Mosquitoes are an interesting topic due to their medical importance, as they play an active role in the transmission of many pathogens and parasites, acting as vectors for various pathologies that are deadly to humans...Mosquitoes are an interesting topic due to their medical importance, as they play an active role in the transmission of many pathogens and parasites, acting as vectors for various pathologies that are deadly to humans, such as dengue, yellow fever, chikungunya, West Nile virus, encephalitis and malaria, among many others that are less common. In terms of morbidity and mortality caused by vector-borne diseases, mosquitoes are the most dangerous animals for humanity and, although they also play a role in the ecosystem as a food source for other organisms, their importance for public health cannot be overlooked. As highly efficient vectors, they put more than three billion people at risk, mainly in tropical and subtropical regions as well as in Europe, since heat waves and flooding are becoming more frequent and severe, and summers are getting longer and warmer, accelerating mosquito development, biting rates, and the incubation of the pathogens within their bodies. Female mosquitoes bite to acquire proteins for the development of their ovaries and eggs and, in the process, acquire pathogens and/or parasites from one vertebrate host and transmit them to another, usually after a short period of replication. Three of their four life stages are lived in still freshwater, so it is crucial to understand their range of action when they reach adulthood and leave the water, in order to plan and implement local prevention measures. A set of georeferenced abundance data collected in mainland Portugal over seven years was linked to cartographed water bodies in a geographic information system to estimate the distances at which Culex pipiens s.l. had a significant presence, with criteria based on the size of the catches. The result allows for an estimate of the fly range of those mosquitoes, which can be used to focus countermeasures.展开更多
Objective:To investigate mosquitocidal effects of ethanolic extract of(lowers of Tagetes erecta(T.erecta) and its chloroform and petroleum ether soluble fractions against the larvae of Culex quinquefasciatus(Cx.quinqu...Objective:To investigate mosquitocidal effects of ethanolic extract of(lowers of Tagetes erecta(T.erecta) and its chloroform and petroleum ether soluble fractions against the larvae of Culex quinquefasciatus(Cx.quinquefasciatus).Methods:The fresh flowers of T.erecta were extracted in cold with ethanol(5.0 L) and after concentration,the ethanol extract was fractionated with chloroform and petroleum ether to afford a brownish syrupy suspension of ethanol extract(50.0 g),petroleum ether soluble fraction(18.6 g) and chloroform soluble fraction(23.8 g).The larvicidal effect of ethanol extract and their solvent fractions were determined by the standard procedure of WHO against different instars of Cx.quinquefasciatus.Results:Among the tested samples the chloroform soluble fractions showed the highest toxicity and consequently,the lowest LC_(50) values(14.14 μ g/mL,17.06 μ g/mL.36.88 μ g/mL and 75.48 μ g/mL) for all the instars larvae of Cx.quinquefasciatus.The larvae showed comparative tolerance in the course of increasing age and time.Conclusions:It can be concluded that the flowers of T.erecta are very effective natural larvicide and could be useful against Cx.quinquefasciatus.展开更多
Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),A...Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),Aedes aegypti(Ae.aegypti) and Anopheles stephensi(An. stephensi).Methods:The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions.The hatch rates were assessed 48 h after treatment.The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm under the laboratory conditions. Results:The crude extract of E.coronaria exerted zero hatchability(100%mortality) at 250.200 and 150 ppm for Cx.quinqitefasciatus,Ae.aegypti and An.stephensi,respectively.The crude extract of C.pulchenima exerted zero hatchability(100%mortality) at 375.300 and 225 ppm for Cx.quinquefasciatus,Ae.aegypti and An.Stephensi,respectively.The methanol extract of E. coronaria found to be more repellenct than C.pukherrima extract.A higher concentration of 5.0 mg/cm^2 provided 100%protection up to 150.180 and 210 min against Cx.quinquefasciatus,Ae. aegypti and An.stephensi,respectively.The results clearly showed that repellent activity was dose dependent.Conclusions:From the results it can be concluded the crude extracts of E.coronaria and C.pukherrima are an excellent potential for controlling Cx.quinquefasciatus,Ae.aegypti and An.stephensi mosquitoes.展开更多
