Effect of pyriproxyfen and ivermectin on survival and reproductive perfomance of plague flea vectors, xenopsylla cheopis
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Date
2023-11
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Sokoine University of Agriculture
Abstract
EXTENDED ABSTRACT
One of the primary carriers of plague in many tropical and subtropical regions of the world is Xenopsylla Cheopis. Targeting flea vectors by sprinkling or dusting homes and surroundings with chemical insecticides is the primary method for controlling plague. However, the likelihood of insecticide resistance has increased because to the prolonged use and excessive reliance on chemical insecticides. Ivermectin and pyriproxyfen, which target both endoparasites and ectoparasites, will limit their actions and reduce their susceptibility to resistance. These substances have however not tested against plague fleas. The objectives of this study were to evaluate the effects of pyriproxyfen and ivermectin on reproduction and survival, as well as the viability of incorporating them into the current management methods. Two experimental designs were used; the first exposure to pyriproxyfen was investigated for its efficacy against adult, fecundity, and larval stages of the oriental rat flea. The contact bioassays against both the larval and adult stages of fleas conducted through series of laboratory experiments. In adult fleas, treatment and controls groups were tested in four replicates while larvae were six replicates. Exposure time of pyriproxyfen for adult fleas were 30 minutes and none for larvae
Twelve rats were used in total for the second exposure method of the ivermectin and pyriproxyfen . Four rats were given 0.2 ml of ivermectin, four were given 0.3 g of pyriproxyfen powder, and four were left untreated. The adult fleas were exposed for 12 hours, and 10 days of observation followed. The survival curve of adult fleas was produced after data analysis using the R software. Additionally, the least square method was used to calculate the impact of pyriproxyfen and ivermectin on adult mortality. The survival rate of adult Xenopysylla cheopis fleas in a treatment group shown to be 100% at day 0. As time passed, there was a decreasing chance that the treated group would survive, and by day six, every flea in the treated group had died (P=0.0313).
In comparison to the control group, the treatment group significantly produced less eggs (<0.0001). In the treatment group of flea larvae,
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90% of the larvae died by day eight, and by day 20 of monitoring and observation, there were no cocooned flea larvae. 98% of the larvae in a control group survived and 60% of them formed cocoons. According to the research, adult fleas, egg viability, egg laying, and larval growth are all affected when 2g of pyriproxyfen mixed with sand and dried cattle blood powder is directly applied to them. Pyriproxyfen alone was considerably less toxic to adult fleas during a period of 24 hours, and mortalities began from day 2 and increased. However, similar hormone with other exposure methods in conjunction with ivermectin in action have shown that this is not the case.
Pyriproxyfen was very effective in day four using the least square method, with an LS mean of 3.75 and a 0% egg-laying rate. Maximum mortalities were achieved at day five with an LS mean of 4.5 and a P-value of (0.0001), and 5% less eggs were deposited by adult fleas that were exposed to ivermectin. The combination of pyriproxyfen and ivermectin was effective against adult fleas, with the largest mortalities occurring on days three and four with LS Means of 4.75 and 5, respectively, and no eggs being deposited during the course of the monitoring period of ten days. This combination of pyriproxyfen and ivermectin may be utilized to better control the plague in endemic areas and as flea vector control agents.
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dessertation
Keywords
Pyriproxyfen, Ivermectin, Survival, Reproductive Perfomance, Plague Flea Vectors, Xenopsylla Cheopis