Rapid diagnosis of canine respiratory coronavirus, canine influenza virus, canine distemper virus and canine parainfluenza virus with a Taqman probe-based multiplex real-time PCR

Canine Infectious Respiratory Disease Complex (CIRDC) is a highly infectious diseases. Canine respiratory coronavirus (CRCoV), Canine influenza virus (CIV), Canine distemper virus (CDV), and Canine parainfluenza virus (CPiV) are crucial pathogens causing CIRDC. Due to the similar clinical symptoms induced by these viruses, differential diagnosis based solely on symptoms can be challenging. In this study, a multiplex real-time PCR assay was developed for detecting the four RNA viruses of CIRDC. Specific primers and probes were designed to target M gene of CRCoV, M gene of CIV, N gene of CDV and NP gene of CPiV. The detection limit is 10 copies/μL for CIV or CRCoV, while the detection limit of CDV or CPiV is 100 copies/μL. Intra-group and inter-group repeatability coefficient of variation (CV) were both less than 2 %. A total of 341 clinical canine samples were analyzed, and the results indicated that the method developed in our study owns a good consistency and better specificity compared with the conventional reverse transcription PCR. This study provides a new method to enable the simultaneous detection of all four pathogens in a single reaction, improving the efficiency for monitoring the prevalence of four viruses in CIRDC, which benefits the control of CIRDC.

Persistent paramyxovirus infections: in co-infections the parainfluenza virus type 5 persistent phenotype is dominant over the lytic phenotype

Parainfluenza virus type 5 (PIV5) can either have a persistent or a lytic phenotype in cultured cells. We have previously shown that the phenotype is determined by the phosphorylation status of the phosphoprotein (P). Single amino acid substitutions at critical residues, including a serine-to-phenylalanine substitution at position 157 on P, result in a switch between persistent and lytic phenotypes. Here, using PIV5 vectors expressing either mCherry or GFP with persistent or lytic phenotypes, we show that in co-infections the persistent phenotype is dominant. Thus, in contrast to the cell death observed with cells infected solely with the lytic variant, in co-infected cells persistence is immediately established and both lytic and persistent genotypes persist. Furthermore, 10-20 % of virus released from dually infected cells contains both genotypes, indicating that PIV5 particles can package more than one genome. Co-infected cells continue to maintain both genotypes/phenotypes during cell passage, as do individual colonies of cells derived from a culture of persistently infected cells. A refinement of our model on how the dynamics of virus selection may occur in vivo is presented.

An Improved Duplex Real-Time Quantitative RT-PCR Assay with a Canine Endogenous Internal Positive Control for More Sensitive and Reliable Detection of Canine Parainfluenza Virus 5

A duplex real-time quantitative reverse transcription-polymerase chain reaction (dqRT-PCR) assay was successfully developed to simultaneously detect canine parainfluenza virus 5 (CPIV5) and a canine endogenous internal positive control (EIPC) in canine clinical samples. Two sets of primers and probes for the CPIV5 L and canine 16S rRNA genes were included in the dqRT-PCR assay to detect CPIV and monitor invalid results throughout the qRT-PCR process. The developed dqRT-PCR assay specifically detected CPIV5 but no other canine pathogens. Furthermore, 16S rRNA was stably amplified by dqRT-PCR assay in all samples containing canine cellular materials. The assay's sensitivity was determined as below ten RNA copies per reaction, with CPIV5 L gene standard RNA and 1 TCID₅₀/mL with the CPIV5 D008 vaccine strain, which was 10-fold higher than that of the previous HN gene-specific qRT-PCR (HN-qRT-PCR) assays and was equivalent to that of the previous N gene-specific qRT-PCR (N-qRT-PCR) assays, respectively. Moreover, the Ct values of the CPIV5-positive samples obtained using the dqRT-PCR assay were lower than those obtained using the previous HN- and N-qRT-PCR assays, indicating that the diagnostic performance of the dqRT-PCR assay was superior to those of previous HN- and N-qRT-PCR assays. The calculated Cohen's kappa coefficient values (95% confidence interval) between dqRT-PCR and the HN- or N-specific qRT-PCR assays were 0.97 (0.90-1.03) or 1.00 (1.00-1.00), respectively. In conclusion, the newly developed dqRT-PCR assay with high sensitivity, specificity, and reliability will be a promising diagnostic tool for the detection of CPIV5 in clinical samples and useful for etiological and epidemiological studies of CPIV5 infection in dogs.