Objective:To determine lead level primarily in Culex quinquefasciatus(Cx.quinquefasciatus), and Culex gelidus(Cx.gelidus) larvae inhabiting lead consuming factories,and to putatively estimate eco-toxicological impact ...Objective:To determine lead level primarily in Culex quinquefasciatus(Cx.quinquefasciatus), and Culex gelidus(Cx.gelidus) larvae inhabiting lead consuming factories,and to putatively estimate eco-toxicological impact of effluents from the firms.Methods:Third instars larvae were sampled by standard dipping method and lead concentrations in the larvae and their respective surrounding factory aquatic environments were determined through standard atomic absorption spectrophotometry(AAS).Results:Cx.quinquefasciatus was the most abundant species followed by Cx.gelidus.The levels of lead were higher in the Cx.quinquefasciatus(1.08-47.47μg/g),than in the wastewaters surface(0.01-0.78 μg/mL) from the factories or closer areas around factories. Other species were not reaching the.criteria for lead determination.Conclusions:The Cx. quinquefasciatus larvae can bio-accumulate the metal and can potentially serve as a biomarker of lead contamination,to complemente conventional techniques.展开更多
Objective:To investigate the larvicidal and ovicidal efficacy of different extracts of Andrographis paniculata（A.paniculata） against Culex quinquefasciatus（Cx.quinquefasciatus） Say and Aedes aegypti（Ae.aegypti ...Objective:To investigate the larvicidal and ovicidal efficacy of different extracts of Andrographis paniculata（A.paniculata） against Culex quinquefasciatus（Cx.quinquefasciatus） Say and Aedes aegypti（Ae.aegypti ） L（Diptera:Culicidae）.Methods:Larvicidal efficacy of the crude leaf extracts of A.paniculata with five different solvents like benzene,hexane,ethyl acetate, methanol and chloroform was tested against the early third instar larvae of Cx.quinquefasciatus and Ae.aegypti.The ovicidal activity was determined against two mosquito species to various concentrations ranging from 50-300 ppm under the laboratory conditions.Results:The benzene, hexane,ethyl acetate,methanol and chloroform leaf extract of A.paniculata was found to be more effective against Cx.quinquefasciatus than Ae.aegypti.The LC<sub>50</sub> values were 112.19,137.48, 118.67,102.05,91.20 ppm and 119.58,146.34,124.24,110.12,99.54 ppm respectively.Among five tested solvent,methanol and ethyl acetate crude extract was found to be most effective for ovicidal activity against two mosquito species.The extract of methanol and ethyl acetate exerted 100%mortality at 200 ppm against Cx.quinquefasciatus and at 250 ppm against Ae.aegypti. Conclusions:From the results it can be concluded the crude extract of A.paniculata was a potential for controlling Cx.quinquefasciatus and Ae.aegypti mosquitoes.展开更多
Objective:To investigate the larvicidal activity of synthesized silver nanoparticles（Ag NPs） utilizing aqueous bark extract of Ficus racemosa（F.racemosa） was tested against fourth instar larvae of filariasis vecto...Objective:To investigate the larvicidal activity of synthesized silver nanoparticles（Ag NPs） utilizing aqueous bark extract of Ficus racemosa（F.racemosa） was tested against fourth instar larvae of filariasis vector,Culex quinquefasciatus（Cx.quinquefasciatus） and japanese encephalitis vectors,Culex gelidus（Cx.gelidus）.Methods:The synthesized Ag NPs was characterized by UV-vis spectrum,X-ray diffraction（XRD）,Scanning electron microscopy（SEM） and Fourier transform infrared（FTIR）.The larvicidal activities were assessed for 24 h against the larvae of Cx.quinquefasciatus and Cx.gelidus with varying concentrations of aqueous bark extract off.racemosa and synthesized Ag NPs.LC<sub>50</sub> and r<sup>2</sup> values were calculated.Results:The maximum efficacy was observed in crude aqueous extract of F.racemosa against the larvae of Cx.quinquefasciatus and Cx.gelidus(LC<sub>50</sub>=67.72 and 63.70 mg/L;r<sup>2</sup>=0.995 and 0.985) and the synthesized Ag NPs(LC<sub>50</sub>=12.00 and 11.21 mg/L;r<sup>2</sup>=0.997 and 0.990).respectively.Synthesized Ag NPs showed the XRD peaks at 2θvalues of 27.61,29.60,35.48,43.48 and 79.68 were identified as （210）,（121）,（220）,（200） and（311） reflections,respectively.The FTIR spectra of Ag NPs exhibited prominent peaks at 3 425,2 878,1 627 and 1 382 in the region 500-3 000 cm<sup>-1</sup>.The peaks correspond to the presence of a stretching vibration of（NH） C=O group.SEM analysis showed shape in cylindrical,uniform and rod with the average size of 250.60 nm.Conclusions:The biosynthesis of silver nanoparticles using bark aqueous extract of F.racemosa and its larvicidal activity against the larvae of disease spreading vectors.The maximum larvicidal efficacy was observed in the synthesized Ag NPs.展开更多
