scholarly journals The frequencies of knockdown resistance mutations in phlebotomine sandflies under different degrees of indoor residual spraying

2021 ◽  
Vol 72 (4) ◽  
pp. 229-236
Author(s):  
Akihiro Kuroki ◽  
Kentaro Itokawa ◽  
Yusuf Özbel ◽  
Osamu Komagata ◽  
Yasutaka Osada ◽  
...  
Keyword(s):  
Indoor Residual Spraying ◽  
Knockdown Resistance ◽  
Resistance Mutations ◽  
Phlebotomine Sandflies

scholarly journals The Pattern of Knockdown Resistance Mutations Correlated to the Annual Average Temperature in Field Populations of Aedes Albopictus (Diptera: Culicidae) in China

2021 ◽  
Author(s):  
Hanming Chen ◽  
Qiuming Zhou ◽  
Haowei Dong ◽  
Hao Yuan ◽  
Jie Bai ◽  
...  
Keyword(s):  
Dengue Fever ◽  
Mutation Rate ◽  
Aedes Albopictus ◽  
Mutant Allele ◽  
Pearson Correlation ◽  
Point Mutations ◽  
National Database ◽  
Knockdown Resistance ◽  
Resistance Mutations ◽  
Annual Average

Abstract Background: Aedes albopictus is the main vector of dengue fever in China, distributed from north to south in China. Insecticides are an important method to control the mosquitoes, especially in the outbreak of dengue fever, but insecticide resistance raises the risk of failure to control vector-borne diseases. Knockdown resistance (kdr) caused by point mutations in the VGSC gene is a key mechanism that confers resistance to pyrethroids. To explore the characteristics and possible evolution trend of kdr mutation in Ae. albopictus, we analyzed the kdr mutations of field populations in China in this study.Methods: A total of 1 549 Ae. albopictus were collected from 18 sites in China from 2017 to 2019, as well as 50 individuals from three sites in the 1990s. A fragment of approximately 350 bp from part of S6 segment in the VGSC gene domain III was amplified and sequenced. The haplotypes of VGSC gene were recorded and the parsimony network was constructed using TCS 1.21. The data of annual average temperatures (AAT) of collection sites was acquired from national database. The correlation between AAT of the collection site and the kdr mutation rate was analyzed by Pearson Correlation using SPSS 21.0. Results: The overall frequency of mutant allele F1534 is 45.62%. Nine mutant alleles were detected at codon 1534 in fifteen field populations, namely TCC/TCG (S) (38.86%), TTG/CTG/CTC/TTA (L) (3.71%), TGC (C) (2.68%), CGC (R) (0.27%) and TGG (W) (0.10%). Only one mutant allele ACC (T) was found at codon 1532 with frequency of 6.39% in ten field populations. Moreover, multiple mutations at I1532 and F1534 in a sample appeared in five populations. The 1534 mutation rate was significantly positive related to AAT (Coefficient=0.624, p=0.0056), while the 1532 mutation rate was significantly negative related to AAT (Coefficient=-0.645, p=0.0038). Thirteen haplotypes were inferred, in which six mutant haplotypes were formed by one step, and the other six haplotypes were formed by one more mutations. In the samples from 1990s, no mutant allele was detected at codon 1532 of VGSC gene. However, F1534S/TCC was found in HNHK94 with an unexpected frequency of 100%.ConclusionsKdr mutations are widespread in the field populations of Ae. albopictus in China. Two novel mutant alleles F1534W/TGG and F1534R/CGC were the detected. The 1534 kdr mutation appeared in the population of Ae. albopictus no later than 1990s. F1534 mutation rate is positive correlated to AAT, while I1532 mutation rate is negative correlated to AAT. Insecticide using should be carefully managed to slow down the spread of high-resistance Ae. albopictus populations.

Molecular Monitoring of Knockdown Resistance in Head Louse (Phthiraptera: Pediculidae) Populations in Iran

2021 ◽  
Author(s):  
Fereshteh Ghahvechi Khaligh ◽  
Navid Dinparast Djadid ◽  
Mostafa Farmani ◽  
Zahra Asadi Saatlou ◽  
Samira Frooziyan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Head Louse ◽  
Molecular Techniques ◽  
Common Mechanism ◽  
Amino Acid Substitutions ◽  
Head Lice ◽  
Knockdown Resistance ◽  
Resistance Mutations ◽  
Accurate Detection ◽  
Genotype Frequencies

