Pantropic Canine Coronavirus Research Articles

Pantropic canine coronavirus induces canine M1 macrophage polarization in vitro

Emerging coronavirus infections are a major threat to global public health. In this respect, a novel recombination of canine coronavirus (CCoV) and feline coronavirus (FCoV) was described among human biological samples, giving rise to a potential zoonosis. Despite all efforts, the host‒virus immune response related to CCoV is still unknown. In this study, pantropic CCoV infection of canine macrophages, derived from peripheral blood monocytes, was performed. After infection, macrophages were first polarized to the M1 and/or M2 phenotype. Moreover, infection kinetics, cell viability, apoptosis, mitochondrial dysfunction associated with reactive oxygen species and oxide nitric production were measured. Our results demonstrated that virus infection mainly polarized host macrophages to the classically activated (M1) phenotype, as demonstrated by amoeboid morphology with numerous fibrillary cytoplasmic processes followed by classical phenotypes. Viral infection released new particles 18 h post-infection associated with a decrease in viable cells. Furthermore, upon CCoV infection, M1 cells exhibited reduced phagocytosis properties, as evidenced by a neutral red uptake assay. This in vitro method opens an avenue for further studies on host-virus interaction.

Molecular characterization of canine coronaviruses: an enteric and pantropic approach

Canine coronavirus (CCoV) generally causes an infection with high morbidity and low mortality in dogs. In recent years, studies on coronaviruses have gained a momentum due to coronavirus outbreaks. Mutations in coronaviruses can result in deadly diseases in new hosts (such as SARS-CoV-2) or cause changes in organ-tissue affinity, as occurred with feline infectious peritonitis virus, exacerbating their pathogenesis. In recent studies on different types of CCoV, the pantropic strains characterized by hypervirulent and multi-systemic infections are believed to be emerging, in contrast to classical enteric coronavirus infections. In this study, we investigated emerging hypervirulent and multi-systemic CCoV strains using molecular and bioinformatic analysis, and examined differences between enteric and pantropic CCoV strains at the phylogenetic level. RT-PCR was performed with specific primers to identify the coronavirus M (membrane) and S (spike) genes, and samples were then subjected to DNA sequencing. In phylogenetic analysis, four out of 26 samples were classified as CCoV-1. The remaining 22 samples were all classified as CCoV-2a. In the CCoV-2a group, six samples were in branches close to enteric strains, and 16 samples were in the branches close to pantropic strains. Enteric and pantropic strains were compared by molecular genotyping of CCoV in dogs. Phylogenetic analysis of hypervirulent pantropic strains was carried out at the amino acid and nucleotide sequence levels. CCoV was found to be divergent from the original strain. This implies that some CCoV strains have become pantropic strains that cause multisystemic infections, and they should not be ruled out as the cause of severe diarrhea and multisystemic infections.

Circulation of pantropic canine coronavirus in autochthonous and imported dogs, Italy.

Canine coronavirus (CCoV) strains with the ability to spread to internal organs, also known as pantropic CCoVs (pCCoVs), have been detected in domestic dogs and wild carnivores. Our study focused on the detection and molecular characterization of pCCoV strains circulating in Italy during the period 2014–2017 in autochthonous dogs, in dogs imported from eastern Europe or illegally imported from an unknown country. Samples from the gut and internal organs of 352 dogs were screened for CCoV; putative pCCoV strains, belonging to subtype CCoV‐IIa, were identified in the internal organs of 35 of the examined dogs. Fifteen pCCoV strains were subjected to sequence and phylogenetic analyses, showing that three strains (98960‐1/2016, 98960‐3/2016, 98960‐4/2016) did not cluster either with Italian or European CCoVs, being more closely related to alphacoronaviruses circulating in Asia with which they displayed a 94%–96% nucleotide identity in partial spike protein gene sequences. The pCCoV‐positive samples were also tested for other canine viruses, showing co‐infections mainly with canine parvovirus.

