Acanthocheilonema Reconditum (Spirurida: Onchocercidae) in the Oral Cavity of a Dog in Northeastern Brazil: Case Report

An 11-year-old male dog presenting exophthalmia and perforation of the cornea of the left eye was seen at the veterinary hospital of the State University of Maranhão. Upon physical examination, irregularly shaped granulomas of crumbly appearance were observed on the dog’s tongue. The dog was sent for ocular enucleation surgery. The following tests were requested: complete blood count, serum biochemistry, hemoparasite investigation, chest X-Ray, echocardiogram, electrocardiogram, cytology and nodule histopathology. The blood count revealed neutrophilia, signs of anemia, increased total plasma protein and thrombocytopenia. Serum biochemistry and the imaging examinations showed normal results. The cytological examination on the tongue nodules showed microfilariae and the histopathological examination showed chronic glossitis. Polymerase chain reaction (PCR) and genetic sequencing were performed on a blood sample, which made it possible to identify the species Acanthocheilonema reconditum. This is the first record worldwide of the occurrence of microfilariae of A. reconditum on tongue nodules. This finding serves to alert dermatologists and dentists regarding the need for a differential diagnosis for types of oral cavity lesions of unknown etiological origin.