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

Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

Background: Low-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions. Results: A total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract. Conclusions: The pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine

Principales viroses des Nouveaux Animaux de Compagnie (NAC), furet, lapin, rongeurs

Les Nouveaux Animaux de Compagnie et à plus forte raison les petits mammifères fortement appréciés du grand public, représentent aujourd'hui une part non négligeable de la clientèle du vétérinaire canin. De nombreux virus, dont certains comportent un risque zoonotique, peuvent affecter ces animaux, et il est important pour le clinicien de savoir les prévenir, les diagnostiquer et les traiter. Nous allons nous intéresser aux données bibliographiques actuelles sur les principales maladies virales qui peuvent affecter le furet, le lapin et les rongeurs de compagnie (rat, souris, cobaye).TOULOUSE-EN Vétérinaire (315552301) / SudocMAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

Méthodes de dépistage et de diagnostic de la leucose féline

La leucose féline, ou infection du chat par le virus leucémogène félin (FeLV), est l'une des principales causes de décès non-accidentels chez le chat. Les praticiens sont quotidiennement confrontés à des affections qui peuvent être liées à l'infection par le FeLV, et à la nécessité de faire un diagnostic fiable et précoce de l'infection. Du fait du grand nombre d'affections liées directement ou indirectement à l'infection par le FeLV, de l'évolution de l'infection, et de l'existence de formes atypiques, il peut être difficile de diagnostiquer l'infection. Outre les chats symptomatiques qui doivent être testés, le dépistage chez les chats sains est recommandé et très fréquemment réalisé afin de détecter les porteurs du FeLV. Les tests de dépistage doivent également être aussi fiables que possible. C'est pourquoi de nombreux tests ont été développés depuis des années, basés sur la détection du virus, des antigènes ou des acides nucléiques viraux. Les praticiens doivent connaître quels sont les tests les plus indiqués dans chaque cas, que ce soit pour un diagnostic ou un dépistage.TOULOUSE-EN Vétérinaire (315552301) / SudocMAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

Etude bibliographique de l'implication des retrovirus endogènes chez les mammifères et pathologies associées

Les Retrovirus endogènes représentent une découverte récente de la génétique et de la virologie. Aucune association stricte n'a pu être démontrée à ce jour avec des maladies humaines. Chez les animaux, certaines pathologies cancéreuses sont induites par leur présence. Ce travail fait état des connaissances actuelles concernant l'implication des Retrovirus endogènes chez les mammifères. Chez quatre animaux (souris, chat, mouton et koala) la présence de Retrovirus endogènes a des conséquences pathologiques importantes. Malgré certaines actions directes au cours de processus pathogènes, le rôle majeur de ces séquences intégrées au génome est de favoriser des recombinaisons génétiques avec des formes exogènes de ces virus, et d'induire ainsi une évolution accélérée et/ou une pathogénicité accrue des Retrovirus. Parallèlement aux implications pathogènes, ces séquences apportent de nouvelles fonctions grâce aux gènes présents au sein des provirus endogènes, permettant l'évolution du génome de l'hôte et le protégeant notamment de certaines infections rétrovirales exogènes.TOULOUSE-EN Vétérinaire (315552301) / SudocMAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

Constitutive IFNα protein production in bats

Posté sur bioRxiv le 22 juin 2021.International audienceBats are the only mammals with self-powered flight and account for 20% of all extant mammalian diversity. In addition, they harbor many emerging and reemerging viruses, including multiple coronaviruses, several of which are highly pathogenic in other mammals, but cause no disease in bats. How this relationship between bats and viruses exists is not yet fully understood. Existing evidence supports a specific role for the innate immune system, in particular type I interferon (IFN) responses, a major component of antiviral immunity. Previous studies in bats have shown that components of the IFN pathway are constitutively activated at the transcriptional level. In this study, we tested the hypothesis that the type I IFN response in bats is also constitutively activated at the protein level. For this we utilized highly sensitive Single Molecule (Simoa) digital ELISA assays, previously developed for humans that we adapted to bat samples. We prospectively sampled four non-native chiroptera species from French zoos. We identified a constitutive expression of IFNα protein in the circulation of healthy bats, and concentrations that are physiologically active in humans. Expression levels differed according to the species examined, but was not associated with age, sex, or health status suggesting constitutive IFNα protein expression independent of disease. These results confirm a unique IFN response in bat species that may explain their ability to coexist with multiple viruses in the absence of pathology. These results may help to manage potential zoonotic viral reservoirs and potentially identify new anti-viral strategies

Feline Coronavirus Antivirals: A Review

Feline coronaviruses (FCoV) are common viral pathogens of cats. They usually induce asymptomatic infections but some FCoV strains, named Feline Infectious Peritonitis Viruses (FIPV) lead to a systematic fatal disease, the feline infectious peritonitis (FIP). While no treatments are approved as of yet, numerous studies have been explored with the hope to develop therapeutic compounds. In recent years, two novel molecules (GS-441524 and GC376) have raised hopes given the encouraging results, but some concerns about the use of these molecules persist, such as the fear of the emergence of viral escape mutants or the difficult tissue distribution of these antivirals in certain affected organs. This review will summarize current findings and leads in the development of antiviral therapy against FCoV both in vitro and in vivo, with the description of their mechanisms of action when known. It highlights the molecules, which could have a broader effect on different coronaviruses. In the context of the SARS-CoV-2 pandemic, the development of antivirals is an urgent need and FIP could be a valuable model to help this research area

Porcine epidemic diarrhea: the return of an old disease

In 2013, 40 years after the first case of porcine epidemic diarrhea (PED) in Europe, PED has emerged in USA that was free of that disease before. The coronavirus, etiological agent of the disease and called PEDV, spread quickly within all the country and in America leading to a significant impact on the pig production. Two types of viral strains have been identified: highly virulent "non-InDel" strains and "InDel" strains because of insertion/deletion in the S gene and associated with less severe clinical cases. PEDV infection causes watery diarrhea and a mortality of up to 100 % in piglets. This review sums up the current knowledge on the virus, its transmission and its worldwide molecular epidemiology, on the physiopathology of the disease and the control measures.En 2013, 40 ans après le premier cas de diarrhée épidémique porcine (DEP) en Europe, la DEP est apparue aux États-Unis jusqu’alors indemne de cette maladie. Le coronavirus responsable de la maladie, le virus de la DEP (PEDV) s’est rapidement propagé dans tout le pays et dans plusieurs pays d’Amérique entraînant un impact significatif sur la production de porcs (perte de 10 % de la production totale aux États-Unis). Deux types de souches ont été identifiés : des souches hautement virulentes dites « non-InDel », et des souches dites « InDel » de part des insertions/délétions dans le gène S et associées à des cas cliniques moins sévères. L’infection par le PEDV provoque l’apparition de diarrhées aqueuses et peut entraîner 100 % de mortalité chez les porcelets nouveau-nés. Cette revue fait le bilan des connaissances actuelles sur le virus, sa transmission et l’épidémiologie moléculaire mondiale, sur la physiopathologie de la maladie et les moyens de contrôle