Insecticide resistance spectra and resistance mechanisms in populations of Japanese encephalitis vector mosquitoes, Culex tritaeniorhynchus and Cx. gelidus, in Sri Lanka

2000 ◽  
Vol 14 (4) ◽  
pp. 430-436 ◽  
Author(s):  
S. H. P. P. Karunaratne ◽  
J. Hemingway
Keyword(s):  
Sri Lanka ◽  
Insecticide Resistance ◽  
Japanese Encephalitis ◽  
Resistance Mechanisms ◽  
Culex Tritaeniorhynchus

Molecular and biochemical characterization of a sand fly population from Sri Lanka: evidence for insecticide resistance due to altered esterases and insensitive acetylcholinesterase

2005 ◽  
Vol 95 (4) ◽  
pp. 371-380 ◽  
Author(s):  
S.N. Surendran ◽  
S.H.P.P. Karunaratne ◽  
Z. Adamsn ◽  
J. Hemingway ◽  
N.J. Hawkes
Keyword(s):  
Sri Lanka ◽  
Insecticide Resistance ◽  
Biochemical Characterization ◽  
Preliminary Evidence ◽  
Resistance Mechanisms ◽  
Sand Fly ◽  
Cross Resistance ◽  
Cytochrome P450 Monooxygenases ◽  
Sand Flies

AbstractWith an increasing incidence of cutaneous leishmaniasis in Sri Lanka, particularly in northern provinces, insecticide-mediated vector control is under consideration. Optimizing such a strategy requires the characterization of sand fly populations in target areas with regard to species composition and extant resistance, among other parameters. Sand flies were collected by human bait and cattle-baited net traps on Delft Island, used as an illegal transit location by many refugees returning to the north of Sri Lanka from southern India where leishmaniasis is endemic. For species identification, genomic DNA was extracted and a fragment of the ribosomal 18S gene amplified. The sequence from all flies analysed matched that of Phlebotomus argentipes Annandale & Brunetti, the primary vector in India and the most likely vector in Sri Lanka. Independent morphological analysis also identified P. argentipes. To establish the current susceptibility status of vector species, data were obtained at the biochemical level, from which potential cross-resistance to alternative insecticides can be predicted. The Delft Island collection was assayed for the activities of four enzyme systems involved in insecticide resistance (acetylcholinesterase, non-specific carboxylesterases, glutathione-S-transferases and cytochrome p450 monooxygenases), establishing baselines against which subsequent collections can be evaluated. There was preliminary evidence for elevated esterases and altered acetylcholinesterase in this population, the first report of these resistance mechanisms in sand flies to our knowledge, which probably arose from the malathion-based spraying regimes of the Anti-Malarial Campaign.

scholarly journals Voltage-Gated Sodium Channel (Vgsc) Mutation-Based Pyrethroid Resistance in Aedes aegypti Populations of Three Endemic Dengue Risk Areas of Sri Lanka

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Tharaka Ranathunge ◽  
Lahiru Udayanga ◽  
Sumudu Sarasija ◽  
Samudra Karunathilaka ◽  
Shavindhya Nawarathne ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Insecticide Resistance ◽  
Pyrethroid Resistance ◽  
Control Strategies ◽  
Resistance Mechanisms ◽  
Allele Frequencies ◽  
Multiple Use ◽  
Pyrethroid Insecticides ◽  
Dengue Control ◽  
Mutation Allele

Background. Pyrethroid insecticides are widely used in many countries for chemical-based control of Ae. aegypti. Regardless of their efficacy, the constant use of insecticides has induced insecticide resistance mechanisms, such as knockdown resistance (kdr) in mosquitoes. Sri Lankan Vector Controlling Entities (VCE) have been using a variety of pyrethroid insecticides as the primary approach for dengue control. However, development of any resistance among the Aedes mosquitoes has been limitedly studied in the country. Therefore, the current study was conducted to evaluate the prevalence of F1534C, V1016G, and S989P mutations among Ae. aegypti mosquito populations in three dengue endemic high-risk regions of Sri Lanka. Methodology. Immature (both pupae and larvae) stages of Ae. aegypti mosquitoes were collected from Colombo, Gampaha, and Kandy districts of Sri Lanka from February 2018 to December 2019. Polymerase Chain Reaction- (PCR-) based assay for molecular genotyping of mutations was performed to identify the prevalence of kdr mutations in collected Ae. aegypti populations, separately. The frequencies of the resistant and susceptible kdr alleles were determined by using the Hardy–Weinberg equilibrium. Results. The Ae. aegypti populations from Colombo, Gampaha, and Kandy districts showed 46%, 42%, and 22% of F1534C mutation allele frequencies, along with 15%, 12%, and 6% of V1016G mutation allele frequencies, respectively. The mutation allele frequencies of S989 in Colombo, Gampaha, and Kandy districts were 9.5%, 8.5%, and 4.5%, respectively. The wild-type (PP) genotype remained predominant within all the three districts, whereas the homogenous (QQ) mutation genotype occurred only in minority. The abundance of Q allele frequency in Ae. aegypti mosquitoes was relatively higher for all the three mutations in Colombo. Conclusions. The findings clearly indicate that long-term insecticide applications and multiple use of pyrethroids have led to the acquisition of kdr mutations, leading to the development of insecticide resistance among local Ae. aegypti populations, especially in the Colombo and Gampaha districts. Therefore, evaluation of the prevalence levels of these kdr mutations highlights the necessity for shifting towards novel vector control strategies.

