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

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.

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The pattern of kdr mutations correlated with the temperature in field populations of Aedes albopictus in China

Parasites & Vectors ◽

10.1186/s13071-021-04906-z ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Hanming Chen ◽

Qiuming Zhou ◽

Haowei Dong ◽

Hao Yuan ◽

Jie Bai ◽

...

Keyword(s):

Dengue Fever ◽

Mutation Rate ◽

Aedes Albopictus ◽

Mutant Allele ◽

Control Method ◽

Pearson Correlation ◽

Temperate Climate ◽

National Database ◽

Evolutionary Trend ◽

Climate Zones

Abstract Background Aedes albopictus is the primary vector of dengue fever in China. This mosquito species has a wide distribution range in China and can be found in the tropical climate zones of southern provinces through to temperate climate zones of northern provinces. Insecticides are an important control method, especially during outbreaks of dengue fever, but increasing insecticide resistance raises the risk of failure to control vector-borne diseases. Knockdown resistance (kdr) caused by point mutations in the voltage-gated sodium channel (VGSC) gene is a key mechanism that confers resistance to pyrethroids. In this study we explored the characteristics and possible evolutionary trend of kdr mutation in Ae. albopictus based on analysis of the kdr mutations in field populations of mosquitoes in China. Methods A total of 1549 adult Ae. albopictus were collected from 18 sites in China from 2017 to 2019 and 50 individuals from three sites in the 1990s. A fragment of approximately 350 bp from part of the S6 segment in the VGSC gene domain III was amplified and sequenced. Using TCS software version 1.21A, we constructed haplotypes of the VGSC gene network and calculated outgroup probability of the haplotypes. Data of annual average temperatures (AAT) of the collection sites were acquired from the national database. The correlation between AAT of the collection site and the kdr mutation rate was analyzed by Pearson correlation using SPSS software version 21.0. Results The overall frequency of mutant allele F1534 was 45.6%. Nine mutant alleles were detected at codon 1534 in 15 field populations, namely TCC/TCG (S) (38.9%), TTG/CTG/CTC/TTA (L) (3.7%), TGC (C) (2.9%), CGC (R) (0.3%) and TGG (W) (0.1%). Only one mutant allele, ACC (T), was found at codon 1532, with a frequency of 6.4% in ten field populations. Moreover, multiple mutations at alleles I1532 and F1534 in a sample appeared in five populations. The 1534 mutation rate was significantly positively related to AAT (Pearson correlation: r(18) = 0.624, P = 0.0056), while the 1532 mutation rate was significantly negatively related to AAT (Pearson correlation: r(18) = − 0.645, P = 0.0038). Thirteen haplotypes were inferred, in which six mutant haplotypes were formed by one step, and one additional mutation formed the other six haplotypes. In the samples from the 1990s, no mutant allele was detected at codon 1532 of the VGSC gene. However, F1534S/TCC was found in HNHK94 with an unexpected frequency of 100%. Conclusions Kdr mutations are widespread in the field populations of Ae. albopictus in China. Two novel mutant alleles, F1534W/TGG and F1534R/CGC, were detected in this study. The 1534 kdr mutation appeared in the population of Ae. albopictus no later than the 1990s. The F1534 mutation rate was positively correlated with AAT, while the I1532 mutation rate was negatively correlated with AAT. These results indicate that iInsecticide usage should be carefully managed to slow down the spread of highly resistant Ae. albopictus populations, especially in the areas with higher AAT. Graphical abstract

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Knockdown Resistance (kdr) Mutations I1532T and F1534S Were Identified in Aedes albopictus Field Populations in Zhejiang Province, Central China

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.702081 ◽

2021 ◽

Vol 11 ◽

Author(s):

Yuyan Wu ◽

Qinmei Liu ◽

Yunpeng Qi ◽

Yinping Wu ◽

Qinxiang Ni ◽

...