2022 AAHA Canine Vaccination Guidelines

These guidelines are an update and extension of previous AAHA peer-reviewed canine vaccination guidelines published in 2017. Vaccination is a cornerstone of canine preventive healthcare and one of the most cost-effective ways of maintaining a dog's health, longevity, and quality of life. Canine vaccination also serves a public health function by forming a barrier against several zoonotic diseases affecting dogs and humans. Canine vaccines are broadly categorized as containing core and noncore immunizing antigens, with administration recommendations based on assessment of individual patient risk factors. The guidelines include a comprehensive table listing canine core and noncore vaccines and a recommended vaccination and revaccination schedule for each vaccine. The guidelines explain the relevance of different vaccine formulations, including those containing modified-live virus, inactivated, and recombinant immunizing agents. Factors that potentially affect vaccine efficacy are addressed, including the patient's prevaccination immune status and vaccine duration of immunity. Because animal shelters are one of the most challenging environments for prevention and control of infectious diseases, the guidelines also provide recommendations for vaccination of dogs presented at or housed in animal shelters, including the appropriate response to an infectious disease outbreak in the shelter setting. The guidelines explain how practitioners can interpret a patient's serological status, including maternally derived antibody titers, as indicators of immune status and suitability for vaccination. Other topics covered include factors associated with postvaccination adverse events, vaccine storage and handling to preserve product efficacy, interpreting product labeling to ensure proper vaccine use, and using client education and healthcare team training to raise awareness of the importance of vaccinations.

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.

Detection of porcine parainfluenza virus type-1 antibody in swine serum using whole-virus ELISA, indirect fluorescence antibody and virus neutralizing assays

BACKGROUND

Porcine parainfluenza virus 1 (PPIV-1) is a respiratory virus in the family Paramyxoviridae and genus Respirovirus. It is closely related to bovine parainfluenza virus 3, human parainfluenza virus 1, and Sendai virus. Recent reports suggest PPIV-1 is widespread in swine herds in the United States and abroad. However, seroprevalence studies and the ability to evaluate cross neutralization between heterologous strains is not possible without validated antibody assays. This study describes the development of an indirect fluorescence antibody (IFA) assay, a whole virus enzyme-linked immunosorbent assay (wv-ELISA) and a serum virus neutralization (SVN) assay for the detection of PPIV-1 antibodies using 521 serum samples collected from three longitudinal studies and two different challenge strains in swine.

RESULTS

The area under the curve (AUC) of the wv-ELISA (95% CI, 0.93-0.98) was significantly higher (p = 0.03) compared to the IFA (95% CI, 0.90-0.96). However, no significant difference was observed between the IFA and wv-ELISA when compared to the SVN (95% CI, 0.92-0.97). All three assays demonstrated relatively uniform results at a 99% true negative rate, with only 11 disagreements observed between the IFA, wv-ELISA and SVN.

CONCLUSIONS

All three serology assays detected PPIV-1 antibody in swine serum of known status that was collected from experimental studies. The SVN detected seroconversion earlier compared to the IFA and the wv-ELISA. Both the wv-ELISA and the SVN had similar diagnostic performance, while the IFA was not as sensitive as the wv-ELISA. All three assays are considered valid for routine diagnostic use. These assays will be important for future studies to screen seronegative swine for research, determine PPIV-1 seroprevalence, and to evaluate vaccine efficacy against PPIV-1 under experimental and field conditions.

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.

Molecular detection and whole genome characterization of Canine Parainfluenza type 5 in Thailand

Parainfluenza virus type 5 (PIV-5) causes respiratory infection in several animal species and humans. Canine parainfluenza virus type 5 (CPIV-5) causes respiratory disease in domestic dogs worldwide. In this study, we conducted a cross-sectional survey of CPIV-5 in dogs with respiratory symptoms from small animal hospitals in Thailand from November 2015 to December 2018. Our results showed that 32 out of 571 nasal swab samples (5.6%) were positive for CPIV-5 by RT-PCR specific to the NP gene. To characterize the viruses, three representative CPIV-5 were subjected to whole genome sequencing, and an additional ten CPIV-5 were subjected to HN, F, SH and V/P gene sequencing. Pairwise sequence comparison and phylogenetic analysis showed that Thai CPIV-5 was closely related to the CPIV-5 isolated from China and Korea. In conclusion, this study constitutes a whole genome characterization of CPIV-5 from dogs in Thailand. The surveillance of CPIV-5 should be further investigated at a larger scale to determine the dynamics, distribution and potential zoonotic transmission of CPIV-5.

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.