文摘Mosquitoes are an interesting topic due to their medical importance, as they play an active role in the transmission of many pathogens and parasites, acting as vectors for various pathologies that are deadly to humans, such as dengue, yellow fever, chikungunya, West Nile virus, encephalitis and malaria, among many others that are less common. In terms of morbidity and mortality caused by vector-borne diseases, mosquitoes are the most dangerous animals for humanity and, although they also play a role in the ecosystem as a food source for other organisms, their importance for public health cannot be overlooked. As highly efficient vectors, they put more than three billion people at risk, mainly in tropical and subtropical regions as well as in Europe, since heat waves and flooding are becoming more frequent and severe, and summers are getting longer and warmer, accelerating mosquito development, biting rates, and the incubation of the pathogens within their bodies. Female mosquitoes bite to acquire proteins for the development of their ovaries and eggs and, in the process, acquire pathogens and/or parasites from one vertebrate host and transmit them to another, usually after a short period of replication. Three of their four life stages are lived in still freshwater, so it is crucial to understand their range of action when they reach adulthood and leave the water, in order to plan and implement local prevention measures. A set of georeferenced abundance data collected in mainland Portugal over seven years was linked to cartographed water bodies in a geographic information system to estimate the distances at which Culex pipiens s.l. had a significant presence, with criteria based on the size of the catches. The result allows for an estimate of the fly range of those mosquitoes, which can be used to focus countermeasures.
基金Supported by a grant from Ministry of Science and Technology,Bangladesh(No.BPROM/SHA-9/B-ANI-PRO/2009/324)
文摘Objective:To investigate mosquitocidal effects of ethanolic extract of(lowers of Tagetes erecta(T.erecta) and its chloroform and petroleum ether soluble fractions against the larvae of Culex quinquefasciatus(Cx.quinquefasciatus).Methods:The fresh flowers of T.erecta were extracted in cold with ethanol(5.0 L) and after concentration,the ethanol extract was fractionated with chloroform and petroleum ether to afford a brownish syrupy suspension of ethanol extract(50.0 g),petroleum ether soluble fraction(18.6 g) and chloroform soluble fraction(23.8 g).The larvicidal effect of ethanol extract and their solvent fractions were determined by the standard procedure of WHO against different instars of Cx.quinquefasciatus.Results:Among the tested samples the chloroform soluble fractions showed the highest toxicity and consequently,the lowest LC_(50) values(14.14 μ g/mL,17.06 μ g/mL.36.88 μ g/mL and 75.48 μ g/mL) for all the instars larvae of Cx.quinquefasciatus.The larvae showed comparative tolerance in the course of increasing age and time.Conclusions:It can be concluded that the flowers of T.erecta are very effective natural larvicide and could be useful against Cx.quinquefasciatus.
文摘Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),Aedes aegypti(Ae.aegypti) and Anopheles stephensi(An. stephensi).Methods:The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions.The hatch rates were assessed 48 h after treatment.The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm under the laboratory conditions. Results:The crude extract of E.coronaria exerted zero hatchability(100%mortality) at 250.200 and 150 ppm for Cx.quinqitefasciatus,Ae.aegypti and An.stephensi,respectively.The crude extract of C.pulchenima exerted zero hatchability(100%mortality) at 375.300 and 225 ppm for Cx.quinquefasciatus,Ae.aegypti and An.Stephensi,respectively.The methanol extract of E. coronaria found to be more repellenct than C.pukherrima extract.A higher concentration of 5.0 mg/cm^2 provided 100%protection up to 150.180 and 210 min against Cx.quinquefasciatus,Ae. aegypti and An.stephensi,respectively.The results clearly showed that repellent activity was dose dependent.Conclusions:From the results it can be concluded the crude extracts of E.coronaria and C.pukherrima are an excellent potential for controlling Cx.quinquefasciatus,Ae.aegypti and An.stephensi mosquitoes.
