dogs in southern Ontario, Canada, is currently lacking. This study therefore aimed to identify risk factors for Giardia infection in dogs that visit off-leash dog parks in southern Ontario. From May-November 2018, fecal samples were collected from 466 dogs in 12 off-leash dog parks in the Niagara and Hamilton regions of Ontario. A survey that asked questions pertaining to travel history (i.e., area of residence, locations and regions visited in the previous 6 months), basic medical history (i.e., spay/neuter status, veterinary visits, use of deworming medication), consumption of a raw diet, and the physical (i.e., age, sex, breed) and behavioral characteristics (i.e., off-leash activities, hunting activities) of each dog sampled was administered to the respective owner. All fecal samples were examined with the Giardia plate ELISA (IDEXX Laboratories) for parasite antigen. Multivariable logistic regression analyses were conducted on the survey data to investigate putative risk factors for Giardia infection. Overall, 11.8% (95% CI: 9.2-15.1%) of samples tested positive for Giardia antigen. Results from the multivariable logistic regression analyses identified an interaction between dog age and spay/neuter status that was significantly associated with Giardia infection. The odds of infection were greater in intact as compared to neutered adult dogs (OR: 3.6, 95% CI: 1.7-7.9, p = 0.001), and in neutered juvenile dogs as compared to neutered adults (OR: 5.2, 95% CI: 2.2-12.2, p < 0.001). The results provide veterinarians with evidence-based information for identifying dogs at greatest risk of Giardia infection in southern Ontario.

Identifying hepatic genes regulating the ovine response to gastrointestinal nematodes using RNA-Sequencing

Gastrointestinal nematode (GIN) infections are considered the most important disease of grazing sheep and due to increasing anthelmintic resistance, chemical control alone is inadequate. Resistance to Gastrointestinal nematode infection is a heritable trait, and through natural selection many sheep breeds have higher resistance. Studying the transcriptome from GIN-exposed and GIN-unexposed sheep using RNA-Sequencing technology can provide measurements of transcript levels associated with the host response to Gastrointestinal nematode infection, and these transcripts may harbor genetic markers that can be used in selective breeding programs to enhance disease resistance. The objective of this study was to compare liver transcriptomes of sheep naturally exposed to Gastrointestinal nematode s, with either high or low parasite burdens, to GIN-unexposed control sheep in order to identify key regulator genes and biological processes associated with Gastrointestinal nematode infection. Differential gene expression analysis revealed no significant differentially expressed genes (DEG) between sheep with a high or low parasite burden (p-value ≤0.01; False Discovery Rate (FDR) ≤ 0.05; and Fold-Change (FC) of > ±2). However, when compared to the control group, low parasite burden sheep showed 146 differentially expressed genes (64 upregulated and 82 downregulated in the low parasite burden group relative to the control), and high parasite burden sheep showed 159 differentially expressed genes (57 upregulated and 102 downregulated in the low parasite burden group relative to the control) (p-value ≤0.01; FDR ≤0.05; and FC of > ±2). Among these two lists of significant differentially expressed genes, 86 differentially expressed genes (34 upregulated, 52 downregulated in the parasited group relative to the control) were found in common between the two parasite burden groups compared to the control (GIN-unexposed sheep). Functional analysis of these significant 86 differentially expressed genes found upregulated genes involved in immune response and downregulated genes involved in lipid metabolism. Results of this study offer insight into the liver transcriptome during natural Gastrointestinal nematode exposure that helps provide a better understanding of the key regulator genes involved in Gastrointestinal nematode infection in sheep.

Vector-borne and other pathogens of potential relevance disseminated by relocated cats

Large populations of unowned cats constitute an animal welfare, ecological, societal and public health issue worldwide. Their relocation and homing are currently carried out in many parts of the world with the intention of relieving suffering and social problems, while contributing to ethical and humane population control in these cat populations. An understanding of an individual cat’s lifestyle and disease status by veterinary team professionals and those working with cat charities can help to prevent severe cat stress and the spread of feline pathogens, especially vector-borne pathogens, which can be overlooked in cats. In this article, we discuss the issue of relocation and homing of unowned cats from a global perspective. We also review zoonotic and non-zoonotic infectious agents of cats and give a list of practical recommendations for veterinary team professionals dealing with homing cats. Finally, we present a consensus statement consolidated at the 15th Symposium of the Companion Vector-Borne Diseases (CVBD) World Forum in 2020, ultimately to help veterinary team professionals understand the problem and the role they have in helping to prevent and manage vector-borne and other pathogens in relocated cats.

Graphical Abstract

Prevalence of intestinal parasites in dogs in southern Ontario, Canada, based on fecal samples tested using sucrose double centrifugation and Fecal Dx® tests

In southern Ontario, Canada, there is a lack of information concerning the prevalence of intestinal parasites in dogs. As such, this study aimed to characterize the prevalence of intestinal parasites in dogs visiting off-leash parks in the region using sucrose double centrifugation and Fecal Dx® tests. Additionally, data obtained via the sucrose double centrifugation method were used to evaluate the performance of the Fecal Dx® tests. Fecal samples were collected from 466 dogs aged ≥6 months from May to November 2018 (mean age = 3.7 years). Overall, eleven intestinal parasites were identified using sucrose double centrifugation. Roundworm eggs (Toxocara canis and Baylisascaris procyonis), hookworm eggs (Ancylostoma caninum and Uncinaria stenocephala), and whipworm eggs (Trichuris vulpis) were identified in 1.07% (95% confidence interval [CI] 0.38-2.56%), 5.79% (95% CI 3.85-8.31%), and 5.15% (95% CI 3.33-7.57) of samples, respectively. Using the Fecal Dx® tests, 1.07% (95% CI 0.38-2.56%), 4.29% (95% CI 2.64-6.55%), and 2.15% (95% CI 1.03-3.91) of the samples tested positive for roundworm, hookworm, and whipworm antigen, respectively. To assess the level of agreement between the Fecal Dx® tests and sucrose double centrifugation, three methods were used. Cohen's kappa indicated a fair-to-moderate level of agreement between Fecal Dx® tests and sucrose double centrifugation. In contrast, the prevalence-adjusted bias-adjusted kappa and Gwet's first-order agreement coefficient indicated almost perfect agreement between these tests, ranging from 0.87 to 0.99 among the parasites examined. This study provides valuable information on the prevalence of intestinal parasites in mature dogs in southern Ontario that will help guide parasite control recommendations for dogs in this region.

