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Environmental Science & Technology Mar 2023To assess the contamination and potential risk of snow melt with polar compounds, road and background snow was sampled during a melting event at 23 sites at the city of...
To assess the contamination and potential risk of snow melt with polar compounds, road and background snow was sampled during a melting event at 23 sites at the city of Leipzig and screened for 489 chemicals using liquid chromatography high-resolution mass spectrometry with target screening. Additionally, six 24 h composite samples were taken from the influent and effluent of the Leipzig wastewater treatment plant (WWTP) during the snow melt event. 207 compounds were at least detected once (concentrations between 0.80 ng/L and 75 μg/L). Consistent patterns of traffic-related compounds dominated the chemical profile (58 compounds in concentrations from 1.3 ng/L to 75 μg/L) and among them were 2-benzothiazole sulfonic acid and 1-cyclohexyl-3-phenylurea from tire wear and denatonium used as a bittern in vehicle fluids. Besides, the analysis unveiled the presence of the rubber additive 6-PPD and its transformation product -(1.3-dimethylbutyl)-'-phenyl--phenylenediamine quinone (6-PPDQ) at concentrations known to cause acute toxicity in sensitive fish species. The analysis also detected 149 other compounds such as food additives, pharmaceuticals, and pesticides. Several biocides were identified as major risk contributors, with a more site-specific occurrence, to acute toxic risks to algae (five samples) and invertebrates (six samples). Ametryn, flumioxazin, and 1,2-cyclohexane dicarboxylic acid diisononyl ester are the main compounds contributing to toxic risk for algae, while etofenprox and bendiocarb are found as the main contributors for crustacean risk. Correlations between concentrations in the WWTP influent and flow rate allowed us to discriminate compounds with snow melt and urban runoff as major sources from other compounds with other dominant sources. Removal rates in the WWTP showed that some traffic-related compounds were largely eliminated (removal rate higher than 80%) during wastewater treatment and among them was 6-PPDQ, while others persisted in the WWTP.
Topics: Animals; Crustacea; Environmental Monitoring; Fishes; Freezing; Risk Assessment; Snow; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical; Water Purification; Phenylenediamines; Benzoquinones
PubMed: 36862848
DOI: 10.1021/acs.est.2c05784 -
Environmental Science and Pollution... Apr 2023Insecticides are dedicated to impair the insect organisms, but also have an impact on other, non-target organisms, including humans. In this way, they became important...
Insecticides are dedicated to impair the insect organisms, but also have an impact on other, non-target organisms, including humans. In this way, they became important risk factor for disturbance of physiological homeostasis and can be involved in the development of diseases or in deterioration of existing conditions. The influence of sublethal doses of various insecticides on vertebrates' and invertebrates' organisms has been previously observed. In this paper, we have evaluated the impact of exposure to extremely low dose of neurotoxin, bendiocarb (0.1 nM), a commonly used carbamate insecticide on a model organism in neurobiology-Periplaneta americana. The assessment was performed on all levels of animal organism from molecular (oxidative stress parameters: phosphorylation level of proteins, cAMP level, protein kinase A and C levels, and octopamine) to physiological (heart beat and gas exchange tests) and behavioral (motor skills assay, grooming test). Exposure to such a low level of bendiocarb did not cause direct paralysis of insects, but changed their grooming behavior, decreased heart rate, and increased gas exchange. We also observed the increased parameters of oxidative stress as well as stressogenic response to 0.1 nM bendiocarb exposure. Exposure to a trace amount of bendiocarb also increased sensitivity to effective doses of the same insecticide, thus acts as preconditioning. These results force us to reconsider the possible risk from frequent/continuous exposure to traces of pesticide residues in the environment to human health.
Topics: Animals; Humans; Insecticides; Periplaneta; Cockroaches; Phenylcarbamates
PubMed: 36745351
DOI: 10.1007/s11356-023-25602-8 -
Malaria Journal Jan 2023The objective of this study was to estimate malaria transmission and insecticide resistance status in malaria vectors in Adjrako village from Zè District in Southern...
BACKGROUND
The objective of this study was to estimate malaria transmission and insecticide resistance status in malaria vectors in Adjrako village from Zè District in Southern Benin. The present study was carried out prior to investigations on infectivity of blood from asymptomatic carriers of Plasmodium falciparum to malaria vector mosquitoes.
