Leishmaniose tegumentar em porquinho-da-índia (Cavia porcellus): relato de caso

Abstract

Leishmaniasis is a group of infectious diseases caused by protozoa of the genus Leishmania, which can affect various animal species, including humans. Guinea pigs (Cavia porcellus) are the vertebrate hosts of Leishmania enriettii. Transmission to these rodents occurs through the bite of a female invertebrate, with sandflies being the most likely vectors. The outbreak in question involves three cases of cutaneous leishmaniasis in guinea pigs, which were treated at the University Veterinary Hospital Superintendence (SUHVU) of the Universidade Federal da Fronteira Sul. Clinically, the animals presented severe nodular and crusted cutaneous lesions, primarily on the nasal region and ears. Cytology from lesion samples collected by fine-needle aspiration (FNA) revealed a large number of parasitized macrophages with abundant cytoplasm containing multiple vacuoles compatible with Leishmania sp. in its amastigote form, ovoid in shape, with identifiable kinetoplast and nucleus. Two animals were euthanized, and histopathological evaluations and organ sample collections for histopathology and molecular diagnosis through immunohistochemistry and conventional polymerase chain reaction (PCR) were conducted. Skin histopathology revealed acanthosis, thickening of the granular layer, and both para- and orthokeratotic hyperkeratosis. The lesions consisted of necrotic foci and marked diffuse inflammation, predominantly histiocytic, with resident macrophages displaying abundant cytoplasm filled with amastigote forms. The skin appendages were obliterated by inflammation. Immunohistochemistry confirmed the presence of the parasite in the skin, while in the liver, antigenic remnants in the centrilobular region were merely indicative of the parasite's presence. The PCR test was confirmatory, with skin and spleen bands from samples of one of the affected animals being compatible with the control band of L. enriettii. This is the first report of this subspecies in cases of spontaneous infection in the southeastern region of Paraná.