Resistance Status of Anopheles maculipennis and Anopheles superpictus to the Conventional Insecticides in Northeastern Caspian Littoral, Iran

Background: Malaria resurgence has occurred in the northern half parts of Iran. The resurgence of malaria in the prone area could arise from various factors, e.g. wide use of pesticides in the agriculture sector and factors such as habitual patterns of movement of local people from problematic southeastern foci in Iran toward the Caspian Littoral. There are no new data on the resistance status of main malaria vectors in the Caspian Littoral, and this study was aimed at renewal data on conventional insecticides. Methods: The field strain of adult Anopheles superpictus and Anopheles maculipennis were collected using the hand catch method and transferred to the laboratory. The susceptibility tests were carried out against DDT 4%, Malathion 5%, Permethrin 0.75%, Deltamethrin 0.05%, and Lambda-cyhalothrin 0.05%, followed by the WHO’s procedure. Results: The primary malaria vector in Caspian Littoral is An. maculipennis, revealed to be still resistant to DDT and mortality rate, LT50 and LT90 of female mosquitoes were 75.0%, 54.2, minutes and 111.3 minutes. The under ’verification required’ status of An. maculipennis was also revealed to Lambda-cyhalothrin based on recent WHO’s criteria. The malaria vector An. superpictus is also considered the second malaria vectors in the west parts of the studied area, which showed to be susceptible to all insecticides tested. Conclusion: DDT resistance is persisted in An. maculipennis despite stopping residual spraying with DDT since 1978 in the Caspian Littoral, but the occurrence of pyrethroid under ’verification required’ status is a progressive threat to the possible development of cross-resistance in the future.

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Insecticides Susceptibility Status of Malaria Vectors in a High Malaria Endemic Tribal District Gadchiroli (Maharashtra) of India

JOURNAL OF COMMUNICABLE DISEASES ◽

10.24321/0019.5138.202137 ◽

2021 ◽

Vol 53 (03) ◽

pp. 33-50

Author(s):

RK Singh ◽

Keyword(s):

World Health ◽

Malaria Vectors ◽

Synthetic Pyrethroids ◽

Lambda Cyhalothrin ◽

Deltamethrin Resistance ◽

Cone Bioassay ◽

Susceptibility Tests ◽

Health Organization ◽

Susceptibility Status ◽

Major Malaria Vector

Background and Objective: The current study was undertaken to determine insecticide susceptibility of malaria vectors in various villages of high malaria endemic PHCs of Gadchiroli district of Maharashtra. Methods: Adult malaria vectors were collected from the human dwellings/ cattle sheds of 156 villages of 18 malaria endemic PHCs. Susceptibility tests were carried out for different insecticides against An. culicifacies and An. fluviatilis mosquitoes as per the World Health Organization (WHO) procedure. Cone bioassays were also done to assess the quality and efficacy of indoor residual spray. Results:An. fluviatilis could be collected from 23 villages only and all the populations were fully susceptible to synthetic pyrethroid (deltamethrin) while being tolerant to organophosphorous (malathion). Susceptibility of An. culicifacies from 156 villages indicated that only 3 populations of An. culicifacies were resistant to deltamethrin while 57 populations were fully susceptible and other 96 populations were tolerant to deltamethrin. Resistance was recorded in 25 populations of An. culicifacies against malathion and 30 populations were tolerant to malathion insecticide. Remaining populations of An. fluviatilis and An. culicifacies were highly resistant to organochlorine. Results of cone bioassay revealed the mortality ranged from 32.5-51.1% on cemented and 27.5-43.3% on the mud wall sprayed with lambda cyhalothrin. Conclusion: The current study indicates that resistance has developed to synthetic pyrethroids in the major malaria vector An. culicifacies. Therefore, there is an urgent need for the evaluation of new insecticide molecules for better control of malaria vectors.