METHODS
Human landing collections (HLCs) were performed in Adjrako village during the rainy season (September-November 2021). In this village, host-seeking mosquitoes were collected during three nights per survey from 22:00 to 06:00 in six randomly selected houses. Malaria vectors were dissected in orders to determinate their parity. Plasmodium falciparum infection in malaria vectors was determined by qPCR and the entomological inoculation rate (EIR) was calculated. The World Health Organization (WHO) insecticide susceptibility test-kits were used to evaluate the susceptibility of Anopheles gambiae sensu lato (s.l.) to deltamethrin at 0.05% and bendiocarb at 0.1%.
RESULTS
A total of 3260 females of mosquitoes belonging to 4 genera (Anopheles, Culex, Aedes and Mansonia) were collected. Most of the mosquitoes collected were An. gambiae sensu lato (s.l.). The entomological inoculation rate (EIR) for the three collection months was 8.7 infective bites per person and the parity rate was 84%. Mortality rates of An. gambiae s.l. exposed to 0.05% deltamethrin and 0.1% bendiocarb were 18% and 96%, respectively, indicating that this vector population was resistant to deltamethrin and possibly resistant to bendiocarb in the study area.
CONCLUSION
This study showed that malaria transmission is effective in the study area and that An. gambiae s.l. is the main malaria vector. The entomological parameters indicate this study area is potentially favourable for investigations on P. falciparum asymptomatic carriers.
Topics: Animals; Female; Humans; Plasmodium falciparum; Malaria; Anopheles; Benin; Mosquito Vectors; Malaria, Falciparum; Insecticide Resistance
PubMed: 36670482
DOI: 10.1186/s12936-023-04450-4 -
Tropical Medicine and Health Jan 2023Vector control is the most effective malaria control and prevention measure. Among these, IRS and LLINs are the most important chemical insecticide interventions used in...
BACKGROUND
Vector control is the most effective malaria control and prevention measure. Among these, IRS and LLINs are the most important chemical insecticide interventions used in malaria prevention and control strategies in Ethiopia. However, the long-term effectiveness of these strategies is under threat due to the emergency and spread of insecticide resistance in the principal malaria vector. Therefore, this study was carried out, under standardized laboratory conditions to assess the killing effect of some insecticides against An. gambiae s.l.
METHODS
Mosquitoes in late instar larvae and pupae stages were collected from different breeding habitats of the study sites using a soup ladle (350 ml capacity). The immature was reared to adults at optimum temperature and humidity in a field insectary using the WHO protocol. Four insecticides representing three chemical classes were used against adult mosquitoes. These were permethrin, deltamethrin, pirimiphos-methyl and bendiocarb. Susceptibility tests were carried out from September to December 2021 using the WHO standard procedures. Mortality rate, variation, interaction effect and knockdown times (KDT50 and KDT95%) were computed using descriptive statistics, multivariate analysis of variance and log-probit regression model using SPSS version 20 software.
RESULTS
Totally, 1300 Anopheles gambiae s.l. were tested to determine the susceptibility status to the four insecticides. Among these, 90.7% of them were susceptible to insecticides, whereas the remaining 9.3% of specimens were resistant to the insecticides. The results of the analysis of variance showed that mortality significantly varied between insecticides (F = 26.06, DF = 3, P < .0001), but not between study locations (F = 1.56, DF = 3, P = 0.212). On the other hand, the mean comparison of dead mosquitoes showed some signs of interaction between bendiocarb and locations, but not other insecticides and locations.
CONCLUSIONS
This study revealed that the knockdown times and effectiveness of different insecticides varied in different study sites. Therefore, insecticide resistance information is very essential for concerned bodies to make informed and evidence-based decisions on vector control.
PubMed: 36639818
DOI: 10.1186/s41182-023-00497-w -
Current Research in Parasitology &... 2023Insecticide resistance threatens recent progress on malaria control in Africa. To characterize pyrethroid resistance in Uganda, (.) and were analyzed from 11 sites...
