Canine respiratory viruses

Predominance of Canine Parainfluenza Virus and Mycoplasma in Canine Infectious Respiratory Disease Complex in Dogs

Canine infectious respiratory disease complex (CIRDC) is caused by different viruses and bacteria. Viruses associated with CIRDC include canine adenovirus type 2 (CAV-2), canine distemper virus (CDV), canine influenza virus (CIV), canine herpesvirus type 1 (CHV-1), canine respiratory coronavirus (CRCoV), and canine parainfluenza virus (CPIV). Bacteria associated with CIRDC include Bordetella bronchiseptica, Streptococcus equi subspecies zooepidemicus (S. zooepidemicus), and Mycoplasma spp. The present study examined the prevalence of CIRDC pathogens in specimens received by a Veterinary Diagnostic Laboratory in Georgia, USA., from 2018 to 2022. Out of 459 cases, viral agents were detected in 34% of cases and bacterial agents were detected in 58% of cases. A single pathogen was detected in 31% of cases, while two or more pathogens were identified in 24% of cases. The percentages of viral agents identified were CAV-2 (4%), CDV (3%), CPIV (16%), CRCoV (7%), and CIV (2%). The percentages of bacterial agents were B. bronchiseptica (10%), Mycoplasma canis (24%), Mycoplasma cynos (21%), and S. zooepidemicus (2%). Over the five-year period, the positive cases ranged from 2-4% for CAV-2, 1-7% for CDV, 1-4% for CHV-1, 9-22% for CPIV, 4-13% for CRCoV, and 1-4% for CIV. Overall, the most prevalent pathogens associated with CIRDC were CPIV, M. canis, and M. cynos.

Development and Validation of a Panel of One-Step Four-Plex qPCR/RT-qPCR Assays for Simultaneous Detection of SARS-CoV-2 and Other Pathogens Associated with Canine Infectious Respiratory Disease Complex

Canine infectious respiratory disease complex (CIRDC) is the primary cause of respiratory disease in the canine population and is caused by a wide array of viruses and bacterial pathogens with coinfections being common. Since its recognition in late 2019, Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been reported to cause respiratory disease in dogs. Therefore, the rapid detection and differentiation of SARS-CoV-2 from other common viral and bacterial agents is critical from a public health standpoint. Here, we developed and validated a panel of four one-step multiplex qPCR/RT-qPCR assays for the detection and identification of twelve pathogens associated with CIRDC (canine adenovirus-2, canine distemper virus, canine herpesvirus-1, canine influenza A virus, canine parainfluenza virus, canine pneumovirus, canine respiratory coronavirus, SARS-CoV-2, Bordetella bronchiseptica, Streptococcus equi subsp. zooepidemicus, Mycoplasma cynos, and M. canis), as well as the identification of three main CIV subtypes (i.e., H3N2, H3N8, and H1N1). All developed assays demonstrated high specificity and analytical sensitivity. This panel was used to test clinical specimens (n = 76) from CIRDC-suspected dogs. M. canis, M. cynos, and CRCoV were the most frequently identified pathogens (30.3%, 25.0%, and 19.7% of samples, respectively). The newly emerging pathogens CPnV and SARS-CoV-2 were detected in 5.3% of samples and coinfections were identified in 30.3%. This new multiplex qPCR/RT-qPCR panel is the most comprehensive panel developed thus far for identifying CIRDC pathogens, along with SARS-CoV-2.

Canine Parainfluenza Virus Infection in a Dog with Acute Respiratory Disease

Simple Summary

A one-day history of dry paroxysmal cough, associated with retching, induced by canine parainfluenza virus without the simultaneous presence of other pathogens, has been reported in a vaccinated household dog. The dog did not show nasal discharge or fever, but it was possible to evoke a dry cough through the palpation of the trachea. Radiographic findings of the thorax showed a diffuse unstructured interstitial pattern with the involvement of multiple lung lobes. Trachea-bronchoscopy and broncho-alveolar lavage were carried out. Edema without exudate and congested mucosa from the larynx to bronchi were observed. Cytological evaluation was negative for the presence of inflammatory or infectious processes. Nucleic acids were extracted from the collected specimens; biomolecular investigations tested positive only for canine parainfluenza virus and negative for all other pathogens associated with “kennel cough”. At first, the afebrile onset and the coughing fits suggested the presence of a foreign body, a common occurrence in Southern Italy during summer. The clinical signs and the absence of findings by cytology have directed the clinicians towards the correct diagnosis, with the support of biomolecular assays, which are fundamental to avoid underestimating the circulation of this virus, even in owned dogs.

Abstract

The canine infectious respiratory disease complex (CIRDC) is an endemic respiratory syndrome caused by different bacterial and viral pathogens. This report describes a case of canine parainfluenza virus infection in a vaccinated household dog with an acute respiratory symptom (dry cough), who underwent clinical and endoscopic investigations for a suspected foreign body. Cytological investigations carried out on the broncho-alveolar lavage fluid (BALF) tested negative for the presence of inflammatory or infectious processes and could have been misleading the clinicians. By the molecular analyses (PCR) carried out on the BALF, canine parainfluenza virus was exclusively detected without the simultaneous presence of other respiratory pathogens associated to CIRDC. This case report emphasizes the role of molecular diagnostics in the differential diagnosis of respiratory diseases, in order to avoid underestimating the circulation of the parainfluenza virus in the canine population.

The impact of the COVID-19 pandemic on a cohort of Labrador retrievers in England

Background

The COVID-19 pandemic is likely to have affected the welfare and health of dogs due to surges in adoptions and purchases, changes in the physical and mental health and financial status of dog owners, changes in dogs’ lifestyle and routines and limited access to veterinary care. The aims of this study were to investigate whether COVID-19 restrictions were associated with differences in Labrador retrievers’ lifestyle, routine care, insurance status, illness incidence or veterinary attendance with an illness, who were living in England and enrolled in Dogslife, an owner-based cohort study. Longitudinal questionnaire data from Dogslife that was relevant to the dates between the 23rd of March and the 4th of July 2020, during COVID-19 restrictions in England, were compared to data between the same dates in previous years from 2011 to 2019 using mixed regression models and adjusted chi-squared tests.

Results

Compared with previous years (March 23rd to July 4th, 2010 to 2019), the COVID-19 restrictions study period (March 23rd to July 4th 2020) was associated with owners reporting increases in their dogs’ exercise and worming and decreases in insurance, titbit-feeding and vaccination. Odds of owners reporting that their dogs had an episode of coughing (0.20, 95% CI: 0.04–0.92) and that they took their dogs to a veterinarian with an episode of any illness (0.58, 95% CI: 0.45–0.76) were lower during the COVID-19 restrictions compared to before. During the restrictions period, owners were less likely to report that they took their dogs to a veterinarian with certain other illnesses, compared to before this period.

Conclusions

Dogslife provided a unique opportunity to study prospective questionnaire data from owners already enrolled on a longitudinal cohort study. This approach minimised bias associated with recalling events prior to the pandemic and allowed a wider population of dogs to be studied than is available from primary care data. Distinctive insights into owners’ decision making about their dogs’ healthcare were offered. There are clear implications of the COVID-19 pandemic and associated restrictions for the lifestyle, care and health of dogs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03319-z.