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The Current Insecticide Resistance in Main Malaria Vector Anopheles arabiensis in Yemen

Journal of Tropical Medicine ◽

10.1155/2020/5625019 ◽

2020 ◽

Vol 2020 ◽

pp. 1-5

Author(s):

Zalalham Al-Koleeby ◽

Ahmed El Aboudi ◽

Mithaq Assada ◽

Mohamed Al-Hadi ◽

Mohammed Abdalr Ahman ◽

...

Keyword(s):

Insecticide Resistance ◽

Malaria Vector ◽

Anopheles Arabiensis ◽

Resistance Management ◽

Indoor Residual Spraying ◽

Malaria Vectors ◽

Test Procedures ◽

Phenotypic Resistance ◽

Lambda Cyhalothrin ◽

Susceptibility Tests

Control of malaria vectors in Yemen relies on both indoor residual spraying using carbamate (bendiocarb) and long-lasting pyrethroids-treated nets. This paper reports the results of studies conducted to monitor the insecticide resistance of the main malaria vector, Anopheles arabiensis, to the insecticides currently used in the vector control in four different locations. Susceptibility tests were performed following the WHO test procedures. Two pyrethroids (lambda-cyhalothrin 0.05% and deltamethrin 0.05%) and one carbamate (bendiocarb 0.1%) were tested at diagnostic doses (DD). The five-fold DD of lambda-cyhalothrin and deltamethrin (0.25%) were also used to yield information on the intensity of resistance. Besides, tests with synergists were performed to assess the involvement of detoxifying enzyme in the phenotypic resistance of the populations of An. arabiensis to pyrethroids. The results of the performed susceptibility bioassay showed that the vector is susceptible to bendiocarb and resistant to lambda-cyhalothrin and deltamethrin in the four studied areas. The pyrethroids resistance is solely metabolic. This information could help policy-makers to plan insecticide resistance management. Bendiocarb is still an effective insecticide in the form of IRS. Concerning LLINS, it would be interesting to assess their effectiveness, combining a pyrethroid with PBO for the control of the pyrethroid-resistant malaria vector.

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Efficacy of broflanilide (VECTRON T500), a new meta-diamide insecticide, for indoor residual spraying against pyrethroid-resistant malaria vectors

Scientific Reports ◽

10.1038/s41598-021-86935-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Corine Ngufor ◽

Renaud Govoetchan ◽

Augustin Fongnikin ◽

Estelle Vigninou ◽

Thomas Syme ◽

...

Keyword(s):

Indoor Residual Spraying ◽

Malaria Vectors ◽

Cross Resistance ◽

Malaria Vector Control ◽

Mosquito Vectors ◽

Experimental Huts ◽

Application Rates ◽

Wettable Powder ◽

Cone Bioassay ◽

Pirimiphos Methyl

AbstractThe rotational use of insecticides with different modes of action for indoor residual spraying (IRS) is recommended for improving malaria vector control and managing insecticide resistance. Insecticides with new chemistries are urgently needed. Broflanilide is a newly discovered insecticide under consideration. We investigated the efficacy of a wettable powder (WP) formulation of broflanilide (VECTRON T500) for IRS on mud and cement wall substrates in laboratory and experimental hut studies against pyrethroid-resistant malaria vectors in Benin, in comparison with pirimiphos-methyl CS (Actellic 300CS). There was no evidence of cross-resistance to pyrethroids and broflanilide in CDC bottle bioassays. In laboratory cone bioassays, broflanilide WP-treated substrates killed > 80% of susceptible and pyrethroid-resistant An. gambiae sl for 6–14 months. At application rates of 100 mg/m2 and 150 mg/m2, mortality of wild pyrethroid-resistant An. gambiae sl entering experimental huts in Covè, Benin treated with VECTRON T500 was similar to pirimiphos-methyl CS (57–66% vs. 56%, P > 0.05). Throughout the 6-month hut trial, monthly wall cone bioassay mortality on VECTRON T500 treated hut walls remained > 80%. IRS with broflanilide shows potential to significantly improve the control of malaria transmitted by pyrethroid-resistant mosquito vectors and could thus be a crucial addition to the current portfolio of IRS insecticides.

