Molecular diagnosis and quantification parasitic load in domestic cats of endemic area serologically positive for visceral leishmaniasis

Abstract

Visceral leishmaniasis (VL) is a zoonosis of epidemiological relevance, caused by intracellular protozoa of the genus Leishmania. Due to the intense urbanization of leishmaniasis, the involvement of other domestic species in the epidemiology of VL makes possible new endemic foci. In Brazil, the migration from rural to urban areas was a factor that accelerated the expansion of the VL, especially in the Northeast and Southeast. Since the first evidence of transmission of Leishmania infantum by xenodiagnosis, the cat came to be considered a reservoir host of the disease in areas endemic. Cats can co-inhabit with wild and domestic animals, favoring the spread of the infection by this species. Because of the specificity of clinical findings of Feline Leishmaniasis (FL), the absence of signs and the similarity of the clinical aspects of this disease with other diseases in cats, this zoonosis should be systematically included in the clinical suspicion of cats in areas endemic for human and canine leishmaniasis. The leishmaniasis is well established in canids, however there are few studies about the epidemiology and clinical disease in felines. Thus more researches are necessary to determine the importance of domestic cat in the VL cycle, and evaluate the molecular epidemiology of this zoonose and the parasitological and serological tests. Thus, we intend to quantify the parasite load of seropositive cats for Leishmania infantum, by means of parasitological staining techniques, imprint of tissues and Real time PCR (q-PCR) in tissues of spleen, liver, kidney, lymph node, and skin; evaluate and compare the PCR (Polymerase Chain Reaction) of blood and tissue impressions; evaluate the effectiveness of the PCR from swabs of conjunctiva, nose and oral cavity. In this study, 30 adult cats will be included, regardless of sex and race, donated by the Center for Zoonosis Control (CZC), Bauru, SP. All animals may or may not show clinical signs compatible with leishmaniasis, and all tests shall be submitted to serological diagnosis of Immunofluorescent Antibody Test (IFAT) and ELISA. The animals will be divided into two groups: 20 serologically positive cats (n = 20) with or without clinical signs and 10 cats with or without symptoms and with negative serology for the control group (n = 10). Secretions and blood samples will be collected from conjunctival, oral and nasal swabs for PCR analysis and after euthanasia, fragments of the tissues will be collected for performing histopathological and molecular studies to quantify the parasite load by real-time PCR and gene sequencing for subsequent identification of the species. (AU)