First national-scale evaluation of temephos resistance in Aedes aegypti in Peru

Abstract

Background The development of resistance against insecticides in Aedes aegypti can lead to operational failures in control programs. Knowledge of the spatial and temporal trends of this resistance is needed to drive effective monitoring campaigns, which in turn provide data on which vector control decision-making should be based. Methods Third-stage larvae (L3) from the F1 and F2 generations of 39 Peruvian field populations of Ae. aegypti mosquitoes from established laboratory colonies were evaluated for resistance against the organophosphate insecticide temephos. The 39 populations were originally established from eggs collected in the field with ovitraps in eight departments of Peru during 2018 and 2019. Dose–response bioassays, at 11 concentrations of the insecticide, were performed following WHO recommendations. Results Of the 39 field populations of Ae. aegypti tested for resistance to temephos , 11 showed high levels of resistance (resistance ratio [RR] > 10), 16 showed moderate levels of resistance (defined as RR values between 5 and 10) and only 12 were susceptible (RR < 5). The results segregated the study populations into two geographic groups. Most of the populations in the first geographic group, the coastal region, were resistant to temephos, with three populations (AG, CR and LO) showing RR values > 20 (AG 21.5, CR 23.1, LO 39.4). The populations in the second geographic group, the Amazon jungle and the high jungle, showed moderate levels of resistance, with values ranging between 5.1 (JN) and 7.1 (PU). The exception in this geographic group was the population from PM, which showed a RR value of 28.8 to this insecticide. Conclusions The results of this study demonstrate that Ae. aegypti populations in Peru present different resistance intensities to temephos, 3 years after temephos use was discontinued. Resistance to this larvicide should continue to be monitored because it is possible that resistance to temephos could decrease in the absence of routine selection pressures. Graphical Abstract

Container characteristics and density of Aedes aegypti larvae: a field trial of Ziziphus mauritiana leaf extract

“…Control of dengue in tropical countries is mainly achieved through surveillance of Aedes aegypti larvae and eliminating larval development habitats by using chemicals such as abate (temephos), which is considered the most effective method [37]. However, challenges were raised regarding the acceptability due to the unpleasant odor and the continuous use of chemical insecticides causing resistance to vector mosquitoes [38]. It is noteworthy to consider herbal larvicides produced from plants, such as Ziziphus mauritiana, as environmentally friendly larvicides [39].…”

Widespread Resistance to Temephos in Aedes aegypti (Diptera: Culicidae) from Mexico

“…Since 2000, resistance to temephos has been reported in Cuba and Venezuela, Panama, Brazil, El Salvador, the island of Martinique in the French Antilles, Argentina, Colombia, Trinidad, Costa Rica, and Ecuador [5,6,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. More recent reports have come from Peru, Mexico, and other non-Latin American countries such as Thailand, Malaysia, and India [7,9,10,[45][46][47][48][49]. However, some of these studies report the susceptibility of Ae.…”

“…This same pattern was also found in Peru, where 27 out of 39 populations of Ae. aegypti displayed moderate to high temephos resistance [7]. Few studies have been conducted to assess the susceptibility of Ae.…”

Evaluation of Larvicidal Activity of Kaempferia galanga Extracts Against Aedes aegypti Larvae

“…Long-term use of temephos has given rise to resistant strains in Ae. aegypti mosquito populations in various countries, such as recent reports in Brazil 8 , Cuba 9 , Indonesia 10 , Malaysia 11 and Peru 12 , in addition to genotoxic effects in humans 13 .…”