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Spatial Distribution Patterns of Malaria Vectors and Sample Size Determination in Spatially Heterogeneous Environments: A Case Study in the West Kenyan Highland

Journal of Medical Entomology ◽

10.1603/0022-2585-41.6.1001 ◽

2004 ◽

Vol 41 (6) ◽

pp. 1001-1009 ◽

Cited By ~ 36

Author(s):

Guofa Zhou ◽

Noboru Minakawa ◽

Andrew Githeko ◽

Guiyun Yan

Keyword(s):

Spatial Distribution ◽

Sample Size ◽

Distribution Patterns ◽

Sample Size Determination ◽

Malaria Vectors ◽

Heterogeneous Environments ◽

Size Determination ◽

The West ◽

Spatial Distribution Patterns

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Comparative Study of the Effect of Solvents on the Efficacy of Neonicotinoid Insecticides Against Malaria Vector Populations Across Africa

10.21203/rs.3.rs-1197098/v1 ◽

2022 ◽

Author(s):

Magellan Tchouakui ◽

Tatiane Assatse ◽

Leon M. J. Mugenzi ◽

Benjamin D. Menze ◽

Daniel Nguiffo-Nguete ◽

...

Keyword(s):

Democratic Republic Of Congo ◽

Natural Populations ◽

Resistance Mechanisms ◽

Lower Mortality ◽

Malaria Vectors ◽

Cross Resistance ◽

Metabolic Resistance ◽

Resistance Development ◽

Development Of Resistance ◽

Bottle Test

Abstract Background New insecticides with a novel mode of action such as neonicotinoids have recently been recommended for public health by WHO. Resistance monitoring of such novel insecticides requires a robust protocol to monitor the development of resistance in natural populations. In this study, we comparatively used three different solvents to assess the susceptibility of malaria vectors to neonicotinoids across Africa.MethodsMosquitoes were collected from May to July 2021 from three agricultural settings in Cameroon (Njombe-Penja, Nkolondom, and Mangoum), the Democratic Republic of Congo (Ndjili-Brasserie), Ghana (Obuasi), and Uganda (Mayuge). Using the CDC bottle test, we compared the effect of three different solvents (ethanol, acetone, MERO) on the efficacy of neonicotinoids against Anopheles gambiae s.l. In addition, TaqMan assays were used to genotype key pyrethroid-resistant markers in An. gambiae and to evaluate potential cross-resistance between pyrethroids and clothianidin.ResultsLower mortality were observed when using absolute ethanol or acetone alone as solvent (11.4- 51.9% mortality in Nkolondom, 31.7- 48.2% in Mangoum, 34.6- 56.1% in Mayµge, 39.4- 45.6% in Obuasi, 83.7- 89.3% in Congo and 71.05- 95.9% in Njombe pendja) compared to acetone + MERO for which 100% mortality were observed for all the populations. Synergist assays (PBO, DEM and DEF) revealed a significant increase of mortality suggesting that metabolic resistance mechanisms are contributing to the reduced susceptibility. A negative association was observed between the L1014F-kdr mutation and clothianidin resistance with a greater frequency of homozygote resistant mosquitoes among the dead than among survivors (OR=0.5; P=0.02). However, the I114T-GSTe2 was in contrast significantly associated with a greater ability to survive clothianidin with a higher frequency of homozygote resistant among survivors than other genotypes (OR=2.10; P=0.013). ConclusionsThis study revealed a contrasted susceptibility pattern depending on the solvents with ethanol/acetone resulting to lower mortality, thus possibly overestimating resistance, whereas the MERO consistently showed a greater efficacy of neonicotinoids but it could prevent to detect early resistance development. Therefore, we recommend monitoring the susceptibility using both acetone alone and acetone+MERO (8-10µg/ml for clothianidin) to capture the accurate resistance profile of the mosquito populations.

