Infection of young foals with Equine Parvovirus-Hepatitis following a fatal non-biologic case of Theiler's disease.

Theiler's disease (TD) is a (sub-)acute hepatitis in adult horses and one of the most common causes of acute hepatic failure. Recent findings indicate that equine parvovirus hepatitis (EqPV-H) likely causes TD and that its transmission occurs via iatrogenic and/or natural routes. Following the death of an EqPV-H positive mare with TD, close-contact mares and foals in the same paddock were monitored to evaluate if there was any evidence of EqPV-H. For this purpose, the serum of close contact horses was examined 6 and 42 days after the mare's death for the presence of EqPV-H DNA and changes in liver-associated serum biochemical parameters. The foals had higher EqPV-H viral loads than the mares. Apart from the mare that was euthanized, none of the horses included in this study showed signs of severe disease and nor did they have particularly elevated liver enzymes. Nucleotide sequence analysis revealed no major differences between the viral DNA detected in the serum of the dead mare and any of the in-contact horses. In conclusion, our data confirmed previous findings that horizontal transmission of EqPV-H may occur through close contact between horses.

The impact of the initial public health response to COVID-19 on swine health surveillance in Ontario.

COVID-19 restrictions and the pandemic have affected animal health and food production through the disease's effects on human activities. COVID-19 impact on swine health surveillance can be assessed by investigating submissions and test positivity for pathogens before and after COVID-19 restrictions. PRRSV, Influenza A virus, Mycoplasma hyopneumoniae and PCV-2 are considered important and economically challenging respiratory diseases for the swine populations. By reviewing test results from swine samples submitted for diagnostic testing to a regional diagnostic laboratory, and by assessing total submissions, total positive tests, and the proportion of positive tests at weekly intervals with time series techniques and generalized linear regression models, we evaluated COVID-19's impact on the monitoring of these respiratory pathogens in Ontario, Canada. We classified weeks that fell from week 12 through week 24 in each year as pandemic equivalent weeks and the non-pandemic weeks included all other weeks. The pandemic period in 2020 resulted in a significantly higher number of submissions (p < 0.05) and PRRSV positive submission counts (p < 0.05) when compared to equivalent time periods in previous years; however, no changes could be detected in the odds of weekly PRRSV submission positivity. Weekly positive proportions of PCV-2 tests were higher during the pandemic period in 2020 compared with the pandemic equivalent period in 2018 and 2017. The counts of submissions that requested tests for PRRSV, Influenza A virus and M. hyopneumonia combined, as well as the number of submissions and the proportions of submissions that tested negative for these multiple respiratory pathogens were not significantly different between the pandemic period in 2020 and other periods examined. Our findings indicate that swine producers, in conjunction with various private and public veterinary support services, continued monitoring and performing diagnostic screening on farms for economically important animal diseases despite complications resulting from COVID-19 public health restrictions. PRRSV continues to have a serious impact on swine health. The absence of an increased proportion of negative tests for individual or groups of pathogens, or an accompanying increase in submissions during the 2020 pandemic period suggests that no new undetected pathogens with an impact on respiratory signs in swine were introduced during this time.

Evaluation of 2 ELISAs to determine Borrelia burgdorferi seropositivity in horses over a 12-month period.

The blacklegged tick (Ixodes scapularis), which transmits Borrelia burgdorferi, the causative agent of Lyme disease, has undergone rapid range expansion in Ontario. In horses, Lyme disease remains an enigmatic disease, with limited understanding of the pathogenesis and many issues pertaining to selection and interpretation of laboratory tests. We evaluated B. burgdorferi seropositivity in naturally exposed horses over a 12-mo period and compared paired samples with 2 common serologic tests. Serum samples were collected in 2017, ~1 y after initial testing, from a cohort of 22 horses that were seropositive in a 2016 seroprevalence study. Samples were tested using a C6 ELISA and a multiplex ELISA targeting outer surface proteins A, C, and F. 1 y after initial testing, 14 of 22 (64%) horses remained seropositive; 7 (32%) were positive on the multiplex ELISA, 2 (9%) on C6 ELISA, and 5 (23%) on both tests. Repeatability was 100% for the C6 ELISA, and 95% for the multiplex ELISA, with no significant difference between paired sample multiplex titer values. Our results indicate strong intra-test reliability, although further investigation is required to determine the clinical significance of serologic testing.