Development of a three-panel multiplex real-time PCR assay for simultaneous detection of nine canine respiratory pathogens

Infectious respiratory disease is one of the most common diseases in dogs worldwide. Several bacterial and viral pathogens can serve as causative agents of canine infectious respiratory disease (CIRD), including Mycoplasma cynos, Mycoplasma canis, Bordetella bronchiseptica, canine adenovirus type 2 (CAdV-2), canine herpesvirus 1 (CHV-1), canine parainfluenza virus (CPIV), canine distemper virus (CDV), canine influenza virus (CIA) and canine respiratory coronavirus (CRCoV). Since these organisms cause similar clinical symptoms, disease diagnosis based on symptoms alone can be difficult. Therefore, a quick and accurate test is necessary to rapidly identify the presence and relative concentrations of causative CIRD agents. In this study, a multiplex real-time PCR panel assay was developed and composed of three subpanels for detection of the aforementioned pathogens. Correlation coefficients (R²) were >0.993 for all singleplex and multiplex real-time PCR assays with the exception of one that was 0.988; PCR amplification efficiencies (E) were between 92.1% and 107.8% for plasmid DNA, and 90.6-103.9% for RNA templates. In comparing singular and multiplex PCR assays, the three multiplex reactions generated similar R² and E values to those by corresponding singular reactions, suggesting that multiplexing did not interfere with the detection sensitivities. The limit of detection (LOD) of the multiplex real-time PCR for DNA templates was 5, 2, 3, 1, 1, 1, 4, 24 and 10 copies per microliter for M. cynos, M. canis, B. brochiseptica, CAdV-2, CHV-1, CPIV, CDV, CIA and CRCoV, respectively; and 3, 2, 6, 17, 4 and 8 copies per microliter for CAdV-2, CHV-1, CPIV, CDV, CIA and CRCoV, respectively, when RNA templates were used for the four RNA viruses. No cross-detection was observed among the nine pathogens. For the 740 clinical samples tested, the newly designed PCR assay showed higher diagnostic sensitivity compared to an older panel assay; pathogen identities from selected samples positive by the new assay but undetected by the older assay were confirmed by Sanger sequencing. Our data showed that the new assay has higher diagnostic sensitivity while maintaining the assay's specificity, as compared to the older version of the panel assay.

Difference Analysis Between Canine Adenovirus Types 1 And 2

Canine adenoviruses (CAdVs) include type 1 (CAdV-1, virulent strain) and type 2 (CAdV-2, attenuated strain). In recent years, the incidences of CAdV infections are increasing. However, they are difficult to distinguish when the symptoms are untypical. It is pivotal to find the differences between the two virus types for scientific, epidemiological, and specific treatment. CAdV-1 (virulent strain) and CAdV-2 (attenuated strain) induced canine hepatitis (ICH) and tracheobronchitis (ITB), respectively, but the clinical symptom is not obvious. CAdV-1 and CAdV-2 have the same genome structure, diameter, morphological features, and cytopathic features, but the same character hinder the diagnose time of the serotypes. CAdV-1 and CAdV-2 have a difference in the genome sequence, coding proteins, viral activity, hemagglutination patterns. After infection, pathogenicity and transmission route are different between the two serotypes. Sequence alignment, PCR, Real time-PCR assay are useful methods to distinguish the two serotypes. The attenuated live CAdV-2 vaccine is currently used to protect against CAdV-1, but it also has a risk. The further research should focus on the pathogenicity mechanism and the useful vaccine for the two serotypes of canine adenovirus.

One Health: EAACI Position Paper on coronaviruses at the human-animal interface, with a specific focus on comparative and zoonotic aspects of SARS-CoV-2

The latest outbreak of a coronavirus disease in 2019 (COVID‐19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), evolved into a worldwide pandemic with massive effects on health, quality of life, and economy. Given the short period of time since the outbreak, there are several knowledge gaps on the comparative and zoonotic aspects of this new virus. Within the One Health concept, the current EAACI position paper dwells into the current knowledge on SARS‐CoV‐2’s receptors, symptoms, transmission routes for human and animals living in close vicinity to each other, usefulness of animal models to study this disease and management options to avoid intra‐ and interspecies transmission. Similar pandemics might appear unexpectedly and more frequently in the near future due to climate change, consumption of exotic foods and drinks, globe‐trotter travel possibilities, the growing world population, the decreasing production space, declining room for wildlife and free‐ranging animals, and the changed lifestyle including living very close to animals. Therefore, both the society and the health authorities need to be aware and well prepared for similar future situations, and research needs to focus on prevention and fast development of treatment options (medications, vaccines).

Isolation and genetic characterization of canine adenovirus type 2 from a domestic dog showing neurological symptoms

Canine adenoviruses (CAVs) are of two types: canine adenovirus type 1 (CAV-1), which causes infectious canine hepatitis, and canine adenovirus type 2 (CAV-2), which is mainly associated with the respiratory type of disease in dogs. Due to the widespread use of modified live vaccines to control canine adenoviral infections and subsequently reduced disease incidence, CAVs are often neglected by clinicians. Although a number of studies are available about CAV-1 prevalence in India, only meagre information is available about CAV-2. This study reports the CAV-2 infection in a vaccinated dog with neurological and respiratory symptoms which was found negative for other canine pathogens like canine distemper virus and canine parvovirus. The virus was successfully isolated from rectal swab in MDCK cells and characterized by immunofluorescence assay and virus neutralization test. On phylogenetic analysis of partial E3 region, the Indian CAV-2 grouped in a separate clade different from established subgroups. An insertion of "G" nucleotide was reported at nucleotide (nt.) position 1077 in the E3 gene of Indian CAV-2 isolates which led to a frameshift in the coding region of E3 gene thereby imparting additional eleven amino acids to its C-terminal end in comparison to isolates from other parts of the world. This may have an implication on the functional role of E3 protein inside the cell. This study reinforces the unique signature insertion in the E3 gene of Indian CAV-2 and is the second study in the world to report the association of CAV-2 with neurological disease in dogs.

Oral vaccination of dogs with a monovalent live-avirulent vaccine confers 1 year of immunity against Bordetella bronchiseptica challenge

This experimental challenge study assessed immune protection 1 year after a single dose of live-attenuated oral Bordetella bronchiseptica (Bb) vaccine in dogs. Forty Bb-seronegative 7-9-week-old puppies were randomly assigned at Day 0 to receive a single oral dose of either Bb vaccine (n = 20; vaccinated group) or sterile water (n = 20; control group). Groups were housed separately until comingling 1 day pre-challenge (Day 365). Challenge with virulent aerosolized Bb occurred at Day 366. Clinical scores were obtained at Days 1-7, and 366-380. Bb microagglutination test (MAT) titers were obtained at Days -7, 0, monthly post-vaccination, and Days 358, 365, and 380. Nasal swabs were collected for microbiological assessment at Days -7, 0, 365, and 367-380. Oral Bb vaccination was not associated with side effects. Pre-challenge, vaccinated dogs developed persistent Bb MAT titers and control dogs remained seronegative. Post-challenge, duration of cough was longer in control dogs (least square means [LSM], 8.6 days) than vaccinated dogs (LSM, 1.5 days; P < 0.0001), with more control dogs having cough on 2 or more consecutive days (control group, n = 17/19, 89.5%; vaccinated group, n = 3/19, 15.8%; P = 0.0011). Post-challenge, Bb shedding occurred in all control dogs and 5/19 (26%) vaccinated dogs. Average duration of Bb shedding was longer in the control group (11.9 days vs. 0.6 days; P < 0.0001) and nasal Bb loads were higher in the control group (P < 0.00001). Orally administered Bb vaccine stimulated immunity that was still protective against virulent Bb challenge after 1 year.

