Background:

Sinonasal aspergillosis (SNA) is the second most common cause of nasal discharge in dogs. The diagnosis is confirmed through anamnesis, physical and complementary exams. Aspergillus fumigatus is the species most frequently isolated from dogs with fungal involvement of the upper respiratory tract. Canine SNA is a disease with worldwide distribution but, surprisingly, the disease has never been described in Brazil. The prognosis of SNA is usually good. The objective of this report is to describe the first case of canine sinonasal aspergillosis in Brazil. Case A 18-months old, male, Rottweiler breed dog was referred to the Hospital de Clínicas Veterinárias at the Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Southern Brazil, for purulent nasal discharge, variably bloody, and sneezing of approximately 6 months duration. During this period, the dog was treated with various antibiotics with no success and lost 10 kg of corporal mass. The alterations found in the physical exam were bilateral sanguinopurulent nasal discharge, depigmentation of nose and paranasal region, as well as subnutrition. The dog was anesthetized and sinus and chest x-rays were performed (latero-lateral and ventrodorsal positions). In the radiographic analysis, it was verified the lessening of radiolucency on the left nostril, indicating the destruction of the nasal concha. The chest radiographies did not show alterations. A rhinoscopy was carried out showing destruction in the endoturbinate, purulent discharge and presence of a dark color mass in the frontal sinus, which was collected for histopathological and microbiological culture exams. Histopathologic examination revealed the presence of hyaline, branching septate hyphae, consistent with Aspergillus spp. and inflammatory cells. Culture identified Aspergillus fumigatus. Bacteriological culture was negative. Antibodies to Aspergillus fumigatus were detected by counter electrosyneresis. The haemogram showed lymphocytosis and monocytosis. The dog was treated with itraconazole (5 mg/kg of body weight, orally, twice a day for 30 days). After this period, nasal discharge decreased and a good repigmentation was observed with the dog showing improvement of his appetite and energy level.

Discussion:

The presence of antibodies to Aspergillus spp. does not always confirm canine nasal aspergillosis. Serological tests can yield 5% to 15% false positive results in dogs. Therefore, it is necessary to perform complementary exams such as radiography, rhinoscopy, histopathology and fungal culture in order to confirm the diagnosis. For many years, aspergillosis was considered as an incurable chronic rhinitis characterized by the turbinate destruction, nasal discharge and intermittent epistaxis. The reported prevalence of canine SNA in animals affected by disorders in the upper respiratory may range from 7 to 34%. Consequently, predisposed animals (like dolichocephalic dogs) are serious candidates to develop nasal aspergillosis that, in many cases, may be not diagnosed. This first report of canine sinonasal aspergillosis in Brazil reinforces the importance of consider this disease as a differential diagnosis in cases of nasal disease in dogs with clinical rhinosinusitis mainly in tropical countries.(AU)