Serological prevalence of canine respiratory coronavirus in southern Italy and epidemiological relationship with canine enteric coronavirus.

Canine respiratory coronavirus (CRCoV) has been detected in dogs suffering from respiratory disease and is thought to be involved in canine infectious respiratory disease (CIRD) complex. Canine enteric coronavirus (CECoV) is a widespread pathogen of dogs, responsible for mild to severe diarrhea in pups. The purpose of this study was to establish the seroprevalence of CRCoV in Italy and its relationship to CECoV type II seroprevalence. The age and year of sample collection from seropositive dogs was also assessed. Of adult domestic dogs, 23.3% had antibodies to CRCoV, compared with 86.1% with antibodies to CECoV. Amongst a population of kenneled pups, 4.0% had antibodies to CRCoV, and 97.0% had antibodies to CECoV.     

Serological prevalence of canine respiratory coronavirus

Canine respiratory coronavirus (CRCoV) has recently been detected in dogs; it is a group 2 coronavirus showing similarity to bovine coronavirus (BCoV) but is distinct from canine enteric coronavirus (CECoV). CRCoV may play an important role in canine infectious respiratory disease (CIRD) either by predisposing to further and potentially more serious viral and bacterial infections or possibly as a primary pathogen. The prevalence of serum antibodies to CRCoV, in a population of dogs in the south east of England, has been shown previously to be 30.1% on the first day of entry to a rehoming kennel [Erles, K., Toomey, C., Brooks, H.W., Brownlie, J., 2003. Detection of a group 2 coronavirus in dogs with canine infectious respiratory disease. Virology 310, 216-223]. The purpose of this study was to establish the prevalence of CRCoV in the general canine population within as well as outside the UK. An ELISA, used to test for the presence of antibodies to CRCoV in canine serum samples, identified seropositive dogs in UK, USA, Canada, Republic of Ireland and Greece. The development of an ELISA based on CRCoV antigen and immunofluorescence assay are described here. 54.7% (547/1000) of North American and 36.0% (297/824) of United Kingdom dogs were seropositive for CRCoV. The age and geographical distribution of seropositive dogs was also assessed. The cross-reactivity demonstrated between CRCoV antibodies from different countries and a UK viral isolate suggests immunological similarity. The overall prevalence of this virus in both North America and the UK suggests that CRCoV has international significance and that further epidemiological studies are required.     

Canine coronavirus in Australian dogs

OBJECTIVE: To estimate the frequency of serum antibodies (IgG and IgM) to canine coronavirus (CCV) in the Australian dog population and evaluate the role of CCV as a causative agent of gastroenteritis. DESIGN: A serological survey of antibodies to CCV among different dog populations. PROCEDURE: The development and characterisation of an indirect ELISA for the detection of antibodies (IgG and IgM) to CCV was undertaken. Sera collected from both diarrhoeal and non-diarrhoeal dogs from various populations throughout Australia were tested for these antibodies to CCV. RESULTS: Serum samples (1396) collected from 1984 to 1998 were tested for the presence of IgG antibodies to CCV. Samples were divided into two categories on the basis of the number of dogs housed together. The groups were either an open population containing dogs housed as groups of three or less, or kennel populations. Sera from 15.8% of the open population and 40.8% of kennelled dogs were positive for CCV antibodies. The prevalence of antibodies varied from zero to 76% in kennelled dogs. About 23% of 128 dogs positive for IgG antibodies to CCV were also positive for IgM antibodies to CCV, indicating recent CCV infection. Of those dogs that were presented with clinical signs of gastroenteritis such as diarrhoea and vomiting (n = 29), 85% were positive in the IgM ELISA and 85.7% in the IgG ELISA for antibodies to CCV. In comparison, for those dogs presented without any history of gastroenteritis only 15% were positive for IgM and 30% positive for IgG. CONCLUSION: Serological evidence indicates that infection with CCV in dogs is widespread throughout the Australian mainland. The prevalence of antibodies varies greatly among different populations, with an average of 40.8% positive in kennelled populations and 15.8% in the open population.     

