Canine Respiratory Disease Research Articles

Canine respiratory disease outbreak involving canine pneumovirus at an American animal shelter

AbstractAn outbreak of canine infectious respiratory disease complex was attributed to canine pneumovirus in a municipal animal shelter in the northeastern United States. The outbreak comprised eight fatalities and over 100 cases in dogs of all signalments. Cases were characterised by mild to severe signs indicating upper airway, lower airway, and systemic involvement. Nasopharyngeal samples submitted to one commercial and one university laboratory for quantitative polymerase chain reaction testing revealed several canine infectious respiratory disease complex pathogens. However, only the university lab detected canine pneumovirus: multiple nasopharyngeal and lung samples tested positive. Vaccination status, lack of response to antimicrobials, and improvement after implementation of canine infectious respiratory disease outbreak management strategies tailored to canine pneumovirus characteristics indicate substantial involvement of this virus. The outbreak resolved within 1 month of adherence to clean break procedures, limitation of incoming dogs, and deep clean of the premises. This case highlights the difficulty in reliably detecting canine pneumovirus and how population management deficits permit canine infectious respiratory disease complex outbreaks.

Canine bufavirus (Carnivore protoparvovirus-3) infection in dogs with respiratory disease.

Canine bufavirus (CBuV) or Carnivore protoparvovirus-3, a nonenveloped DNA virus belonging to the genus Protoparvovirus, family Parvoviridae, has been identified in dogs with respiratory and enteric diseases. Although CBuV detection has been reported in multiple countries, descriptions of pathologic findings associated with infection have not yet been provided. In this study, the authors necropsied 14 dogs (12 puppies and 2 adult dogs) from a breeding colony that died during multiple outbreaks of respiratory diseases. Postmortem investigations revealed extensive bronchointerstitial pneumonia with segmental type II pneumocyte hyperplasia in all necropsied puppies but less severe lesions in adults. With negative results of common pathogen detection by ancillary testing, CBuV DNA was identified in all investigated dogs using a polymerase chain reaction (PCR). Quantitative PCR demonstrated CBuV DNA in several tissues, and in situ hybridization (ISH) indicated CBuV tissue localization in the lung, tracheobronchial lymph node, and spinal cord, suggesting hematogenous spread. Dual CBuV ISH and cellular-specific immunohistochemistry were used to determine the cellular tropism of the virus in the lung and tracheobronchial lymph node, demonstrating viral localization in various cell types, including B-cells, macrophages, and type II pneumocytes, but not T-cells. Three complete CBuV sequences were successfully characterized and revealed that they clustered with the CBuV sequences obtained from dogs with respiratory disease in Hungary. No additional cases were identified in small numbers of healthy dogs. Although association of the bufavirus with enteric disease remains to be determined, a contributory role of CBuV in canine respiratory disease is possible.

In Vitro Characteristics of Canine Primary Tracheal Epithelial Cells Maintained at an Air–Liquid Interface Compared to In Vivo Morphology

Culturing respiratory epithelial cells at an air-liquid interface (ALI) represents an established method for studies on infection or toxicology by the generation of an in vivo-like respiratory tract epithelial cellular layer. Although primary respiratory cells from a variety of animals have been cultured, an in-depth characterization of canine tracheal ALI cultures is lacking despite the fact that canines are a highly relevant animal species susceptible to various respiratory agents, including zoonotic pathogens such as severe acute respiratory coronavirus 2 (SARS-CoV-2). In this study, canine primary tracheal epithelial cells were cultured under ALI conditions for four weeks, and their development was characterized during the entire culture period. Light and electron microscopy were performed to evaluate cell morphology in correlation with the immunohistological expression profile. The formation of tight junctions was confirmed using transepithelial electrical resistance (TEER) measurements and immunofluorescence staining for the junctional protein ZO-1. After 21 days of culture at the ALI, a columnar epithelium containing basal, ciliated and goblet cells was seen, resembling native canine tracheal samples. However, cilia formation, goblet cell distribution and epithelial thickness differed significantly from the native tissue. Despite this limitation, tracheal ALI cultures could be used to investigate the pathomorphological interactions of canine respiratory diseases and zoonotic agents.

Retrospective study of 1050 dogs with respiratory symptoms in Japan (2005-2020).