Keyword(s):

Aedes Albopictus ◽

Mutant Allele ◽

Pyrethroid Resistance ◽

Southern China ◽

Zhejiang Province ◽

Central China ◽

Knockdown Resistance ◽

Resistance Mutations ◽

Deltamethrin Resistance ◽

Domain Iii

Aedes albopictus is the only vector that can transmit the dengue virus in Zhejiang Province, central China, and it can develop insecticide resistance due to long-term exposure to pyrethroids. The presence of knockdown resistance (kdr) mutations is one of the mechanisms responsible for pyrethroid resistance, and has been reported in some Ae. albopictus populations in southern China. However, little is known about the DNA diversity of the voltage-gated sodium channel (VGSC) gene in Ae. albopictus populations in central China. Four Ae. albopictus field populations were collected, in Yiwu (YW), Quzhou (QZ), Wenzhou (WZ), and Jiaxing (JX) from Zhejiang Province, central China. The susceptibility of Ae. albopictus adults to three pyrethroids (beta-cypermethrin, deltamethrin, and permethrin) was tested using the WHO tube assay, and Kdr mutations were identified via PCR and sequencing. The relationship between kdr mutations and pyrethroid phenotypes was also analyzed. Of the four populations, none was sensitive to any pyrethroid tested, and the YW population showed the strongest pyrethroid resistance. Non-synonymous kdr mutations were detected in codons 1532 and 1534, domain III. At codon 1534, one mutant allele, TCC(S), was detected in the four populations with a frequency of 42.08%, while at codon 1532, one mutant allele, ACC(T), was detected in the JX and QZ populations, with frequencies of 4.22 and 3.03%, respectively. The F1534S mutant allele was positively correlated with both beta-cypermethrin and deltamethrin resistance phenotypes (OR > 1, P < 0.05), whereas the I1532T mutant allele was possibly negatively correlated with beta-cypermethrin, deltamethrin, and permethrin resistance phenotypes (OR < 1, P > 0.05). In conclusion, resistance and resistance mutations regarding to three pyrethroids are already present in the Ae. Albopictus populations from Zhejiang, central China, which prompts the need to use non-insecticide-based methods of insect control.

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Aedes albopictus (Skuse, 1894) infected with the American-Asian genotype of dengue type 2 virus in Medellín suggests its possible role as vector of dengue fever in Colombia

Biomédica ◽

10.7705/biomedica.v37i0.3474 ◽

2017 ◽

Vol 37 ◽

pp. 135 ◽

Cited By ~ 4

Author(s):

Andrés Gómez-Palacio ◽

Juan Suaza-Vasco ◽

Sandra Castaño ◽

Omar Triana ◽

Sandra Uribe

Keyword(s):

Aedes Aegypti ◽

Dengue Fever ◽

Aedes Albopictus ◽

Distribución Geográfica ◽

Dengue Type 2 Virus

Introducción. Aedes aegypti y Ae. albopictus son reconocidos vectores de arbovirus como los del dengue, la fiebre amarilla, el chikungunya y el Zika, en regiones tropicales y subtropicales del mundo. En Colombia, la distribución geográfica de Ae. albopictus ha sufrido un incremento y hoy incluye ciudades como Cali y Medellín. Hasta ahora, sin embargo, no se ha recabado información concluyente sobre su infección viral y su capacidad de transmisión a los humanos.Objetivo. Determinar la infección natural por dengue en ejemplares de Ae. albopictus recolectados en un área urbana de Medellín.Materiales y métodos. Se recolectaron individuos de Ae. albopictus en el campus de la Universidad Nacional de Colombia, sede Medellín. Se confirmó su clasificación taxonómica mediante el análisis del gen citocromo oxidasa I (COI), y se extrajo el ARN total para la identificación del virus del dengue y de los respectivos serotipos. La presencia del genotipo DENV se infirió mediante el análisis del gen NS3.Resultados. El análisis del COI corroboró el estatus taxonómico de Ae. albopictus. Uno de los mosquitos procesados fue positivo para DENV-2 y el análisis del NS3 mostró una gran similitud con el genotipo asiático-americano.Conclusión. Se reporta la infección con DENV-2 en Ae. albopictus en Medellín, Colombia. La presencia del genotipo asiático-americano en una zona urbana sugiere su posible circulación entre humanos y en Ae. albopictus, lo cual alerta sobre su eventual papel en la transmisión del DENV-2, y sobre la necesidad de incluir esta especie en la vigilancia entomológica en Colombia.