Seroprevalence and evaluation of risk factors associated with seropositivity for Borrelia burgdorferi in Ontario horses.

BACKGROUND: Recently, the blacklegged tick (Ixodes scapularis), which is the vector of Borrelia burgdorferi, has undergone a range expansion from the northeastern and mid-west United States to areas of southeastern Canada, including parts of Ontario. Understanding the seroprevalence of antibodies against B. burgdorferi in horses and risk factors for exposure is important for monitoring and preventing this emerging disease. STUDY DESIGN: Cross-sectional study of 551 horses in southern, central, and eastern Ontario, Canada. OBJECTIVES: To assess the seroprevalence of B. burgdorferi in horses in Ontario, Canada; to evaluate risk factors associated with seropositivity; and, to compare the performance of two diagnostic tests. METHODS: Serum samples were obtained from clinically healthy horses in Ontario, Canada, along with completed questionnaires that were used for the risk factor analysis. Sera were tested with a Multiplex ELISA (Animal Health Diagnostic Center, Cornell University) and C6 ELISA (IDEXX SNAP® 4Dx® Plus test, IDEXX Laboratories). RESULTS: The seroprevalence of B. burgdorferi on at least one test was 17% (91/551), though only 15 (16%) horses tested positive with both tests. A spatial cluster of cases was detected in Eastern Ontario. The odds of being seropositive for B. burgdorferi on the C6 ELISA were significantly increased when oak trees were present by pastures (OR = 7.3 (1.8-29.2), P = .005), while the odds were significantly decreased when regular tick checks were performed (OR = 0.1 (0.01-0.7), P = 0.02). MAIN LIMITATIONS: Recruitment focused on known areas with blacklegged ticks as well as areas of higher horse density, which may have led to selection bias. CONCLUSIONS: The expansion of blacklegged tick populations poses an ongoing risk for horses. Assessment of diagnostic testing options and risk factors is important for diagnosis and prevention, and with further investigation this information may be used to propose changes in management.

The association of Equine Parvovirus-Hepatitis (EqPV-H) with cases of non-biologic-associated Theiler's disease on a farm in Ontario, Canada.

Theiler's disease was confirmed within a group horses located on a farm in southwestern Ontario during the summer and autumn of 2005. Five sudden deaths occurred between 3 July and 21 August, 2005, none of which were necropsied, however two of the horses showed clinical signs compatible with hepatic encephalopathy prior to death. No horse on the farm had received a biologic product of equine blood origin in the preceding six months. The only biologics used on the property were the administration of killed vaccines for rabies, tetanus and West Nile Virus to all horses 30 days prior to the onset of the first sudden death. Between 22 August, 2005 and 21 October, 2005, a further four horses died suddenly or were euthanized with all having a confirmed histopathologic diagnosis of acute hepatic necrosis. Serum was collected from all horses on the farm on 30 September, 2005 and this was repeated on 29 October, 2005. Equine parvovirus-hepatitis (EqPV-H) DNA was detected by quantitative-PCR in the serum of 61.8% (34/55) of the horses on the farm on either one or both sampling dates with viral loads ranging from <3.75 × 103 copies/mL to 3.64 × 107 copies/mL. EqPV-H DNA was present in serum samples of three horses with a confirmed diagnosis of Theiler's disease, five horses with subclinical liver disease, and in clinically normal in-contact horses. Subsequent phylogenetic analysis based on partial NS1 of EqPV-H revealed not only high similarity on nucleotide level within the sequenced samples but also within other previously published sequences.