15 Differentially Expressed Long Non-coding RNA Associated with Gastrointestinal Nematode Infection in Divergent Immune Response Sheep

Gastrointestinal nematode infection is one of the major production problems for sheep producers worldwide due its high incidence, morbidity, and mortality in affected flocks. The study of long non-coding RNA (lncRNA) in liver tissue of high (HIR) and low immune responder (LIR) sheep to GINs using RNA-Sequencing technology may provide a better understanding of the gene regulation mechanism associated with the host response to the infection. The aim of this study was to identify differentially expressed (DE) lncRNA between HIR and LIR natural infested sheep and control group. Liver tissue samples from the 13 divergent animals (out of a population of 211) based on their immunoglobulin G levels after vaccination using Hen Egg White (HEW) Lysozyme, and immature abomasum worm counts [HIR (&gt; 4000) (n = 5), LIR (&lt; 1500) (n=5) and control (no parasite challenge) (n=4) groups] were used to perform transcriptomic analysis using RNA-Sequencing. The “Large Gap read mapping “and “Transcript Discovery” tools from CLC Genomics Workbench 20.0.4 (CLC Bio, Aarhus, Denmark), were used to map reads to a reference genome (Oar_rambouillet_v1.0) and transcript discovery, respectively. The FEELnc software was used to identify, from predicted transcript model, potential lncRNAs and classify those transcripts into intro putative lncRNAs and protein coding RNAs. As preliminary results, 8 and 48 DE lncRNAs for HIR and LIR compared to control group were identified, respectively using an adjusted p-value False Discovery Rate (FDR) &lt; 0.05 and Fold change (FC) abs &gt; 2. Functional analyses using the list of DE lncRNAs identified metabolic pathways related to immune function. In depth analysis will help to better understand the physiological mechanisms of resilience of high immune sheep.

Investigation of the occurrence of Angiostrongylus vasorum in coyotes in southern Ontario, Canada

In North America, the only endemic focus for Angiostrongylus vasorum (French heartworm) was historically thought to occur in the southeastern part of the island of Newfoundland. However, reports of A. vasorum infection in wild canids in West Virginia, USA, and Nova Scotia, Canada, suggest the introduction of the parasite to mainland North America. We screened for A. vasorum in coyotes from across southern Ontario. Additionally, we evaluated the performance of ELISAs for detection of circulating A. vasorum antigen (Ag-ELISA) and antibodies against A. vasorum (Ab-ELISA) designed for use in sera or blood of foxes for use with coyotes in this region. Autopsies were performed on 397 coyotes, and lung tissue extract prepared from each carcass was tested via both ELISAs. The sensitivity and specificity for both tests were estimated in the absence of a gold standard using a 2-test single population Bayesian model; sensitivity and specificity priors were based on the performance of the assays in foxes in Switzerland. Eight coyotes tested positive for A. vasorum antigen; no animal was antibody positive. The estimated sensitivity and specificity of the Ag-ELISA were 90.8% (95% credible interval [CrI]: 83.8–95.6%) and 95.5% (95% CrI: 93.4–97.2%), respectively. For the Ab-ELISA, the estimated sensitivity and specificity were 41.9% (95% CrI: 32.1–51.9%) and 98.0% (95% CrI: 96.3–99.0%), respectively. Based on these findings and negative postmortem data for the same animals, there is insufficient evidence to suggest the presence of A. vasorum in southern Ontario coyotes.

Evaluation of the prevalence of Echinococcus multilocularis in dogs that visit off-leash dog parks in southern Ontario, Canada

Prior to 2012, Echinococcus multilocularis was not known to occur in any host in Ontario, Canada. However, since that year, five cases of alveolar echinococcosis have been diagnosed in dogs that resided at the western end of Lake Ontario. In addition, E. multilocularis has been shown to be a common infection in wild canids (i.e. coyotes and foxes) across southern Ontario with a high-risk infection cluster in the area surrounding the western shores of Lake Ontario and northern shores of Lake Erie. In regions endemic for E. multilocularis, dog ownership is considered a risk factor for human alveolar echinococcosis. A study was therefore carried out to determine the prevalence of E. multilocularis intestinal infections in dogs within the high-risk infection cluster. From May to November 2018, faecal samples were collected from 477 dogs aged ≥6 months that visited 12 off-leash dog parks in the Halton, Hamilton and Niagara public health units. Faecal samples were analysed via a magnetic capture probe DNA extraction and real-time PCR method for E. multilocularis DNA. Overall, 0% (97.5% CI: 0%-0.80%) of samples tested positive. This result informs preventive recommendations for E. multilocularis infections in dogs in this region.

Spatio-temporal clustering of Baylisascaris procyonis, a zoonotic parasite, in raccoons across different landscapes in southern Ontario

Baylisascaris procyonis, the raccoon roundworm, is a parasite found throughout North America and parts of Europe. More than 150 species of mammals and birds including humans can develop neurological disease following infection with the larval stage of this parasite. To investigate whether B. procyonis infections in raccoons cluster in space, time, or space-time, we used data from 1353 Ontario raccoons submitted to the Canadian Wildlife Health Cooperative between 2013 and 2016. We identified a significant spatial cluster of increased infection prevalence in southern Ontario centered over a major metropolitan area, as well as a significant cluster of decreased infection prevalence in a primarily agricultural region in southwestern Ontario. Furthermore, we identified statistically significant temporal clusters in the fall in annual scans of data from 2014, 2015 and 2016. Examination of both Bernoulli and space-time permutation models for space-time analysis suggested that the purely spatial and temporal clusters were not explained by relatively short and spatially discrete events in space-time. The identified annual temporal clusters are consistent with previous research on the seasonality of B. procyonis infection in raccoons. Recognition of the spatial infection clusters will help identify potential geographic and anthropogenic factors associated with the occurrence of B. procyonis infection in raccoons. Given the zoonotic potential of this parasite, identification of a cluster of high infection prevalence in a major metropolitan area has implications for public education and risk management strategies.

Evaluation of the SNAP® 4Dx® plus test for the detection of Dirofilaria immitis antigen and characterization of exposure to tick-borne pathogens in wild canids in southern Ontario

Population-level surveys for Dirofilaria immitis in wild canids typically rely on identification of the parasite at necropsy. More recently, some studies have employed the use of the SNAP® 4Dx® Plus test. However, since the assay was designed for use with domestic dogs it needs to be validated for use with wild canids for accurate interpretation of results. We therefore evaluated the performance of the SNAP® 4Dx® Plus test for detection of D. immitis in wild canids in southern Ontario. Overall, 199 wild canid carcasses were collected from across the region and assessed for the presence of D. immitis parasites at necropsy; ten were infected. Lung tissue extract (LE) and thoracic fluid filter paper extract (TFE) prepared from each wild canid were tested via the SNAP® 4Dx® Plus test, which simultaneously tests for the presence of D. immitis antigen and antibodies to Borrelia burgdorferi, Anaplasma spp., and Ehrlichia spp. The prevalence adjusted bias adjusted kappa (PABAK) and Gwet's first-order-agreement coefficient (AC1) were used to assess the level of agreement between sample pairs. The PABAK and AC1 between LF and TFE applied to the SNAP® 4Dx® Plus test and the necropsy-confirmed D. immitis status indicated a very high level of agreement for all sample pairs. Compared to necropsy-confirmed D. immitis status, the estimated sensitivity and specificity of the SNAP® 4Dx® Plus test for D. immitis antigen in LE was 80 % (95 % CI 44.4-97.5%) and 98.9 % (95 % CI 96.2-99.9%), respectively. For the TFE, the sensitivity was 70 % (95 % CI 34.8-93.3%) and the specificity was 97.9 % (95 % CI 94.7-99.4%). With respect to the tick-borne pathogen components, 1.5 % (3/199; 95 % CI 0.3-4.5%) of wild canids tested positive for B. burgdorferi antibody; 1.0 % (2/199; 95 % CI 0-3.8%) of LE samples were positive and 0.5 % (1/199; 95 % CI 0-3.1%) of TFE samples were positive. No samples tested positive for antibody to Anaplasma spp. (95 % CI 0-2.3%) or Ehrlichia spp. (95 % CI 0-2.3%). Collectively, the results suggest that the SNAP® 4Dx® Plus test may be a suitable test for use with LE and TFE for the detection of D. immitis antigen in wild canids from southern Ontario.

