Banca de DEFESA: DANIELLE PEREIRA DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : DANIELLE PEREIRA DA SILVA
DATE: 08/03/2022
TIME: 13:00
LOCAL: Departamento de Parasitologia Animal
TITLE:

Mortality assessment of Ctenocephalides felis felis larvae by entomopathogenic nematodes Heterorhabditis amazonensis (NEPET11) under different experimental conditions.

KEY WORDS:

EPNs, Heterorhabditis amazonensis, fleas, Ctenocephalides felis felis, larval stage, biological control.

PAGES: 43
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Parasitárias de Animais
SUMMARY:

Fleas are hematophagous ectoparasites that feed blood on warm-blooded animals. They have great importance in parasitology as vectors of different etiological agents capable of causing diseases in different vertebrate hosts. The use of entomopathogenic nematodes (EPNs) has been studied as an alternative in the biological control of arthropods, in an attempt to reduce, for example, environmental contamination and resistance to chemical substances. The present study aims to evaluate the susceptibility and mortality of seven-day-old larvae of Ctenocephalides felis felis by entomopathogenic nematodes of the species Heterorhabditis amazonensis, strain NEPET11, under different experimental conditions. The experiment was divided into two stages, in which 70 seven-day-old larvae of C. felis felis were used, divided into seven plates, six of which were exposed to the solution containing the NEPs and a control. The Petri dishes submitted to infection contained 10 flea larvae and 600 μL of solution with infective juveniles (IJs) of entomopathogenic nematodes (120 NEPs/larva), whereas the control contained 10 flea larvae and 600 μL of distilled water, both were kept in climatized chamber at a temperature of 25±1ºC, 70-80UR, being observed for a period of 48 hours to assess larval mortality. The infection was confirmed through the dissection of a flea larva from each Petri dish and the observation of the presence of juveniles and/or adults inside it. In the second stage, 10 Petri dishes containing seven-day-old larvae of C. felis felis infected by IJs of H. amazonensis NEPET11 at a concentration of 120 IJs/flea larva were used. Five Petri dishes were kept in BOD at a temperature of 25±1°C, 70-80UR and the other five were kept at room temperature. In addition to these, there were two control Petri dishes containing 10 flea larvae and 600 μL of distilled water, kept under the same conditions. The percentage of flea larvae mortality was evaluated by analysis of variance (ANOVA), followed by Tukey's test with a significance level of 5% (p≤0.05) using the SISVAR statistical program. In the first experimental stage, it was possible to verify the infection of flea larvae by H. amazonensis, with an average mortality percentage equal to 98.33%. In the second experimental stage, the infection was also successful in the two conditions tested. The mean percentage of mortality after 48 hours of observation was 96% for plates kept in BOD and 98% for those kept in ambient conditions, with no significant difference between them. In both stages it was not possible to recover the infective juveniles in White's trap. The present study suggests that C. felis felis flea larvae are susceptible to infection by H. amazonensis NEPET11, and that EPN has a high virulence for the stage of the evaluated life cycle of this flea species, being efficient when used under experimental conditions.The EPNs can be a promising tool for the biological control of fleas, however, more studies should be carried out using both the host species and the nematode species, since this was the first study evaluating the infection of C. felis felis larvae by H. amazonensis.

BANKING MEMBERS:
Presidente - 2221840 - MELISSA CARVALHO MACHADO DO COUTO CHAMBARELLI
Interno - 2181861 - AVELINO JOSE BITTENCOURT
Interno - 1109555 - JAIRO PINHEIRO DA SILVA
Externo à Instituição - CAIO MÁRCIO DE OLIVEIRA MONTEIRO - UFG
Externo à Instituição - ISABELLA VILHENA FREIRE MARTINS - UFES