Canine circovirus and Canine adenovirus type 1 and 2 in dogs with parvoviral enteritis

Canine parvovirus type 2 (CPV-2) is one of the most relevant pathogens associated with enteritis in dogs and is frequently reported in association with the detection of other pathogens in faeces. In this study the concomitant presence of Canine circovirus (CanineCV) and Canine adenovirus (CAdV) DNA in faecal or intestine samples of 95 dogs with parvovirus enteritis sampled in Italy (1995–2017) was investigated and the viruses identified were genetically characterised. Potential correlations with the antigenic variant of CPV-2 and with signalment data and outcome were evaluated. Twenty-eight of 95 (29.5%) CPV-2 infected dogs tested positive to other viruses: 7/28 were also positive to CanineCV, 1/28 to CAdV-1, 18/28 to CAdV-2, 1/28 to CanineCV and CAdV-2, and 1/28 to CAdV-1 and CAdV-2. The frequency of CAdV DNA detection and coinfections was significantly higher in purebred dogs compared to mixed breed ones (P = 0.002 and 0.009, respectively). The presence of coinfection was not associated with any other relevant data available, including CPV-2 variant and final outcome. The detection of CanineCV in a dog sampled in 2009 allowed to backdating its circulation in dogs. The eight CanineCV completely sequenced were phylogenetically related to the CanineCV identified in dogs, wolves and a badger from Europe, USA, Argentina and China. Nine CAdV were partially sequenced and phylogenetic analysis showed a separate branch for the oldest CAdV-2 identified (1995). From the results obtained in this study population, CanineCV and CAdV coinfections in dogs with parvoviral enteritis did not result in more severe disease.

Antimicrobial resistance profiles of bacteria associated with lower respiratory tract infections in cats and dogs in England

BACKGROUND

Bacterial lower respiratory tract infections (bLRTIs) are common and potentially life threatening in cats and dogs. Antibiotic treatment is often initiated before the diagnosis of bLRTI; therefore improved knowledge of the aetiology and antibiotic susceptibility patterns of these infections is essential to inform empiric antibiotic choices.

METHODS

A retrospective study of microbiological, cytological results and their drug susceptibilities from lower respiratory samples (n = 1989) processed in a UK commercial laboratory between 2002 and 2012 was carried out.

RESULTS

Thirty-nine per cent of feline samples and 50% of canine samples were positive for bacterial growth with most yielding a single organism (72 % and 69%, respectively). Bordetella bronchiseptica (20.2% from dogs and 2.3% from cats), Pasteurella spp. (23.2%, 31.8%), E. coli (16.2%, 13.6%) and Pseudomonas spp. (11.1%, 11.4%) were most frequently isolated from cytologically positive samples which contained intracellular bacteria (10%, 14%). Amoxycillin-clavulanate, cephalothin, cefovecin, oxytetracycline and trimethoprim/sulfamethoxazole showed modest in vitro activity against E. coli from dogs (approximately 70% susceptibility). Pseudomonas spp. were resistant to enrofloxacin (50%), ticarcillin (25%) and marbofloxacin (13%) but showed lower or zero resistance to aminoglycosides (approximately 7%) and ciprofloxacin (0%). Multi drug resistance (acquired resistance to three or more antimicrobial drug classes) was particularly common among E. coli isolates, with 23% from feline samples and 43% from canine samples.

CONCLUSION

Resistance to certain first-choice antibiotics was detected in bLRTIs highlighting the need for continued monitoring and sound evidence to inform decision-making in the management of these infections.

The Gut Viral Metagenome Analysis of Domestic Dogs Captures Snapshot of Viral Diversity and Potential Risk of Coronavirus

The close relations between dogs (Canis lupus familiaris) and humans lay a foundation for cross species transmissions of viruses. The co-existence of multiplex viruses in the host accelerate viral variations. For effective prediction and prevention of potential epidemic or even pandemic, the metagenomics method was used to investigate the gut virome status of 45 domestic healthy dogs which have extensive contact with human beings. A total of 248.6 GB data (505, 203, 006 valid reads, 150 bp in length) were generated and 325, 339 contigs, which were best matched with viral genes, were assembled from 46, 832, 838 reads. In the aggregate, 9,834 contigs (3.02%) were confirmed for viruses. The top 30 contigs with the most reads abundance were mapped to DNA virus families Circoviridae, Parvoviridae and Herpesviridae; and RNA virus families Astroviridae, Coronaviridae and Picornaviridae, respectively. Numerous sequences were assigned to animal virus families of Astroviridae, Coronaviridae, Circoviridae, etc.; and phage families of Microviridae, Siphoviridae, Ackermannviridae, Podoviridae, Myoviridae and the unclassified phages. Further, several sequences were homologous with the insect and plant viruses, which reflects the diet and habitation of dogs. Significantly, canine coronavirus was uniquely identified in all the samples with high abundance, and the phylogenetic analysis therefore showed close relationship with the human coronavirus strain 229E and NL63, indicating the potential risk of canine coronavirus to infect humans by obtaining the ability of cross-species transmission. This study emphasizes the high detection frequency of virus harbored in the enteric tract of healthy contacted animal, and expands the knowledge of the viral diversity and the spectrum for further disease-association studies, which is meaningful for elucidating the epidemiological and biological role of companion animals in public health.

Clinical and molecular aspects of veterinary coronaviruses

Coronaviruses are a large group of RNA viruses that infect a wide range of animal species. The replication strategy of coronaviruses involves recombination and mutation events that lead to the possibility of cross-species transmission. The high plasticity of the viral receptor due to a continuous modification of the host species habitat may be the cause of cross-species transmission that can turn into a threat to other species including the human population. The successive emergence of highly pathogenic coronaviruses such as the Severe Acute Respiratory Syndrome (SARS) in 2003, the Middle East Respiratory Syndrome Coronavirus in 2012, and the recent SARS-CoV-2 has incentivized a number of studies on the molecular basis of the coronavirus and its pathogenesis. The high degree of interrelatedness between humans and wild and domestic animals and the modification of animal habitats by human urbanization, has favored new viral spreads. Hence, knowledge on the main clinical signs of coronavirus infection in the different hosts and the distinctive molecular characteristics of each coronavirus is essential to prevent the emergence of new coronavirus diseases. The coronavirus infections routinely studied in veterinary medicine must be properly recognized and diagnosed not only to prevent animal disease but also to promote public health.

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.

Complete genome analysis confirms that the pygmy marmoset adenovirus is a variant of the skunk adenovirus 1 - Short communication

The complete genomic sequence along with phylogenetic analyses of an adenovirus (AdV), isolated from a dead captive pygmy marmoset (Callithrix pygmaea) from a Hungarian zoo is reported. Earlier, based on the phylogenetic analysis of the sequence of a PCR-amplified fragment from the DNA polymerase gene, the pygmy marmoset AdV (PMAdV) has been reported to cluster closest to certain chiropteran AdVs. In the following years similar AdVs were discovered in additional mammalian hosts, including a skunk (Mephitis mephitis), African pygmy hedgehogs (Atelerix albiventris), North American porcupines (Erethizon dorsatum) and grey fox (Urocyon cinereoargenteus). After the full genome analysis of the skunk adenovirus (SkAdV-1), a novel species Skunk mastadenovirus A (SkAdV-A) has been established. The AdVs, originating from the African pygmy hedgehogs, have been found to belong to virus species SkAdV-A. Partial gene sequences from the porcupine AdVs have also implied their very close genetic relatedness to SkAdV-A. The complete genomic sequence of PMAdV, examined in this study, was found to share 99.83% nucleotide identity with SkAdV-1, thus unequivocally represents a genomic variant of SkAdV-1. The observation that viruses classifiable as SkAdV-A are able to infect and cause diseases in several, distantly related mammals seems to deserve further studies to elucidate the infection biology of this intriguing AdV.