Factors associated with Echinococcus multilocularis infection in coyotes in southern Ontario

Echinococcus multilocularis was recently reported in wild canids across southern Ontario, a newly recognized endemic area in Canada. In such areas, a comprehensive understanding of factors associated with infection in definitive hosts (wild canids) is critical for mitigating risk of transmission to humans. However, little is known about the transmission dynamics of the parasite in definitive hosts for this region. A study was therefore carried out to investigate the association of host-level (sex, body condition), environmental (southern Ontario region, land cover), temporal (season, hunting season, calendar year) and extraneous factors (submitter type) with E. multilocularis infection in coyotes in southern Ontario. Between November 2015 and March 2017, 416 coyotes were collected from across the region as part of a study that investigated the prevalence and distribution of the parasite in wild canids; approximately 24% of coyotes were positive for E. multilocularis. Associations between infection and factors of interest were assessed via a mixed-effects logistic regression model with a random intercept for submitter to account for clustering. Coyotes with poor body condition were at greater odds of E. multilocularis infection than those in good condition (odds ratio [OR] 2.14; 95% CI: 1.08-4.26; p = .030). A negative association was observed between infection in coyotes and the proportion of natural land in a coyote's estimated home range (OR: 0.67; 95% CI: 0.52-0.85; p = .001). Coyotes from the western region of southern Ontario had lower odds of infection compared to coyotes from the central region (OR: 0.26; 95% CI: 0.12-0.55; p < .001). These results can be used to help guide future public health prevention strategies for human alveolar echinococcosis.

Comparison of ITS-2 rDNA nemabiome sequencing with morphological identification to quantify gastrointestinal nematode community species composition in small ruminant feces

Mixed gastrointestinal nematode (GIN) infections are a common and significant cause of financial loss for small ruminant producers. Morphologic examination of third-stage larvae (L₃) can be used to identify species composition in feces but has limitations due to the requirement for specialized expertise and the extensive time (8-15 d depending on method used) and labour involved. Moreover, differential development and survival of larvae during coproculture to the third stage often occurs. Deep amplicon sequencing of the ITS-2 rDNA locus of first-stage larvae (L₁) allows for higher throughput with reduced specialist labour and reduces the risk of misidentification. Harvesting of L₁ soon after hatching is also faster and further reduces labour as well as biases that can occur due to differential larval development and survival. This study compares the results of morphologic examination of L₃ with those of ITS-2 rDNA deep amplicon sequencing of L₁ from a set of pooled fecal samples. The proportions of eggs that were successfully recovered as larvae following culture to L₃ and L₁ were also compared. Larval recovery rate was significantly lower from L₃ cultures than from L₁ cultures (p < 0.001); eggs were 238.7 times less likely to develop to L₃ than to L₁ (95 % confidence interval for odds ratio 80.0-712.0). Significantly lower proportions of Teladorsagia circumcincta (odds ratio = 3.1, p = 0.008) and higher proportions of Trichostrongylus spp. (p = 0.009) were identified using morphologic examination of L₃ compared with deep amplicon sequencing of L₁ on the same samples. This is consistent with previous reports of differential survival of these species in L₃ cultures. These results indicate that deep amplicon sequencing of L₁ may reduce bias introduced by differential GIN survival to L₃ in small ruminants.

DEMOGRAPHIC AND ENVIRONMENTAL FACTORS ASSOCIATED WITH BAYLISASCARIS PROCYONIS INFECTION OF RACCOONS (PROCYON LOTOR) IN ONTARIO, CANADA

The raccoon (Procyon lotor) roundworm, Baylisascaris procyonis, is an emerging wildlife zoonosis of public health significance in North America. Although the adult stage typically causes no disease in raccoons, the larval stage can cause significant disease in a variety of species, including humans. Raccoons often use human environments, which may increase the risk of B. procyonis exposure in people, particularly in urban settings. Because of this, our objectives were to identify host and environmental risk factors associated with the prevalence and intensity of B. procyonis infection in raccoons in Ontario, Canada. Between 2013 and 2016, 1,539 raccoons were collected and examined for the presence of B. procyonis. Thereafter, we analyzed our data for the influence of age, sex, fat stores, human population size, land use classification, season, and year of collection on the prevalence and intensity of infection. With multilevel logistic regression models, we identified significant associations between prevalence and host age, prevalence and amount of fat stores, and prevalence and season of collection; a significant two-way interaction was also identified between host sex and land use classification. Additionally, by using multilevel negative binomial regression models, we identified significant associations between the intensity of parasite infection and season of collection, as well as three significant two-way interactions: host sex and land use classification, host age and land use classification, and host sex and amount of fat stores. These findings help provide a more complete understanding of B. procyonis ecology in raccoons, including identifying associations between different environments and B. procyonis, which may assist in the development of future risk management strategies.

Prevalence of Baylisascaris procyonis in raccoon latrines in southern Ontario, Canada

Raccoon latrines represent sites of potential infection by the zoonotic parasite Baylisascaris procyonis for wildlife and humans. Our objective was to determine the prevalence of B. procyonis at raccoon latrine sites in southern Ontario. Thirty raccoon latrines were sampled between June - July 2018; multiple scats were collected and homogenized to form a representative sample of each latrine. To determine the presence or absence of B. procyonis eggs in each sample, we used the Cornell-Wisconsin centrifugal floatation technique. Twenty-three percent (7/30) of homogenized samples tested positive for B. procyonis. Eggs per gram of feces ranged from 1 to 388 (median = 1.28, IQR = 0.32-232.5). Baylisascaris procyonis positive latrines were found in conservation areas heavily used by people, which may represent a possible source of exposure for humans in these areas.