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The Stone Age in Beechamwell

Proceedings of the Prehistoric Society of East Anglia ◽

10.1017/s0958841800022833 ◽

1913 ◽

Vol 1 (3) ◽

pp. 320-321

Author(s):

R. C. Nightingale

Keyword(s):

Small Area ◽

Average Depth ◽

Stone Age ◽

The West ◽

Narrow Strip ◽

Northern Half ◽

Top Soil ◽

Northern Side ◽

Boulder Clay ◽

Grey Colour

The greater part of the northern side of the parish of Beechamwell consists of marl and chalk with a top-soil of from one to eighteen feet of gravelly sand. The average depth of this is about eight feet. On the top of it there is a layer of turf or of cultivable soil from three-quarters of a foot to a foot and a-half in depth. There is a narrow strip of boulder clay deposit on which ice-scratched, worked flints are found. There is also a tongue of gravel one and a-half-mile long and half-a-mile wide at its widest part. On this, generally, very few worked flints have been found; fragments of pottery in some numbers have been found all over it however. On the edge of this strip, adjacent on the west to the boulder clay, several worked flints have been picked up, and a hoard of about 200 splinters and flakes was found lying between the sand and the turf, a foot deep here.The greater part of the worked flints are found in an area of about half-a-mile square. The axes, whole or in fragments, are found scattered over the whole of the northern half of the parish. The first axe, however, I found was lying beside a path through the old fen that lies on the south side of Beechamwell. The worked flints found near the moraine are of a peculiar grey colour, and nearly all scimitar-shaped.Flints are found in beds in the chalk and are still plentiful on the surface of the soil, although many have been picked off it for building and road-mending. The small area on which the worked flints are so numerous is the highest ground in Beechamwell.

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Adulticide Resistance Status of Aedes albopictus (Diptera: Culicidae) in Sabah, Malaysia: A Statewide Assessment

Journal of Medical Entomology ◽

10.1093/jme/tjz117 ◽

2019 ◽

Vol 56 (6) ◽

pp. 1715-1725

Author(s):

N M R Elia-Amira ◽

C D Chen ◽

V L Low ◽

K W Lau ◽

A Haziqah-Rashid ◽

...

Keyword(s):

Mortality Rate ◽

Correlation Analysis ◽

Aedes Albopictus ◽

Mortality Rates ◽

The Other ◽

Cross Resistance ◽

Lambda Cyhalothrin ◽

East Malaysia ◽

Statewide Assessment ◽

Susceptibility Status

Abstract Resistance status of Aedes albopictus (Diptera: Culicidae) collected from Sabah, East Malaysia, was evaluated against four major classes of adulticides, namely pyrethroid, carbamate, organochlorine, and organophosphate. Adult bioassays conforming to WHO standard protocols were conducted to assess knockdown and mortality rates of Ae. albopictus. Among tested pyrethroid adulticides, only cyfluthrin, lambda-cyaholthrin, and deltamethrin were able to inflict total knockdown. The other adulticide classes mostly failed to cause any knockdown; the highest knockdown rate was only 18.33% for propoxur. With regards to mortality rate, Ae. albopictus was unanimously susceptible toward all pyrethroids, dieldrin, and malathion, but exhibited resistance toward bendiocarb, propoxur, dichlorodiphenyltrichloroethane, and fenitrothion. Additionally, correlation analysis demonstrated cross-resistance between bendiocarb and propoxur, and malathion and propoxur. In conclusion, this study has disclosed that pyrethroids are still generally effective for Aedes control in Sabah, Malaysia. The susceptibility status of Ae. albopictus against pyrethroids in descending order was cyfluthrin > lambda-cyhalothrin > deltamethrin > etofenprox > permethrin.

