In this paper,we analyze a stage structured mathematical model for the transmission of malaria and its control by killing mosquitoes in larvae(immature)stage.Both the Mosquito and human populations are divided into su...In this paper,we analyze a stage structured mathematical model for the transmission of malaria and its control by killing mosquitoes in larvae(immature)stage.Both the Mosquito and human populations are divided into susceptible and infective class.Sus-ceptible class of mosquito population is further divided into mature and immature.The model is analyzed by using stability theory of nonlinear ordinary differential equations.Basic reproduction ratio is derived which is found to be the decreasing function of maturation delay and larvicidal activity.In addition,it is observed that biting rate of mosquito,transmission efficiency of parasitic infection from infective human to mosquito and critical value of maturation delay are the key parameters determining the stability switch in the system.Numerical simulation is also carried out to confirm the analytical results obtained in the paper.展开更多
The issues of pyrethroid resistance and outdoor malaria parasite transmission have prompted the WHO to call for the development and adoption of viable alternative vector control methods.Larval source management is one...The issues of pyrethroid resistance and outdoor malaria parasite transmission have prompted the WHO to call for the development and adoption of viable alternative vector control methods.Larval source management is one of the core malaria vector interventions recommended by the Ministry of Health in many African countries,but it is rarely implemented due to concerns on its cost-effectiveness.New long-lasting microbial larvicide can be a promising cost-effective supplement to current vector control and elimination methods because microbial larvicide uses killing mechanisms different from pyrethroids and other chemical insecticides.It has been shown to be effective in reducing the overall vector abundance and thus both indoor and outdoor transmission.In our opinion,the long-lasting formulation can potentially reduce the cost of larvicide field application,and should be evaluated for its cost-effectiveness,resistance development,and impact on non-target organisms when integrating with other malaria vector control measures.In this opinion,we highlight that long-lasting microbial larvicide can be a potential cost-effective product that complements current front-line long-lasting insecticidal nets(LLINs)and indoor residual spraying(IRS)programs for malaria control and elimination.Microbial larviciding targets immature mosquitoes,reduces both indoor and outdoor transmission and is not affected by vector resistance to synthetic insecticides.This control method is a shift from the conventional LLINs and IRS programs that mainly target indoor-biting and resting adult mosquitoes.展开更多
Background:Plants are known to produce a diverse group of natural metabolites with different biological activities.Centaurea ensiformis P.H.Davis,Origanum hypericifolium O.Schwartz&P.H.Davis,and Paeonia turcica Da...Background:Plants are known to produce a diverse group of natural metabolites with different biological activities.Centaurea ensiformis P.H.Davis,Origanum hypericifolium O.Schwartz&P.H.Davis,and Paeonia turcica Davis&Cullen are endemic plant species that grow on mountains in select regions in Türkiye and have been used in traditional Turkish medicine for various ailments.Methods:As first,we evaluated the larvicidal and antibiofilm activities of ethanol,ethyl acetate,acetone,and water extracts obtained from these plants.Antioxidant activities of the extracts were also investigated.Results:All tested extracts were effective at concentrations>25 ppm on Aedes aegypti larval mortality with the lethal concentration 50(LC_(50))values ranging between 32.82-48.35 ppm and LC90 between 46.26-63.2 ppm.O.hypericifolium was the most effective plant,ethanol extracts presented LC50 values of 32.82 ppm.Extracts demonstrated varying degrees of antibiofilm activity depending on the dose and bacterial species.Origanum hypericifolium extracts notably inhibited biofilms of Staphylococcus aureus(up to 98%inhibition),while P.turcica showed moderate efficacy against the same bacterial species.Pseudomonas aeruginosa biofilms displayed high resistance to all extracts.Conclusion:The results indicated that these endemic Turkish plants possess promising larvicidal and antibiofilm potential,particularly Origanum hypericifolium.Extracts analyzed by liquid chromatography-tandem mass spectrometry contained caffeic acid,myricetin,cinnamic acid,quercetin,gallic acid,epicatechin,and ascorbic acid.Further research should explore their potential applications in mosquito control and biofilm-related infections.展开更多