Few studies have investigated the incidence of respiratory diseases based on anatomical sites or the relationship between breed and these diseases. The objective of this study was to investigate the prevalence of canine respiratory diseases among dogs in Japan, with relationship to the breed. We retrospectively reviewed the medical records of dogs with respiratory symptoms and calculated the odds ratio (OR) to evaluate the relationship between breed and disease. A total of 1050 dogs with respiratory symptoms were included in this study. Miniature dachshunds were the most common breed affected by respiratory diseases. Among tracheobronchial diseases, there was a significant association between some small breeds and tracheobronchial collapse, miniature dachshunds (OR: 4.44, 8.43, 95% confidence interval [CI]: 3.17-6.22, 4.33-16.0) and chronic bronchitis and bronchiectasis. Among nasal diseases, miniature dachshunds (OR: 27.2, 95% CI: 16.8-44.8) and golden retrievers (OR: 21.0, 95% CI: 6.43-69.3) were the most affected by non-infectious rhinitis and nasal aspergillosis, respectively. Brachycephalic obstructive airway syndrome was the most common disease among pharyngeal and laryngeal diseases, with a relationship with breed being found in some brachycephalic breeds, and Pomeranians (OR: 2.7, 95% CI: 1.42-5.17). Respiratory diseases in dogs are strongly correlated with popular breeds in Japan. Miniature dachshunds, in particular, are associated with many respiratory diseases, which may differ from international reports. Thus, this result may help in the early detection, prevention, treatment, and elucidation of the pathophysiology of canine respiratory diseases.

Epidemiology, genetic diversity, and association of canine circovirus infection in dogs with respiratory disease

Although canine circovirus (CanineCV)-associated with gastroenteritis has been well documented, the virus is also detectable in the respiratory discharge of dogs with respiratory disease. In this study, an epidemiological approach was used to explore the association between the presence of CanineCV and respiratory symptoms in dogs. Respiratory swabs were collected from 76 healthy dogs and 114 dogs with respiratory illness and tested for CanineCV using conventional PCR (cPCR). Furthermore, lung tissues collected from 15 necropsied dogs showing pneumonia were tested using the real-time PCR (qPCR) and in situ hybridization (ISH) technique. A total of 8.95% (17/190) of dogs were CanineCV positive, with a significant association (p = 0.013) in dogs with respiratory signs. Four necropsied dogs were qPCR positive with the CanineCV-DNA labeling localized in tracheobronchial lymphoid cells (3/4), pulmonary parenchyma, capillary endothelia, and mononuclear cells harboring in alveoli (2/4). Full-length genome sequences of seven CanineCV strains were analyzed, indicating that the detected CanineCV genome clustered in the CanineCV-4 genotype. Genetic recombination was also evident in the replicase (Rep) gene. Although the role of CanineCV primarily affecting lung lesions could not be determined from this study, the presence of CanineCV DNA in pulmonary-associated cells indicated the potential association of the virus with canine respiratory disease; thus, linking causality must be examined in further studies.

Assessment of Nasal Structure Using CT Imaging of Brachycephalic Dog Breeds.

Simple SummaryFrench bulldogs and pugs are classified as brachycephalic dogs and are characterized by short, stenotic noses. The outward characteristics of this breed can cause dyspnea, which may be surgically improved. However, brachycephalic dog breeds have different rates of disease progression and response to treatment. We hypothesized that this difference was due to the difference in the structure of the nasal cavity. To verify this, the ratio of the airway cross-sectional area to the total nasal cavity area was compared between the three brachycephalic dog breeds using head computed tomography (CT) images. The results revealed that the distribution of narrow and wide airway locations in the nasal cavity differed among the breeds. The method used in this study was suitable for observing and evaluating canine nasal structures. These results provide a new approach for the diagnosis of canine respiratory diseases and improve our understanding of the pathogenesis of brachycephalic dogs.The response to treatment of brachycephalic airway syndrome (BAS) varies among brachycephalic dog breeds. We hypothesized that variations in nasal structure are one of the factors responsible for this difference. To confirm this variation, we measured the ratio of the airway cross-sectional area to the total nasal cavity area (AA/NC) in three brachycephalic dog breeds. Head CT images of French bulldogs, shih tzus, and pugs were retrospectively collected. Four specific transverse planes were used to calculate AA/NC ratios. Fifty brachycephalic dogs were included in the study: French bulldogs (n = 20), shih tzus (n = 20), and pugs (n = 10). The AA/NC ratio of Shih Tzus was larger in the rostral nasal cavity and smaller toward the caudal area, whereas the other two breeds showed an inverse tendency. The results obtained from the current research indicate that the AA/NC ratio can be used to evaluate the structure of the nasal cavity. Moreover, analyzing the point with the smallest AA/NC ratio can be useful in quantifying nasal airway obstruction and the severity of BAS. These results will be useful in understanding the complexity of BAS pathophysiology and in the implementation of treatment.