Lifestyle as Risk Factor for Infectious Causes of Death in Young Dogs: A Retrospective Study in Southern Italy (2015-2017)

Infectious diseases are a common cause of death in young dogs. Several factors are thought to predispose young dogs to microbiological infections. Identifying the cause of death is often a challenge, and broad diagnostic analysis is often needed. Here, we aimed to determine the infectious causes of death in young dogs aged up to 1 year, examining how it relates to age (under and over 6 months), lifestyle (owned versus ownerless), breed (purebred and crossbreed), and gender. A retrospective study was conducted in a 3-year period (2015-2017) on 138 dead dogs that had undergone necropsy and microbiological diagnostics. Enteritis and pneumonia were the most commonly observed lesions. Polymicrobism was more prevalent (62.3%) than single-agent infections and associated with a higher rate of generalised lesions. Ownerless dogs showed over a three-fold higher predisposition to viral coinfections than owned dogs. Above all, canine parvovirus was the most prevalent agent (77.5%), followed by canine coronavirus (31.1%) and canine adenovirus (23.9%); ownerless pups had a higher predisposition to these viruses. Escherichia coli (23.9%), Clostridium perfringens type A (18.1%), and Enterococcus spp. (8.7%) were the most commonly identified bacteria, which mostly involved in coinfections. A lower prevalence of CDV and Clostridium perfringens type A was observed in puppies under 6 months of age. In conclusion, this study is the first comprehensive survey on a wide panel of microbiological agents related to necropsy lesions. It lays the groundwork for future studies attempting to understand the circulation of infectious agents in a determined area.

Molecular detection of canine respiratory pathogens between 2017 and 2018 in Japan

A molecular survey was conducted to understand recent distribution of pathogens associated with canine infectious respiratory disease (CIRD) in Japan. Nasal and/or pharyngeal swabs were collected from asymptomatic dogs and those with CIRD, living in private house or in kennels. PCR-based examination was conducted for detecting nine pathogens. Among private household dogs, 50.8% with CIRD, 11.1% with respiratory disease other than CIRD, and 4.3% asymptomatic were positive for more than one pathogen, whereas in kennel-housed dogs, 42.9% with CIRD and 27.3% asymptomatic were positive. Bordetella bronchiseptica was most frequently detected, followed by canine herpesvirus 1, canine parainfluenza virus, canine pneumovirus, Mycoplasma cynos, and canine adenovirus type 2. In kennel environment, asymptomatic dogs might act as reservoirs carrying the respiratory pathogens.

Aetiology of Canine Infectious Respiratory Disease Complex and Prevalence of its Pathogens in Europe

The canine infectious respiratory disease complex (CIRDC) is an endemic worldwide syndrome involving multiple viral and bacterial pathogens. Traditionally, Bordetella bronchiseptica (Bb), canine adenovirus type 2 (CAV-2), canine distemper virus (CDV), canine herpesvirus (CHV) and canine parainfluenza virus (CPiV) were considered the major causative agents. Lately, new pathogens have been implicated in the development of CIRDC, namely canine influenza virus (CIV), canine respiratory coronavirus (CRCoV), canine pneumovirus (CnPnV), Mycoplasma cynos and Streptococcus equi subspecies zooepidemicus. To better understand the role of the different pathogens in the development of CIRDC and their epidemiological relevance in Europe, prevalence data were collected from peer-reviewed publications and summarized. Evidence of exposure to Bb is frequently found in healthy and diseased dogs and client-owned dogs are as likely to be infected as kennelled dogs. Co-infections with viral pathogens are common. The findings confirm that Bb is an important cause of CIRDC in Europe. CAV-2 and CDV recovery rates from healthy and diseased dogs are low and the most likely explanation for this is control through vaccination. Seroconversion to CHV can be demonstrated following CIRDC outbreaks and CHV has been detected in the lower respiratory tract of diseased dogs. There is some evidence that CHV is not a primary cause of CIRDC, but opportunistically re-activates at the time of infection and exacerbates the disease. The currently available data suggest that CIV is, at present, neither a prevalent nor a significant pathogen in Europe. CPiV remains an important pathogen in CIRDC and facilitates co-infection with other viral and bacterial pathogens. CnPnV and CRCoV are important new elements in the aetiology of CIRDC and spread particularly well in multi-dog establishments. M. cynos is common in Europe and is more likely to occur in younger and kennelled dogs. This organism is frequently found together with other CIRDC pathogens and is significantly associated with more severe respiratory signs. S. zooepidemicus infection is not common and appears to be a particular problem in kennels. Protective immunity against respiratory diseases is rarely complete, and generally only a reduction in clinical signs and excretion of pathogen can be achieved through vaccination. However, even vaccines that only reduce and do not prevent infection carry epidemiological advantages. They reduce spread, increase herd immunity and decrease usage of antimicrobials. Recommending vaccination of dogs against pathogens of CIRDC will directly provide epidemiological advantages to the population and the individual dog.

Development of an Immunochromatographic Strip for Rapid Detection of Canine Adenovirus

Although canine adenovirus (CAdV) is highly prevalent in dogs, there is currently a lack of a quick diagnostic method. In this study, we developed a rapid immunochromatographic strip (ICS) assay using colloidal gold coupled to CAdV-2-specific monoclonal antibodies (mAbs). BALB/c mice were immunized with a purified CAdV-2 suspension, and four mAbs (belonging to two different epitopes) were generated and designated as 2C1, 7D7, 10D1, and 4G1. Western blot and protein spectral analysis indicated that the hexon protein of CAdV-2 recognized all four mAbs. The colloidal gold-coupled 7D7 and 2C1 mAbs were chosen for inclusion in the rapid ICS assay. The optimal concentrations of the coating antibody (2C1), the capture antibody (7D7), and the goat anti-mouse antibody were 1.0 mg/ml, 10 μg/ml, and 2.0 mg/ml, respectively. The limit of detection was approximately 2.0 × 10² tissue culture infective dose (TCID₅₀)/ml. Other common canine viruses were tested to evaluate the specificity of the ICS, and positive results were observed for only CAdV-1 and CAdV-2. The ICS test was conducted on 360 samples to detect CAdV, and the results were compared with those of polymerase chain reaction (PCR) tests. The ICS test was found to be a sufficiently sensitive and specific detection method for the convenient and rapid detection of CAdV.

Cross-sectional investigation and risk factor analysis of community-acquired and hospital-associated canine viral infectious respiratory disease complex

Canine infectious respiratory disease complex (CIRDC) is associated with multiple factors. The possible transmission source can be via community-acquired infection (CAI) or hospital-associated infection (HAI), but the variable factors within these two routes are not well described. This study aimed to (i) investigate a cross-sectional incidence of canine respiratory viruses, including influenza (CIV), parainfluenza, distemper (CDV), respiratory coronavirus (CRCoV), adenovirus-2, and herpesvirus, in respiratory-diseased dogs, and (ii) analyze the possibly related risk factors. In total 209 dogs with respiratory illness, consisting of 133 CAI and 76 HAI dogs, were studied. Both nasal and oropharyngeal swabs were sampled from each dog and subjected for CIRDC virus detection using multiplex PCRs. Common six viruses associated with CIRDC were detected in both groups with CIV and CRCoV being predominantly found. Only CDV was significantly more prevalent in CAI than HAI dogs. Multiple virus detections were found in 81.2% and 78.9% of CAI and HAI dogs, respectively. Co-detection of CIV and CRCoV was represented the highest proportion and most often found with other CIRD viruses. Moreover, the clinical severity level was notably related to the age of infected dogs, but not to the vaccination status, sex and transmission route. Since healthy or control dogs were not included in this study, the prevalence of the CIRD virus infections could not be assessed.

Presumptive Development of Fibrotic Lung Disease From Bordetella bronchiseptica and Post-infectious Bronchiolitis Obliterans in a Dog

A 7-month-old Miniature Poodle acquired from a pet store developed cough and subsequently respiratory distress compatible with Bordetella bronchiseptica infection. Partial but incomplete resolution of clinical signs and thoracic radiographic/computed tomographic imaging lesions were noted with use of susceptibility-guided antimicrobials. Additionally, a concern for an infectious nidus led to left cranial lung lobectomy at 9 months of age. Histopathology predominantly revealed polypoid and constrictive bronchiolitis obliterans (i.e., small airway disease). Intermittent antimicrobial administration over the next 5 years failed to blunt progressive clinical signs. At 8 years, necropsy confirmed severe airway-centered interstitial fibrosis. This pattern of fibrosis was strongly suggestive of underlying small airway disease as the trigger. In retrospect, post-infectious bronchiolitis obliterans (PIBO), a syndrome in young children caused by pulmonary infections but not yet recognized in pet dogs, likely initiated a pathway of fibrosis in this dog. In dogs with risk factors for community-acquired pathogens such as Bordetella bronchiseptica, PIBO is a differential diagnosis with development of severe, persistent respiratory signs incompletely responsive to appropriate antimicrobials. Untreated PIBO may lead to airway-centered interstitial fibrosis. Future study is required to determine if targeted therapy of PIBO could alter the course of end-stage pulmonary fibrosis.

