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An Urban Experience
C. Clercx1
1University of Li├Ęge, Department of Clinical Sciences of Companion Animals and Equine, LIEGE-SART TILMAN, Belgium
Canine eosinophilic bronchopneumopathy (EBP) is a disease characterised by eosinophilic infiltration of lung and bronchial mucosa, considered to be manifestations of immunological hypersensitivity. Although the aetiology of EBP is still unknown, the association of eosinophilic infiltration and predominance of CD4+ T-cells is in favour of a dominant Th2 immune response mounted
in the lower airways 1. Suspected and known causes of pulmonary hypersensitivities in humans and animals include fungi, molds, drugs, bacteria, and parasites. However, in many cases, no underlying cause is found. The role of inhaled allergens in EBP is still unclear.
Signalment and clinical presentation
Dogs affected with EBP are usually young adults (4 to 6 years), although the disease can be diagnosed in animals younger than 1 year or older than 10 2345
A breed predisposition has been shown for Siberian huskies and malamutes, but the disease can be diagnosed in large breeds (mainly Labradors, rottweilers, german shepherds), less commonly in smaller breeds (such as jack russel terriers, daschunds), but very rarely in miniature, or in giant breeds.
Usually, the general condition is good, unless the disease is associated with concomittant bacterial bronchopneumonia. The main clinical signs include mainly cough, gagging and retching and are present in 100% of the cases. Some dyspnea is a very frequently present. A less commonly encountered sign is nasal discharge.
Diagnostic tests
Diagnostic elements for the diagnosis of idiopathic
EBP include anamnetic factors (breed, young age, previous response to corticosteroids and clinical
signs), radiographic and bronchoscopic findings,
blood eosinophilia, tissue eosinophilic infiltration as demonstrated by cytological and histopathological examinations, response to adequate treatment, and
also rests on exclusion of other respiratory diseases5. The most common radiographic findings are a mixed moderate to severe bronchointerstitial pattern. Computed tomographic findings associated with eosinophilic
bronchopneumopathy are variable and heterogeneous, and include marked to moderate bronchial wall thickening, plugging of the bronchial lumen by mucus/ debris, bronchiectasis, presence of pulmonary nodules and lymphadenopathy 6. Bronchoscopy can reveal typical macroscopic features such as the presence of abundant yellow-green mucous or mucopurulent material, severe thickening of the mucosa with irregular or polypoid surface and in some cases partial airway closure during expiration 5. Peripheral blood eosinophilia is frequent,
but not always observed. BALF or brush cytology demonstrates a marked eosinophilic component; frequently, more than 50% of the inflammatory cells are eosinophils. In most cases, eosinophilic infiltration of the bronchial mucosa can also be observed in biopsies. Concomittant neutrophilic infiltration can be seen.
Differential diagnosis
In the dog, occult heartworm disease caused by Dirofilaria immitis can cause eosinophilic pneumonitis. Migration of larvae of Angiostrongylus vasorum through pulmonary parenchyma may also result in eosinophilic pneumonia in dogs. Infection by the nematode worm Angiostrongylus vasorum (also called the French heartworm disease) is an emerging disease, with reported increase in both distribution and incidence in United Kingdom, Europe, South Africa and Canada.
The expanding geographic range might be related to
the influence of the climate on parasite distribution. The worm infects dogs and foxes and is spread through ingestion of intermediate hosts, including slugs and snails. Other bronchopulmonary parasites, like Capillaria aerophila, Oslerus osleri, Filaroides hirthi, Crenosema vulpis or Paragonimus kellicotti, are also implicated in the afflux of eosinophils in the airways (O. osleri) or lungs (other parasites) in dogs, and can mimic EBP. Frequency of bronchial disease due to infection by Crenosoma Vulpis is also becoming emerging on the continent
7. Therefore infection by Angiostrongylus vasorum or Crenosoma Vulpis should now be considered in the differential diagnosis in dogs with chronic cough. The presence of parasites should be searched, using BALF analysis, faeces examination (Baermann sedimentation procedure) or in clinic antigen detection test in blood.
In the meantime, appropriate antihelminthic drugs can be used in order to treat the animal against potential parasites.

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