Prevalence and distribution of Dirofilaria immitis infection in wild canids in southern Ontario

Wild canids represent a potential reservoir host for Dirofilaria immitis infection in dogs in Ontario. Since wild canids are not protected by chemoprophylaxis, understanding the epidemiology of D. immmitis in these populations may help elucidate the background risk of infection for dogs. The aim of this study was to determine the prevalence and distribution of D. immitis infection in wild canids across southern Ontario. From February 2016 to March 2017, 290 wild canid carcasses (273 coyotes and 17 foxes) were collected from across the region and assessed for the presence of D. immitis at the time of necropsy. Overall, D. immitis infection was identified in 4.8% (95% CI 2.8-8.0%) of these wild canid carcasses. Among coyotes, 5.1% (95% CI 3.0-8.5%) were positive; no evidence of D. immitis was found in the 17 foxes. Dirofilaria immitis infections in wild canids were detected in two regions of southern Ontario: 12 of the 14 D. immitis infections were detected in the south-western region and two were detected in the eastern region. Our findings provide preliminary insights into the prevalence and geographical distribution of D. immitis in coyotes and foxes in southern Ontario.

Echinococcus multilocularis Infection, Southern Ontario, Canada

Alveolar echinococcosis, the disease caused by infection with the intermediate stage of the Echinococcus multilocularis tapeworm, is typically fatal in humans and dogs when left untreated. Since 2012, alveolar echinococcosis has been diagnosed in 5 dogs, 3 lemurs, and 1 chipmunk in southern Ontario, Canada, a region previously considered free of these tapeworms. Because of human and animal health concerns, we estimated prevalence of infection in wild canids across southern Ontario. During 2015–2017, we collected fecal samples from 460 wild canids (416 coyotes, 44 foxes) during postmortem examination and analyzed them by using a semiautomated magnetic capture probe DNA extraction and real-time PCR method for E. multilocularis DNA. Surprisingly, 23% (95% CI 20%–27%) of samples tested positive. By using a spatial scan test, we identified an infection cluster (relative risk 2.26; p = 0.002) in the western-central region of the province. The cluster encompasses areas of dense human population, suggesting zoonotic transmission.

Epidemiology of canine heartworm (Dirofilaria immitis) infection in domestic dogs in Ontario, Canada: Geographic distribution, risk factors and effects of climate

Dirofilaria immitis is the causal agent of heartworm, a mosquito-borne parasite that primarily infects domestic and wild canids. The infection is endemic in parts of Canada, and Ontario has been identified as the province where the majority of heartworm infections occur. Test results for blood samples submitted by veterinary clinics for the years 2007-2016 were used to conduct a spatial risk analysis of heartworm among domestic dogs in Ontario. The geographic extent of the apparent heartworm prevalence was examined through smoothed choropleth maps for all 49 census division regions. Furthermore, the regions were assessed for local clusters in apparent prevalence using the flexible spatial scan statistic. Three clusters were found and located in western, southern and eastern Ontario, respectively. A spatial Poisson regression model for heartworm prevalence among pet dog populations in southern Ontario census divisions was fit to determine the association between human population size, heartworm development units (HDUs), climate moisture index (CMI), precipitation and directions, east or north, with heartworm infection. The model identified the spatial distribution of HDUs and CMI as positively associated with heartworm infection and therefore important predictors of the infection. In contrast, human population size, increasing northern latitude and drier areas were negatively associated with heartworm infection. The east direction and precipitation were not significant.

Baylisascaris procyonis infection in raccoons: A review of demographic and environmental factors influencing parasite carriage

Baylisascaris procyonis, the roundworm of raccoons (Procyon lotor), is an emerging helminthic zoonosis in North America. Since the larval form is capable of causing neurological disease in more than 150 species of birds and mammals including humans, understanding factors that influence carriage of the parasite by raccoons is important for mitigating risk. This review examines the current literature to identify major demographic and environmental risk factors associated with B. procyonis carriage in wild raccoons. Raccoon age and season of sample collection were most commonly identified as risk factors, with increased prevalence found in juvenile animals and when sample collection occurred in the fall. Human urbanization and agricultural land use were also observed as potential risk factors; however, there are inconsistencies in the direction of influence these risk factors have on the prevalence of infection. Further investigation into the role of environmental risk factors is required to better understand how human activities influence parasite carriage in raccoons. Additionally, future research using multivariable statistical models guided by epidemiological principles to control for confounding variables and identify interaction effects will help clarify the effect of these demographic and environmental factors. Developing a better understanding of the primary risk factors for parasite carriage in raccoons will help identify areas of higher risk for environmental contamination and will aid in the development and refinement of education and management programs to reduce the risk of human exposure.

Prevalence of Borrelia burgdorferi, Anaplasma spp., Ehrlichia spp. and Dirofilaria immitis in Canadian dogs, 2008 to 2015: a repeat cross-sectional study

Background

Vector-borne pathogens are emerging concerns in multiple regions of Canada. Determining regional prevalence of canine vector-borne pathogens and documenting change will improve clinician awareness, enable targeted prevention, enhance diagnosis and ideally reduce the risk of disease. Study objectives were to: (i) estimate the prevalence of positive canine vector-borne test results from samples submitted in Canada; (ii) assess change in prevalence over time, from baseline (2008) to 2015; and (iii) estimate the prevalence of pathogen co-infections.

Methods

This repeat cross-sectional study evaluated 753,468 test results for D. immitis antigen and B. burgdorferi, Ehrlichia canis/ewingii/muris serology, and 753,208 test results for Anaplasma phagocytophilum/platys serology using the SNAP® 4Dx®Test and SNAP 4Dx® Plus Test.

Results

Based on all submitted samples from Canada (2008–2015), the period seroprevalence of B. burgdorferi, Ehrlichia spp., Anaplasma spp. and D. immitis antigen were 2.0%, 0.5%, 0.4% and 0.2%, respectively. Over the 7 years (2008 compared to 2015) we observed a significant increase in seroprevalence for B. burgdorferi (144.4%) and Ehrlichia spp. (150%). Co-infections (positive for two or more pathogens on a single 4 pathogen test kit) were estimated at 5.4% (1162/21,612) of total positive tests.

Conclusions

The temporal rise and geographical differences in prevalence detected for these pathogens (notably B. burgdorferi) are consistent with anecdotal information on canine illness related to tick-borne pathogen exposure in multiple regions of Canada, particularly canine Lyme disease.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3299-9) contains supplementary material, which is available to authorized users.

