Banca de QUALIFICAÇÃO: ANGELIS MARIA ALVES FALCÃO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ANGELIS MARIA ALVES FALCÃO
DATE: 31/10/2024
TIME: 09:00
LOCAL: Videoconferência - Link para acesso: https://meet.google.com/dth-rmqt-mee
TITLE:

Interactions between vectors and hosts in the transmission dynamics of Visceral Leishmaniasis in endemic areas

KEY WORDS:

Leishmania, Lutzomyia longipalpis, dogs, saliva, parasitemia, skin.

PAGES: 83
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Rio Grande do Norte (RN) is an endemic area for human and canine visceral leishmaniasis (VL). The transmission cycle of this parasitic disease is anthropozoonotic and Lutzomyia longipalpis is the vector of greatest epidemiological importance in the Americas. During the blood meal, the vector releases chemical factors, such as saliva, which has anti-hemostatic activity, facilitating blood suction, but has also been shown to facilitate the chemotaxis process of macrophages and neutrophils. Studies have shown that co-inoculation by the insect vector can increase transmissibility from the infected mammalian host to the insect vector, as well as the establishment of infection in the mammalian host from an infected insect. This study aims to determine the vector infection rate for Leishmania infantum and the main food sources of sandflies in an endemic area and the role of Lutzomyia longipalpis saliva in dogs infected by Leishmania infantum. To this end, 248 female sandflies were collected using light traps in the vicinity of homes with the following characteristics: (1) households with a recent history of human VL, (2) close neighbors of a household with human VL and (3) households no recent history of human VL. DNA from each female sand fly was extracted and L. infantum infection and food sources were identified by qPCR.In addition, dogs with visceral leishmaniasis screened by the canine visceral leishmaniasis surveillance survey of the Zoonosis Surveillance Unit (UVZ) were recruited. Peripheral blood was collected from dogs in the test group, before intradermal inoculation of 20 salivary glands in the ears of dogs and in the control group, inoculated with saline solution. After 24 hours, the dogs' blood was collected again to evaluate parasitemia and protein profile in canine plasma. A total of 248 female sandflies were captured and molecular analysis detected L. infantum DNA in 56%. Sand flies captured from households affected by human VL were 3.73 (95% CI = 1.64 to 8.48; p = 4.92e-04) times more likely to carry L. infantum DNA compared to captured sand flies in households with no recent history of VL. Multiple sources of blood were detected, with dogs being the main source of food in the three areas studied. A significant increase in Leishmania present in blood was observed for all samples from dogs inoculated with saliva. (p=0.0034). While in the group inoculated with saline solution there was no significant increase in parasitemia. The concentration of Leishmania present in the DNA of the skin, including tissue from the ear and axillary region on the contralateral side, not inoculated with saline and saliva, was higher in both groups when compared to the amount of Leishmania present in the left ear, used for inoculation. We conclude that there is an important reservoir of L. infantum in the vicinity of the residences of human VL cases and dogs are the main blood sources for the sandflies captured in the studied areas. Additionally, we conclude that intradermal administration of Lu. longipalpis saliva causes an increase in parasitemia in dogs naturally infected with L. infantum. These findings support a better understanding of transmission in endemic areas of visceral leishmaniasis and discussion of possible VL control measures.

COMMITTEE MEMBERS:
Externo à Instituição - FABIANO OLIVEIRA
Externa ao Programa - 1714243 - DANIELLA REGINA ARANTES MARTINS SALHA - nullPresidente - 1837354 - JULLIANE TAMARA ARAUJO DE MELO CAMPOS