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Molecular Identification of Mutations Conferring Resistance to Azoxystrobin in Cercospora nicotianae

Plant Disease ◽

10.1094/pdis-02-20-0441-re ◽

2020 ◽

Author(s):

Hua Li ◽

William Barlow ◽

Ed Dixon ◽

Bernadette F. Amsden ◽

Robert Hirsch ◽

...

Keyword(s):

Characteristic Curve ◽

Point Mutations ◽

Receiver Operator Characteristic Curve ◽

Resistance Mutations ◽

Pcr Assay ◽

Cytb Sequence ◽

Qoi Fungicides ◽

Quinone Outside Inhibitor ◽

Tobacco Production ◽

Moderately Resistant

Cercospora nicotianae, the causal agent of frogeye leaf spot (FLS) of tobacco, has been exposed to quinone outside inhibitor (QoI) fungicides for over a decade through azoxystrobin applications targeting other major foliar diseases. From 2016 to 2018, a total of 124 isolates were collected from tobacco fields throughout Kentucky. Sensitivity of these isolates to azoxystrobin was previously characterized by determining the effective concentration to inhibit 50% conidial germination (EC50). Based on azoxystrobin EC50, isolates were categorized into three discrete groups: high azoxystrobin sensitivity (< 0.08 µg/ml), moderate azoxystrobin sensitivity (0.14 to 0.64 µg/ml) and low azoxystrobin sensitivity (> 1.18 µg/ml). Variability in sensitivity in a limited number of C. nicotianae isolates was previously shown to be a result of resistance mutations in the fungicide target gene. To improve understanding of C. nicotianae cytochrome b (cytb) structure, the gene was cloned from three isolates representing each EC50group, and sequences were compared. Our analysis showed that cytb gene in C. nicotianae consists of 1161 nucleotides encoding 386 amino acids. Cytb sequence among the cloned isolates was identical with the exception of the F129L and G143A point mutations. To more rapidly determine the resistance status of C. nicotianae isolates to azoxystrobin, a PCR assay was developed to screen for mutations. Using this assay, 80% (n=99) of testedC. nicotianae isolates carried an F129L mutation and were moderately resistant to azoxystrobin, and 7% (n=9) carried the G143A mutation and were highly resistant. A receiver operator characteristic curve analysis suggested the PCR assay is a robust diagnostic tool to identify C. nicotianae isolates with different sensitivity to azoxystrobin in Kentucky tobacco production. The prevalence of both the F129L and G143A mutations in C. nicotianae from Kentucky differs from other pathosystems where resistance to QoI fungicides has been identified, in which the majority of sampled isolates of the pathogen species have a broadly-occurring cytb mutation.

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Presence of the knockdown resistance (kdr) mutations in the head lice (Pediculus humanus capitis) collected from primary school children of Thailand

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0008955 ◽

2020 ◽

Vol 14 (12) ◽

pp. e0008955

Author(s):

Narisa Brownell ◽

Sakone Sunantaraporn ◽

Kobpat Phadungsaksawasdi ◽

Nirin Seatamanoch ◽

Switt Kongdachalert ◽

...

Keyword(s):

Head Louse ◽

Point Mutations ◽

Human Head ◽

Amino Acid Sequences ◽

Primary School Children ◽

Head Lice ◽

Knockdown Resistance ◽

Pediculosis Capitis ◽

Α Subunit ◽

Blood Sucking

Human head lice are blood-sucking insects causing an infestation in humans called pediculosis capitis. The infestation is more prevalent in the school-aged population. Scalp itching, a common presenting symptom, results in scratching and sleep disturbance. The condition can lead to social stigmatization which can lead to loss of self-esteem. Currently, the mainstay of treatment for pediculosis is chemical insecticides such as permethrin. The extended use of permethrin worldwide leads to growing pediculicide resistance. The aim of this study is to demonstrate the presence of the knockdown resistance (kdr) mutation in head lice populations from six different localities of Thailand. A total of 260 head lice samples in this study were collected from 15 provinces in the 6 regions of Thailand. Polymerase chain reaction (PCR) was used to amplify the α subunit of voltage-sensitive sodium channel (VSSC) gene, kdr mutation (C→T substitution). Restriction fragment length polymorphism (RFLP) patterns and sequencing were used to identify the kdr T917I mutation and demonstrated three genotypic forms including homozygous susceptible (SS), heterozygous genotype (RS), and homozygous resistant (RR). Of 260 samples from this study, 156 (60.00%) were SS, 58 (22.31%) were RS, and 46 (17.69%) were RR. The overall frequency of the kdr T917I mutation was 0.31. Genotypes frequencies determination using the exact test of Hardy-Weinberg equilibrium found that northern, central, northeastern, southern, and western region of Thailand differed from expectation. The five aforementioned localities had positive inbreeding coefficient value (Fis > 0) which indicated an excess of homozygotes. The nucleotide and amino acid sequences of RS and RR showed T917I and L920F point mutations. In conclusion, this is the first study detecting permethrin resistance among human head lice from Thailand. PCR-RFLP is an easy technique to demonstrate the kdr mutation in head louse. The data obtained from this study would increase awareness of increasing of the kdr mutation in head louse in Thailand.

