A survey of canine respiratory pathogens in New Zealand dogs

Abstract

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.

A serological survey of canine respiratory coronavirus in New Zealand

“…Unfortunately, the timing of sample collection was not provided by Knesl et al (2009), but in the current study the lowest seroprevalences were observed in July (29%) and August (32%), which were similar to the 29% reported by Knesl et al (2009). This may also be supported by the fact that 50% of dogs tested as part of another New Zealand-based survey were seropositive for CRCoV (Sowman et al 2018). The number of samples tested in that study was only 93, but, as in the current study, the samples were collected over a period of several months from July 2012 to August 2013.…”

“…Based on a single cross-sectional survey of 251 dogs, Knesl et al (2009) reported that 73 (29%) dogs were seropositive for CRCoV. In another New Zealand-based study, 47/94 (50%) dogs sampled had antibody to CRCoV (Sowman et al 2018). Some of the dogs affected by ICT seroconverted to CRCoV between acute and convalescent sampling, suggesting that CRCoV infection was associated with the development of disease in those dogs.…”

“…Some of the dogs affected by ICT seroconverted to CRCoV between acute and convalescent sampling, suggesting that CRCoV infection was associated with the development of disease in those dogs. However there was a poor match between diseased and healthy dogs in terms of age, breed, and use, so no conclusions could be made regarding aetiological involvement of CRCoV in development of ICT (Sowman et al 2018).…”

Evolutionary genetics of canine respiratory coronavirus and recent introduction into Swedish dogs

“…This disease is multi-factorial, and a recent European survey reported that CRCoV, canine pneumovirus and the bacteria Mycoplasma cynos, besides the previously established main causes (mainly CPIV and B. bronchiseptica), all played a role in the disease (Mitchell et al, 2017). To date, the highest prevalence of CRCoV remains in rehoming centres (Erles and Brownlie, 2005;Erles et al, 2003;Mitchell et al, 2017), or other instances where dogs may be cohoused, such as in racing greyhounds (Sowman et al, 2018). Epidemiology is unclear in pet dogs, such as those sampled in our study, but we predict that occasions where many dogs meet…”

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

“…zooepidemics. Although CIRD is the most common, worldwide, its etiology or epidemiology may vary across countries [6,12,18,19,21,28,31].…”