The switch between acute and persistent paramyxovirus infection caused by single amino acid substitutions in the RNA polymerase P subunit

Paramyxoviruses can establish persistent infections both in vitro and in vivo, some of which lead to chronic disease. However, little is known about the molecular events that contribute to the establishment of persistent infections by RNA viruses. Using parainfluenza virus type 5 (PIV5) as a model we show that phosphorylation of the P protein, which is a key component of the viral RNA polymerase complex, determines whether or not viral transcription and replication becomes repressed at late times after infection. If the virus becomes repressed, persistence is established, but if not, the infected cells die. We found that single amino acid changes at various positions within the P protein switched the infection phenotype from lytic to persistent. Lytic variants replicated to higher titres in mice than persistent variants and caused greater infiltration of immune cells into infected lungs but were cleared more rapidly. We propose that during the acute phases of viral infection in vivo, lytic variants of PIV5 will be selected but, as the adaptive immune response develops, variants in which viral replication can be repressed will be selected, leading to the establishment of prolonged, persistent infections. We suggest that similar selection processes may operate for other RNA viruses.

As well as causing acute infections that result in mild to serious disease, many RNA viruses can establish prolonged or persistent infections in some infected individuals, that occasionally lead to chronic or reactive disease. Little is known about the molecular mechanisms involved in the establishment of such infections. Using parainfluenza virus type 5 (PIV5) as a model, we show how lytic and persistent variants of the virus can be selected on the basis of single amino acid substitutions and propose that the selection of persistent variants as the adaptive immune response develops following an acute infection might be a mechanism these viruses have evolved to enhance their transmission rates. As well as being of fundamental interest, understanding the molecular basis by which RNA viruses establish persistent infections may improve our understanding of virus epidemiology (and hence improve the control of virus infections) and of virus:host interactions that influence the relationship between virus persistence and chronic/relapsing disease. Furthermore, the knowledge of how RNA viruses, such as PIV5, establish persistent infections may lead to improve vaccine design since vectors which can establish persistent infections may induce longer-lasting more robust immunity.

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.

European surveillance of emerging pathogens associated with canine infectious respiratory disease

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The largest study of its kind in the field to date, including high-risk kennelled dogs, and for the first time, pet dogs and dogs from other cohorts.

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A clearly identifiable link between disease and the emerging pathogens: canine respiratory coronavirus and canine pneumovirus.

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Provides, substantial evidence of CIRD and the circulation of the novel pathogens studied in pet dogs, and dogs from other cohorts.

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Demonstrates the role and limitations of current vaccine strategies in managing CIRD outbreaks, and the need for including emerging pathogens.

Canine infectious respiratory disease (CIRD) is a major cause of morbidity in dogs worldwide, and is associated with a number of new and emerging pathogens. In a large multi-centre European study the prevalences of four key emerging CIRD pathogens; canine respiratory coronavirus (CRCoV), canine pneumovirus (CnPnV), influenza A, and Mycoplasma cynos (M. cynos); were estimated, and risk factors for exposure, infection and clinical disease were investigated.

CIRD affected 66% (381/572) of the dogs studied, including both pet and kennelled dogs. Disease occurrence and severity were significantly reduced in dogs vaccinated against classic CIRD agents, canine distemper virus (CDV), canine adenovirus 2 (CAV-2) and canine parainfluenza virus (CPIV), but substantial proportions (65.7%; 201/306) of vaccinated dogs remained affected.

CRCoV and CnPnV were highly prevalent across the different dog populations, with overall seropositivity and detection rates of 47% and 7.7% for CRCoV, and 41.7% and 23.4% for CnPnV, respectively, and their presence was associated with increased occurrence and severity of clinical disease. Antibodies to CRCoV had a protective effect against CRCoV infection and more severe clinical signs of CIRD but antibodies to CnPnV did not.

Involvement of M. cynos and influenza A in CIRD was less apparent. Despite 45% of dogs being seropositive for M. cynos, only 0.9% were PCR positive for M. cynos. Only 2.7% of dogs were seropositive for Influenza A, and none were positive by PCR.

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.

The challenges in developing effective canine infectious respiratory disease vaccines

Objectives

Canine infectious respiratory disease (CIRD) is a disease of multifactorial aetiology, where multiple pathogens act sequentially or synergistically to cause disease. It is common within large dog populations, such as those in re‐homing or training kennels. Vaccines are vital in its management of CIRD, but they often fail to prevent disease. Recently, a number of novel pathogens have been identified in CIRD outbreaks and represent new targets for vaccination.

Key findings

Innate immune responses provide a vital first line of defence against the infectious agents involved in the development of CIRD. Once breeched, adaptive mucosal immunity is necessary to prevent infection and limit spread. Current vaccines target only a few of the agents involved in CIRD. Evidence, from the limited amount of published data, indicates that although vaccinating against these agents reduces infection rates, duration of shedding and severity of disease, it does not induce sterilising immunity; and this has important consequences for the management of the disease, and the future of CIRD vaccine development.