Serological and molecular evidence that canine respiratory coronavirus is circulating in Italy

Canine respiratory coronavirus (CRCoV) is a group II coronavirus that was firstly identified in lung samples of dogs with canine infectious respiratory disease (CIRD) in UK in 2003. We report for the first time the identification of CRCoV in Italy, together with serological evidence that the virus has been circulating in the Italian dog population as from 2005. Serological investigations on 216 dog sera, carried out by an ELISA test using the strictly related bovine coronavirus (BCoV) as antigen, revealed an overall CRCoV seroprevalence of 32.06% in the last 2 years. RT-PCR targeting the S-gene of CRCoV was carried out on 109 lung samples collected from carcasses of dogs submitted for diagnostic investigations. Positive results were obtained from the lungs of a dog of the Apulia region that was co-infected with canine parvovirus type 2. Sequence analysis of the S-gene fragment amplified by RT-PCR (595bp) showed similarity to group II coronaviruses, with the highest nucleotide identity (98%) to the only CRCoV strain currently available in the GenBank database (strain T101). The results of the present study show that CRCoV is present also in continental Europe, although further studies are required to determine the real pathogenic potential of the virus.     

Prevalence of enteropathic Escherichia coli in dogs with acute and chronic diarrhoea

Samples of faeces from 57 dogs with acute diarrhoea, 82 dogs with chronic diarrhoea, 34 clinically healthy household dogs and 88 kennelled control dogs were analysed by hybridisation, using DNA probes to detect enteropathogenic Escherichia coli (EPEC) and enterotoxigenic E coli (ETEC), verocytotoxin-producing E coli (VTEC), enterohaemorrhagic E coli (EHEC), enteroinvasive E coli (EIEC) and enteroaggregative E coli (EAggEC). Samples of duodenal juice from 60 of the 82 dogs with chronic diarrhoea were also examined. Significantly more of the dogs with diarrhoea were excreting EPEC (acute 35.1 per cent, chronic 31.7 per cent) and VTEC (acute 24.6 per cent, chronic 28 per cent) than the kennelled dogs (EPEC 17.1 per cent, VTEC 0 per cent) or the household control dogs (EPEC 6 per cent, VTEC 5.9 per cent). Enteropathic E coli was also detected in the duodenal juice of 23 of 60 (38.3 per cent) of the dogs with chronic diarrhoea. The EPEC attaching and effacing A (eaeA) gene and the verocytotoxin 1 (VR1) gene coding for VTEC were often found together. There was good agreement between in vitro studies and hybridisation for the detection of eaeA and VT1. Isolates from the dogs with diarrhoea adhered significantly more to Hep-2 cells, and VT1-positive strains from the dogs with diarrhoea consistently killed more than 50 per cent of Vero cells.     

Quantification of mRNA encoding cytokines and chemokines and assessment of ciliary function in canine tracheal epithelium during infection with canine respiratory coronavirus (CRCoV)

One of the first lines of defence against viral infection is the innate immune response and the induction of antiviral type I interferons (IFNs). However some viruses, including the group 2 coronaviruses, have evolved mechanisms to overcome or circumvent the host antiviral response. Canine respiratory coronavirus (CRCoV) has previously been shown to have a widespread international presence and has been implicated in outbreaks of canine infectious respiratory disease (CIRD). This study aimed to quantify pro-inflammatory cytokine mRNAs following infection of canine air-interface tracheal cultures with CRCoV. Within this system, immunohistochemistry identified ciliated epithelial and goblet cells as positive for CRCoV, identical to naturally infected cases, thus the data obtained would be fully transferable to the situation in vivo. An assay of ciliary function was used to assess potential effects of CRCoV on the mucociliary system. CRCoV was shown to reduce the mRNA levels of the pro-inflammatory cytokines TNF-alpha and IL-6 and the chemokine IL-8 during the 72 h post-inoculation. The mechanism for this is unknown, however the suppression of a key antiviral strategy during a period of physiologic and immunological stress, such as on entry to a kennel, could potentially predispose a dog to further pathogenic challenge and the development of respiratory disease.     