Neurologic Baylisascaris procyonis infection in a young dog.

A 14-week-old female Boston terrier-cross dog with intermittent gastroenteritis and an eosinophilia developed progressive neurologic disease with ataxia progressing to uncontrolled paddling. Autopsy revealed Baylisascaris procyonis larvae in 4 of 7 brain sections, with severe eosinophilic meningoencephalitis. Diagnosis was confirmed with polymerase chain reaction (PCR) and DNA sequencing tests of fresh and paraffin-embedded brain in conjunction with the compatible histologic appearance.

Infection neurologique à Baylisascaris procyonis chez une jeune chienne. Une jeune chienne terrier de Boston de race croisée âgée de 14 semaines a été atteinte de gastroentérite intermittente et d'éosinophilie et a développé une maladie neurologique progressive avec de l'ataxie progressant à des mouvements involontaires. L'autopsie a révélé une larve de Baylisascaris procyonis dans 4 des 7 sections du cerveau, avec une méningo-encéphalite éosinophilique grave. Le diagnostic a été confirmé par amplification en chaîne par polymérase (PCR) et des tests de séquençage de l'ADN de tissus du cerveau frais et inclus dans la paraffine conjointement à l'apparence histologique compatible.(Traduit par Isabelle Vallières).

Hepatic Dicrocoelium dendriticum infection in a miniature horse.

A miniature horse which died following humane seizure from an Ontario farm was emaciated with serous atrophy of fat. Autopsy revealed hepatic atrophy and moderate periportal fibrosis. Eggs and trematodes seen in the liver were identified as Dicrocoelium dendriticum. This appears to be the first reported case of infection of equids in North America with Dicrocoelium dendriticum.

Infection parDicrocoelium dendriticumhépatique chez un cheval miniature. Un cheval miniature qui est mort à la suite d'une saisie humanitaire dans une ferme de l'Ontario était émacié et avait une atrophie séreuse des tissus adipeux. L'autopsie a révélé une atrophie hépatique et une fibrose périportale modérée. Des oeufs et des trématodes observés dans le foie ont été identifiés comme Dicrocoelium dendriticum. Il semblerait qu'il s'agit du premier cas signalé d'infection des équidés par Dicrocoelium dendriticum en Amérique du Nord.(Traduit par Isabelle Vallières).

Equid herpesvirus 9 (EHV-9) isolates from zebras in Ontario, Canada, 1989 to 2007.

The objective of this study was to identify and partially characterize 3 equid herpesviruses that were isolated postmortem from zebras in Ontario, Canada in 1989, 2002, and 2007. These 3 virus isolates were characterized by plaque morphology, restriction fragment length polymorphism (RFLP) of their genomic deoxyribonucleic acid (DNA), real-time polymerase chain reaction (PCR) assay, and sequence analyses of the full length of the glycoprotein G (gG) gene (ORF70) and a portion of the DNA polymerase gene (ORF30). The isolates were also compared to 3 reference strains of equid herpesvirus 1 (EHV-1). Using rabbit kidney cells, the plaques for the isolates from the zebras were found to be much larger in size than the EHV-1 reference strains. The RFLP patterns of the zebra viruses differed among each other and from those of the EHV-1 reference strains. Real-time PCR and sequence analysis of a portion of the DNA polymerase gene determined that the herpesvirus isolates from the zebras contained a G at nucleotide 2254 and a corresponding N at amino acid position 752, which suggested that they could be neuropathogenic EHV-1 strains. However, subsequent phylogenetic analysis of the gG gene suggested that they were EHV-9 and not EHV-1.