Characterization of Canine Influenza Virus A (H3N2) Circulating in Dogs in China from 2016 to 2018.

Avian H3N2 influenza virus follows cross-host transmission and has spread among dogs in Asia since 2005. After 2015–2016, a new H3N2 subtype canine influenza epidemic occurred in dogs in North America and Asia. The disease prevalence was assessed by virological and serological surveillance in dogs in China. Herein, five H3N2 canine influenza virus (CIV) strains were isolated from 1185 Chinese canine respiratory disease samples in 2017–2018; these strains were on the evolutionary branch of the North American CIVs after 2016 and genetically far from the classical canine H3N2 strain discovered in China before 2016. Serological surveillance showed an HI antibody positive rate of 6.68%. H3N2 was prevalent in the coastal areas and northeastern regions of China. In 2018, it became the primary epidemic strain in the country. The QK01 strain of H3N2 showed high efficiency in transmission among dogs through respiratory droplets. Nevertheless, the virus only replicated in the upper respiratory tract and exhibited low pathogenicity in mice. Furthermore, highly efficient transmission by direct contact other than respiratory droplet transmission was found in a guinea pig model. The low-level replication in avian species other than ducks could not facilitate contact and airborne transmission in chickens. The current results indicated that a novel H3N2 virus has become a predominant epidemic strain in dogs in China since 2016 and acquired highly efficient transmissibility but could not be replicated in avian species. Thus, further monitoring is required for designing optimal immunoprophylactic tools for dogs and estimating the zoonotic risk of CIV in China.

Intake Vaccinations Reduced Signs of Canine Respiratory Disease During an Outbreak at an Animal Shelter.

Animal shelters provide an ideal environment for the spread of disease. Dogs are often housed in close quarters with others of unknown vaccine histories, and experience high levels of sustained stress. As a result, Canine Infection Respiratory Disease (CIRD) is often prevalent and difficult to control. The aims of this study were to (1) identify specific pathogens responsible for CIRD in a city shelter in West Texas, USA, and (2) determine whether intake vaccinations decrease proportion of dogs exhibiting signs of CIRD even during an outbreak. A laboratory analysis of conjunctival, pharyngeal, and nasal swabs (n = 15 dogs) and fecal samples (n = 6 kennels) showed prevalence of various CIRD pathogens (e.g., canine adenovirus-2, canine parainfluenza virus, canine distemper virus). All fifteen dogs tested positive for at least one pathogen, with the most prevalent pathogen being Canine Distemper Virus (CDV; n = 12). All of the kennels (n=6) tested positive for Canine Distemper Virus. Health data on dogs (n = 1,258) over the age of 6 weeks were assessed from May to August 2017. Beginning in July, both stray and owner-surrendered dogs were vaccinated with Nobivac® Canine 1-DAPPv 5 Way and Nobivac® Intra-Trac® 3 upon intake, which differed from the previous policy. For each day in the study, we calculated the proportion of dogs in each nasal discharge category, the proportion of dogs observed coughing, and the mean fecal score across all dogs. We conducted a linear regression between the proportion of the shelter vaccinated and the proportion of dogs coughing. At the beginning of the vaccination phase, ~25% of the dogs were coughing. However, as the proportion of the dogs vaccinated increased, the proportion of dogs coughing decreased. There was a significant decrease of 7% of the proportion of dogs coughing when vaccination was at least at 90% compared to when it was <90%. These data suggest that the shelter in this study was experiencing a CIRD outbreak, with CDV being primary pathogen, and that it is possible to substantially reduce illness by implementing a vaccination on intake protocol. The current study provides support for the importance of vaccination in animal shelter welfare.