Detection of selected viral pathogens in dogs with canine infectious respiratory disease in Austria

Objectives

To assess the prevalence of canine parainfluenza virus, canine adenovirus type 2, canine distemper virus, canine respiratory coronavirus and influenza virus A infections in: (1) privately‐owned or, (2) kennelled dogs showing signs consistent with canine infectious respiratory disease and, (3) clinically healthy dogs in Vienna, Austria.

Materials and Methods

Prospectively, nasal and tonsillar swabs from 214 dogs affected with infectious respiratory disease, and 50 healthy control dogs were tested for nucleic acids specific to the various viral infections. Concurrent bronchoalveolar lavage fluid from 31 dogs with chronic respiratory disease was investigated for the same viral pathogens. Additionally, anti‐canine respiratory coronavirus antibody concentrations were measured in paired blood samples from 30 acutely diseased dogs.

Results

Canine respiratory coronavirus (7.5%) and canine parainfluenza virus (6.5%) were the most commonly detected viruses in samples from the upper airways of dogs with respiratory infections. Serological results showed a significant seroconversion in response to coronavirus in 50% of the examined cases. None of the samples was positive for influenza virus A‐specific nucleic acid. Canine coronavirus‐specific nucleic acid was detected in 4.0% of healthy dogs.

Clinical Significance

Canine coronavirus should be considered as a clinically relevant cause of infectious respiratory disease in crowded dog populations. For sample collection, the nasal mucosa can be recommended as the favoured site. Analysis of paired serum samples aids verification of canine coronavirus infection in respiratory disease.

Canine infectious respiratory disease: New insights into the etiology and epidemiology of associated pathogens

Canine infectious respiratory disease (CIRD) is a syndrome where multiple viral and bacterial pathogens are involved sequentially or synergistically to cause illness. There is limited information regarding the prevalence of pathogens related to CIRD in the United States as well as the role of co-infections in the pathogenesis of the syndrome. We aimed to conduct a comprehensive etiologic and epidemiologic study of multiple CIRD agents in a diverse dog population using molecular methods and statistical modeling analyses. In addition, a novel probe-based multiplex real-time PCR was developed to simultaneously detect and differentiate two species of Mycoplasma (M. canis and M. cynos). Canine adenovirus, canine distemper virus, canine parainfluenza virus, coronavirus, influenza A virus (H3N2 and H3N8), Bordetella bronchiseptica, M. canis, M. cynos and Streptococcus equi subsp. zooepidemicus were investigated in specimens from clinically ill and asymptomatic dogs received at the Athens Veterinary Diagnostic Laboratory. Results showed low occurrence of classical CIRD agents such as B. bronchiseptica, canine adenovirus and distemper virus, while highlighting the potential role of emerging bacteria such as M. canis and M. cynos. Statistical modeling analyses of CIRD pathogens emphasized the impact of co-infections on the severity of clinical presentation, and showed that host factors, such as animal age, are the most important predictors of disease severity. This study provides new insights into the current understanding of the prevalence and role of co-infections with selected viruses and bacteria in the etiology of CIRD, while underscoring the importance of molecular diagnosis and vaccination against this disease.

Novel Parvovirus Related to Primate Bufaviruses in Dogs

A novel protoparvovirus species, related genetically to human bufaviruses, was identified in dogs with respiratory signs. The canine bufavirus was distantly related to the well-known canine protoparvovirus, canine parvovirus type 2, sharing low amino acid identities in the nonstructural protein 1 (40.6%) and in the capsid protein 1 (33.4%). By screening collections of fecal, nasal, and oropharyngeal samples obtained from juvenile dogs (<1 year of age), canine bufavirus DNA appeared as a common component of canine virome. The virus was common in the stool samples of dogs with or without enteric disease and in the nasal and oropharyngeal swab samples of dogs with respiratory signs. However, the virus was not detected in nasal and oropharyngeal swab samples from animals without clinical signs.

Outcomes of and risk factors for presumed canine H3N2 influenza virus infection in a metropolitan outbreak

OBJECTIVE To determine clinical signs, case fatality rate, and factors associated with positive results of PCR testing for canine influenza virus (CIV) in dogs during an H3N2 CIV outbreak in the Atlanta area. DESIGN Cross-sectional study. ANIMALS 220 dogs with a nasal swab specimen submitted to an Atlanta-area diagnostic laboratory between May 1 and July 2, 2015, for PCR assay detection of CIV specifically or CIV and 5 other respiratory pathogens. PROCEDURES Veterinarians of tested dogs were surveyed by various means to collect information regarding clinical signs, survival status at the time of survey completion, vaccination history (≤ 12 months prior to testing), and travel history (≤ 2 months prior to testing). Data were compared between CIV-positive and CIV-negative dogs. RESULTS Surveys for 120 (55%) dogs were completed. Forty (33%) of these dogs had positive results of CIV testing. No significant differences were identified between CIV-positive and CIV-negative dogs regarding breed, sex, reproductive status, duration of clinical signs prior to testing, other dogs in the household, or travel history. When other factors were controlled for, CIV-positive dogs were more likely to be adult (> 1 year of age) than juvenile (≤ 1 year of age) and to be inappetent. Only 1 (3%) CIV-positive dog died during the study period (shortly after it was evaluated because of respiratory signs). CONCLUSIONS AND CLINICAL RELEVANCE From May 1 to July 2, 2015, the reported clinical signs of dogs tested during the Georgia H3N2 CIV outbreak were similar to those reported for dogs with H3N8 CIV infection, and the case fatality rate was low.

Multiplex PCR methods for detection of several viruses associated with canine respiratory and enteric diseases

Viral respiratory and intestinal infections are the most common causes of canine viral illness. Infection with multiple pathogens occurs in many cases. Rapid diagnosis of these multiple infections is important for providing timely and effective treatment. To improve diagnosis, in this study, two new multiplex polymerase chain reactions (mPCRs) were developed for simultaneous detection of canine respiratory viruses (CRV) and canine enteric viruses (CEV) using two separate primer mixes. The viruses included canine adenovirus type 2 (CAV-2), canine distemper virus (CDV), canine influenza virus (CIV), canine parainfluenza virus (CPIV), canine circovirus (CanineCV), canine coronavirus (CCoV) and canine parvovirus (CPV). The sensitivity of the mPCR results showed that the detection limit of both mPCR methods was 1×10⁴ viral copies. Twenty nasal swabs (NS) and 20 anal swabs (AS) collected from dogs with symptoms of respiratory disease or enteric disease were evaluated using the novel mPCR methods as a clinical test. The mPCR protocols, when applied to these respiratory specimens and intestinal samples, could detect 7 viruses simultaneously, allowing rapid investigation of CRV (CAV-2, CDV, CIV and CPIV) and CEV (CAV-2, CanineCV, CCoV and CPV) status and prompt evaluation of coinfection. Our study provides an effective and accurate tool for rapid differential diagnosis and epidemiological surveillance in dogs.