L'objectif de la présente étude était d'identifier et de caractériser partiellement trois herpesvirus équins isolés de zèbres décédés en Ontario, Canada en 1989, 2002, et 2007. Ces trois isolats viraux furent caractérisés par morphologie des plages de lyse, par polymorphisme de taille des fragments de restriction (RFLP) de leur ADN génomique, par épreuve de réaction d'amplification en chaîne par la polymérase (PCR) en temps réel, et analyse de la séquence de la toute la longueur du gène de la glycoprotéine G (gG) (ORF70) et une portion du gène de la polymérase de l'ADN (ORF30). Les isolats furent également comparés à trois souches de référence d'herpesvirus équin de type 1 (EHV-1). L'examen de la culture des virus sur des cellules rénales de lapin a permis de constater que les plages de lyse causées par les isolats provenant des zèbres étaient beaucoup plus grandes que celles causées par les souches de référence d'EHV-1. Les patrons de RFLP des virus de zèbres différaient entre eux ainsi que des souches de référence d'EHV-1. Les analyses par PCR en temps réel et l'analyse de séquence d'une portion du gène de la polymérase de l'ADN ont permis de déterminer que les isolats d'herpesvirus provenant de zèbres avaient un G comme nucléotide à la position 2254 et un acide aminé N correspondant à la position 752, ce qui suggère qu'il pourrait s'agir de souches neuropathogènes d'EHV-1. Toutefois, des analyses phylogénétiques subséquentes du gène gG suggèrent qu'il s'agirait plutôt d'EHV-9 et non d'EHV-1.(Traduit par Docteur Serge Messier).

The first case of porcine epidemic diarrhea in Canada.

In January, 2014, increased mortality was reported in piglets with acute diarrhea on an Ontario farm. Villus atrophy in affected piglets was confined to the small intestine. Samples of colon content were PCR-positive for porcine epidemic diarrhea virus (PEDV). Other laboratory tests did not detect significant pathogens, confirming this was the first case of PED in Canada.

Premier cas de diarrhée épidémique porcine au Canada. En janvier 2014, une mortalité accrue a été signalée chez des porcelets atteints de diarrhée aiguë dans une ferme de l'Ontario. L'atrophie des villosités chez les porcelets touchés a été confinée au petit intestin. Des échantillons du contenu du côlon étaient positifs par RCP pour le virus de la diarrhée épidémique porcine (VDEP). D'autres tests de laboratoire n'ont pas détecté d'agents pathogènes importants, ce qui confirme qu'il s'agit du premier cas de DEP au Canada.(Traduit par Isabelle Vallières).

A prospective study of sheep and goat abortion using real-time polymerase chain reaction and cut point estimation shows Coxiella burnetii and Chlamydophila abortus infection concurrently with other major pathogens.

From 2009 to 2011, 163 sheep and 96 goat abortion submissions were received at the Animal Health Laboratory, University of Guelph, Ontario, Canada, for gross and histologic examination, as well as real-time polymerase chain reaction (PCR) testing for Chlamydophila abortus and/or Coxiella burnetii. Additional testing included immunohistochemistry for Toxoplasma gondii and Chlamydophila spp., routine bacterial culture and selective culture for Campylobacter spp., examination of modified acid-fast-stained placenta smears, enzyme-linked immunosorbent assay testing for Chlamydophila spp., and virus isolation. The final diagnosis made for each case by individual pathologists, based on gross and histologic lesions, as well as ancillary testing, was used as a standard to determine the significance of C. abortus and C. burnetii infection. Coxiella burnetii was identified by real-time PCR in 113 of 163 (69.0%) and 72 of 96 (75%) sheep and goat abortion submissions, respectively, but was considered to be significant in causing abortion in only 11 of 113 (10%) sheep and 15 out of 72 (21%) goat submissions that tested positive. Chlamydophila abortus was identified by real-time PCR in 42 of 162 (26%) and 54 of 92 (59%) sheep and goat submissions, respectively, but was considered the cause of the abortion in 16 of 42 (38%) sheep and 34 of 54 (63%) goat submissions that tested positive. Optimal sensitivity and specificity cut points for the real-time PCR copy number for C. abortus and C. burnetii were determined using the final pathology diagnosis as the reference test.