Pathology and bronchoalveolar lavage fluid cellular and oxidative stress changes in canine pneumonia in Nigeria

Studies on canine respiratory diseases are scant in the literature especially in Africa, unlike the situation on ruminants. This study is on the pathology and bronchoalveolar cellular and oxidative stress changes in naturally occurring canine pneumonia in Nigeria. The dogs used were collected from cases submitted for necropsy in the institutional Department of Veterinary Pathology. Gross examination, bronchoalveolar lavage (BAL) cytology, oxidative biochemical assay of BAL fluid (BALf) supernatant and histology of sections from all the lung lobes were done using standard procedures. Grossly, 22 (31%) were normal while 48 (69%) were congested, haemorrhagic and/or pneumonic out of the 70 canine lungs examined. Microscopically, there were pulmonary congestion (4%), pulmonary oedema (20%), pulmonary haemorrhages (7%), atelectasis (4%), interstitial pneumonia (10%), bronchointerstitial pneumonia (14%) and bronchopneumonia (9%). The BALf cytology of pneumonic lungs showed increases in neutrophils, alveolar macrophages, lymphocytes and haemosiderophages including free and phagocytosed bacteria, and fungal hyphae. Glutathione peroxidase (GPx) and glutathione transferase (GST) activities increased in congested and bronchointerstitial pneumonic lungs but were reduced in other pneumonic lungs. The superoxide dismutase (SOD) activity was significantly reduced in the pneumonic canine lungs. Hydrogen peroxide generation increased in congestion and oedema, bronchopneumonia and bronchointerstitial pneumonia. Malondialdehyde (MDA) level increased in other congested and pneumonic lungs. There was also significant positive correlation of BALf pro-oxidant assay to the type and severity of pneumonia (+ 0.75, P < 0.05). Pneumonias account for 57.2% of the respiratory conditions of which bronchointerstitial and interstitial pneumonias are the prevalent types. The study also showed that oxidative stress markers in BALf may serve as predictors of pneumonia especially in the early stages. Since treatment recommendations for pneumonia often centre primarily on supportive care and anti-oxidant and antibiotic administration, further studies on causal agents, treatment and prevention strategies for canine pneumonia in Nigeria are warranted.

Nasal virome of dogs with respiratory infection signs include novel taupapillomaviruses.

Using viral metagenomics, we characterized the mammalian virome of nasal swabs from 57 dogs with unexplained signs of respiratory infection showing mostly negative results using the IDEXX Canine Respiratory Disease RealPCR™ Panel. We identified canine parainfluenza virus 5, canine respiratory coronavirus, carnivore bocaparvovirus 3, canine circovirus and canine papillomavirus 9. Novel canine taupapillomaviruses (CPV21-23) were also identified in 3 dogs and their complete genome sequenced showing L1 nucleotide identity ranging from 68.4 to 70.3% to their closest taupapillomavirus relative. Taupapillomavirus were the only mammalian viral nucleic acids detected in two affected dogs, while a third dog was coinfected with low levels of canine parainfluenza 5. A role for these taupapillomavirues in canine respiratory disease remains to be determined.Electronic supplementary materialThe online version of this article (10.1007/s11262-019-01634-6) contains supplementary material, which is available to authorized users.

Study on canine respiratory disease and evaluating the effect of treatment at the Animal Clinic, Can Tho University

The research was carried out to investigate the clinical diagnosis in dogs with respiratory tract disease and evaluate the treatment effect in the Animal Clinic of Can Tho University. The determination of respiratory tract disease in dogs was performed by cross-sectional study in 736 dogs that reared in Cantho city. The results showed that 143 out of 736 (19.43%) dogs had signs of respiratory tract disease by the clinical diagnosis. In addition, the respiratory tract disease in dogs was age-, breeds- and rearing modality-; and gradually increased according to age of dogs (P0.05). The results indicated that dogs had the clinical diagnosis in the upper airways (79.72%) and lower airways (20.28%). Cough combined nasal discharge at the highest rate (18.18%), followed by cough combined nasal discharge and eye rheum (13.99%), increase of respiratory rhythm (13.29%), cough combined nasal discharge and increase of respiratory rhythm (10.49%), nasal discharge combined eye rheum (10.49%), cough combined nasal discharge and rales (9.79%), cough combined rales and depression (6.99%), dry cough (6.29%), cough combined increase of respiratory rhythm and depression (5.59%), nosebleed (2.80%) and nosebleed combined increase of respiratory rhythm (2.10%). The effectiveness of treatment using Marbofloxacin and Cefuroxime was similar; and the adjustment for base clinical signs of the respiratory tract disease was high or rich in both treatments with Marbofloxacin and Cefuroxime.