A survey of canine respiratory pathogens in New Zealand dogs

AIMS To determine which of the common canine respiratory pathogens circulate among selected populations of healthy and diseased dogs in New Zealand. METHODS Coagulated blood samples for serology and oropharyngeal swabs for virology were collected from healthy dogs (n=47) and from dogs with acute respiratory disease (n=49). For diseased dogs a convalescent blood sample was also collected 3-4 weeks later. Oropharyngeal swabs were subjected to virus isolation and tested for canine parainfluenza virus (CPIV), canine adenovirus (CAdV) 2, canine herpesvirus (CHV), canine respiratory coronavirus (CRCoV), canine influenza virus (CIV), canine distemper virus (CDV), Bordetella bronchiseptica, Streptococcus equi subsp. zooepidemicus, and Mycoplasma cynos nucleic acids by quantitative PCR (qPCR). Sera were tested for CRCoV antibody using competitive ELISA and results expressed as percent of inhibition (POI). RESULTS The mean age of diseased dogs (2.7, min <0.5, max 8.5 years) was lower than the mean age of healthy dogs (5.3, min <0.5, max 17 years) (p<0.001). In total, 20/94 (21%) dogs were positive for at least one agent by qPCR. Diseased dogs were most commonly positive for M. cynos (8/47, 17%), followed by CPIV (3/47, 6%) and B. bronchiseptica (3/47, 6%), while healthy dogs were most commonly positive for CAdV-2 (6/47, 13%), followed by M. cynos (2/47, 4%). All samples were negative for CIV, CRCoV, CDV and S. equi subsp. zooepidemicus. Viruses were not isolated from any of the samples tested. In total, 47/93 (50%) dogs were seropositive for CRCoV on at least one sampling occasion. Samples from diseased dogs were more frequently seropositive for CRCoV, with higher POI, than samples from healthy dogs. CONCLUSIONS AND CLINICAL RELEVANCE We showed that CAdV-2, CPIV, CHV, CRCoV, B. bronchiseptica and M. cynos circulated among sampled dogs. The convenience sampling methodology, with a poor match between the populations of diseased and healthy dogs in terms of age, breed and use, together with the relatively small sample size precluded inference of any causal relationships between infection with a given pathogen and development of disease. None-the-less, our data suggest that further investigation into epidemiology and disease association of CRCoV and M. cynos is warranted. In addition, circulation of novel respiratory pathogens among dogs in New Zealand should be considered in future studies, as 70/94 (74%) diseased dogs were negative for all the pathogens tested.

Long-term shedding of Canine alphaherpesvirus 1 in naturally infected newborn pups

The long-term shedding of Canine alphaherpesvirus 1 (CaHV-1) by neonatal pups with natural infection is reported. The pups belonged to a litter of 11 pointers of a breeding kennel in southern Italy, 9 of which developed a fatal form of systemic infection, as resulted by the detection of CaHV-1 in internal organs (kidney, liver, lung and brain) of one of this dogs and in the vaginal swab of their mother. The two remaining animals displayed a milder form of disease, with one pup showing ocular involvement, and underwent a progressive recovery. These pups were monitored from 11 to 36  days of age, showing a long-term shedding of the virus through the nasal and ocular secretions and the faeces. CaHV-1 shedding, as assessed by means of a specific and sensitive real-time PCR assay, occurred mainly through the nasal secretions, although the pup displaying ocular disease shed the virus at high titres and for a long period even in the ocular secretions.

Prevalence of respiratory viruses isolated from dogs in Thailand during 2008-2009

Background: A highly contagious respiratory disease in canines is infectious tracheobronchitis or kennel cough characterized by inflammation of the upper respiratory tract. The cause of kennel cough has been associated with multiple or complex agents such as canine adeno virus (CAV), canine influenza virus (CIV), canine distemper virus (CDV), and canine para influenzavirus (CPIV). Objective: Study the prevalence of canine respiratory viruses detected from in Thailand during 2008-2009. Methods: Nasal swab samples collected from 102 healthy dogs and 109 dogs with respiratory diseases. Then CAV, CIV, CDV, and CPIV were detected by in-house nested PCR and further confirmed by nucleotide sequencing. Results: Nested PCR showed that primers designed and used in this study yielded high specificity without any non-specific amplification. The prevalence of CAV, CIV, CDV and CPIV in healthy dogs was 0%, 2.94%, 2.94%, and 0.98%, whereas that found in dogs with respiratory diseases was 9.17%, 1.83%, 2.75%, and 11.93%, respectively. In healthy dogs, co-infection with CPIV + CDV was detected in only 0.98%. On the other hand, dogs with respiratory symptoms showed multiple infections with CAV + CIV in 1.83%, CIV + CPIV in 0.92%, CAV + CPIV in 1.83%, and CAV + CDV + CPIV in 0.92%. Conclusion: The prevalence data obtained from this study may be useful for outbreak preventions and to raise awareness of potential transmission of the newly emerged canine influenza virus to humans.

Characterization of a Novel Bat Adenovirus Isolated from Straw-Colored Fruit Bat (Eidolon helvum)

Bats are important reservoirs for emerging zoonotic viruses. For extensive surveys of potential pathogens in straw-colored fruit bats (Eidolon helvum) in Zambia, a total of 107 spleen samples of E. helvum in 2006 were inoculated onto Vero E6 cells. The cell culture inoculated with one of the samples (ZFB06-106) exhibited remarkable cytopathic changes. Based on the ultrastructural property in negative staining and cross-reactivity in immunofluorescence assays, the virus was suspected to be an adenovirus, and tentatively named E. helvum adenovirus 06-106 (EhAdV 06-106). Analysis of the full-length genome of 30,134 bp, determined by next-generation sequencing, showed the presence of 28 open reading frames. Phylogenetic analyses confirmed that EhAdV 06-106 represented a novel bat adenovirus species in the genus Mastadenovirus. The virus shared similar characteristics of low G + C contents with recently isolated members of species Bat mastadenoviruses E, F and G, from which EhAdV 06-106 diverged by more than 15% based on the distance matrix analysis of DNA polymerase amino acid sequences. According to the taxonomic criteria, we propose the tentative new species name “Bat mastadenovirus H”. Because EhAdV 06-106 exhibited a wide in vitro cell tropism, the virus might have a potential risk as an emerging virus through cross-species transmission.

Novel adenoviruses detected in British mustelids, including a unique Aviadenovirus in the tissues of pine martens (Martes martes)

Several adenoviruses are known to cause severe disease in veterinary species. Recent evidence suggests that canine adenovirus type 1 (CAV-1) persists in the tissues of healthy red foxes (Vulpes vulpes), which may be a source of infection for susceptible species. It was hypothesized that mustelids native to the UK, including pine martens (Martes martes) and Eurasian otters (Lutra lutra), may also be persistently infected with adenoviruses. Based on high-throughput sequencing and additional Sanger sequencing, a novel Aviadenovirus, tentatively named marten adenovirus type 1 (MAdV-1), was detected in pine marten tissues. The detection of an Aviadenovirus in mammalian tissue has not been reported previously. Two mastadenoviruses, tentatively designated marten adenovirus type 2 (MAdV-2) and lutrine adenovirus type 1 (LAdV-1), were also detected in tissues of pine martens and Eurasian otters, respectively. Apparently healthy free-ranging animals may be infected with uncharacterized adenoviruses with possible implications for translocation of wildlife.

Detection of canine adenovirus 1 in red foxes (Vulpes vulpes) and raccoons (Procyon lotor) in Germany with a TaqMan real-time PCR assay

We developed a real-time (rt)PCR assay based on TaqMan probe technology for the specific detection of canine adenovirus 1 (CAdV-1). The assay is able to detect three 50% tissue culture infectious dose/mL in CAdV-1–containing cell culture supernatant. Viral genomes were not amplified of canine adenovirus 2 or of several bovine, porcine, and avian adenoviruses. In silico analysis provided no indication of amplification of other heterologous genomes. The sensitivity of the real-time assay exceeded that of a conventional gel-based CAdV-1 PCR by a factor of 100. Following the integration of the novel PCR into the Hessian wildlife-monitoring program, CAdV-1 DNA was detected in none of the tested raccoons ( n = 48) but in 11 of 97 foxes.