Echinococcus multilocularis in a wild free-living eastern chipmunk (Tamias striatus) in Southern Ontario: A case report and subsequent field study of wild small mammals

Southern Ontario has recently been identified as a risk area for Echinococcus multilocularis, based on surveys of foxes (Vulpes vulpes) and coyotes (Canis latrans) which act as definitive hosts of the parasite. In this manuscript, we describe the first detection of E. multilocularis in an eastern chipmunk (Tamias striatus) in North America. This case, submitted to the Canadian Wildlife Health Cooperative (CWHC) in August 2016 as part of ongoing wildlife disease surveillance activities, represents the first report of alveolar echinococcosis in a wild, free living, intermediate host from southern Ontario, providing further evidence of an established sylvatic cycle of E. multilocularis in this region. The finding prompted a field investigation to identify additional cases of alveolar echinococcosis in small mammals in the summer of 2017. Echinococcus multilocularis was not detected in any of the 196 small mammals submitted to the CWHC from across southern Ontario or in any of the 43 small mammals trapped in the area where the infected chipmunk was found. However, given the suspected low prevalence and patchy distribution of E. multilocularis in small mammals, our negative results do not preclude the established presence of the parasite. This case emphasizes the importance of passive surveillance networks for monitoring new and emerging diseases in wildlife populations.

Temporal trends in Giardia occurrence in the Grand River and surrounding tributaries, Waterloo, Ontario (2005-2013), a retrospective analysis of surveillance data

Giardia contamination in the Grand River Watershed (south-western Ontario, Canada) was monitored from 2005 to 2013 as part of FoodNet Canada. Our study objectives were to describe the temporal pattern of Giardia occurrence and determine whether water quality parameters and bacterial indicators could act as effective markers for Giardia occurrence. Water samples were collected monthly from the Grand River near a drinking water intake point (2005-2013) and also collected intermittently from other areas in the watershed during the study period. Samples were tested for Giardia cysts using the US EPA method 1623. Samples were also tested for chemical and microbial water quality indicators. Univariable and multivariable linear regression models were built to examine whether temporal, water quality and bacterial indicators were associated with Giardia cyst concentration. Giardia cysts were identified in 89% of samples (n = 228), with highest measured concentrations downstream of a waste water treatment plant outfall. Year and season were found to be predictors for Giardia occurrence. Concentrations were significantly higher in the winter and fall compared to the summer, and significantly higher in 2007 compared to other study years. After controlling for season, year and sampling location, dissolved oxygen was the only variable significantly associated with Giardia cyst concentration. Seasonal peaks in Giardia cyst concentrations in samples collected near the intake for the drinking water plant did not align with the seasonal peak in human Giardiasis cases in this region that are reported annually by public health authorities. This suggests that the risk of contracting Giardiasis from treated drinking water in this community is possibly low when the treatment plant is functioning adequately. Instead, waterborne exposure is likely the result of seasonal behaviours surrounding recreational water use. Therefore, the collective findings of our study are important to help inform future risk management studies and guide public health protection policies.

Canine infection with Borrelia burgdorferi, Dirofilaria immitis, Anaplasma spp. and Ehrlichia spp. in Canada, 2013-2014

BACKGROUND

Canine test results generated by veterinarians throughout Canada from 2013-2014 were evaluated to assess the geographical distribution of canine infection with Borrelia burgdorferi, Dirofilaria immitis, Ehrlichia spp., and Anaplasma spp.

METHODS

The percent positive test results of 115,636 SNAP® 4Dx® Plus tests from dogs tested were collated by province and municipality to determine the distribution of these vector-borne infections in Canada.

RESULTS

A total of 2,844/115,636 (2.5%) dogs tested positive for antibody to B. burgdorferi. In contrast, positive test results for D. immitis antigen and antibodies to Ehrlichia spp. and Anaplasma spp. were low, with less than 0.5% of dogs testing positive for any one of these three agents nationwide. Provincial seroprevalence for antibodies to B. burgdorferi ranged from 0.5% (Saskatchewan)-15.7% (Nova Scotia); the areas of highest percent positive test results were in proximity to regions in the USA considered endemic for Lyme borreliosis, including Nova Scotia (15.7%) and Eastern Ontario (5.1%). These high endemic foci, which had significantly higher percent positive test results than the rest of the nation (P < 0.0001), were surrounded by areas of moderate to low seroprevalence in New Brunswick (3.7%), Quebec (2.8%), and the rest of Ontario (0.9%), as well as northward and westward through Manitoba (2.4%) and Saskatchewan (0.5%). Insufficient results were available from the westernmost provinces, including Alberta and British Columbia, to allow analysis.

CONCLUSION

Increased surveillance of these vector-borne disease agents, especially B. burgdorferi, is important as climate, vector range, and habitat continues to change throughout Canada. Using dogs as sentinels for these pathogens can aid in recognition of the public and veterinary health threat that each pose.

Public Health Follow-up of Suspected Exposure to Echinococcus multilocularis in Southwestern Ontario

In the 3 years since the first report of canine alveolar echinococcosis (AE) in Ontario, three additional cases have been diagnosed in the province. Of the four cases reported to date, three have had no known history of travel outside the province. It is possible that this development is an indication of previously unrecognized environmental contamination with Echinococcus multilocularis eggs in some areas of the province. If so, there is the potential for an emerging threat to human health. This article describes a local public health department's investigation of the possible exposure to E. multilocularis of a number of individuals who had had contact with the latest of the four cases of canine AE, and summarizes a comprehensive decision process that can be used by public health departments to assist in the follow-up of such exposures.

Risk factors for carriage of antimicrobial-resistant Salmonella spp and Escherichia coli in pet dogs from volunteer households in Ontario, Canada, in 2005 and 2006

OBJECTIVE To determine pet-related management factors associated with the carriage of antimicrobial-resistant Salmonella spp and Escherichia coli in a population of pet dogs. SAMPLE 138 dogs from 84 households in Ontario, Canada. PROCEDURES From October 2005 through May 2006, dogs and households in Ontario, Canada, were recruited to participate in a cross-sectional study. Fecal samples were submitted for culture of Salmonella spp and E coli, which provided 515 bacterial isolates for antimicrobial susceptibility testing. Multilevel logistic regression models with random effects for household and dog were created to identify pet-related management factors associated with antimicrobial resistance. RESULTS Bacterial species, feeding a homemade diet or adding homemade food to the diet, feeding a raw diet or adding anything raw to the diet, feeding a homemade raw food diet, and feeding raw chicken in the past week were significant risk factors for antimicrobial resistance in this population of dogs. CONCLUSIONS AND CLINICAL RELEVANCE In this study, several potentially important pet-related risk factors for the carriage of antimicrobial-resistant Salmonella spp and E coli in pet dogs were identified. Further evaluation of risk factors for antimicrobial resistance in dogs may lead to development of evidence-based guidelines for safe and responsible dog ownership and management to protect the public, especially pet owners who are immunocompromised.

