Use of serological and molecular techniques in distinguishing dogs vaccinated and naturally infected by Leishmania (L.) infantum chagasi

Author(s)

Joedh dos Santos

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2021-09-21

Examining board members

José Angelo Lauletta Lindoso; Marcia Dalastra Laurenti; Flaviane Alves de Pinho; José Eduardo Tolezano

• Advisor: José Angelo Lauletta Lindoso

Abstract

In Brazil, Visceral leishmaniasis (LV) is caused by Leishmania (L.) infantum chagasi and transmitted by sandflies of the genus Lutzomyia, with the dog being the main urban reservoir. The interruption of transmission is based on the identification and elimination of infected dogs and, more recently, the possibility of using collars impregnated with insecticides and immunization prevention with the use of vaccines. Within this context of immunization, one of the problems is the distinction between immunized dogs and those naturally infected, since the methods currently used in serological surveys do not allow to differentiate naturally infected from immunized dogs. In this way and so, searching for tools that distinguish these two populations of dogs in areas of transmission of canine visceral leishmaniasis. The objective of this work is to evaluate whether, through serological methods (rapid TR-DPP®, ELISA L. major-like and ELISA-LESA) and molecular (conventional PCR) tests, it is possible to distinguish immunized dogs from naturally infected dogs. Samples of serum and DNA extracted from lymph nodes were used, coming from a cohort of dogs immunized and not immunized with two different commercial vaccines, with or without the use of a collar impregnated with insecticide, from the city of Panorama-SP. 600 samples collected at the times were evaluated: -1 to 0 (1st time), after 180 (2st time) and 360 days (3st time). The results were interpreted using the Cochran Q (p *), Chi-square (p **) and kappa tests. Our results suggest that the serological methods used in this study, do not allow to distinguish vaccinated dogs from those naturally infected and the detection of DNA in a lymph node sample is the confirmatory method of infection of dogs by L. infantum. Furthermore, our results allow us to conclude that none of the prevention methods used in this cohort were able to prevent infection, since there was detection of L. infantum DNA in all groups studied (AU)

• FAPESP's process: 18/12188-8 - Use of sorological and molecular techniques in the distinction of vaccinated and naturally infected dogs by Leishmania (l.) infantum chagasi
• Grantee: Joedh dos Santos
• Support Opportunities: Scholarships in Brazil - Master