Insecticide resistance threatens recent progress on malaria control in Africa. To characterize pyrethroid resistance in Uganda, (.) and were analyzed from 11 sites with varied vector control strategies. Mosquito larvae were collected between May 2018 and December 2020. Sites were categorized as receiving no indoor-residual spraying ('no IRS', = 3); where IRS was delivered from 2009 to 2014 and in 2017 and then discontinued ('IRS stopped', = 4); and where IRS had been sustained since 2014 ('IRS active', = 4). IRS included bendiocarb, pirimiphos methyl and clothianidin. All sites received long-lasting insecticidal nets (LLINs) in 2017. Adult mosquitoes were exposed to pyrethroids; with or without piperonyl butoxide (PBO). (.) and were identified using PCR. (.) were genotyped for /, , , , and , while were examined for /. Overall, 2753 (.), including 1105 (.) and 1648 were evaluated Species composition varied by site; only nine (.) were collected from 'IRS active' sites, precluding species-specific comparisons. Overall, mortality following exposure to permethrin and deltamethrin was 18.8% (148/788) in (.) and 74.6% (912/1222) in . Mortality was significantly lower in (.) than in in 'no IRS' sites (permethrin: 16.1 67.7%, < 0.001; deltamethrin: 24.6 83.7%, < 0.001) and in 'IRS stopped' sites (permethrin: 11.3 63.6%, < 0.001; deltamethrin: 25.6 88.9%, < 0.001). When PBO was added, mortality increased for (.) and . Most (.) had the mutation (95% frequency) and the resistance allele (87%), while the frequency of and were lower (52% and 55%, respectively). Resistance to pyrethroids was widespread and higher in (.). Where IRS was active, dominated. Addition of PBO to pyrethroids increased mortality, supporting deployment of PBO LLINs. Further surveillance of insecticide resistance and assessment of associations between genotypic markers and phenotypic outcomes are needed to better understand mechanisms of pyrethroid resistance and to guide vector control.
PubMed: 36590346
DOI: 10.1016/j.crpvbd.2022.100106 -
PloS One 2022Prevention and control of Aedes-borne viral diseases such as dengue rely on vector control, including the use of insecticides and reduction of larval sources. However,...
Prevention and control of Aedes-borne viral diseases such as dengue rely on vector control, including the use of insecticides and reduction of larval sources. However, this is threatened by the emergence of insecticide resistance. This study aimed to update the spatial distribution, the insecticide resistance profile of A. aegypti and A. albopictus and the potential resistant mechanisms implicated in the city of Douala. Immature stages of Aedes were collected in August 2020 in eight neighbourhoods in Douala and reared to adult stages. Adult bioassays, and piperonyl butoxide (PBO) synergist assays were carried out according to World Health Organization recommendations. Expression of some candidate metabolic genes including Cyp9M6F88/87, Cyp9J28a, Cyp9J10 and Cyp9J32 in A. aegypti, and Cyp6P12 in A. albopictus were assessed using qPCR. A. aegypti adults G0 were screened using real time melting curve qPCR analyses to genotype the F1534C, V1016I and V410L Aedes kdr mutations. Overall, A. aegypti is the predominant Aedes species, but analyses revealed that both A. albopictus and A. aegypti coexist in all the prospected neighbourhoods of Douala. High level of resistance was observed to three pyrethroids tested in both Aedes species. In A. aegypti a lower mortality rate was reported to permethrin (5.83%) and a higher mortality rate to deltamethrin (63.74%). Meanwhile, for A. albopictus, lower (6.72%) and higher (84.11%) mortality rates were reported to deltamethrin. Similar analysis with bendiocarb, revealed for A. aegypti a loss of susceptibility. However, in A. albopictus samples, analyses revealed a susceptibility in Logbessou, and confirmed resistance in Kotto (59.78%). A partial recovery of mortality was found to insecticides after pre-exposure to PBO. Cyp6P12 was found significantly overexpressed in A. albopictus permethrin resistant and Cyp9M6F88/87 for A. aegypti deltamethrin resistant. F1534C, V1016I and V410L mutations were detected in A. aegypti from different neighbourhoods and by considering the combination of these three kdr 14 genotypes were found. These findings provide relevant information which should be capitalised in the implementation of arbovirus vector control strategies and insecticide resistance management.