Macrocyclic lactone resistance in Dirofilaria immitis: Failure of heartworm preventives and investigation of genetic markers for resistance

Macrocyclic lactone (ML) endectocides are used as chemoprophylaxis for heartworm infection (Dirofilaria immitis) in dogs and cats. Claims of loss of efficacy (LOE) of ML heartworm preventives have become common in some locations in the USA. We directly tested whether resistance to MLs exists in LOE isolates of D. immitis and identified genetic markers that are correlated with, and therefore can predict ML resistance. ML controlled studies showed that LOE strains of D. immitis established infections in dogs despite chemoprophylaxis with oral ivermectin or injectable moxidectin. A whole genome approach was used to search for loci associated with the resistance phenotype. Many loci showed highly significant differences between pools of susceptible and LOE D. immitis. Based on 186 potential marker loci, Sequenom(®) SNP frequency analyses were conducted on 663 individual parasites (adult worms and microfilariae) which were phenotypically characterized as susceptible (SUS), confirmed ML treatment survivors/resistant (RES), or suspected resistant/loss of efficacy (LOE) parasites. There was a subset of SNP loci which appears to be promising markers for predicting ML resistance, including SNPs in some genes that have been associated with ML resistance in other parasites. These data provide unequivocal proof of ML resistance in D. immitis and identify genetic markers that could be used to monitor for ML resistance in heartworms.

Comparison of calculation methods used for the determination of anthelmintic resistance in sheep in a temperate continental climate

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. FECR4 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.

Evaluation of the utility of subjective clinical parameters for estimating fecal egg counts and packed cell volume in Canadian sheep flocks

A study was conducted in sheep on Canadian farms to describe the relationship between packed cell volume (PCV) or fecal egg counts (FEC) and subjective clinical parameters that may indicate the severity of parasitic gastroenteritis. Twenty-one farms in Ontario (ON) and 8 farms in Quebec (QC) were purposively selected and visited during April-May (spring) and August (summer) 2007. At each farm visit, blood and fecal samples were collected from 10 ewes and 10 female lambs; body condition score (BCS), dag score (DS), fecal consistency score (FCS) and FAMACHA score were recorded for all sampled sheep. Packed cell volume was determined for all blood samples, and FEC were performed for all fecal samples. Summary statistics and simple correlations were performed for the parameters recorded. Two mixed models with random effects at the farm level were developed; one using PCV as the response variable and another using the natural log of eggs per gram of feces (lnEPG). Finally, the residuals from both models were correlated to the covariates in the models. The mean PCV values during the spring were 29.7% and 36.7% for lambs, and 28.8% and 31.1% for ewes, in ON and QC, respectively. During the summer, the mean PCV was 32.0% and 32.8% for lambs, and 30.1% and 29.9% for ewes, in ON and QC, respectively. The arithmetic mean FEC per gram of feces (EPG) during the spring was 3 and 2 for lambs, and 1266 and 789 for ewes, in ON and QC, respectively, whereas during summer the arithmetic mean EPG was 907 and 237 for lambs, and 458 and 246 for ewes, in ON and QC, respectively. Results from simple correlations indicated that PCV was negatively correlated with lnEPG (r = -0.255; r(2) = 6.5%) and FAMACHA (r = -0.312; r(2) = 9.7%), and positively correlated with BCS (r = 0.317; r(2) = 10%). LnEPG was negatively correlated with BCS (r = -0.232; r(2) = 5.4%) and PCV (r = -0.255; r(2) = 6.5%), but positively correlated with FAMACHA (r = 0.178; r(2) = 3.2%) and DS (r = 0.086; r(2) = 0.7%). Results from the models indicated that PCV and lnEPG residuals were negatively correlated with FAMACHA, FCS and almost all categories of BCS and DS, although the correlations were very low. The main results from this study suggested that none of the subjective clinical parameters evaluated were highly correlated with PCV or lnEPG and therefore were not good predictors of lnEPG or PCV on the studied farms in Ontario and Quebec.

Knowledge, attitudes, and practices related to pet contact by immunocompromised children with cancer and immunocompetent children with diabetes

OBJECTIVE

To compare knowledge, attitudes, and risks related to pet contact in households with and without immunocompromised children.

STUDY DESIGN

A questionnaire was distributed to parents of children diagnosed with cancer (immunocompromised; n=80) or diabetes (immunocompetent; n=251) receiving care at the Children's Hospital of Eastern Ontario. Information was collected on knowledge of pets as sources of disease, concerns regarding pet-derived pathogens, and pet ownership practices. Data were analyzed with multivariable logistic regression.

RESULTS

The questionnaire was completed by 65% (214 of 331) of the individuals to whom it was given. Pet ownership was common; 45% of respondents had a household pet when their child was diagnosed, and many (households with a child with diabetes, 49%; households with a child with cancer, 20%) acquired a new pet after diagnosis. Most households that obtained a new pet had acquired a pet considered high risk for infectious disease based on species/age (diabetes, 73%; cancer, 77%). Parents of children with cancer were more likely than parents of children with diabetes to recall being asked by a physician/staff member if they owned a pet (OR, 5.9) or to recall receiving zoonotic disease information (OR, 5.3), yet these interactions were reported uncommonly (diabetes, ≤13%; cancer, ≤48%). Greater knowledge of pet-associated pathogens was associated with recalled receipt of previous education on this topic (OR, 3.9). Pet exposure outside the home was reported frequently for children in non-pet-owning households (diabetes, 48%; cancer, 25%).

CONCLUSION

Improved zoonotic disease education is needed for pet-owning and non-pet-owning households with immunocompromised children, with ongoing provision of information while the children are at increased risk of disease. Additional efforts from pediatric and veterinary healthcare professionals are required.

Pilot project to investigate over-wintering of free-living gastrointestinal nematode larvae of sheep in Ontario, Canada

This study investigated the overwintering survival and infectivity of free-living gastrointestinal nematode (GIN) stages on pasture. The presence of GIN larvae was assessed on 3 sheep farms in Ontario with a reported history of clinical haemonchosis, by collecting monthly pasture samples over the winter months of 2009/2010. The infectivity of GIN larvae on spring pastures was evaluated using 16 tracer lambs. Air and soil temperature and moisture were recorded hourly. Free-living stages of Trichostrongylus spp. and Nematodirus spp. were isolated from herbage samples. Gastrointestinal nematodes were recovered from all tracer lambs on all farms; Teladorsagia sp. was the predominant species. Very low levels of Haemonchus contortus were recovered from 1 animal on 1 farm. The results suggest that Haemonchus larvae do not survive well on pasture, while Teladorsagia sp., Trichostrongylus spp. and Nematodirus spp. are able to overwinter on pasture in Ontario and are still infective for sheep in the spring.

Paragonimosis in a cat and the temporal progression of pulmonary radiographic lesions following treatment

A 16 mo old cat presented with a 5 mo history of dyspnea, coughing, and gagging. Radiographic findings revealed seven nodules measuring 1-3 cm distributed multifocally in the lungs. Examination of feces revealed large numbers of eggs of Paragonimus kellicotti. Two fenbendazole treatment regimens (28 mg/kg per os q 12 hr for 21 days) and prednisone were required to eliminate the infection. Resolution of pulmonary nodules was monitored for 8 mo following successful treatment, and four lesions were still partially visible at 8 mo.