Genome Sequence of a Novel Canine Picornavirus Isolated from an American Foxhound

A candidate new canine picornavirus was isolated from a respiratory swab collected from an American foxhound (Canis lupus familiaris) in 1968. The assembled genome sequence of strain A128thr is 7,618 bases in length, comprising a complete protein-coding sequence of the 2,213-amino-acid polyprotein and partial terminal untranslated sequences.

Discovery of a novel canine respiratory coronavirus support genetic recombination among betacoronavirus1

Although canine respiratory coronavirus (CRCoV) is an important respiratory pathogen that is prevalent in many countries, only one complete genome sequence of CRCoV (South Korea strain K37) has been obtained to date. Genome-wide analyses and recombination have rarely been conducted, as small numbers of samples and limited genomic characterization have previously prevented further analyses. Herein, we report a unique CRCoV strain, denoted strain BJ232, derived from a CRCoV-positive dog with a mild respiratory infection. Phylogenetic analysis based on complete genome of all available coronaviruses consistently show that CRCoV BJ232 is most closely related to human coronavirus OC43 (HCoV-OC43) and BCoV, forming a separate clade that split off early from other Betacoronavirus 1. Based on the phylogenetic and SimPlot analysis we propose that CRCoV-K37 was derived from genetic recombination between CRCoV-BJ232 and BCoV. In detail, spike (S) gene of CRCoV-K37 clustered with CRCoV-BJ232. However orf1ab, membrane (M) and nucleocapsid (N) genes were more related to Bovine coronavirus (BCoV) than CRCoV-B232. Molecular epidemic analysis confirmed the prevalence of CRCoV-BJ232 lineage around the world for a long time. Recombinant events among Betacoronavirus 1 may have implications for CRCoV transmissibility. All these findings provide further information regarding the origin of CRCoV.

The detection and differentiation of canine respiratory pathogens using oligonucleotide microarrays

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Multiple canine respiratory pathogens were differentiated simultaneously.

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Wild type and vaccine strains of canine distemper virus were distinguished.

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Results were read with naked eye and no reader equipment was needed.

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High sensitivity, specificity and efficiency.

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Low money and time costs.

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.

Prevalence of respiratory pathogens detected in dogs with kennel cough in Poland

Kennel cough is a multifactorial disease occurring all over the world; however, its epidemiology is still not fully understood. To the authors’ knowledge, no studies monitoring the occurrence of infectious agents responsible for kennel cough have been carried out in Poland. Therefore, the objective of our study was to determine which of the four pathogens most frequently isolated in other countries are predominant in north-eastern Poland. Swabs from the upper respiratory tract and tracheal lavage fluids from dogs (n = 40) exhibiting symptoms of this disease were analysed. Canine herpesvirus, canine parainfluenza virus, canine adenovirus type 2 andBordetella bronchisepticawere identified by polymerase chain reaction. At least one of the above-listed infectious agents was found in all dogs. The predominant pathogen within the area under our study, both in mono- and co-infections, was canine herpesvirus (32/40), whereas canine adenovirus type 2 occurred least frequently (4/40). The effectiveness of detection of selected pathogens from both types of study material was also compared. Tracheal lavage fluid was more suitable for the isolation of canine herpes virus, canine parainfluenza virus, andBordetella bronchiseptica. Swabs from the upper respiratory tract were more suitable for the isolation of canine adenovirus type 2.

Development and application of multiplex PCR assays for detection of virus-induced respiratory disease complex in dogs

Canine infectious respiratory disease complex (CIRDC) viruses have been detected in dogs with respiratory illness. Canine influenza virus (CIV), canine parainfluenza virus (CPIV), canine distemper virus (CDV), canine respiratory coronavirus (CRCoV), canine adenovirus type 2 (CAdV-2) and canine herpesvirus 1 (CaHV-1), are all associated with the CIRDC. To allow diagnosis, two conventional multiplex polymerase chain reactions (PCR) were developed to simultaneously identify four RNA and two DNA viruses associated with CIRDC. The two multiplex PCR assays were then validated on 102 respiratory samples collected from 51 dogs with respiratory illness by sensitivity and specificity determination in comparison to conventional simplex PCR and a rapid three-antigen test kit. All six viruses were detected in either individual or multiple infections. The developed multiplex PCR assays had a >87% sensitivity and 100% specificity compared to their simplex counterpart. Compared to the three-antigen test kit, the multiplex PCR assays yielded 100% sensitivity and more than 83% specificity for detection of CAdV-2 and CDV, but not for CIV. Therefore, the developed multiplex PCR modalities were able to simultaneously diagnose a panel of CIRDC viruses and facilitated specimen collection through being suitable for use of nasal or oral samples.

Detection of respiratory viruses in shelter dogs maintained under varying environmental conditions

Three dog shelters in Rio Grande do Sul were investigated for associations between the occurrence of respiratory viruses and shelter environmental conditions. Nasal secretions randomly collected during the cold season were tested via PCR, and this data collection was followed by nucleotide sequencing of the amplicons. In shelter #1 (poor sanitary and nutritional conditions, high animal density and constant contact between dogs), 78% (58/74) of the nasal samples were positive, 35% (26/74) of which were in single infections and 44% (32/74) of which were in coinfections. Shelters #2 and #3 had satisfactory sanitary and nutritional conditions, outdoors exercise areas (#2) and animal clustering by groups (#3). In shelter #2, 9% (3/35) of the samples were positive for Canine parainfluenza virus (CPIV), and 6% (2/35) were positive for Canid herpesvirus 1 (CaHV-1). In shelter #3, 9% (7/77) of the samples were positive for Canine adenovirus type 2 (CAdV-2), and 1% (1/77) were positive for Canine distemper virus (CDV). The amplicon sequences (CPIV and CDV nucleoprotein gene; CAdV-2 E3 gene; CaHV-1 glycoprotein B gene) showed 94-100% nucleotide identity with GenBank sequences. Our results demonstrate that CPIV, CAdV-2 and CDV are common in dog shelters and that their frequencies appear to be related with environmental and nutritional conditions. These results indicate the need for control/prevention measures, including vaccination and environmental management, to minimize these infections and improve dog health.

Molecular surveillance of traditional and emerging pathogens associated with canine infectious respiratory disease

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A molecular survey for CIRD agents was conducted during years 2011–2013.

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Canine parainfluenza virus was the most frequently detected pathogens.

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The emerging pathogens canine respiratory coronavirus, Mycoplasma cynos and canine pneumovirus were sporadically detected.

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Most severe forms of respiratory disease were observed in dogs infected with M. cynos alone or in combination with either CRCoV or M. canis.

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CIRD vaccines should be updated to include emerging pathogens.

A molecular survey for traditional and emerging pathogens associated with canine infectious respiratory disease (CIRD) was conducted in Italy between 2011 and 2013 on a total of 138 dogs, including 78 early acute clinically ill CIRD animals, 22 non-clinical but exposed to clinically ill CIRD dogs and 38 CIRD convalescent dogs. The results showed that canine parainfluenza virus (CPIV) was the most commonly detected CIRD pathogen, followed by canine respiratory coronavirus (CRCoV), Bordetella bronchiseptica, Mycoplasma cynos, Mycoplasma canis and canine pneumovirus (CnPnV). Some classical CIRD agents, such as canine adenoviruses, canine distemper virus and canid herpesvirus 1, were not detected at all, as were not other emerging respiratory viruses (canine influenza virus, canine hepacivirus) and bacteria (Streptococcus equi subsp. zooepidemicus). Most severe forms of respiratory disease were observed in the presence of CPIV, CRCoV and M. cynos alone or in combination with other pathogens, whereas single CnPnV or M. canis infections were detected in dogs with no or very mild respiratory signs. Interestingly, only the association of M. cynos (alone or in combination with either CRCoV or M. canis) with severe clinical forms was statistically significant. The study, while confirming CPIV as the main responsible for CIRD occurrence, highlights the increasing role of recently discovered viruses, such as CRCoV and CnPnV, for which effective vaccines are not available in the market.