The detection and differentiation of canine respiratory pathogens using oligonucleotide microarrays

Canine respiratory diseases are commonly seen in dogs along with co-infections with multiple respiratory pathogens, including viruses and bacteria. Virus infections in even vaccinated dogs were also reported. The clinical signs caused by different respiratory etiological agents are similar, which makes differential diagnosis imperative. An oligonucleotide microarray system was developed in this study. The wild type and vaccine strains of canine distemper virus (CDV), influenza virus, canine herpesvirus (CHV), Bordetella bronchiseptica and Mycoplasma cynos were detected and differentiated simultaneously on a microarray chip. The detection limit is 10, 10, 100, 50 and 50 copy numbers for CDV, influenza virus, CHV, B. bronchiseptica and M. cynos, respectively. The clinical test results of nasal swab samples showed that the microarray had remarkably better efficacy than the multiplex PCR-agarose gel method. The positive detection rate of microarray and agarose gel was 59.0% (n=33) and 41.1% (n=23) among the 56 samples, respectively. CDV vaccine strain and pathogen co-infections were further demonstrated by the microarray but not by the multiplex PCR-agarose gel. The oligonucleotide microarray provides a highly efficient diagnosis alternative that could be applied to clinical usage, greatly assisting in disease therapy and control.

Crenosoma vulpis in wild and domestic carnivores from Italy: a morphological and molecular study.

Crenosoma vulpis is a metastrongyloid nematode primarily associated with respiratory tract infections of red foxes in North America and Europe. Sporadic cases have also been reported in domestic dogs. The present study aimed to provide morphological, molecular, and epidemiological data on the geographical distribution of this nematode throughout Italy. From 2012 to 2014, 12 of the 138 foxes examined, three dogs and one badger scored positive for C. vulpis. Forty adults were isolated from foxes and the badger, whereas first-stage larvae were detected in the three dogs. All specimens were morphologically identified as C. vulpis, and 28 nematodes were also molecularly characterized by sequencing mitochondrial (12S ribosomal DNA (rDNA)) and nuclear (18S rDNA) ribosomal genes. Four haplotypes were identified based on the 12S rDNA target gene, with the most representative (78.5%) designated as haplotype I. No genetic variability was detected for the 18S rDNA gene. The molecular identification was consistent with the distinct separation of species-specific clades inferred by the phylogenetic analyses of both mitochondrial and ribosomal genes. Data herein reported indicates that C. vulpis has a wide distribution in foxes from southern Italy, and it also occurs in dogs from southern and northern regions of the country. Practitioners should consider the occurrence of this nematode in the differential diagnosis of canine respiratory disease, particularly in dogs living close to rural areas where foxes are present.

The Focused Scientific Sessions and Abstracts in Montreal

Experimental Disease: Featured speakers will comment on mouse models of human breast cancer, microbial provocation and susceptibility to gastrointestinal inflammation, host–bacterial interactions in inflammatory bowel disease, and characterization of attaching and effacing E. coli in pigs. Natural Disease: Featured speakers will comment on Beluga whales from the local St Lawrence estuary, bovine neonatal pancytopenia, and canine respiratory disease complex. Industrial and Toxicological Pathology: Featured speakers will comment on Alzheimer disease and novel biomarkers of skeletal muscle, reproductive pathology in nonclinical safety assessment, and genomic and mechanistic insights in druginduced vascular injury in rats. Posters will be on display throughout the meeting. Poster presenters may be available by their presentation during the refreshment breaks corresponding with the platform sessions of the same topic. This exchange is always well received because it is a dedicated time to meet the folks behind our science and to talk pathology with colleagues. It has been a great year for the Focused Scientific Sessions Committees—thanks to the large number of quality abstracts submitted for the meeting. There is a little something for everyone in the diverse and enlightening program. I am looking forward to at errific meeting, inat errific venue, and Ih ope to see as many of you there as possible. I also want to extend special thanks to Focused Session Chairs, their committees, and the ACVP administrative staff who truly make it all happen.

