Banca de QUALIFICAÇÃO: AMANDA NONATO DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : AMANDA NONATO DOS SANTOS
DATE: 30/10/2023
TIME: 09:00
LOCAL: Sala 202 - Bloco G
TITLE:

Evaluation of the effectiveness of a new prototype for testing bite protection of female Aedes aegypti (Diptera: Culicidae).

KEY WORDS:

Artificial feeding, DEET, Insecticide, Membrane, Repellent

PAGES: 69
BIG AREA: Ciências Biológicas
AREA: Parasitologia
SUBÁREA: Entomologia e Malacologia de Parasitos e Vetores
SUMMARY:

Avoiding vector bites and vector control continue to be the most important lines of defense against the transmission of pathogens by mosquitoes. Repellents are effective because they act by preventing mosquito contact with the skin, in addition to the advantages of low cost, convenience, and ease of application. Considering the importance of evaluating new potentially repellent substances, the aim of this study was to evaluate different sources of stimulus and exposure times for the use of a new, easily constructed and handled prototype for bite protection tests with Aedes aegypti, with the goal of avoiding direct contact of the tested substances with human skin. To do this, bite protection tests were conducted using a polypropylene container measuring 11.5 x 10 x 7.5 cm, with a snap-on lid and two openings: (i) on the side of the container (1.56 cm) for mosquito insertion and removal; (ii) on the top (3.54 cm) for mosquito access to a polyamide screen (12 cm²), with a support edge made of EVA to prevent contact between the screen and the container. Groups of ten females aged 5 to 7 days, separated after 3 days of mating and fasting for 36 hours before the experiment, were pre-selected, inserted, and acclimated for five minutes. After this period, they were exposed to three sources of stimuli placed on the containers: (i) human blood, (ii) artificial food (SkitoSnack) using artificial feeders, and (iii) human forearm (N=20) during different time intervals (2, 5, and 10 minutes). The number of mosquitoes that landed and fed on the stimuli over different time intervals was recorded. Subsequently, the Complete Protection Time (CPT) of DEET at 200 nmol/cm² was evaluated, as well as the time, number of landings, and engorgement after CPT. In general, there were no significant differences in the average number of landings between the stimuli, only between the time periods. An increase in the number of mosquito landings was observed up to the third minute, followed by a reduction after the eighth minute of observation, regardless of the stimulus source. As for engorgement, there was a proportional increase in fed mosquitoes over time, and after 5 minutes of observation, there was greater engorgement using blood and the arm as stimuli. When analyzing the CPT of DEET, significant differences were observed for the arm (74.9 minutes) compared to artificial feeding (SkitoSnack) (51.7 minutes) and blood (49.5 minutes), and the time for a second mosquito to land after CPT was nearly twice that observed for CPT, regardless of the stimulus. The average number of landings after CPT at the end of the total observation time (3 hours and 45 minutes) was lower on the arm (6.4) compared to SkitoSnack (9.93) and blood (9.06). The number of mosquitoes engorged in treatments with DEET-impregnated fabric and in the control after CPT did not differ between the tested stimuli. We conclude that mosquitoes land and engorge on the tested prototype under the conditions used, regardless of the stimulus source and exposure time. For use in bioprospecting experiments, our results suggest that the use of blood on a membrane and a 5-minute exposure time are the best conditions for future experiments.

COMMITTEE MEMBERS:
Interna - ***.337.517-** - GEISA PAULINO CAPRINI EVARISTO - FIOCRUZ
Externa ao Programa - ***.446.996-** - GENIMAR REBOUÇAS JULIÃO - UNIR