scholarly journals Multiple insecticide resistance mechanisms in Anopheles gambiae s.l. populations from Cameroon, Central Africa

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Philippe Nwane ◽  
Josiane Etang ◽  
Mouhamadou Chouaїbou ◽  
Jean Claude Toto ◽  
Alphonsine Koffi ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Anopheles Gambiae ◽  
Central Africa ◽  
Resistance Mechanisms ◽  
Anopheles Gambiae S.L

scholarly journals Modeling the distribution of Culex tritaeniorhynchus to predict Japanese encephalitis distribution in the Republic of Korea

2010 ◽  
Vol 5 (1) ◽  
pp. 45 ◽  
Author(s):  
Penny Masuoka ◽  
Terry A. Klein ◽  
Heung-Chul Kim ◽  
David M. Claborn ◽  
Nicole Achee ◽  
...  
Keyword(s):  
Japanese Encephalitis ◽  
Republic Of Korea ◽  
Culex Tritaeniorhynchus ◽  
The Republic

scholarly journals Insecticide resistance in Anopheles stephensi in Somali Region, eastern Ethiopia

2020 ◽  
Author(s):  
Solomon Yared ◽  
Araya Gebressielasie ◽  
Lambodhar Damodaran ◽  
Victoria Bonnell ◽  
Karen Lopez ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Anopheles Stephensi ◽  
Mortality Rates ◽  
Resistance Mechanisms ◽  
World Health ◽  
Malaria Vectors ◽  
Resistance Locus ◽  
Eastern Ethiopia ◽  
Pyrethroid Insecticides ◽  
Pirimiphos Methyl

Abstract Background The movement of malaria vectors into new areas is a growing concern in the efforts to control malaria. The recent report of Anopheles stephensi in eastern Ethiopia has raised the necessity to understand the insecticide resistance status of the vector in the region to better inform vector-based interventions. The aim of this study was to evaluate insecticide resistance in An. stephensi in eastern Ethiopia using two approaches: 1) World Health Organization (WHO) bioassay tests in An. stephensi; and 2) genetic analysis of insecticide resistance genes in An. stephensi in eastern Ethiopia. Methods Mosquito larvae and pupae were collected from Kebri Dehar. Insecticide susceptibility of An. stephensi was tested withmalathion 5%, bendiocarb 0.1%, propoxur 0.1%, deltamethrin 0.05%, permethrin 0.75%, Pirimiphos-methyl 0.25% and DDT 4%, according to WHO standard protocols. In this study, the knockdown resistance locus (kdr) in the voltage gated sodium channel (vgsc) and ace1R locus in the acetylcholinesterase gene (ace-1) were analysed in An. stephensi. Results All An. stephensi samples were resistant to carbamates, with mortality rates of 23% and 21% for bendiocarb and propoxur, respectively. Adult An. stephensi was also resistant to pyrethroid insecticides with mortality rates 67% for deltamethrin and 53% for permethrin. Resistance to DDT and malathion was detected in An. stephensi with mortality rates of 32% as well as An. stephensi was resistance to pirimiphos-methyl with mortality rates 14%. Analysis of the insecticide resistance loci revealed the absence of kdr L1014F and L1014S mutations and the ace1R G119S mutation. Conclusion Overall, these findings support that An. stephensi is resistant to several classes of insecticides, most notably pyrethroids. However, the absence of the kdr L1014 gene may suggest non-target site resistance mechanisms. Continuous insecticide resistance monitoring should be carried out in the region to confirm the documented resistance and exploring mechanisms conferring resistance in An. stephensi in Ethiopia.

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