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Effect of non-antifungal agrochemicals on the pathogenic fungus Cryptococcus gattii

Medical Mycology ◽

10.1093/mmy/myz018 ◽

2019 ◽

Vol 58 (1) ◽

pp. 47-53 ◽

Cited By ~ 3

Author(s):

Hellem Cristina Silva Carneiro ◽

Noelly Queiroz Ribeiro ◽

Rafael Wesley Bastos ◽

Daniel Assis Santos

Keyword(s):

Crop Production ◽

Pathogenic Fungus ◽

Cryptococcus Gattii ◽

Agricultural Products ◽

Cross Resistance ◽

Human Pathogens ◽

High Concentrations ◽

Susceptibility Tests ◽

Susceptible Subpopulations

Abstract The chemical control of pests and weeds is employed to improve crop production and the quality of agricultural products. The intensive use of pesticides, however, may cause environmental contamination, thus altering microbial communities. Cryptococcus gattii is an environmental yeast and the causative agent of cryptococcosis in both humans and animals. Up to this day, the effects of agrochemicals on human pathogens living in nature are still widely unknown. In this work, we analyzed the susceptibility of C. gattii to nonfungicide agrochemicals (herbicides and insecticides). Microdilution and drug-combination susceptibility tests were performed for the herbicides flumioxazin (FLX), glyphosate (GLY), isoxaflutole (ISO), pendimethalin (PEND), and also for the insecticide fipronil (FIP). Moreover, these compounds were combined with the clinical antifungals amphotericin B and fluconazole. The MIC values found for the agrochemicals were the following: < 16 μg/ml, for flumioxazin; 128 to 256 μg/ml, for FIP, ISO, and PEND; and >256 μg/ml, for GLY. Synergistic and antagonistic interactions, depending on the strain and concentration tested, were also observed. All strains had undergone adaptation to increasing levels of agrochemicals, in order to select the less susceptible subpopulations. During this process, one C. gattii strain (196 L/03) tolerated high concentrations (50 to 900 μg/ml) of all pesticides assessed. Subsequently, the strain adapted to flumioxazin, isoxaflutole and pendimethalin showed a reduction in the susceptibility to agrochemicals and clinical antifungals, suggesting the occurrence of cross-resistance. Our data point to the risk of exposing C. gattii to agrochemicals existing in the environment, once it might impact the susceptibility of clinical antifungals.

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Study on the Relation among Agriculture and Forests of Arunachal Pradesh

International Journal of Plant and Environment ◽

10.18811/ijpen.v6i01.09 ◽

2020 ◽

Vol 6 (01) ◽

pp. 85-90

Author(s):

Babita Kumari ◽

Hitesh Solanki

Keyword(s):

Food Security ◽

The State ◽

Arunachal Pradesh ◽

The West ◽

Agriculture Sector ◽

The North ◽

International Borders ◽

Percent Increase ◽

Per Capita ◽

Agricultural Yield

The state of Arunachal Pradesh is the northeastern most state of India. It covers the states of Assam and Nagaland to the south. It also comprises of international borders with Bhutan in the west, Myanmar in the east, and a disputed border with China in the north at the McMahon Line. The state has its agriculture as the main source of livelihood for a majority of the region’s rural population. In the last 10 years, the per capita land availability in the region has reduced by 18.4 percent and now remains a meager 0.16 ha. The reduction is attributed to the rapid increase in population and consequent fragmentation of the land. Similarly, per capita, cereal availability has also reduced by 9.4 percent in the last 10 years. The present per capita cereal availability is only 0.16 kg, thus making it very important to ensure food security in the region at any cost. Agricultural productivity in the region is not adequate to produce sufficiently for the increasing population. The average agricultural yield at present is 2.1 tonnes ha-1 (excluding the Maldives) after an increase of 8.1 percent in the last 10 years. The increase is attributed to increased use of fertilizers (69 kg ha-1, which is a 40 percent increase in the last 10 years in the region, excluding the Maldives) and the inclusion of more areas from forests into the agriculture sector. This situation has, in its turn, taken its toll by depleting and threatening the remaining biodiversity of the region.

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