A systematic review and meta-analysis of factors associated with anthelmintic resistance in sheep

BACKGROUND

Anthelmintic drugs have been widely used in sheep as a cost-effective means for gastro-intestinal nematode (GIN) control. However, growing anthelmintic resistance (AHR) has created a compelling need to identify evidence-based management recommendations that reduce the risk of further development and impact of AHR.

OBJECTIVE

To identify, critically assess, and synthesize available data from primary research on factors associated with AHR in sheep.

METHODS

Publications reporting original observational or experimental research on selected factors associated with AHR in sheep GINs and published after 1974, were identified through two processes. Three electronic databases (PubMed, Agricola, CAB) and Web of Science (a collection of databases) were searched for potentially relevant publications. Additional publications were identified through consultation with experts, manual search of references of included publications and conference proceedings, and information solicited from small ruminant practitioner list-serves. Two independent investigators screened abstracts for relevance. Relevant publications were assessed for risk of systematic bias. Where sufficient data were available, random-effects Meta-Analyses (MAs) were performed to estimate the pooled Odds Ratio (OR) and 95% Confidence Intervals (CIs) of AHR for factors reported in ≥2 publications.

RESULTS

Of the 1712 abstracts screened for eligibility, 131 were deemed relevant for full publication review. Thirty publications describing 25 individual studies (15 observational studies, 7 challenge trials, and 3 controlled trials) were included in the qualitative synthesis and assessed for systematic bias. Unclear (i.e. not reported, or unable to assess) or high risk of selection bias and confounding bias was found in 93% (14/15) and 60% (9/15) of the observational studies, respectively, while unclear risk of selection bias was identified in all of the trials. Ten independent studies were included in the quantitative synthesis, and MAs were performed for five factors. Only high frequency of treatment was a significant risk factor (OR=4.39; 95% CI=1.59, 12.14), while the remaining 4 variables were marginally significant: mixed-species grazing (OR=1.63; 95% CI=0.66, 4.07); flock size (OR=1.02; 95% CI=0.97, 1.07); use of long-acting drug formulations (OR=2.85; 95% CI=0.79, 10.24); and drench-and-shift pasture management (OR=4.08; 95% CI=0.75, 22.16).

CONCLUSIONS

While there is abundant literature on the topic of AHR in sheep GINs, few studies have explicitly investigated the association between putative risk or protective factors and AHR. Consequently, several of the current recommendations on parasite management are not evidence-based. Moreover, many of the studies included in this review had a high or unclear risk of systematic bias, highlighting the need to improve study design and/or reporting of future research carried out in this field.

Hepatic alveolar hydatid disease (Echinococcus multilocularis) in a boxer dog from southern Ontario

A 2-year-old boxer dog from southern Ontario was evaluated because of acute onset lethargy. Exploratory laparotomy revealed a hemorrhagic, destructive, liver mass. Histology, immunohistochemistry, and polymerase chain reaction confirmed Echinococcus multilocularis as the cause of the hepatic mass. This constitutes the first description of endemic E. multilocularis in Ontario.

Comparison of calculation methods used for the determination of anthelmintic resistance in sheep in a temperate continental climate

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. FECR4 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.

Development of a Taenia ovis transmission model and an assessment of control strategies

The metacestode stage of the tapeworm, Taenia ovis, causes cystic lesions in the skeletal and cardiac muscle of sheep, which can result in the condemnation of the entire carcass. In recent years, Canadian farms have seen a marked increase in the number of condemnations due to T. ovis. Mathematical transmission models provide a useful tool for predicting parasite transmission and for evaluating the efficacy of potential control options. To date, no model has been developed exclusively for T. ovis. In the work described here, a compartmental, deterministic transmission model was developed to better understand the transmission dynamics of T. ovis on Canadian sheep farms. The model was intended to be practical, and represent the transmission of infection burdens in lambs that result in carcass condemnation, or transmission to canids. All transmission parameters were obtained from the literature or, when unavailable, expert opinion. The model incorporated each stage of the parasite lifecycle using the most probable transmission route on Canadian sheep farms; including definitive host (guard dogs), intermediate host (pastured lambs), and environment. Based on literature, the model performed as expected, and provided a reasonable estimate of parasite prevalence in lambs. In addition, modeling allowed the efficacy of potential control options to be evaluated and compared. Model simulations suggested that infection risk in market lambs could be eliminated through the regular treatment of guardian dogs every fifth week with an appropriate cestocide, or through eliminating carcass consumption by guardian dogs.

A cross-sectional study examining the prevalence and risk factors for anti-microbial-resistant generic Escherichia coli in domestic dogs that frequent dog parks in three cities in south-western Ontario, Canada

Anti-microbial resistance can threaten health by limiting treatment options and increasing the risk of hospitalization and severity of infection. Companion animals can shed anti-microbial-resistant bacteria that may result in the exposure of other dogs and humans to anti-microbial-resistant genes. The prevalence of anti-microbial-resistant generic Escherichia coli in the faeces of dogs that visited dog parks in south-western Ontario was examined and risk factors for shedding anti-microbial-resistant generic E. coli identified. From May to August 2009, canine faecal samples were collected at ten dog parks in three cities in south-western Ontario, Canada. Owners completed a questionnaire related to pet characteristics and management factors including recent treatment with antibiotics. Faecal samples were collected from 251 dogs, and 189 surveys were completed. Generic E. coli was isolated from 237 of the faecal samples, and up to three isolates per sample were tested for anti-microbial susceptibility. Eighty-nine percent of isolates were pan-susceptible; 82.3% of dogs shed isolates that were pan-susceptible. Multiclass resistance was detected in 7.2% of the isolates from 10.1% of the dogs. Based on multilevel multivariable logistic regression, a risk factor for the shedding of generic E. coli resistant to ampicillin was attending dog day care. Risk factors for the shedding of E. coli resistant to at least one anti-microbial included attending dog day care and being a large mixed breed dog, whereas consumption of commercial dry and home cooked diets was protective factor. In a multilevel multivariable model for the shedding of multiclass-resistant E. coli, exposure to compost and being a large mixed breed dog were risk factors, while consumption of a commercial dry diet was a sparing factor. Pet dogs are a potential reservoir of anti-microbial-resistant generic E. coli; some dog characteristics and management factors are associated with the prevalence of anti-microbial-resistant generic E. coli in dogs.

Pet husbandry and infection control practices related to zoonotic disease risks in Ontario, Canada

Background

Many human infections are transmitted through contact with animals (zoonoses), including household pets. Despite this concern, there is limited knowledge of the public’s pet husbandry and infection control practices. The objective of this study was to characterize zoonotic disease related-husbandry and infection preventive practices in pet-owning households in Ontario, Canada.

