Banca de DEFESA: Mayra de Sousa Félix de Lima
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.STUDENT : Mayra de Sousa Félix de Lima
DATE: 08/02/2024
TIME: 14:00
LOCAL: Plataforma Teams
TITLE:
Impregnated dog collars for Visceral Leishmaniasis control: assessment of the susceptibility of Lutzomyia longipalpis to the pyrethroid deltamethrin
KEY WORDS:
Lutzomyia longipalpis, Visceral Leishmaniasis, Resistance
PAGES: 112
BIG AREA: Ciências da Saúde
AREA: Medicina
SUMMARY:
Visceral Leishmaniasis (VL) is an important public health problem with autochthonous cases registered in 24 Brazilian states. The main vector of VL is the sandfly Lutzomyia longipalpis and dogs (Canis familiaris) are the main domestic reservoirs of the protozoan Leishmania infantum. The use of collars impregnated with 4% deltamethrin is associated with chemical control against Lu. longipalpis which may contribute to the emergence of resistance in sandflies. In this work, the susceptibility profile of different Lu. longipalpis populations to pyrethroid deltamethrin in areas where impregnated collars are used to control VL was characterized. The susceptible population of Lu. longipalpis originated from the insectarium of the Insect Biochemistry and Physiology Laboratory of the Oswaldo Cruz Institute/RJ. The field populations came from the cities of Foz do Iguaçu/PR (FOZ), Teresina/PI (TER), Fortaleza/CE (FOR), Caucáia/CE (CAU), Montes Claros/MG (MOC) and Cavalcante/GO (CAV). Sandflies were collected using CDC and/or HP- type light traps installed in peridomicile during 3 consecutive nights, between 5 pm and 8 am. Field populations were exposed to CDC bottle bioassays (Wheaton de 250 ml) impregnated with DD at 21.9 ug/bottle and 30 µg/bottle. DoseResponse (DR) experiments, using doses of 1, 3, 5, 7, 9 and 11 μg/bottle were conducted. The bottles in the control group were impregnated only with acetone. An average of 20 sandflies (♂♂ and ♀♀ mixed) per bottle were used and the exposure time was 60 minutes. Three bioassays were conducted on different days, and the mortality reading was 24 hours carried out by a single researcher. A total of 4,094 sandflies were used in the CDC bottle bioassays. Lu. longipalpis was the most frequently collected species in all localities (94%), followed by Migonemyia migonei (0.7%), Evandromyia lenti (0.5%), Evandromyia sallesi (0.3%) and Nyssomyia whitmani (0. 1%). For DD of 21.9 μg/bottle, populations from the cities of FOZ, MOC, CAV and TER were susceptible, while CAU presented a mortality rate of 87.1%, suggesting resistance and FOR demonstrated a value of 94.9%, suggesting possible resistance. For the DD of 30 μg/bottle, CAU and TER showed the possibility of resistance, but the other populations were susceptible. RR50 varied between 2.27 and 0.54 and RR95 between 4.18 and 0.33, indicating low resistance. The angular coefficient values of the TER, CAU, FOR and MOC sandfly populations showed less homogeneity and a higher frequency of individuals with resistance alleles. The length of time collars were implemented in each city may have influenced the susceptibility of the populations analyzed. It is suggested to use the CAV population as LRS for future studies on the susceptibility of sandflies to insecticides. The majority of populations of Lu. longipalpis were susceptible to the pyrethroid deltamethrin in areas where impregnated collars were used, except the Caucaia/CE population which was resistant to the DD of 21.9 μg/bottle. Resistance monitoring of the Lu. longipalpis should be carried out in new areas, in order to support VL control actions in Brazil.
COMMITTEE MEMBERS:
Presidente - 1974062 - MARCOS TAKASHI OBARA
Interno - 3343228 - RODRIGO GURGEL GONCALVES
Externa à Instituição - Grasielle Caldas D’Ávila Pessoa - UFMG
Externa à Instituição - Kauara Brito Campos - MS