Seroprevalence of Ehrlichia canis infections in police dogs in Spain

A seroepidemiological study of Ehrlichia canis was made in police dogs in Madrid (Spain). AntiEhrlichia canis antibodies were detected by indirect fluorescent antibody test for the detection of IgG.

The results obtained (three positive dogs out of a population of 131 animals) represents a seroprevalence of canine ehrlichiosis of 2.29%. This seroprevalence is one of the lowest described for this type of population.

The seroprevalence obtained from hunting dogs kennelled in Madrid in 1993 was 66.7% (24 positive out of a population of 36). Environmental conditions (temperature, humidity, rainfall, etc.) in both populations were very similar. We suggest that these conflicting results are due to the different prophylactic programmes used in these two populations.     

Hypercalcaemia associated with angiostrongylus vasorum in three dogs

Hypercalcaemia was identified in three dogs that presented primarily for evaluation of respiratory disease. Angiostrongylosis was diagnosed in all three cases and both the respiratory signs and the hypercalcaemia resolved with treatment. Infection with Angiostrongylus vasorum is known to lead to formation of pulmonary granulomata. Granulomatous disease in humans may lead to hypercalcaemia secondary to increased unregulated production of 1,25-dihydroxycholecalciferol by activated macrophages in the granulomata. In one of the three dogs, 1,25-dihydroxycholecalciferol was measured and found to be increased, providing supportive evidence for a similar mechanism in dogs. To the authors' knowledge, hypercalcaemia has not previously been reported in association with angiostrongylosis in dogs. Since prolonged untreated hypercalcaemia may lead to permanent impairment of renal function, dogs with angiostrongylosis should be evaluated for the presence of hypercalcaemia.     

Evidence of prior infection with influenza A/Texas/77 (H3N2( virus in dogs with clinical parainfluenza.

Eighty dogs exhibiting clinical signs of respiratory disease were sampled for influenza virus isolation and serologically tested for hemagglutination inhibiting antibody to influenza A/Hong Kong/68, A/Victoria/75, A/Texas/77 and A/USSR/77. Forty-one animals without clinical signs of respiratory disease were also examined serologically. Hemagglutinating agents were isolated from nasal and/or pharyngeal swabs taken from 21 of the 80 dogs with clinical respiratory disease. Twenty of these 21 isolates were canine parainfluenza virus. Twenty-one of 80 clinically ill animals (26.3%) and eight of 41 normal animals (19.5%) had low level hemagglutination inhibiting antibody to influenza A/Texas/77. There was no evidence that human influenza caused the respiratory disease in the dogs included in this study, since none had an increase in hemagglutination inhibiting antibody to influenza in convalescent sera. The presence of antibody to A/Texas/77, however, does suggest the possibility that these dogs had at some time been infected with this virus, and that dogs could play a role in the epidemiology of influenza in man.     

The seroprevalence of canine respiratory coronavirus and canine influenza virus in dogs in New Zealand

Abstract

AIM: To determine whether canine respiratory coronavirus (CRCoV) and canine influenza virus (CIV) are present in dogs in New Zealand.

METHODS: Serum samples from 251 dogs of varying age, breed and clinical histories were tested for the presence of antibodies to CRCoV and CIV, using indirect fluorescent antibody (IFA) analysis. The population sampled represented a wide geographic area but principally encompassed the central and lower North Island of New Zealand.

RESULTS: Seventy-three of the 251 samples (29%) were seropositive for CRCoV. Dogs <2 years old were less likely to be seropositive for CRCoV than older dogs. None was seropositive for CIV.

CONCLUSIONS: This study revealed the presence of antibodies to CRCoV in dogs in New Zealand. Young dogs are less likely to be seropositive than older dogs, probably due to increased opportunity for exposure to CRCoV over time. Serum antibodies to CIV were not detected in any of the dogs sampled, suggesting that this virus is unlikely to be present in dogs in New Zealand.