Isolation and characterization of bacteria from canine respiratory diseases in and around Hyderabad city, Andhra Pradesh, India

Aim: To identify the organisms causing respiratory diseases in dogs that belongs to areas in and around Hyderabad city. Materials and Methods: Nasal samples were collected using sterile swabs from the canine clinical cases that were presented with the history of respiratory diseases at the University administered Veterinary Hospital, Bhoiguda, Secunderabad and Campus Veterinary Hospital, College of Veterinary Science, Rajendranagar, Hyderabad over a period of 26 months i.e., from October 2008 to November 2010. Clinical signs included coughing, nasal discharge, sneezing, difficulty in breathing, fever, loss of appetite and lethargic behavior. Nasal swabs were immediately transferred, aseptically, into a nutrient broth and were subjected to various cultural tests and microscopic examination. Results: Out of 90 nasal samples, different species of bacteria were isolated. Results from our bacterial culture, microscopic and biochemical studies of the nasal discharges collected from dogs suffering with respiratory diseases revealed various bacteria such as E. coli, Klebsiella spp, Streptococci spp. Staphylococci and mixed infections. Conclusion: This study revealed that the bacteria such as E. coli, Klebsiella spp, Streptococci spp. Staphylococci and mixed infections are the common causative agents that lead to respiratory diseases in dogs belonging to areas in and around Hyderabad city.

Serum and Bronchoalveolar Lavage Fluid Endothelin‐1 Concentrations as Diagnostic Biomarkers of Canine Idiopathic Pulmonary Fibrosis

Diagnosis of canine idiopathic pulmonary fibrosis (IPF) is challenging. Endothelin-1 (ET1) is a biomarker of IPF in humans, but whether ET1 can detect and differentiate IPF from other canine respiratory diseases is unknown. To evaluate whether measurement of the concentration of ET1 in serum and bronchoalveolar lavage fluid (BALF) can be used to distinguish canine IPF from chronic bronchitis (CB) and eosinophilic bronchopneumopathy (EBP). Twelve dogs with IPF, 10 dogs with CB, 6 dogs with EBP, 13 privately owned healthy West Highland White Terriers (WHWT), and 9 healthy Beagle dogs. Prospective, case control study. ET1 concentration was determined by ELISA in serum and in BALF. No significant difference in serum ET1 concentration was detected between healthy Beagle dogs and WHWT. Serum ET1 concentration was higher in dogs with IPF (median interquartile range; 2.32 pg/mL, 2.05-3.38) than healthy Beagle dogs (1.28, 1.07-1.53; P < .001), healthy WHWT (1.56, 1.25-1.85; P < .001), dogs with EBP (0.94 0.68-1.01; P = .001), and dogs with CB (1.54 0.74-1.82; P = .005). BALF ET1 concentration was below the detection limit in healthy WHWT and in dogs with CB, whereas it was measurable in all dogs with IPF. A cut-off serum concentration of 1.8 pg/mL had a sensitivity of 100% and a specificity of 81.2% for detection of IPF, with an area under the receiver operating characteristic curve of 0.818. Serum ET1 can differentiate dogs with IPF from dogs with EBP or CB. ET1 can be detected in BALF of dogs with IPF.

Management of 13 cases of canine respiratory disease using inhaled corticosteroids