Summary

In the process of considering the development of novel CIRD vaccines, this paper focuses on the immunological mechanisms that provide protection for the respiratory tract, the current recommendations for canine vaccination, and the challenges surrounding existing CIRD vaccines, and their future development.

Detection of respiratory viruses and Bordetella bronchiseptica in dogs with acute respiratory tract infections

Canine infectious respiratory disease (CIRD) is an acute, highly contagious disease complex caused by a variety of infectious agents. At present, the role of viral and bacterial components as primary or secondary pathogens in CIRD is not fully understood. The aim of this study was to investigate the prevalence of canine parainfluenza virus (CPIV), canine adenovirus type 2 (CAV-2), canine influenza virus (CIV), canine respiratory coronavirus (CRCoV), canine herpes virus-1 (CHV-1), canine distemper virus (CDV) and Bordetella bronchiseptica in dogs with CIRD and to compare the data with findings in healthy dogs. Sixty-one dogs with CIRD and 90 clinically healthy dogs from Southern Germany were prospectively enrolled in this study. Nasal and pharyngeal swabs were collected from all dogs and were analysed for CPIV, CAV-2, CIV, CRCoV, CHV-1, CDV, and B. bronchiseptica by real-time PCR.

In dogs with acute respiratory signs, 37.7% tested positive for CPIV, 9.8% for CRCoV and 78.7% for B. bronchiseptica. Co-infections with more than one agent were detected in 47.9% of B. bronchiseptica-positive, 82.6% of CPIV-positive, and 100% of CRCoV-positive dogs. In clinically healthy dogs, 1.1% tested positive for CAV-2, 7.8% for CPIV and 45.6% for B. bronchiseptica. CPIV and B. bronchiseptica were detected significantly more often in dogs with CIRD than in clinically healthy dogs (P < 0.001 for each pathogen) and were the most common infectious agents in dogs with CIRD in Southern Germany. Mixed infections with several pathogens were common. In conclusion, clinically healthy dogs can carry respiratory pathogens and could act as sources of infection for susceptible dogs.

Full-genome analysis of a canine pneumovirus causing acute respiratory disease in dogs, Italy

An outbreak of canine infectious respiratory disease (CIRD) associated to canine pneumovirus (CnPnV) infection is reported. The outbreak occurred in a shelter of the Apulia region and involved 37 out of 350 dogs that displayed cough and/or nasal discharge with no evidence of fever. The full-genomic characterisation showed that the causative agent (strain Bari/100-12) was closely related to CnPnVs that have been recently isolated in the USA, as well as to murine pneumovirus, which is responsible for respiratory disease in mice. The present study represents a useful contribution to the knowledge of the pathogenic potential of CnPnV and its association with CIRD in dogs. Further studies will elucidate the pathogenicity and epidemiology of this novel pneumovirus, thus addressing the eventual need for specific vaccines.

Detection of canine pneumovirus in dogs with canine infectious respiratory disease

Canine pneumovirus (CnPnV) was recently identified during a retrospective survey of kenneled dogs in the United States. In this study, archived samples from pet and kenneled dogs in the United Kingdom were screened for CnPnV to explore the relationship between exposure to CnPnV and the development of canine infectious respiratory disease (CIRD). Within the pet dog population, CnPnV-seropositive dogs were detected throughout the United Kingdom and Republic of Ireland, with an overall estimated seroprevalence of 50% (n = 314/625 dogs). In the kennel population, there was a significant increase in seroprevalence, from 26% (n = 56/215 dogs) on the day of entry to 93.5% (n = 201/215 dogs) after 21 days (P <0001). Dogs that were seronegative on entry but seroconverted while in the kennel were 4 times more likely to develop severe respiratory disease than those that did not seroconvert (P < 0.001), and dogs with preexisting antibodies to CnPnV on the day of entry were significantly less likely to develop respiratory disease than immunologically naive dogs (P < 0.001). CnPnV was detected in the tracheal tissues of 29/205 kenneled dogs. Detection was most frequent in dogs with mild to moderate respiratory signs and histopathological changes and in dogs housed for 8 to 14 days, which coincided with a significant increase in the risk of developing respiratory disease compared to the risk of those housed 1 to 7 days (P < 0.001). These findings demonstrate that CnPnV is present in the United Kingdom dog population; there is a strong association between exposure to CnPnV and CIRD in the kennel studied and a potential benefit in vaccinating against CnPnV as part of a wider disease prevention strategy.