Objective:To assess the chemical composition and mosquito larvicidal potentials of essential oils of locally sourced Pinus sylvestris(P.sylvestris)and Syzygium aromatkum(S.aromaticum)against Aedes aegypti(A.aegypti)an...Objective:To assess the chemical composition and mosquito larvicidal potentials of essential oils of locally sourced Pinus sylvestris(P.sylvestris)and Syzygium aromatkum(S.aromaticum)against Aedes aegypti(A.aegypti)and Culex quinquefasciatus(C.quinquefasciatus).Method:The chemical composition of the essential oils of both plants was determined using GCMS while the larvicidal bioassay was carried out using different concentrations of the oils against the larvae of A.aegypti and C.quinquefasciatus in accordance with the standard protocol.Results:The results as determined by GC-MS showed that oil of S.aromaticum has eugenol(80.5%)as its principal constituent while P.sylvestris has 3-Cyclohexene-1-methanol,.alpha.,.alpha.4-trimethyl(27.1%)as its dominant constituent.Both oils achieved over 85%larval mortality within24 h.The larvae of A.aegypti were more susceptible to the oils[LC_(50)(S.aromaticum)=92.56 mg/L,LC_(50)(P.sylvestris)=100.39 mg/L]than C.quinquefasciatus[LC_(50)(S.aromaticum)=124.42 mg/L;LC_(50)(P.sylvestris)=128.00 mg/L].S.aromaticum oil was more toxic to the mosquito larvae than oil of P.sylvatris but the difference in lethal concentrations was insignificant(P>0.05).Condusioii:The results justify the larvicidal potentials of both essential oils and the need to incorporate them in vector management and control.展开更多
Objective: To investigate the larvicidal activity of Syzygium guineense(Myrtaceae)(S. guineense), Monodora myristica and Zanthoxylum heitzii(Rutaceae)(Z. heitzii) extracts against Aedes albopictus(Ae. albopictus).Meth...Objective: To investigate the larvicidal activity of Syzygium guineense(Myrtaceae)(S. guineense), Monodora myristica and Zanthoxylum heitzii(Rutaceae)(Z. heitzii) extracts against Aedes albopictus(Ae. albopictus).Methods: The larvicidal activity of the hydro-ethanolic extracts from these plant species was assessed at three different concentrations(50, 100 and 200 mg/L) on first-instar of Ae. albopictus larvae in comparison with untreated controls. Mortality rate was recorded daily for a period of 12 days. The values of LC_(50) and lethal time killing 50% of the tested individuals(LT_(50)) were calculated using the log-probit analysis.Results: The root extract of S. guineense exhibited the best activity with 100% mortality after 8 days of treatment at 200 mg/L, followed by the fruit extract of Z. heitzii with83.33% mortality at the same concentration. Nonetheless, larvae were most susceptible to the fruit extract of Z. heitzii both in terms of LC_(50)(39.89 mg/L) and LT_(50)(145.68 h). A statistically significant difference between the control and the group treated at 200 mg/L was noticed in all the extracts.Conclusions: The present study shows that the hydro-ethanolic extracts of S. guineense,Monodora myristica and Z. heitzii tested have significant larvicidal activity. These preliminary results are of great interest and some of these plant species can be proposed for the formulation of new bioinsecticides to control Ae. albopictus populations.展开更多
Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L.(Cx. pipiens), the dominant specie...Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L.(Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia.Methods: The tested conventional insecticides were Actikil and Pesgard, while the nonconventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photomicroscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains.Results: Cx. pipiens were more susceptible to Pesgard(LC50: 0.045 and 0.032 mg/L)than Actikil(0.052 and 0.038 mg/L) and Bacilod(0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin synthesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained(concentration which to inhibit the emergence of 50% of mosquito adults), the compound Dudim(0.000 3 and 0.000 1 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal(0.000 4 and 0.000 3 mg/L) for both the field and laboratory strains, respectively.Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia.展开更多
