Pathological, immunohistochemical, and bacteriological findings in dogs infected with Brucella canis

ABSTRACT

This study describes pathological, immunohistochemical, and bacteriological findings in adult dogs and fetuses naturally infected with Brucella (B) canis. A total of 42 dogs including 40 dogs and 2 aborted fetuses were examined. The most common gross lesions in infected dogs were swelling of lymph nodes and spleen. The testes showed marked swelling with multifocal to diffuse reddish discoloration. The most significant histopathological lesions were observed in the placenta. Placental trophoblasts were markedly hypertrophied due to the accumulation of intra-cellular gram-negative bacteria. Lymphocytic inflammation of varying severity was observed in the reproductive organs such as male testis, epididymis, and prostate gland and female uterus. Strong immunolabelling was observed in the cytoplasm of most trophoblasts in the placental tissues using immunohistochemistry. However, immunohistochemical staining did not demonstrate any organisms in other organs of dogs and fetuses. B. canis isolates were most frequently obtained from the whole blood (82.5%) and superficial inguinal lymph node (77.5%) in both sexes. In addition, the isolation rate was higher in male genital organs than in those of females. Hence, management of male dogs is most important because infected dogs can play a role as carriers.