Histopathological and immunohistochemical study of the gastrointestinal tract from a dog naturally infected with Leishmania (Leishmania) chagasi: a case report

Silva, F. LTafuri, W. LOliveira, M. RTafuri, Wg. L

Samples of stomach, duodenum, jejunun, ileum, cecum and colon were collected for Giemsa-smears ("imprints") from one asymptomatic mongrel dog, naturally infected with Leishmania (L) chagasi. Other fragments were obtained and fixed in formalin (10 percent and buffered) for histopathological and immunohistochemical studies. The immunohistochemistry was carried out by a streptavidin-peroxidase technique and it allowed to detect amastigote forms of Leishmania chagasi in the different paraffin gut sections. The principal lesion observed was a discrete to moderate chronic inflammatory reaction in the mucosa and submucosa in all fragments of the gastrointestinal tract (GIT). A chronic cellular exsudate was observed in all GIT tissues and it was composed by mononuclear cells (monocytes, plasmocytes and lymphocytes). A comparison between the two techniques showed that the immunohistochemistry study is the best method to detect amastigote forms of Leishmania