Insecticide resistance mechanisms with novel ‘kdr’ type gene mutations in the tropical bed bug Cimex hemipterus

Abstract

Background The tropical bed bug, Cimex hemipterus , is a serious indoor public health pest in tropical regions causing intense physical discomfort and mental distress to humans. At present, the application of insecticides is the major control strategy. The present study was designed to evaluate the development of resistance and resistance mechanisms in Cimex hemipterus from Kandy district, Sri Lanka. Methods The resistance status of the collected bed bugs was determined against the discriminative dosages of DDT, malathion, propoxur, deltamethrin and permethrin by conducting bioassays according to World Health Organization guidelines. Activities of insecticide metabolizing enzymes, i.e. esterases, glutathione S-transferases (GST) and monooxygenases, and the insensitivity of organophosphate/carbamate target site acetylcholinesterase (AChE), were evaluated by biochemical assays. Regions of the gene of the pyrethroid/DDT target site, the voltage-gated sodium channel regulatory protein (VGSC), were sequenced for possible kdr mutations. Results Survival percentages of bed bug population were 71, 68 and 51% for DDT, malathion and propoxur respectively. KT 50 and KT 90 values, calculated using log-probit mortality curves for deltamethrin were 62.55 and 123.96 h, respectively. These values were much higher for permethrin where KT 50 was 201.10 h and the KT 90 was beyond the detectable range. Results were compared with previous values reported for the same population in 2002. Resistance to propoxur has increased significantly from 11 to 51% with about a 20-fold increase in the number of individuals with elevated esterase mechanism. No significant change has occurred in malathion and DDT resistance, in GST and monooxygenase activities, and in AChE sensitivity for the past 14 years. Six kdr associated mutations (Y/L995H, V1010L, I1011F, L1014F, V1016E, L1017F/S) and a non- kdr associated mutation (A1007S mutation) were found from the α-region of the VGSC gene. Out of the kdr type mutations, only L1014F has been reported previously form C. hemipterus while the others have been reported from other insects. Conclusions The bed bug population has developed high resistance to propoxur with increased esterase activities. KT 50 for deltamethrin and permethrin has increased 125- and 20-fold, respectively, over the period 2002 to 2016. To the authors’ knowledge, this is the first time that the possible involvement of a kdr type mutation in developing pyrethroid resistance in C. hemipterus has been shown in Sri Lanka.

High Levels of Pyrethroid Resistance and Super-Kdr Mutations in the Populations of Tropical Bed Bug, Cimex Hemipterus, in Iran

“…In this study, a similar phenomenon, resistance to insecticides, was found in the eld strains of C. hemipterus to different pyrethroids (bifenthrin, cypermethrin, esfenvalerate, and etofenprox) from Thailand [41], DDT and deltamethrin residues from Malaysia [44], a mixture of deltamethrin and imidacloprid from Australia [51], and permethrin and deltamethrin from Sri Lanka [26]. These conditions were also represented in different populations of the common bed bug for pyrethroids from USA [23], permethrin and deltamethrin from Australia [52], allethrin from Sydney [43], imidacloprid and β-cy uthrin from Malaysia [53,54], several neonicotinoids (imidacloprid, acetamiprid, thiamethoxam, and dinotefuran) from USA [55], bifenthrin from Germany [56], a mixture of deltamethrin and imidacloprid from Australia [52], and bendiocarb from Paris [57].…”

“…These conditions were also represented in different populations of the common bed bug for pyrethroids from USA [23], permethrin and deltamethrin from Australia [52], allethrin from Sydney [43], imidacloprid and β-cy uthrin from Malaysia [53,54], several neonicotinoids (imidacloprid, acetamiprid, thiamethoxam, and dinotefuran) from USA [55], bifenthrin from Germany [56], a mixture of deltamethrin and imidacloprid from Australia [52], and bendiocarb from Paris [57]. Based on the bioassay results and the ndings of previous studies [26,41,44,51], all the bed bug populations in the present study manifested resistance to permethrin. Thus, the reconsideration of control methodologies is of paramount importance in the studied areas.…”

“…In this species, the M918I mutation is always found together with the L1014F mutation and probably plays a synergistic role in enhancing pyrethroid resistance [10,13,19]. Previous investigations have identi ed some novel mutations, such as L899V and D953G, in the vgsc gene of C. hemipterus [25] and six sequential (Y/L995H, A1007S, V1010L, I1011F, V1016E, and L1017F/S) mutations around the L1014F mutation [26]. However, the function of these mutations in pyrethroid resistance is unclear.…”

Widespread Mutations in Voltage-Gated Sodium Channel Gene of Cimex lectularius (Hemiptera: Cimicidae) Populations in Paris

“…Point mutations in the voltage-gated sodium channel (VGSC) gene reduce the target-site sensitivity for pyrethroids and DDT, causing “knockdown resistance” ( kdr ) [ 23 , 24 ]. Three point-mutations are reported from C. lectularius (V419L, L925I, and I936F) and currently nine from C. hemipterus (L899V, M918I, D953G, Y/L995H, V1010L, I1011F, L1014F, V1016E, and L1017F/S) [ 25 , 26 ]. These mutations act by substituting the amino acid sequence of the VGSC protein that prevents the insecticide acting on the nervous system [ 27 , 28 ].…”

Fecundity, Survival and Susceptibility of Bedbugs (Cimex Hemipterus), Exposed to Selected Classes of Insecticides: A Short Report

“…The school has six hostel accommodations for the students which are always almost packed beyond capacity, a condition that favours bedbug infestation A total of two hundred and seventy (270) bedbugs were harvested. Collections were done between 8pm − 10pm daily from May to August 2019 following the methods previously described by Punchihewa et al (2019). The collected bedbugs were transferred to the Yabatech Environmental Biology Laboratory in well labelled containers and they were maintained in aerated clean plastic containers at a temperature of 25 ± 2 o C and relative humidity of 75 ± 10%.…”