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Death and population dynamics affect mutation rate estimates and evolvability under stress in bacteria

10.1101/224675 ◽

2017 ◽

Author(s):

Antoine Frénoy ◽

Sebastian Bonhoeffer

Keyword(s):

Population Dynamics ◽

Mutation Rate ◽

Death Rate ◽

Mutation Rates ◽

Resistance Mutations ◽

Bacterial Populations ◽

Plasmid Segregation ◽

Genome Wide ◽

Response To Stress ◽

Induced Mutagenesis

AbstractThe stress-induced mutagenesis paradigm postulates that in response to stress, bacteria increase their genome-wide mutation rate, in turn increasing the chances that a descendant is able to withstand the stress. This has implications for antibiotic treatment: exposure to sub-inhibitory doses of antibiotics has been reported to increase bacterial mutation rates, and thus probably the rate at which resistance mutations appear and lead to treatment failure.Measuring mutation rates under stress, however, is problematic, because existing methods assume there is no death. Yet sub-inhibitory stress levels may induce a substantial death rate. Death events need to be compensated by extra replication to reach a given population size, thus giving more opportunities to acquire mutations. We show that ignoring death leads to a systematic overestimation of mutation rates under stress.We developed a system using plasmid segregation to measure death and growth rates simultaneously in bacterial populations. We use it to replicate classical experiments reporting antibiotic-induced mutagenesis. We found that a substantial death rate occurs at the tested sub-inhibitory concentrations, and taking this death into account lowers and sometimes removes the signal for stress-induced mutagenesis. Moreover even when antibiotics increase mutation rate, sub-inhibitory treatments do not increase genetic diversity and evolvability, again because of effects of the antibiotics on population dynamics.Beside showing that population dynamic is a crucial but neglected parameter affecting evolvability, we provide better experimental and computational tools to study evolvability under stress, leading to a re-assessment of the magnitude and significance of the stress-induced mutagenesis paradigm.

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Mumame: a software tool for quantifying gene-specific point-mutations in shotgun metagenomic data

Metabarcoding and Metagenomics ◽

10.3897/mbmg.3.36236 ◽

2019 ◽

Vol 3 ◽

Cited By ~ 1

Author(s):

Shruthi Magesh ◽

Viktor Jonsson ◽

Johan Bengtsson-Palme

Keyword(s):

Microbial Communities ◽

Point Mutations ◽

Software Tool ◽

Metagenomic Data ◽

Data Sets ◽

Resistance Mutations ◽

Shotgun Metagenomics ◽

Key Factor ◽

Detection Of Mutations ◽

And Function

Metagenomics has emerged as a central technique for studying the structure and function of microbial communities. Often the functional analysis is restricted to classification into broad functional categories. However, important phenotypic differences, such as resistance to antibiotics, are often the result of just one or a few point mutations in otherwise identical sequences. Bioinformatic methods for metagenomic analysis have generally been poor at accounting for this fact, resulting in a somewhat limited picture of important aspects of microbial communities. Here, we address this problem by providing a software tool called Mumame, which can distinguish between wildtype and mutated sequences in shotgun metagenomic data and quantify their relative abundances. We demonstrate the utility of the tool by quantifying antibiotic resistance mutations in several publicly available metagenomic data sets. We also identified that sequencing depth is a key factor to detect rare mutations. Therefore, much larger numbers of sequences may be required for reliable detection of mutations than for most other applications of shotgun metagenomics. Mumame is freely available online (http://microbiology.se/software/mumame).