CLINICAL RELEVENCE: Canine respiratory coronavirus is present in New Zealand. Although the role of this virus in canine infectious tracheobronchitis has not been fully elucidated, evidence suggests that it may have a causal role in this disease. Veterinarians should consider CRCoV as a differential diagnosis in cases of respiratory disease in dogs in New Zealand. While CIV appears not to be currently present in New Zealand, veterinarians should consider infection with this virus as a differential diagnosis in dogs presenting with respiratory signs.     

Cytological Analysis of Bronchoalveolar Lavage Fluid in the Diagnosis of Spontaneous Respiratory Tract Disease in Dogs: A Retrospective Study

Results of cytological analysis of bronchoalveolar lavage (BAD fluid were compared with clinical diagnoses in dogs that presented with signs of respiratory disease to referral hospitals. Of 68 dogs in which a clinical diagnosis was possible, BAL cytological findings were considered definitive for the diagnosis in 17 cases (25%), supportive of the diagnosis in 34 cases (50%), and not helpful in 17 cases (25%). Findings were most often considered supportive of or definitive for the clinical diagnosis in dogs with alveolar or bronchial radiographic patterns, or the presence of pulmonary masses. BAL results among lung lobes differed in 23 of 63 dogs (37%) with diffuse radiographic patterns. Tracheal wash cytology differed from BAL fluid cytology in 45 of 66 dogs (68%). Bronchoalveolar lavage was a clinically useful procedure for the diagnostic evaluation of dogs with signs of respiratory disease.     

Evaluation of respiratory parameters at presentation as clinical indicators of the respiratory localization in dogs and cats with respiratory distress

Objective ? To describe clinical respiratory parameters in cats and dogs with respiratory distress and identify associations between respiratory signs at presentation and localization of the disease with particular evaluation between the synchrony of abdominal and chest wall movements as a clinical indicators for pleural space disease. Design ? Prospective observational clinical study. Setting ? Emergency service in a university veterinary teaching hospital. Animals ? Cats and dogs with respiratory distress presented to the emergency service between April 2008 and July 2009. Interventions ? None. Measurements and Main Results ? The following parameters were systematically determined at time of admission: respiratory rate, heart rate, temperature, type of breathing, movement of the thoracic and abdominal wall during inspiration, presence of stridor, presence and type of dyspnea, and results of thoracic auscultation. Abdominal and chest wall movement was categorized as synchronous, asynchronous, or inverse. Diagnostic test results, diagnosis, and outcome were subsequently recorded. Based on the final diagnoses, animals were assigned to 1 or more of the following groups regarding the anatomical localization of the respiratory distress: upper airways, lower airways, lung parenchyma, pleural space, thoracic wall, nonrespiratory causes, and normal animals. One hundred and seventy‐six animals (103 cats and 73 dogs) were evaluated. Inspiratory dyspnea was associated with upper airway disease in dogs and expiratory dyspnea with lower airway disease in cats. Respiratory noises were significantly associated and highly sensitive and specific for upper airway disease. An asynchronous or inverse breathing pattern and decreased lung auscultation results were significantly associated with pleural space disease in both dogs and cats (P<0.001). The combination is highly sensitive (99%) but not very specific (45%). Fast and shallow breathing was not associated with pleural space disease. Increased or moist pulmonary auscultation findings were associated with parenchymal lung disease. Conclusions ? Cats and dogs with pleural space disease can be identified by an asynchronous or inverse breathing pattern in combination with decreased lung sounds on auscultation.     

A study of the prevalence and genotypes of Giardia duodenalis infecting kennelled dogs

Giardia duodenalis is a protozoan parasite of animals that is zoonotic. Given the capacity of this organism to spread via the faecal–oral route, animals held in overcrowded and unhygienic conditions are at high risk of infection. Faecal samples from dogs in three kennels in Rome were examined by microscopy and PCR for G. duodenalis, and the prevalence data generated were correlated with variables such as kennel identity, age of dog, length of time the dog had been kennelled and clinical signs.The overall prevalence of the parasite in the faecal samples was 20.5% and was higher in samples from the largest kennel, which had the greatest turnover of dogs, and in faecal samples from younger animals. Giardia cysts were found more frequently in diarrhoeic animals but were also found in dogs with no clinical signs. Although the finding that the majority of isolates were dog-specific rather than zoonotic genotypes suggests that the zoonotic risk from this pathogen is less than previously thought, the higher prevalence of infection in younger dogs may pose a specific public health issue as such animals are more frequently re-homed with families.     