Abstract Knockdown resistance (kdr) is a common mechanism of insecticide resistance in head lice to the conventionally used pyrethroid pediculosis and can be the result of various amino acid substitutions within the voltage-sensitive sodium channel (VSSC). In this study, 54 sequences from varied specimens were investigated to monitor well-known resistance mutations and probable new mutations. The Pediculus humanus capitis de Geer specimens were collected from 13 provinces in Iran. The specimens were stored in 70% ethanol until DNA extraction and PCR amplification of ~900-bp fragment of VSSC. The sequences were analyzed using different bioinformatics software for the detection of well-known kdr substitutions and additional mutations potentially associated with kdr resistance in head lice. There were six new and an old (haplotype I) kdr haplotypes within the Iranian head louse population. K794E, F815I, and N818D amino acid substitutions were reported for the first time. The P813H mutation was the most prevalent amino acid substitution in eight provinces. Among 53 sequences, 26 (49%) were homozygous susceptible, and 27 (51%) were heterozygotes. Thus, 51% of the head lice collected in Iran harbored only the P813H allele. The exact test for the Hardy–Weinberg (H–W) equilibrium showed that genotype frequencies differed significantly from the expectation in East-Azerbaijan and Tehran provinces. Moreover, these populations had an inbreeding coefficient (Fis) <0, indicating the excess of heterozygotes. This observation suggests that the populations of head lice from Iran are currently under active selective pressure. For the rest of the populations, H–W equilibrium and the expectations were significantly in harmony. The results of the current study highlight molecular techniques in the accurate detection of resistance genotypes before their establishment within the head louse population. Accurate detection of resistant genotypes seems to be helpful in decision-making on lice control programs and resistance monitoring and management.

Low Frequency of Knockdown Resistance Mutations in Musca domestica (Muscidae: Diptera) Collected From Northwestern Iran

2018 ◽  
Vol 56 (2) ◽  
pp. 501-505
Author(s):  
Shiva Kamdar ◽  
Mostafa Farmani ◽  
Kamran Akbarzadeh ◽  
Abbas Jafari ◽  
Saber Gholizadeh
Keyword(s):  
Musca Domestica ◽  
Low Frequency ◽  
Knockdown Resistance ◽  
Resistance Mutations ◽  
Northwestern Iran

High frequency of knockdown resistance mutations in the para gene of cat flea (Ctenocephalides felis) samples collected from goats

2020 ◽  
Vol 119 (7) ◽  
pp. 2067-2073 ◽  
Author(s):  
Sedef Erkunt Alak ◽  
Ahmet Efe Köseoğlu ◽  
Çağrı Kandemir ◽  
Turğay Taşkın ◽  
Samiye Demir ◽  
...  
Keyword(s):  
High Frequency ◽  
Ctenocephalides Felis ◽  
Knockdown Resistance ◽  
Resistance Mutations ◽  
Cat Flea

Knockdown Resistance Mutations in Aedes aegypti (Diptera: Culicidae) From Puerto Rico

2016 ◽  
Vol 53 (6) ◽  
pp. 1410-1414 ◽  
Author(s):  
Gustavo Ponce-García ◽  
Samantha Del Río-Galvan ◽  
Roberto Barrera ◽  
Karla Saavedra-Rodriguez ◽  
Karina Villanueva-Segura ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Aedes Aegypti ◽  
Knockdown Resistance ◽  
Resistance Mutations

scholarly journals Comparison of the knockdown resistance locus (kdr) in Anopheles stephensi, An. arabiensis, and Culex pipiens s.l. suggests differing mechanisms of pyrethroid resistance in east Ethiopia

2020 ◽  
Author(s):  
Tamar E. Carter ◽  
Araya Gebresilassie ◽  
Shantoy Hansel ◽  
Lambodhar Damodaran ◽  
Callum Montgomery ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Culex Pipiens ◽  
Anopheles Stephensi ◽  
Pyrethroid Resistance ◽  
Resistance Mechanism ◽  
Target Site ◽  
Resistance Locus ◽  
Knockdown Resistance ◽  
Resistance Mutations ◽  
Vector Species

AbstractThe malaria vector, Anopheles stephensi, which is typically restricted to South Asia and the Middle East, was recently detected in the Horn of Africa. Controlling the spread of this vector could involve integrated vector control that considers the status of insecticide resistance of multiple vector species in the region. Previous reports indicate that the knockdown resistance mutations (kdr) in the voltage-gated sodium channel (vgsc) are absent in both pyrethroid resistant and sensitive variants of An. stephensi in east Ethiopia but similar information on other vector species in the same areas is limited. In this study, kdr and the neighboring intron was analyzed in An. stephensi, An. arabiensis, and Culex pipiens s. l. collected in east Ethiopia between 2016 and 2017. Sequence analysis revealed that all of Cx. pipiens s.l. (n = 42) and 71.6% of the An. arabiensis (n=67) carried kdr L1014F known to confer target-site pyrethroid resistance. Intronic variation was only observed in An. stephensi (segregating sites = 6, haplotypes = 3) previously shown to have no kdr mutations. In addition, no evidence of non-neutral evolutionary processes was detected at the An. stephensi kdr intron which further supports target-site mechanism not being a major resistance mechanism in this An. stephensi population. Overall, these results suggest differences in evolved mechanisms of pyrethroid/DDT resistance in populations of vector species from the same region. Variation in insecticide resistance mechanisms in East Ethiopian mosquito vectors highlight possible species or population specific biological factors and distinct environmental exposures that shape their evolution.

scholarly journals Multiple Origins of Knockdown Resistance Mutations in the Afrotropical Mosquito Vector Anopheles gambiae

PLoS ONE ◽  
2007 ◽  
Vol 2 (11) ◽  
pp. e1243 ◽  
Author(s):  
João Pinto ◽  
Amy Lynd ◽  
José L. Vicente ◽  
Federica Santolamazza ◽  
Nadine P. Randle ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Mosquito Vector ◽  
Knockdown Resistance ◽  
Resistance Mutations ◽  
Multiple Origins
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