Vector competence of Nyssomyia intermedia and Nyssomyia neivai (Diptera, Psychodidae, Phlebotominae) for Leishmania (Viannia) braziliensis

Author(s)

Cecilia de Oliveira Lavitschka

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Medicina Tropical de São Paulo (IMT)
• Defense date: 2017-02-20

Examining board members

Eunice Aparecida Bianchi Galati; Andrey José de Andrade; Lucia Maria Almeida Braz

• Advisor: Mauro Toledo Marrelli; Eunice Aparecida Bianchi Galati

Abstract

Leishmania braziliensis is the agent related to cases of cutaneous and mucocutaneous leishmaniasis in Brazil. Among the sandflies involved in the Leishmania sp transmission in the Southeast Region, Ny. intermedia and Ny. neivai are suspected vectors. However, the incrimination of these species as vectors in the transmission of Leishmania sp. depends of several factors, including vector competence, defined as the ability of the species to develop the agent and transmit it to a vertebrate host. Objective: The present study aimed to demonstrate the vector competence to Ny. intermedia and Ny. neivai for L. braziliensis. Methods: To develop the experiments,specimens of both species were reared under laboratory conditions and the adults obtained were used to evaluate the vector competence. Thefemales were fed in infected hamsters and after oviposition, challenged to take a bloodmeal in suscetible hamsters (without infection). All females fed on infected hamster were dissected. The hamster bitted in the exposition were follow up for two months, after that, were euthanatized to evaluate the infection by PCR. Result: The highest immature mortality occurred in the first instar larval for both species, 27.6% for Ny. intermedia and 53.9% for Ny. neivai. The fourth larval instar had the longest duration, with a median varying between 8 to 12 days. About the females of Ny intermedia, only 0.89% of them develop the flagellates. For Ny. neivai, among 36 females feed on infected hamster, 2 were infected. None female of Ny intermedia take a second blood meal and 3 of Ny. neivai have had. The hamsters bitted by the infected females were follow up for 60 days. After that the hamster were euthanatized and the infection was observed. Conclusion: The vector competence of Ny. neivai to transmit Leishmania braziiensis was demonstrated. The susceptibility of Ny. intermedia to develop this leishmania was corroborated. (AU)

• FAPESP's process: 14/19291-8 - Vector competence of Nyssomyia intermedia and Nyssomyia neivai for Leishmania (Viannia) braziliensis
• Grantee: Cecilia de Oliveira Lavitschka
• Support Opportunities: Scholarships in Brazil - Master