Detection of trypanosomatids in domestic cats of endemic region for visceral leishmaniasis by parasitological, serological and molecular techniques

Author(s)

Maria Fernanda Alves Martin

• Document type: Doctoral Thesis
• Institution: Universidade Estadual Paulista (Unesp)
• Defense date: 2017-06-26
• Advisor: Simone Baldini Lucheis

Abstract

Trypanosomatidae family includes flagellate protozoa of two genera of medical and veterinary importance: Leishmania, the causative agent of leishmaniasis and Trypanosoma, responsible for trypanosomiasis of epidemiological relevance, with the involvement of mammalian hosts and vectors in their life cycle. Nowadays, the domestic cat is considered a host reservoir of leishmanias, after proving by xenodiagnosis, the transmissibility of promastigotes of Leishmania infantum to the phlebotomine vector. Due to the lack of specificity of the clinical findings in Feline Leishmaniasis (FL), similar to the clinical aspects of this disease with other common ones in cats, and to the probable feline resistance to infection, it is possible that, within an endemic area for leishmaniasis, a high percentage of individuals with no clinical signs, and lack of early diagnosis of FL in these areas may imply that the animal continues to pose a potential risk of transmission of leishmaniasis to the vectors. Thus, it was intended to investigate possible associations between positive serology for L.infantum, with tissue parasitism in blood, organs and conjunctival cells of cats from endemic region to visceral leishmaniasis. Thirty-six adult cats, assigned by the Zoonoses Control Center (ZCC) of Bauru-SP, with 31 animals presenting at least one type of clinical alteration, were included in this study. From the serological diagnoses, the positivity was verified in 26 animals, and (66.7%) (24/36) were reactive to the Immunofluorescence Antibody Test (IFAT), (61.1%) (22/36) animals reactives to ELISA test and 10 animals were non-reactive (K = 0.64). The observation of suggestive forms of amastigotes occurred in 12 animals (33.3%), four animals (11.1%) and 12 animals (33.3%), by the parasitological techniques of blood smear, imprint of organs and histochemistry, respectively. Molecular diagnosis was performed using the ITS-1, ITS-2 and HSP70 primers, whose molecular detection by blood PCR was done in 15 animals (41.6%), by tissue PCR in eight animals (22.2 %) and by PCR of conjunctival swabs in four animals (11.1%). Quantification of the parasitic load by blood qPCR occurred in nine animals (25%) and in the qPCR of tissues in two animals (5.5%). After the genetic sequencing, three samples were identified as Trypanosoma theileri, five as Leishmania donovani and one as Leishmania braziliensis. In this way, we verified that the evaluated cats, serologically negative and positive, presented clinical signs, presence of the parasite in cells and parasitic DNA in blood and / or tissues, possibly acting as reservoirs of leishmaniasis in the studied region. The detection of trypanosomatids in biological samples of the studied cats suggests their participation in the maintenance of the parasite in the urban environment. (AU)

• FAPESP's process: 14/15807-0 - Molecular diagnosis and quantification parasitic load in domestic cats of endemic area serologically positive for visceral leishmaniasis
• Grantee: Maria Fernanda Alves Martin
• Support Opportunities: Scholarships in Brazil - Doctorate