Nasopharyngeal turbinates in brachycephalic dogs and cats

This retrospective study reports the presence and incidence of nasal turbinates in the nasopharynx (nasopharyngeal turbinates) in a population of brachycephalic dogs and cats exhibiting signs of upper respiratory disease. Medical records were reviewed for 53 brachycephalic dogs and 10 brachycephalic cats undergoing upper airway endoscopy. Nasopharyngeal turbinates were identified in 21% of brachycephalic animals, including 21% of dogs and 20% of cats. Pugs accounted for 32% of all dogs in the study population and 82% of dogs with nasopharyngeal turbinates. The presence of nasopharyngeal turbinates may play a role in upper airway obstruction in the brachycephalic airway syndrome.     

Arterial blood gas anomaly in canine hepatobiliary disease

Arterial blood gas analysis is an important diagnostic and monitoring tool for respiratory abnormalities. In human medicine, lung complications often occur as a result of liver disease. Although pulmonary complications of liver disease have not been reported in dogs, we have frequently encountered hypoxemia in dogs with liver disorders, especially extrahepatic biliary obstruction. In addition, respiratory disorders account for 20% of perioperative fatalities in dogs. Therefore, in this study, we evaluated the respiratory status in dogs with hepatobiliary disease by arterial blood gas analysis. PaO₂ and PaCO₂ were measured. Alveolar-arterial oxygen difference (AaDO₂), the indicator of gas exchange efficiency, was calculated. Compared to healthy dogs (control group), hepatobiliary disease dogs had significantly lower PaO₂ and higher AaDO₂. Hypoxemia (PaO₂ of ≤80 mmHg) was observed in 28/71 dogs with hepatobiliary disease. AaDO₂ was higher (≥30 mmHg) than the control group range (11.6 to 26.4 mmHg) in 32/71 hepatobiliary disease dogs. By classifying type of hepatobiliary disease, dogs with extrahepatic biliary obstruction and chronic hepatitis showed significantly lower PaO₂ and higher AaDO₂ than in a control group. Dogs with chronic hepatitis also had significantly lower PaCO₂. The present study shows that dogs with hepatobiliary disease have respiratory abnormalities more than healthy dogs. Preanesthetic or routine arterial blood gas analysis is likely beneficial to detect the respiratory abnormalities in dogs with hepatobiliary disease, especially extrahepatic biliary obstruction and chronic hepatitis.     

Isolation of canine adenovirus-2 from the faeces of dogs with enteric disease and its unambiguous typing by restriction endonuclease mapping

Fifty-four faecal specimens obtained from kennelled dogs with diarrhoeal disease were used to inoculate a range of cell types in tissue culture. Particles resembling adenovirus virions were seen in three specimens and 22 stools yielded an adenovirus upon culture. Viral DNA from each isolate was digested with the restriction endonucleases Bam H1 and Pst 1. Agarose gel electrophoresis revealed identical restriction patterns for all isolates. One isolate, 9228, was selected as a prototype and was compared with reference strains of canine adenovirus-2 (CAV-2) (Manhattan and Toronto A26/61) and CAV-1. Isolate 9228 was clearly distinct from CAV-1 but identical to both Manhattan and Toronto (A26/61) strains of CAV-2. However, restriction site polymorphism was observed in 9228 following digestion with Hpa II. Isolate 9228 was similarly compared with all commercially available vaccinal isolates of CAV-2 and was shown to be clearly distinct from these.     

