Contribution to the Understanding of the Pathogenesis and the Therapeutic Management of Canine Idiopathic Eosinophilic Bronchopneumopathy

• Main Author: Morgane, Canonne-Guibert Aude
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2022
• Subjects: Antibodies; Asthma; Biological products; Biopsy; Cellular biology; Chronic illnesses; Dendritic cells; Dogs; Drug dosages; Endoscopy; Epidemiology; Immunoglobulins; Infections; Inflammation; Lung diseases; Medicine; Parasites; Parasitology; Pathogenesis; Pathogens; Pathology; Pharmaceutical sciences; Pneumonia; Respiratory diseases; Serology; Steroids; Surgery; Young adults
• ISBN: 9798384151654

Idiopathic eosinophilic bronchopneumopathy (EBP) is a chronic disease characterized by eosinophilic infiltration of the lung and bronchial mucosa in young adult dogs of medium-large breeds such as Siberian Huskies (Corcoran et al. 1991, Clercx et al. 2000, Clercx & Peeters 2007). Definitive diagnosis of idiopathic EBP requires combination of compatible clinical signs, radiographical features, bronchoscopy findings, cytologic evidence of bronchial or bronchoalveolar eosinophilic infiltration, and exclusion of potential other causes of eosinophilic airway inflammation such as cardio-pulmonary parasites. The aetiology of this chronic inflammatory condition is still unclear. An underlying type I hypersensitivity reaction is highly suspected while the inciting antigens remain mostly unidentified (Clercx et al. 2002, Peeters et al. 2005). The treatment usually consists in oral steroid therapy (Clercx & Peeters 2007). Because of potential side effects or contraindicative comorbidities, the use of inhaled steroid therapy (IST) is common in practice (Clercx & Peeters 2007, Casamian-Sorrosal et al. 2020).As idiopathic EBP is a diagnosis by exclusion, specific investigation of cardio-pulmonary parasites is needed once eosinophilic airway inflammation is demonstrated. Angiostrongylus vasorum is one of the major parasites that are able to cause an eosinophilic airway inflammation. It is important to discriminate between EBP and angiostrongylosis, especially since long-term management and prognosis differ. Over the last 10 years, several studies high-lightened the presence of A. vasorum in all countries of western Europe including neighbouring countries of Belgium (Bourque et al. 2008, Yamakawa et al. 2009, Taubert et al. 2009, Barutzki & Schaper 2009, Van Doorn et al. 2009, Helm et al. 2010, Gredal et al. 2011, Conboy 2011, Gallagher et al. 2012, Traversa et al. 2013). The aims of Study 1 and Study 2 were to investigate a posteriori the possibility of previously undiagnosed angiostrongylosis among a series of coughing and healthy dogs using qPCR on collected and stored broncho-alveolar lavage specimens and to compare the usefulness of qPCR on lavage with non-invasive tests for the diagnosis of angiostrongylosis. Based on results of Study 1, pulmonary angiostrongylosis was negligible in Belgium until 2013 and previous misdiagnosis of idiopathic EBP is unlikely. Study 2confirmed that qPCR on BALF is the most sensitive technique to definitely rule out angiostrongylosis in dogs with eosinophilic inflammation on BALF, as non-invasive diagnostic tools (faecal analysis and rapid serological device) have imperfect sensitivities.Precedent clinical studies unsuccessfully investigated some potential infectious triggers of the development of EBP, including non specific bacteria or fungi (Clercx et al. 2000, Clercx et al. 2002, Johnson et al. 2019a). Although human asthma and canine EBP differ because of the lack of bronchial hyper-responsiveness in dogs with EBP, the role of bacterial genera, that are known to be implicated in induction or exacerbation in humans, has never been investigated in dogs with EBP. In human medicine, infections with specific bacteria such as Mycoplasma pneumoniae and Bordetella pertussis have been associated with asthma for decades (Hansbro et al. 2004, Harju et al. 2006, Blanchard & Raherison 2010, Atkinson 2013). Although Mycoplasma cynoswas recently identified as an emerging and possibly lethal pathogen in dogs with canine infectious respiratory disease (CIRD) (Rycroft et al. 2007, Zeugswetter et al.