A duplex real-time PCR assay based on TaqMan technology for simultaneous detection and differentiation of canine adenovirus types 1 and 2

Canine adenoviruses are a major cause of disease in dogs, coyotes, red foxes and wolves, as well as in other carnivores and marine mammals. Canine adenovirus type 1 (CAdV-1) and canine adenovirus type 2 (CAdV-2) cause infectious canine hepatitis (ICH) and infectious tracheobronchitis (ITB), respectively. In this study, a duplex real-time PCR assay for simultaneous detection and characterisation of CAdV-1 and CAdV-2 was developed by using a single primer pair and virus-specific probes. The assay was validated testing standard DNAs produced on purpose and clinical samples of various matrices known to be positive for CAdV-1, CAdV-2 or both viruses. Precise calculation of DNA loads in samples containing a wide range of viral amounts was allowed by generating a standard curve for absolute quantification. The assay was proven to be highly specific, since no cross-reactions with the different CAdV type was observed, and sensitive, being able to detect less than 10 copies of CAdV-1/CAdV-2 DNA. The low intra-assay and interassay coefficient of variations demonstrated a high repeatability, thus confirming the potential use of this assay for quantitative detection of CAdV-1 and CAdV-2 for rapid diagnosis and epidemiological investigations.

Prevalence and risk factors for viral exposure in rural dogs around protected areas of the Atlantic forest

BACKGROUND

Despite the crucial role of domestic dogs as reservoirs for zoonosis and some of the most threatening diseases for wild carnivores such as distemper and parvovirosis, little is known about the epidemiological features and the risk factors involved in pathogen exposure of dogs that live in human/wildlife interfaces and actually contacts wildlife. Through a cross-sectional serological approach and questionnaire survey, we assessed the prevalence along with individual and environment-associated risk factors for four important viral diseases of rural dogs living in households around six Atlantic Forest fragments in southeast Brazil.

RESULTS

Widespread exposure to canine parvovirus (97%), canine distemper virus (15%) and canine adenovirus (27%) was detected, but none for canine coronavirus. Dogs from small private reserves were more exposed to parvovirus and canine distemper virus than those from larger state parks. Exposure was associated with dog sex and age, lack of health care and the number of people in the households. Remarkably, factors linked to free-ranging behaviour of dogs were associated with the exposure for all pathogens detected.

CONCLUSIONS

According to identified associations, reducing viral pathogen exposure in dogs will require inhibiting dog's movements and access to nearby forests and villages and improving veterinary assistance. Promoting dog vaccination and population control through sterilization around protected areas is also necessary. The study provides support for preventive management actions aimed to protect the health of rural dogs, and consequently of Atlantic Forest's wild carnivores.

Co-infections with respiratory viruses in dogs with bacterial pneumonia

Background

Bacterial pneumonia (BP) is an inflammation of the lower airways and lung parenchyma secondary to bacterial infection. The pathogenesis of BP in dogs is complex and the role of canine respiratory viruses has not been fully evaluated.

Objectives

The aim of this study was to investigate the occurrence of viral co‐infections in dogs with BP and to assess demographic or clinical variables as well as disease severity associated with viral co‐infections.

Animals

Twenty household dogs with BP caused by opportunistic bacteria and 13 dogs with chronic (>30 days) tracheobronchitis caused by Bordetella bronchiseptica (BBTB).

Methods

Prospective cross‐sectional observational study. Diagnosis was confirmed by clinical and laboratory findings, diagnostic imaging, and cytologic and microbiologic analysis of bronchoalveolar lavage or transtracheal wash fluid. Canine parainfluenza virus (CPIV), canine adenovirus, canine herpes virus, canine influenzavirus, canine distemper virus, canine respiratory coronavirus (CRCoV) and canine pneumovirus, as well as B. bronchiseptica and Mycoplasma spp. were analyzed in respiratory samples using PCR assays.

Results

CPIV was detected in 7/20 and CRCoV in 1/20 dogs with BP. Respiratory viruses were not detected in dogs with BBTB. There were no significant differences in clinical variables between BP dogs with and without a viral co‐infection.

Conclusion and Clinical Importance

Respiratory viruses were found frequently in dogs with BP and may therefore play an important role in the etiology and pathogenesis of BP. Clinical variables and disease severity did not differ between BP dogs with and without viral co‐infection.

Prevalence of canine infectious respiratory pathogens in asymptomatic dogs presented at US animal shelters

OBJECTIVES

To determine the prevalence of nine canine infectious respiratory disease (CIRD) pathogens in asymptomatic dogs presented at animal shelters across the United States.

METHODS

Ocular and oronasal swabs from asymptomatic dogs (n = 503) were tested using qPCR assay for Bordetella bronchiseptica, canine adenovirus type 2 (CAV‐2), canine distemper virus (CDV), canine herpesvirus type 1 (CHV), canine influenza virus (CIV), canine parainfluenza virus (CPIV), canine respiratory coronavirus (CRCoV), Mycoplasma cynos and Streptococcus equi subsp zooepidemicus.

RESULTS

A total of 240 (47 · 7%) asymptomatic dogs were PCR‐positive for at least one CIRD pathogen. Prevalence of two‐, three‐, four‐, and five‐pathogen cases was 12 · 7, 3 · 8, 1 · 8, and 0 · 4%, respectively. Mycoplasma cynos (29 · 2%), B. bronchiseptica (19 · 5%), CAV‐2 (12 · 5%), CDV (7 · 4%) and CPIV (3 · 2%) were the most commonly detected pathogens.

CLINICAL SIGNIFICANCE

The prevalence of traditional and newly emerging pathogens associated with CIRD is poorly defined in clinically healthy dogs. This study determined that a high percentage of asymptomatic shelter dogs harbor CIRD pathogens, including the newly emerging pathogen M. cynos and the historically prevalent pathogen B. bronchiseptica.

Investigation of the presence of canine adenovirus (CAdV) in owned dogs in Northern Italy

The use of a modified live canine adenovirus (CAdV) vaccine has greatly reduced the incidence of infectious canine hepatitis (ICH) in dogs. Nevertheless, cases of CAdV type 1 and 2 (CAdV-1 and CAdV-2) infection have been recently reported posing questions about the epidemiological situation of CAdV in dogs. In order to assess the presence of CAdV, samples from 51 dogs presented at a Veterinary Teaching Hospital in Bologna, Italy, for reasons unrelated with CAdV infection, were tested with a polymerase chain reaction (PCR) assay for CAdV. Thirty dogs (58.8%) were PCR positive for CAdV-2 infection and four of them (7.8%) were positive for CAdV-1. Sequence analysis performed on the obtained PCR products suggests that a genetically stable CAdV-1 strain and different CAdV-2 strains circulate in the canine population examined and that coinfections are relatively frequent.

European bats as carriers of viruses with zoonotic potential

Bats are being increasingly recognized as reservoir hosts of highly pathogenic and zoonotic emerging viruses (Marburg virus, Nipah virus, Hendra virus, Rabies virus, and coronaviruses). While numerous studies have focused on the mentioned highly human-pathogenic bat viruses in tropical regions, little is known on similar human-pathogenic viruses that may be present in European bats. Although novel viruses are being detected, their zoonotic potential remains unclear unless further studies are conducted. At present, it is assumed that the risk posed by bats to the general public is rather low. In this review, selected viruses detected and isolated in Europe are discussed from our point of view in regard to their human-pathogenic potential. All European bat species and their roosts are legally protected and some European species are even endangered. Nevertheless, the increasing public fear of bats and their viruses is an obstacle to their protection. Educating the public regarding bat lyssaviruses might result in reduced threats to both the public and the bats.