Serological evidence of Mycoplasma cynos infection in canine infectious respiratory disease

A high proportion of dogs suffer from respiratory disease when they are placed in kennels for vacation or re-homing. The role of Mycoplasma cynos as an initiating agent in canine infectious respiratory disease was investigated by examining the serological response of dogs to this organism at the time of entry into a large re-homing kennel. Forty-two paired serum samples from dogs (21-day interval) were examined for antibody to M. cynos using Western blotting. The development of antibody in the serum was related to clinical disease recorded over the same period. Sixty seven per cent of the dogs showed a two-fold or greater rise in antibody to M. cynos during the first 3 weeks in the kennel. Reactivity with a 45 kDa antigen was dominant. Of those showing a positive serological reaction, 80% had recorded clinical respiratory disease while 20% remained healthy. The findings of this study show that an antibody response to M. cynos is common in dogs entering the re-homing kennel and is positively related to the development of clinical respiratory disease.     

Population sizes and frequency of Malassezia pachydermatis at skin and mucosal sites on healthy dogs

Skin and mucosal carriage of Malassezia pachydermatis was studied in 20 healthy pet dogs of various breeds and in 20 kennelled beagles. Using swabs, anal carriage was detected in 10 pet dogs and 11 beagles and the nose, mouth, prepuce and vulva were shown to be infrequently colonised. M pachydermatis was isolated from the external ear canal of 11 beagles and two pet dogs; both the population sizes and frequency of isolation were significantly (P<0·05) greater in the beagles. The yeast was infrequently isolated from the axilla and groin in low numbers using contact plates and detergent scrub samples but was often cultured from the lower lip and the dorsal interdigital spaces; isolation frequencies and population sizes in the two groups of dogs were not significantly different. These results demonstrate that the anus, external ear canal and lip and interdigital skin of healthy dogs are frequently colonised by M pachydermatis.     

Prevalence of gastrointestinal tract lesions in 73 brachycephalic dogs with upper respiratory syndrome

OBJECTIVES: To determine the prevalence of gastrointestinal tract lesions in brachycephalic dogs with upper respiratory tract disease. METHODS: The gastrointestinal tract and respiratory disorders of 73 brachycephalic dogs presented with upper respiratory signs were evaluated. Clinical signs and endoscopic and histological anomalies of the upper digestive tract were analysed. RESULTS: A very high prevalence of gastrointestinal tract problems in brachycephalic dogs presented with upper respiratory problems was observed clinically, endoscopically and histologically. Endoscopic anomalies of the upper digestive tract were present even in dogs without digestive clinical signs. Furthermore, histological evaluation of the digestive tract sometimes showed inflammatory lesions not macroscopically visible at endoscopy. Statistical analysis showed a relationship between the severity of the respiratory and digestive signs. This was significant in French bulldogs, males and heavy brachycephalic dogs. CLINICAL SIGNIFICANCE: These observations show a correlation between upper respiratory and gastrointestinal tract problems in brachycephalic breeds with upper respiratory disease. Surgical treatment of respiratory disease could improve the digestive clinical signs, and/or gastro-oesophageal medical treatment could improve the outcome for surgically treated brachycephalic dogs.     

Use of breed-specific ranges for the vertebral heart scale as an aid to the radiographic diagnosis of cardiac disease in dogs.

The vertebral heart scale was measured on right lateral recumbent thoracic radiographs of 320 dogs of six popular breeds, including for each breed at least 20 dogs with no clinical signs of cardiovascular or respiratory disease and at least 19 dogs with cardiac or respiratory disease. There were significant differences between the mean values of the scale for the different breeds; the normal boxer dogs had a significantly higher mean value than the normal dogs of all the other breeds, and the labrador retrievers had a significantly higher mean value than all the other breeds except the boxer and the cavalier King Charles spaniel. For all the breeds except the boxer, there was a trend for dogs with cardiac disease (but not respiratory disease) to have higher mean values on the scale than normal dogs of the same breed; however, at the optimal value of the scale for distinguishing between dogs of each breed with and without cardiac disease, the sensitivity and specificity were relatively low, in the range 58 to 83 per cent. The scale was most accurate for the diagnosis of cardiac disease in the Yorkshire terrier and the cavalier King Charles spaniel, breeds affected by predominantly dilative forms of cardiac disease. In contrast, it was very inaccurate in the boxer, a breed that has a higher incidence of cardiac diseases associated with concentric hypertrophy.