Topics: Animals; Insecticide Resistance; Aedes; Insecticides; Permethrin; Cameroon; Mosquito Vectors; Pyrethrins
PubMed: 36512581
DOI: 10.1371/journal.pone.0278779 -
Malaria Journal Nov 2022This study was designed to provide insecticide resistance data for decision-making in terms of resistance management plans in Togo.
BACKGROUND
This study was designed to provide insecticide resistance data for decision-making in terms of resistance management plans in Togo.
METHODS
The susceptibility status of Anopheles gambiae sensu lato (s.l.) to insecticides used in public health was assessed using the WHO tube test protocol. Pyrethroid resistance intensity bioassays were performed following the CDC bottle test protocol. The activity of detoxification enzymes was tested using the synergists piperonyl butoxide, S.S.S-tributlyphosphorotrithioate and ethacrinic acid. Species-specific identification of An. gambiae s.l. and kdr mutation genotyping were performed using PCR techniques.
RESULTS
Local populations of An. gambiae s.l. showed full susceptibility to pirimiphos methyl at Lomé, Kovié, Anié, and Kpèlè Toutou. At Baguida, mortality was 90%, indicating possible resistance to pirimiphos methyl. Resistance was recorded to DDT, bendiocarb, and propoxur at all sites. A high intensity of pyrethroid resistance was recorded and the detoxification enzymes contributing to resistance were oxidases, esterases, and glutathione-s-transferases based on the synergist tests. Anopheles gambiae sensu stricto (s.s.) and Anopheles coluzzii were the main species identified. High kdr L1014F and low kdr L1014S allele frequencies were detected at all localities.
CONCLUSION
This study suggests the need to reinforce current insecticide-based malaria control interventions (IRS and LLINs) with complementary tools.
Topics: Animals; Anopheles; Insecticide Resistance; Pyrethrins; Togo; Insecticides
PubMed: 36437444
DOI: 10.1186/s12936-022-04377-2 -
Parasites & Vectors Nov 2022Insecticide resistance (IR) monitoring is essential for evidence-based control of mosquito-borne diseases. While widespread pyrethroid resistance in Anopheles and Aedes...
BACKGROUND
Insecticide resistance (IR) monitoring is essential for evidence-based control of mosquito-borne diseases. While widespread pyrethroid resistance in Anopheles and Aedes species has been described in many countries, data for Papua New Guinea (PNG) are limited. Available data indicate that the local Anopheles populations in PNG remain pyrethroid-susceptible, making regular IR monitoring even more important. In addition, Aedes aegypti pyrethroid resistance has been described in PNG. Here, Anopheles and Aedes IR monitoring data generated from across PNG between 2017 and 2022 are presented.
METHODS
Mosquito larvae were collected in larval habitat surveys and through ovitraps. Mosquitoes were reared to adults and tested using standard WHO susceptibility bioassays. DNA from a subset of Aedes mosquitoes was sequenced to analyse the voltage-sensitive sodium channel (Vssc) region for any resistance-related mutations.
RESULTS
Approximately 20,000 adult female mosquitoes from nine PNG provinces were tested. Anopheles punctulatus sensu lato mosquitoes were susceptible to pyrethroids but there were signs of reduced mortality in some areas. Some Anopheles populations were also resistant to DDT. Tests also showed that Aedes. aegypti in PNG are resistant to pyrethroids and DDT and that there was also likelihood of bendiocarb resistance. A range of Vssc resistance mutations were identified. Aedes albopictus were DDT resistant and were likely developing pyrethroid resistance, given a low frequency of Vssc mutations was observed.
CONCLUSIONS
Aedes aegypti is highly pyrethroid resistant and also shows signs of resistance against carbamates in PNG. Anopheles punctulatus s.l. and Ae. albopictus populations exhibit low levels of resistance against pyrethroids and DDT in some areas. Pyrethroid-only bed nets are currently the only programmatic vector control tool used in PNG. It is important to continue to monitor IR in PNG and develop proactive insecticide resistance management strategies in primary disease vectors to retain pyrethroid susceptibility especially in the malaria vectors for as long as possible.