To determine the value of inhaled corticosteroids in the management of chronic inflammatory airway disease in dogs. Medical records of dogs that were presented for the investigation of respiratory disease were reviewed retrospectively. Criteria for inclusion were knowledge of previous medical treatment including side effects, diagnosis of the underlying disease, use of inhaled corticosteroids and at least two-months follow-up data. Thirteen dogs that fulfilled the criteria were identified. Ten dogs were diagnosed with chronic bronchitis and three with eosinophilic bronchopneumopathy. Four dogs had not previously received corticosteroid treatment for their respiratory disease, and all these showed a reduction or a resolution of clinical signs without obvious side effects after inhaled corticosteroid therapy. Nine dogs had previously received oral or parenteral corticosteroids for treatment of their respiratory disease, and all had exhibited side effects. Five of these dogs were treated with inhaled corticosteroids alone, and all exhibited an improvement in clinical signs without observable side effects. The remaining four dogs were treated with a combination of inhaled and oral corticosteroids, and all showed improvement in clinical signs and reduction in side effects. Inhaled medication was well tolerated in all dogs. Inhaled corticosteroids were used for the management of chronic bronchitis and eosinophilic bronchopneumopathy in 13 dogs, and these may have the advantage of reducing side effects associated with oral corticosteroids.

Immunohistochemical Detection of Antigens of Distemper, Adenovirus and Parainfluenza Viruses in Domestic Dogs with Pneumonia

The lungs of 35 dogs that died in Mexico from acute or subacute pneumonia were examined immunohistochemically for canine distemper virus (CDV), canine adenovirus (CAV) and canine parainfluenza virus (CpiV), to determine their frequency and occurrence and possible associations. CDV was identified in 27 (77%) cases, CAV in 20 (57%) and CpiV in 18 (51%). The most frequent dual association was that between CDV and CpiV (five cases; 14%). All three viruses, however, were identified in the same lung in 10 cases. Immunolabelling occurred in alveolar macrophages, monocytes, pneumocytes, epithelial cells and syncytial cells. It was concluded that immunohistochemistry is a useful diagnostic tool in canine respiratory disease to complement histopathological examination.

Longitudinal study of viruses associated with canine infectious respiratory disease.

In this investigation a population of dogs at a rehoming center was monitored over a period of 2 years. Despite regular vaccination of incoming dogs against distemper, canine adenovirus type 2 (CAV-2), and canine parainfluenza virus (CPIV), respiratory disease was endemic. Tissue samples from the respiratory tract as well as paired serum samples were collected for analysis. The development of PCR assays for the detection of CPIV, canine adenovirus types 1 and 2, and canine herpesvirus (CHV) is described. Surprisingly, canine adenovirus was not detected in samples from this population, whereas 19.4% of tracheal and 10.4% of lung samples were positive for CPIV and 12.8% of tracheal and 9.6% of lung samples were positive for CHV. As reported previously, a novel canine respiratory coronavirus (CRCoV) was detected in this population (K. Erles, C. Toomey, H. W. Brooks, and J. Brownlie, Virology 310:216-223, 2003). Infections with CRCoV occurred mostly during the first week of a dog's stay at the kennel, whereas CPIV and CHV were detected at later time points. Furthermore, the evaluation of an enzyme-linked immunosorbent assay for detection of antibodies to CPIV and an immunofluorescence assay for detection of antibodies to CHV is described. This study shows that CPIV is present at kennels despite vaccination. In addition, other agents such as CHV and CRCoV may play a role in the pathogenesis of canine respiratory disease, whereas CAV-2 and canine distemper virus were not present in this population, indicating that their prevalence in the United Kingdom is low due to widespread vaccination of dogs.

MYP02 Mycoplasma genetic and phenotypic intrastrain variation correlates with the outcome of canine respiratory disease

The behavioral manifestations of autism, including reduced sociability (reduced tendency to seek social interaction), may be related to underdevelopment of the corpus callosum (CC). The BALB/cJ inbred mouse strain is a useful model system for testing the relationship between reduced sociability and CC underdevelopment. BALB/cJ mice show low levels of sociability, on average, but substantial intrastrain variability in sociability, as well as striking variability in CC development. This study tested the hypothesis that sociability is positively correlated with CC size within the BALB/cJ inbred strain. 30-day-old BALB/cJ and C57BL/6J mice were tested for sociability towards gonadectomized A/J stimulus mice in a social choice task. The size of the corpus callosum was measured histologically at the midsagittal plane. BALB/cJ mice showed a significant positive correlation between the tendency to sniff the stimulus mouse and size of the CC relative to brain weight. C57BL/6J mice showed consistently high levels of sociability and normal corpus callosum development. These results suggest that abnormal white matter structure is associated with deficits in sociability in BALB/cJ mice. Additional studies are warranted to elucidate the relationship between brain connectivity and sociability in this model system.