Beta 2 toxigenic Clostridium perfringens type A colitis in a three-day-old foal.

Beta 2 (ß2)-toxigenic Clostridium perfringens type A was recovered in large numbers from the intestine of a neonatal foal with colitis. The foal had been treated with gentamicin. Necropsy revealed marked distension of cecum and colon with watery, rust-colored homogeneous fluid and gastric infarction. Microscopic colonic lesions were superficial necrosis of 50% of the colonic mucosal surface and scattered 1-3-mm ulcers with subjacent neutrophilic infiltration and large Gram-positive bacilli in the necrotic mucosa. Beta-2 toxin was demonstrated in the lesions by immunohistochemical staining.

The emergence of a new strain of porcine circovirus-2 in Ontario and Quebec swine and its association with severe porcine circovirus associated disease--2004-2006.

In the late fall of 2004 more severe lesions of porcine circovirus-2 associated disease (PCVAD) than usual occurred during an outbreak of porcine circovirus-2 (PCV-2) infection in Ontario nursery and grower/finisher pigs. The lesions were of unprecedented severity and included diffuse bronchointerstitial pneumonia, granulomatous enteritis, vasculitis, interstitial nephritis, and new lesions of splenic infarction. Some affected herds had up to 50% mortality. The outbreak correlated with the sudden emergence of a variant PCV-2, with PCR restriction fragment length polymorphism (RFLP) type 321. Phylogenetic comparison of ORF2 sequences and full genome sequences showed the new variant to be different from the previously dominant RFLP type 422 viruses, and similar to viruses that had occurred in France and other European and Asian countries. A subsequent retrospective study showed a statistically significant increase in the frequency of histological lesions in lymph node, spleen, lung, small intestine, colon and kidney, for pigs spontaneously infected with RFLP type 321, compared with the older RFLP type 422 strain. Viral burden, based on IHC staining in lymph node, also showed a statistically significant increase in pigs infected with the newer variant RFLP type 321, compared with the older RFLP type 422 strain. This enhanced virulence in pigs infected with PCV-2 RFLP type 321 strain may be related to the genetic differences in this new strain of PCV-2. This virus is now the dominant strain of PCV-2 virus found in Ontario and Quebec swine.

A degenerative encephalomyelopathy in 7 Kuvasz puppies.

Seven Kuvasz puppies from 2 same-parentage litters developed weakness and ataxia. Six necropsied dogs had lesions in caudate nucleus, cerebellar nuclei and folia, and spinal cord. Lesions seen were felt to be familial or due to the effects of an amprolium-induced thiamine deficiency on the developing brains of these puppies.

Bovine viral diarrhea virus in alpaca: abortion and persistent infection.

An alpaca herd in eastern Ontario experienced vague signs of illness, including anorexia and lethargy in 9 animals, 2.5 months after the addition of a chronically ill cria and his dam to the farm. Subsequently 2 alpaca had early pregnancy loss; one aborted at 5.5 months gestation and the other at 7 months gestation. Seventeen were found to have serum antibody to bovine viral diarrhea virus (BVDV), with highest titers to BVDV type 1. The fetus that was aborted at 5.5 months gestation, 3 months after the clinical outbreak, was found to be positive for BVDV on immunohistochemical staining, and noncytopathic BVDV type 1b was isolated. Of the 13 cria born alive that season, a single male underweight alpaca cria, born 9 months after the clinical illnesses, was infected with BVDV type 1b. The cria was positive for BVDV at birth, at 3 and 26 days of age and continued to be positive for noncytopathic BVDV using virus isolation, nested reverse transcription PCR, antigen detection ELISA, and immunohistochemical staining until euthanasia at 46 days of age. The cria remained serum antibody negative to both BVDV type 1 and type 2. A diagnosis of persistent infection was made. This is the first report describing persistent infection with BVDV in an alpaca cria.