Κοροναϊός του σκύλου: ένας όχι ‘αθώος’ ιός

Canine coronavirus (CCoV) is a significant aetiologic agent of acute diarrhoea in dogs, specially in puppies. An important characteristic of coronaviruses is their high genetic variability, due to increased mutation frequency and sporadic recombination events. Due to this genetic variability, CCoV is classified in two distinct types, type I and II. CCoV type I strains share increased genetic similarity with Feline coronavirus strains, while CCoV type II consists of the typical reference CCoVs. Moreover, type II strains are classified into one of two subtypes, which include the classical strains (CCoV-IIa) and the new strains (CCoV-IIb), which emerged as a result of recombination among CCoV and Porcine transmissible gastroenteritis virus. Typical disease signs of CCoV infection are anorexia, depression, lethargy, as well as vomiting and diarrhoea. Mortality rate is low, especially in adult dogs with no infection signs. Most dogs recover within 7-10 days. Mixed infections with other viruses, bacteria or parasites may lead to more severe clinical disease. Currently, CCoV appears to have spread worldwide and has been related to mild, acute diarrhoea. However, during the last years, novel CCoV strains associated with outbreaks of lethal gastroenteritis have been detected in Australia and Europe. Genome analysis revealed that these strains shared low similarity with prototype reference strains of CCoV, suggesting that atypical, divergent strains may be related to more severe clinical signs. In addition, over the past decade, strains with an ability to trespass the intestinal tract, leading to lethal systemic infection, have also been isolated. These strains have attracted scientific interest, with research focusing on experimental infections, identification of genetic markers and prophylaxis. Pantropic CCoV strains have been detected across Europe, suggesting that the new, highly pathogenic biotype is circulating among canine population. The high genetic variability of CCoV, the severe mixed infections and the antigenic differences among CCoV types and subtypes raise questions regarding the protective efficacy of the currently commercially available vaccines.

Full-genome sequence of pantropic canine coronavirus.

Pantropic canine coronavirus (CCoV) was first detected in young dogs in Italy in 2005, but the complete genome sequence of this virus had not yet been determined. Here, we report the full-length genome sequence of the prototype strain CB/05, which showed that this virus is genetically similar to CCoV-IIa viruses.

Characterization of pantropic canine coronavirus from Brazil

Characterization of canine coronavirus (CCoV) strains currently in circulation is essential for understanding viral evolution. The aim of this study was to determine the presence of pantropic CCoV type IIa in tissue samples from five puppies that died in Southern Brazil as a result of severe gastroenteritis. Reverse-transcriptase PCR was used to generate amplicons for sequence analysis. Phylogenetic analysis of the CCoV-IIa strains indicated that they were similar to those found in other countries, suggesting a common ancestor of these Brazilian isolates. This is the first report of pantropic CCoV-II in puppies from Latin America and our findings highlight that CCoV should be included as a differential diagnosis when dogs present with clinical signs and lesions typically seen with canine parvovirus infection.

New and Emerging Pathogens in Canine Infectious Respiratory Disease

Canine infectious respiratory disease is a common, worldwide disease syndrome of multifactorial etiology. This review presents a summary of 6 viruses (canine respiratory coronavirus, canine pneumovirus, canine influenza virus, pantropic canine coronavirus, canine bocavirus, and canine hepacivirus) and 2 bacteria (Streptococcus zooepidemicus and Mycoplasma cynos) that have been associated with respiratory disease in dogs. For some pathogens a causal role is clear, whereas for others, ongoing research aims to uncover their pathogenesis and contribution to this complex syndrome. Etiology, clinical disease, pathogenesis, and epidemiology are described for each pathogen, with an emphasis on recent discoveries or novel findings.

European Surveillance for Pantropic Canine Coronavirus

Highly virulent pantropic canine coronavirus (CCoV) strains belonging to subtype IIa were recently identified in dogs. To assess the distribution of such strains in Europe, tissue samples were collected from 354 dogs that had died after displaying systemic disease in France (n = 92), Hungary (n = 75), Italy (n = 69), Greece (n = 87), The Netherlands (n = 27), Belgium (n = 4), and Bulgaria (n = 1). A total of 124 animals tested positive for CCoV, with 33 of them displaying the virus in extraintestinal tissues. Twenty-four CCoV strains (19.35% of the CCoV-positive dogs) detected in internal organs were characterized as subtype IIa and consequently assumed to be pantropic CCoVs. Sequence and phylogenetic analyses of the 5' end of the spike protein gene showed that pantropic CCoV strains are closely related to each other, with the exception of two divergent French viruses that clustered with enteric strains.

A pantropic canine coronavirus genetically related to the prototype isolate CB/05

We report the genetic and biological characterisation of a novel pantropic canine coronavirus (CCoV), strain 450/07, which caused the death of a 60-day-old miniature pinscher. At the genetic level, this virus was strictly related to the prototype strain CB/05, but displayed some unique features. After experimental infection with the new pantropic isolate, most inoculated dogs showed diarrhoea and acute lymphopenia. Gross lesions and histological changes were mainly evident in the gut and lymphoid tissues, although some animals showed remarkable changed also in parenchymatous organs. The viral RNA was detected in the faeces and/or internal organs of most pups. These findings seem to indicate that strain 450/07 is able to spread to internal organs (mainly lymphoid tissues), causing lymphopenia but inducing a mild disease.

Fatal outbreaks in dogs associated with pantropic canine coronavirus in France and Belgium

Infection with pantropic canine coronavirus was detected during outbreaks in France and Belgium. This was concurrent in most cases with canine parvovirus 2c. One outbreak was a deadly acute systemic disease with a single pantropic canine coronavirus infection. This is the first report of a fatality associated with pantropic canine coronavirus alone outside Italy.