文摘Objective:To determine lead level primarily in Culex quinquefasciatus(Cx.quinquefasciatus), and Culex gelidus(Cx.gelidus) larvae inhabiting lead consuming factories,and to putatively estimate eco-toxicological impact of effluents from the firms.Methods:Third instars larvae were sampled by standard dipping method and lead concentrations in the larvae and their respective surrounding factory aquatic environments were determined through standard atomic absorption spectrophotometry(AAS).Results:Cx.quinquefasciatus was the most abundant species followed by Cx.gelidus.The levels of lead were higher in the Cx.quinquefasciatus(1.08-47.47μg/g),than in the wastewaters surface(0.01-0.78 μg/mL) from the factories or closer areas around factories. Other species were not reaching the.criteria for lead determination.Conclusions:The Cx. quinquefasciatus larvae can bio-accumulate the metal and can potentially serve as a biomarker of lead contamination,to complemente conventional techniques.
基金the Department of Science and Technology(DST)(SERC-Fast Track Young Scientist Project),New Delhi,India for providing financial assistance for the present investigation
文摘Objective:To investigate the larvicidal and ovicidal efficacy of different extracts of Andrographis paniculata（A.paniculata） against Culex quinquefasciatus（Cx.quinquefasciatus） Say and Aedes aegypti（Ae.aegypti ） L（Diptera:Culicidae）.Methods:Larvicidal efficacy of the crude leaf extracts of A.paniculata with five different solvents like benzene,hexane,ethyl acetate, methanol and chloroform was tested against the early third instar larvae of Cx.quinquefasciatus and Ae.aegypti.The ovicidal activity was determined against two mosquito species to various concentrations ranging from 50-300 ppm under the laboratory conditions.Results:The benzene, hexane,ethyl acetate,methanol and chloroform leaf extract of A.paniculata was found to be more effective against Cx.quinquefasciatus than Ae.aegypti.The LC<sub>50</sub> values were 112.19,137.48, 118.67,102.05,91.20 ppm and 119.58,146.34,124.24,110.12,99.54 ppm respectively.Among five tested solvent,methanol and ethyl acetate crude extract was found to be most effective for ovicidal activity against two mosquito species.The extract of methanol and ethyl acetate exerted 100%mortality at 200 ppm against Cx.quinquefasciatus and at 250 ppm against Ae.aegypti. Conclusions:From the results it can be concluded the crude extract of A.paniculata was a potential for controlling Cx.quinquefasciatus and Ae.aegypti mosquitoes.
文摘Objective:To investigate the larvicidal activity of synthesized silver nanoparticles（Ag NPs） utilizing aqueous bark extract of Ficus racemosa（F.racemosa） was tested against fourth instar larvae of filariasis vector,Culex quinquefasciatus（Cx.quinquefasciatus） and japanese encephalitis vectors,Culex gelidus（Cx.gelidus）.Methods:The synthesized Ag NPs was characterized by UV-vis spectrum,X-ray diffraction（XRD）,Scanning electron microscopy（SEM） and Fourier transform infrared（FTIR）.The larvicidal activities were assessed for 24 h against the larvae of Cx.quinquefasciatus and Cx.gelidus with varying concentrations of aqueous bark extract off.racemosa and synthesized Ag NPs.LC<sub>50</sub> and r<sup>2</sup> values were calculated.Results:The maximum efficacy was observed in crude aqueous extract of F.racemosa against the larvae of Cx.quinquefasciatus and Cx.gelidus(LC<sub>50</sub>=67.72 and 63.70 mg/L;r<sup>2</sup>=0.995 and 0.985) and the synthesized Ag NPs(LC<sub>50</sub>=12.00 and 11.21 mg/L;r<sup>2</sup>=0.997 and 0.990).respectively.Synthesized Ag NPs showed the XRD peaks at 2θvalues of 27.61,29.60,35.48,43.48 and 79.68 were identified as （210）,（121）,（220）,（200） and（311） reflections,respectively.The FTIR spectra of Ag NPs exhibited prominent peaks at 3 425,2 878,1 627 and 1 382 in the region 500-3 000 cm<sup>-1</sup>.The peaks correspond to the presence of a stretching vibration of（NH） C=O group.SEM analysis showed shape in cylindrical,uniform and rod with the average size of 250.60 nm.Conclusions:The biosynthesis of silver nanoparticles using bark aqueous extract of F.racemosa and its larvicidal activity against the larvae of disease spreading vectors.The maximum larvicidal efficacy was observed in the synthesized Ag NPs.