Methods

A self-administered questionnaire was distributed to individuals at two multi-physician clinics in Waterloo, Ontario, Canada during 2010. One adult from each household was invited to participate in the study.

Results

Four hundred one pet-owners completed the questionnaire. Households reported ownership of dogs (68%), cats (48%), fish (13%), exotic mammals (7%), such as hamsters, and reptiles and birds (each 6%). Across all species, individuals at higher risk of infections (i.e. < 5yrs, ≥ 65yrs, immunocompromised) were often (46-57%) present in households. Children < 16 yrs of age had close pet contact, as households reported dogs (13%) and cats (30%) usually slept in a child’s bed and dogs often licked a child’s face (24%). Household husbandry practices that increase zoonotic disease risk were frequently identified; some fed high-risk foods (i.e. raw eggs, raw meat, or raw animal product treats) to their dogs (28%) or cats (3%); 14% of reptile-owning households allowed the pet to roam through the kitchen or washed it in the kitchen sink. Reported hand washing by children was high for all species (> 76% washed hands sometimes or greater after touching the pet, its feces, or housing), although fewer reported children always washed their hands (3-57%; by species). With a few exceptions, practices were not associated with the presence of higher risk members in the household or recall of having previously received zoonotic disease education.

Conclusions

The results suggest there is a need for education on zoonotic disease prevention practices for pet-owning households with individuals at higher risk of infection and those with high-risk species (e.g., reptiles). Further research is needed to determine the role of education in altering higher risk pet practices.

Isolation of Tritrichomonas foetus from cats sampled at a cat clinic, cat shows and a humane society in southern Ontario

Tritrichomonas foetus is a protozoan parasite that has been associated with chronic diarrhea in cats. This study aimed to determine (i) the prevalence of T foetus shedding in cats from three different populations in southern Ontario, and (ii) associations between the presence of T foetus and potential cat management, health and demographic risk factors. A cross-sectional study was conducted involving 140 cats from a cat clinic in Guelph, 46 cats from a humane society in Guelph and 55 cats from two cat shows. Risk factor information was assessed through a questionnaire. The InPouch TF (feline) culture method was used to determine the presence of T foetus in all samples. Polymerase chain reaction was conducted on all samples positive by the InPouch TF, as well as 132 negative samples. The assays were interpreted in series and the prevalence of T foetus shedding and 95% confidence intervals (CI) were estimated at 0.7% (95% CI: 0.0–3.9%; n = 140) from the cat clinic, 0% (95% CI: 0.0–7.7%; n = 46) from the humane society and 23.6% (95% CI: 13.2–37.0%; n = 55) from the cat shows. ‘Attendance at cat shows’ was the only variable significant in both the univariable and multivariable analyses ( P <0.05). No significant association was found between the presence of T foetus and diarrhea at the time of sampling or having a history of diarrhea in the past 6 months. The prevalence of T foetus was highly variable among populations of cats in southern Ontario, with shedding being most common in show cats.

A longitudinal study on the effect of lambing season on the periparturient egg rise in Ontario sheep flocks

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.

Anthelmintic resistance in sheep flocks in Ontario, Canada

Gastrointestinal nematodes (GIN) are a significant constraint to pasture-based sheep production worldwide. Anthelmintic resistance (AR) has been reported in most sheep-raising areas in the world, yet little is known about the AR status in Canada. This study was conducted to determine the frequency of AR in GIN in sheep flocks in Ontario, Canada. Forty-seven sheep flocks were enrolled in the study, and their level of parasitism was monitored monthly throughout a grazing season by analyzing owner-acquired fecal samples from 15 grazing lambs per flock. When the mean GIN fecal egg count (FEC) reached a threshold of 200 eggs per gram (epg), oral ivermectin was supplied to producers to check ivermectin efficacy; the reduction in mean FEC 14 days after ivermectin treatment was calculated. 'Drench failure' was defined as a reduction in mean FEC of <95%. In those flocks with apparent drench failure, researchers performed a Fecal Egg Count Reduction Test (FECRT), dividing sheep into 4 treatment groups (n=10-15): control (i.e. untreated), ivermectin, and, if sufficient numbers of animals - fenbendazole and levamisole. AR was defined as a reduction in mean FEC <95% and a lower 95% confidence interval <90%. Larval cultures were performed on pooled post-treatment FECRT samples. Larval Development Assays (LDAs) to detect the presence of resistance to thiabendazole and levamisole were performed prior to the ivermectin drench check on pooled owner-acquired fecal samples that reached the 200 epg threshold. Approximately 89% (42/47) of the farms reached the FEC threshold of 200 epg; 93% (39/42) of these farms performed an ivermectin drench check, and 88% (34/39) of these farms had drench failure. The FECRT was performed on 29 of the 34 farms. Resistance to ivermectin, fenbendazole and levamisole was demonstrated on 97% (28/29), 95% (19/20) and 6% (1/17) of the farms tested, respectively, with considerable variability in resistance levels among farms. Haemonchus sp. was the most commonly cultured parasite from post-treatment fecal samples. LDA results for 21 farms were available; of these, 14% (3/21) and 62% (13/21) had low and high levels of thiabendazole resistance, respectively, while none of the farms exhibited resistance to levamisole. Amongst these tested farms, resistance to both ivermectin and benzimidazoles was very common. These findings strongly suggest that AR, particularly in Haemonchus sp., is a serious problem in these sheep flocks. Thus, marked changes in GIN management need to be instituted immediately to mitigate a worsening situation.

Clinical and MRI Findings in Three Dogs with Polycystic Meningiomas

One spayed female Labrador retriever and two castrated male golden retrievers were evaluated for chronic (i.e., ranging from 3 wk to 24 wk) neurologic signs localizable to the prosencephalon. Signs included seizures, circling, and behavior changes. MRI demonstrated extra-axial, contrast-enhancing, multiloculated, fluid-filled, cyst-like lesions with a mass effect, causing compression and displacement of brain parenchyma. Differential diagnoses included cystic neoplasm, abscess or other infectious cyst (e.g., alveolar hydatid cyst), or fluid-filled anomaly (e.g., arachnoid cyst). The cyst-like lesions were attached to the rostral falx cerebri in all cases. In addition, case 2 had a second polycystic mass at the caudal diencephalon. Surgical biopsy (case 3 with a single, rostral tumor via transfrontal craniectomy) and postmortem histology (in cases 1 and 2) confirmed polycystic meningiomas. Tumor types were transitional (cases 1 and 3) and fibrous (case 2), with positive immunohistochemical staining for vimentin. Case 3 was also positive for E-cadherin, s100, and CD34. In all cases, staining was predominantly negative for glial fibrillary acid protein and pancytokeratins, supporting a diagnosis of meningioma. This report describes the first cases of polycystic meningiomas in dogs. Polycystic meningiomas are a rare, but important, addition to the differential diagnoses for intracranial cyst-like lesions, significantly affecting planning for surgical resection and other therapeutic interventions.