Molecular characterization of a canine coronavirus NA/09 strain detected in a dog’s organs

In the present study, the detection of a pantropic canine coronavirus (CCoV) strain in a dog with lethal diarrhoea is reported. RT-PCR and real-time RT-PCR assays were used for the detection, characterization and quantitation of CCoV. Sequence and phylogenetic analysis of the CCoV NA/09 revealed a high degree of sequence identity with the pantropic strain CB/05, indicating the presence of CB/05-like pantropic strains in Greece. The absence of the 38-nucleotide deletion in ORF3b, which is characteristic of CB/05, indicates the need to identify new genetic markers for pantropic variants of CCoV, probably in the spike-protein gene region.

Feline and Canine Coronaviruses: Common Genetic and Pathobiological Features

A new human coronavirus responsible for severe acute respiratory syndrome (SARS) was identified in 2003, which raised concern about coronaviruses as agents of serious infectious disease. Nevertheless, coronaviruses have been known for about 50 years to be major agents of respiratory, enteric, or systemic infections of domestic and companion animals. Feline and canine coronaviruses are widespread among dog and cat populations, sometimes leading to the fatal diseases known as feline infectious peritonitis (FIP) and pantropic canine coronavirus infection in cats and dogs, respectively. In this paper, different aspects of the genetics, host cell tropism, and pathogenesis of the feline and canine coronaviruses (FCoV and CCoV) will be discussed, with a view to illustrating how study of FCoVs and CCoVs can improve our general understanding of the pathobiology of coronaviruses.

Prolonged depletion of circulating CD4 + T lymphocytes and acute monocytosis after pantropic canine coronavirus infection in dogs

A hypervirulent strain (CB/05) of canine coronavirus was employed to infect oronasally 11-week-old pups. Peripheral blood monocytes (CD14 +), T lymphocytes (CD4 + and CD8 +) and B lymphocytes (CD21 +) were studied by flow cytometry within 5 days post-infection (p.i.) and at later time points. Infection with CB/05 resulted in a profound depletion of T cells and a slight loss of B cells in the first week p.i. In particular, while the CD8 + and the B lymphocytes returned to baseline levels by day 7 p.i., the CD4 + T cells remained significantly low until day 30 p.i. and recovered completely only at day 60 p.i. Monocytosis was also observed after CB/05 infection with a peak at day 5 p.i. The prolonged depletion of peripheral CD4 + T cells did not alter the levels of serum IgG or IgM. The impact of CB/05 infection on the immune performance of infected pups is discussed.

An Outbreak of Canine Coronavirus in Puppies in a Greek Kennel

Canine coronavirus (CCoV) is usually the cause of mild gastroenteritis in dogs and is known to have spread worldwide. However, to date, no CCoV cases have been confirmed in Greece. In the present work, the authors investigated an outbreak of enteritis in puppies from a Greek kennel for the presence of CCoV. Dogs were presented with clinical signs of diarrhea, anorexia, weakness, depression, dehydration, and 1 death. Canine coronavirus type II was detected by reverse transcription nested polymerase chain reaction in all 11 puppies, whereas 1 puppy presented dual infection with CCoV type II and canine parvovirus 2. Surprisingly, sequence analysis of the samples revealed higher similarity to the pantropic CCoV II strain CB/05 than to other reference strains, in the most variable region of the S gene.

Experimental infection of dogs with a novel strain of canine coronavirus causing systemic disease and lymphopenia

A pantropic canine coronavirus (CCoV) strain (CB/05) has been recently associated to a fatal outbreak of systemic disease in young dogs. We report the clinical, virological and serological findings in dogs experimentally infected with strain CB/05. The dogs, three 2.5-month-old and two 6-month-old pups, were successfully infected, shedding viral RNA with their faeces for the entire observation period (21 days) and displaying systemic clinical signs resembling those observed during the course of natural infection. Leucopenia (acute lymphopenia) occurred in all infected dogs, with values dropping below 60% of the initial counts. Considering the severity of the CB/05-induced disease, two of the youngest pups were euthanized for ethical reasons at days 8–9 postinfection, whereas the other pups underwent a slow but progressive improvement of their clinical status with complete recovery. At postmortem examination, remarkable lesions were observed in the internal organs of the euthanized pups, that tested positive for CCoV by real-time RT-PCR and virus isolation on cell cultures. All pups seroconverted for CCoV, as shown by the high optical density values and antibody titres detected by ELISA and virusneutralisation tests, respectively. The present study confirms that strain CB/05 is highly pathogenic for dogs, being able to induce a severe disease (and in some cases the death) even in experimental conditions.