THORACIC COMPUTED TOMOGRAPHY FINDINGS IN DOGS EXPERIMENTALLY INFECTED WITH ANGIOSTRONGYLUS VASORUM

Abstract

To characterize the computed tomography (CT) features of thoracic lesions caused by infection with Angiostrongylus vasorum, pre- and postcontrast CT was performed in six experimentally infected Beagles 13 weeks postinoculation and in four of these 9 weeks postchemotherapy. Findings were compared with survey radiographs and necropsy findings. A multicentric bronchoalveolar pattern more pronounced at the lung periphery was present radiographically. On CT, the predominant abnormality underlying this alveolar pattern was multiple large nodules merging to areas of consolidation, and containing air bronchograms of varying extent. These nodular changes corresponded to histopathologic granulomata, consisting mainly of macrophages, multinucleated giant cells, and lymphocytes that had accumulated around larvae and eggs. Morphologically, no bronchial changes were observed on CT or histologically. Quantitatively, however, on CT there was evidence of bronchial thickening at 13 weeks postinoculation and mild very peripheral bronchiectasia 9 weeks postchemotherapy. Regional lymph nodes were enlarged after infection, and smaller after treatment. On postcontrast CT, several suspicious intraluminal filling defects suggestive of thrombosis were found; however, the tortuosity of some pulmonary arteries seen radiographically was not present in CT images. After treatment, the consolidations and large nodules had almost completely disappeared. A remaining radiographic interstitial pattern was characterized on CT as ground-glass opacifications, subpleural interstitial thickening, subpleural lines, and interface signs. These interstitial changes reflected fibrosis as documented histopathologically. CT allowed very detailed and accurate characterization of pulmonary parenchymal lesions, bronchi, and lymphnodes and closely reflected histopathological changes.

Recruitment of arteriovenous pulmonary shunts may attenuate the development of pulmonary hypertension in dogs experimentally infected with Angiostrongylus vasorum

“…7e10 In experimentally-infected Beagles, pulmonary thrombosis induced marked radiographic and computed tomographic changes, and arterial hypoxemia, but these did not result in PH or in echocardiographic changes in cardiac size and function. 3,11 Clearly, many patients with pulmonary thrombosis do not develop PH. Nevertheless, it is interesting to note that some individuals with severe pulmonary lesions do not develop PH, and others with less severe lesions do develop PH.…”

Combined Serological Detection of Circulating Angiostrongylus vasorum Antigen and Parasite-specific Antibodies in Dogs from Hungary

“…Clinical signs in dogs most frequently include respiratory signs such as coughing and dyspnoea, but a broad range of further signs indicating coagulopathies or neurological dysfunctions (Chapman et al 2004;Staebler et al 2005;Wessmann et al 2006;Koch and Willesen 2009), may be the signs most obvious to clinicians and animal owners. This variability and the fact that the disease is often in an advanced stage when noticed by the animal owners make the diagnosis of A. vasorum infections challenging but important: the sooner an appropriate anthelmintic treatment is initiated, the better for the clinical recovery of the dogs and limitation of damage, especially to lung tissues (Dennler et al 2011;Schnyder et al 2009). A fundamental role in the early diagnosis of infections is played by awareness of the local occurrence of the parasite and, correspondingly, disease awareness among vets and animal owners.…”

“…The long-standing method for confirmation of clinical suspicion of dogs infected with A. vasorum, once the dogs are patent at approximately 40 -57 days post infection (Guilhon and Cens 1973;Schnyder et al 2010), is the detection of first stage larvae in faeces performed with the Baermann-Wetzel technique . However, by the time dogs start to be Baermann-positive, damage to the lung parenchyma is already present (Dennler et al 2011;Guilhon and Cens 1969;Neff 1971). In addition, copromicroscopic methods have limitations concerning sensitivity and specificity due to variable larval excretion and the presence of other lungworm larvae (e.g.…”

Serological Detection of Circulating Angiostrongylus vasorum Antigen- and Parasite-Specific Antibodies in Dogs from Poland

“…Patency is described to start after 38-57 days post infection (d.p.i.) (Bolt et al 1994;Schnyder et al 2010), when damage to the lung parenchyma is already present (Guilhon and Cens 1969;Neff 1971;Dennler et al 2011). The sensitivity of copromicroscopic methods is furthermore limited in case of intermittent excretion of larvae (Oliveira-Junior et al 2006;Taubert et al 2008), low parasite load, and during prepatency.…”