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Plasmodium falciparum DHODH inhibitor complexes reveal flexible binding site

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314082072 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1793-C1793

Author(s):

Paul Rowland ◽

Onkar SINGH ◽

Leila Ross ◽

Francisco Gamo ◽

Maria Lafuente-Monasterio ◽

...

Keyword(s):

Drug Resistance ◽

Binding Site ◽

Crystal Structures ◽

Point Mutations ◽

Crystal Form ◽

Drug Binding ◽

Binding Modes ◽

Resistance Mutations ◽

Drug Binding Site

Malaria is a preventable and treatable disease, yet annually there are still hundreds of thousands of malaria-related deaths. The disease is caused by infection with mosquito-borne Plasmodium parasites. With hundreds of millions of cases each year there is a very high potential for drug resistance and this has compromised many existing therapies. One target under investigation is the enzyme dihydroorotate dehydrogenase (DHODH) which catalyses the rate-limiting step of pyrimidine biosynthesis and is an essential enzyme in the malaria parasite. There are currently several Plasmodium-selective DHODH inhibitors under development. To investigate the potential for drug resistance against DHODH inhibitors in vitro resistance selections were carried out using known inhibitors from different structural classes [1]. These studies identified point mutations in the drug binding site which lead to reduced sensitivity to the inhibitors, and in some cases increased sensitivity to a different inhibitor, suggesting a novel combination therapy approach to combat resistance. To help understand the significance of the inhibitor binding site mutations we determined the crystal structures of P. falciparum DHODH in complex with the inhibitors Genz-669178, IDI-6253 and IDI-6273. Co-crystallisation experiments led to a new crystal form in each case. Here we describe the crystal structures, the binding modes of the inhibitors and the great flexibility of the binding site, which is able to adjust to accommodate different inhibitor series. The structural role of the resistance mutations is also discussed.

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IDENTIFICATION OF THE kdr MUTATIONS IN VGSC GENE OF THE DENGUE MOSQUITOES AEDES ALBOPICTUS COLLECTED FROM HANOI AND HAIPHONG

Vietnam Journal of Biotechnology ◽

10.15625/1811-4989/16/2/13437 ◽

2018 ◽

Vol 16 (2) ◽

pp. 273-278

Author(s):

Nguyen Thi Kim Lien ◽

Nguyen Thu Hien ◽

Nguyen Huy Hoang ◽

Nguyen Thi Hong Ngoc ◽

Nguyen Thi Huong Binh

Keyword(s):

Sodium Channel ◽

Aedes Albopictus ◽

Novel Mutation ◽

Resistance Mechanism ◽

Resistance Mechanisms ◽

Resistance Mutations ◽

Well Control ◽

Voltage Gated ◽

Activity Of Enzymes ◽

Dengue Epidemic

Vietnam is one of the countries that is affected by dengue fever in Southeast Asia. The dengue epidemic is becoming increasingly more complex so it is necessary to have a well control to vectors in order to limit the spread of the disease. The Aedes albopictus mosquito is determined as one of the two major vectors that transmitted the dengue. Recent research shows that A. albopictus is present in some parts of Hanoi and Haiphong. In order to control the vector as well as the disease, it is necessary to understand the level of resistance and the resistance mechanism of the vector. Two important resistance mechanisms of insect were known as the mutations in the target protein of the insecticides and enhancing the activity of enzymes that participate in the resolution of the insecticides. In this study, the mosquito samples were collected from Hanoi and Haiphong to identify the level of resistance and detect the knock down resistance mutations in voltage gated sodium channel (VGSC) in membrane of nervecell of mosquito. The results of insecticide susceptibility test showed that A. albopictus in Hanoi and Haiphong were still sensitive to organophosphate but resistant to DDT, carbamate and pyrethroid. Ser989Pro, Ile1011Met, Val1016Gly and Phe1534Cys mutations were not deteced in A. albopictus in Hanoi and Haiphong. However, we detected a novel mutation Tyr986His in VGSC protein.

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

Journal of Medical Entomology ◽

10.1093/jme/tjab101 ◽

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.

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