Topics: Animals; Female; Insecticide Resistance; Arboviruses; DDT; Papua New Guinea; Mosquito Vectors; Pyrethrins; Anopheles; Aedes; Malaria; Larva; Insecticides
PubMed: 36376932
DOI: 10.1186/s13071-022-05493-3 -
Parasites & Vectors Nov 2022The common house mosquito Culex pipiens is known to be a major vector for West Nile virus. In order to decrease risks of West Nile virus outbreaks in Europe,... (Review)
Review
BACKGROUND
The common house mosquito Culex pipiens is known to be a major vector for West Nile virus. In order to decrease risks of West Nile virus outbreaks in Europe, insecticides and the bio-larvicide Bacillus thuringiensis israelensis (Bti) are commonly used for vector control. Alarmingly, insecticide resistance has been reported in Cx. pipiens populations from Southern Europe and several countries neighbouring Europe. For Central and Northern Europe, however, the phenotypic insecticide resistance status of Cx. pipiens has not yet been investigated.
METHODS
A literature review was performed to assess the geographical distribution of insecticide resistance in Cx. pipiens. To fill the gap of knowledge for Central and Northern Europe, WHO susceptibility tests with permethrin, deltamethrin, malathion, bendiocarb and DDT and a larval toxicity test with Bti were performed with a Cx. pipiens population from Belgium, a country in Central Europe.
RESULTS
This research provides the first evidence of widespread phenotypic insecticide resistance in Cx. pipiens. In general, Cx. pipiens developed resistance against multiple insecticides in several countries. Another Cx. pipiens population from Belgium was tested and showed insecticide resistance against deltamethrin, permethrin, DDT and possibly against bendiocarb. The bio-larvicide Bti caused lower mortality than reported for other Cx. pipiens populations in the literature.
CONCLUSIONS
These results indicate the urgent need for insecticide resistance monitoring against commonly used adulticides and larvicides in Europe, for the translation of knowledge gained regarding the limited efficiency and availability of insecticide into EU legislation and the need for innovative non-chemical vector control tools in order to counter the widespread insecticide resistance in Culex populations.
Topics: Animals; Insecticide Resistance; Culex; Insecticides; Permethrin; DDT; Mosquito Control; Mosquito Vectors; West Nile virus; Bacillus thuringiensis
PubMed: 36369170
DOI: 10.1186/s13071-022-05542-x -
Insects Nov 2022The occurrence and spread of insecticide resistance has had a negative effect on the efficacy of insecticide-based tools and is distributed worldwide, including the...
The occurrence and spread of insecticide resistance has had a negative effect on the efficacy of insecticide-based tools and is distributed worldwide, including the Greater Mekong Subregion (GMS). This study aims to determine the insecticide susceptibility of malaria and dengue vectors in malaria and dengue hotspots on the Thai-Myanmar border. Mosquito larvae and pupae were obtained from water sources from December 2019 to April 2020 in Tha Song Yang District, Tak province, western Thailand. WHO bioassay susceptibility tests were conducted with three classes of insecticides to evaluate the knockdown and mortality rates of and female adults. V1016G and F1534C mutations in the voltage-gated sodium channel of were identified using a multiplex PCR. A total of 5764 female mosquitoes were bioassayed in this study, including spp. (92.63%) and F1 (7.37%). After 24 h of observation, s.l. ( = 3885) and s.l. ( = 1138) in Suan Oi (SO) and Tala Oka (TO) were susceptible to pyrethroids, organophosphates and carbamates (except bendiocarb) with 98-100% mortality (MR). Resistance to bendiocarb was detected with a mortality rate of 88.80%, 88.77%, and 89.92% for s.l. ( = 125, 125) and s.l. ( = 66), respectively. The first generation of . adult females were suspected of resistance to deltamethrin ( = 225, MR = 96.89%) and confirmed resistance to permethrin ( = 200, MR = 20.00%). V1016G and F1534C mutations were detected in three genotypes, heterozygote and homozygote forms. The correlation between the alleles and deltamethrin resistance was significant. In conclusion, bendiocarb resistance was found in primary malaria vectors, s.l. and s.l. F1 population was pyrethroids-resistant, associated with alleles. Therefore, molecular analysis should be conducted to gain insights into the mechanism of insecticide resistance. Routine malaria vector control programmes, such as fogging implementation in hotspot villages to induce resistance available in peri-domestic sites, are questionable.
PubMed: 36354859
DOI: 10.3390/insects13111035