Objective:To identify the larvieidal activity of the seagrass extracts.Methods:Seagrass extracts,Syringodium isoelifolium(.S.isoetifolium),Cymodocea serrulata and Hulophila beccarii,were dissolved in DMSO to prepare a...Objective:To identify the larvieidal activity of the seagrass extracts.Methods:Seagrass extracts,Syringodium isoelifolium(.S.isoetifolium),Cymodocea serrulata and Hulophila beccarii,were dissolved in DMSO to prepare a graded series of concentration.Batches of 25 early 4th instars larvae of Aedes aegypti(Ae.aegypti) were transferred to 250 ml.enamel bowl containing199 mL of distilled water and 1 mL of plant extracts(0.01 mg- 0.1 mg).After 24 h the mortality rate was identified with the formulae[(%of lest mortality-%of control mortality)/(100-%of control morlality)]× 100.Each experiment was conducted with three replicates and a concurrent control group.A control group consisted of 1 mL of DMSO and 199 mL of distilled water only.Results:The root extract of S.isoelifolium showed maximum larvicidal activity with minimum concentration of extract of LC_(50)= 0.0604 ± 0.0040)μg/mL with lower confidence limit(LCL)-upper confidence limit(UCL) =(0.051-0.071) and LC_(90)=0.0972 μg/mL followed by leaf extract of S.isoelifolium showed LC_(50)=(0.062 ± 0.005)μ'g/mL.The regression equation of pool and leaf extract of S.isoelifolium for4th instar larvae were Y =4.909- 1.32x(R^2= 0.909) and Y= 2.066+ 1.2x(R^2 =0.897) respectively.The results of the preliminary photochemical constituents shows the presence of saponin,steroids,terpenoid,phenols,protein and sugars.Conclusions:from the present study the ethanolic extracts of seagrass of S.isoelifolium possesses lead compound for development of larvieidal activity.展开更多
Objective:To investigate lethal effect of culture filtrates of Streptomyces citreofluorescens （S.citreofluorescens） against Anopheles stephensi（An.stephensi）,Culex quinquefasciatus（Cx. quinquefasciatus）,and Aede...Objective:To investigate lethal effect of culture filtrates of Streptomyces citreofluorescens （S.citreofluorescens） against Anopheles stephensi（An.stephensi）,Culex quinquefasciatus（Cx. quinquefasciatus）,and Aedes aegypti（Ae.aegypti） larvae vectors for malaria,filarial and dengue. Methods:The culture filtrates obtained from S.cilreofluorescens 2528 was grown in Potato Dextrose Broth（PDB）,filtrated and used for the bioassay after a growth of 15 days.Results:The results demonstrated that the An.stephensi shows mortalities with LC<sub>50</sub>,LG<sub>40</sub> values of first instar 46.8μL/mL,79.5μL/mL,second instar 79.0μL/mL,95.6μL/mL,third instar 79.0μL/mL,136.9μL/mL,and fourth instar 122.6μL/mL,174.5μL/mL Whereas,The Cx.quinquefasciatus were found effective on first instar 40.0μL/mL,138.03μL/mL,second instar 80.0μL/ml,181.97μL/ mL,third instar 100.0μL/mL,309.2μL/mL,and fourth instar 60.0μL/ml,169.82μL/mL.The Ae.aegypti were successfully achieved susceptible with higher concentrations in comparisons of An.stephensi and Cx.quinquefasciatus larvae.These outcomes of the investigations have compared with the Chitinase of Streptomyces griseus（S.griseus） C6137 that shows 90%-95% mortality.Conclusions:These new findings significantly permitted that the culture filtrates of S. citreofluorescens can be used as bacterial larvicides.This is an environmentally safe approach to control the vectors of malaria,dengue and filariasis of tropical areas.展开更多
Objective:To investigate the larvicidal and pupicidal activity of spinosad against Anopheles stephensi Listen.Methods:Spinosad from the actinomycete,Saccharopolyspora spinosa was tested against Anopheles stephensi at ...Objective:To investigate the larvicidal and pupicidal activity of spinosad against Anopheles stephensi Listen.Methods:Spinosad from the actinomycete,Saccharopolyspora spinosa was tested against Anopheles stephensi at different concentrations（0.01,0.02,0.04,0.06 and 0.08 ppm.）, and against first to fourth instar larvae and pupae.Results:The larval mortality ranged from 36.1±1.7 in（0.01 ppm） to 79.3±1.8（0.08 ppm） the first instar larva.The LC<sub>50</sub> and LC<sub>90</sub> values of first, second,third and fourth instar larva were 0.001,0.031,0.034,0.036 and 0.0113,0.102,0.111,0.113, respectively.The pupal mortality ranged from 33.0±2.0（0.01 ppm） to 80.0±0.9（0.08 ppm）.The LC<sub>50</sub> and LC<sub>90</sub> values were 0.028 and 0.1020,respectively.The reduction percentage of Anopheles larvae was 82.7%,91.4%and 96.0%after 24,48,72 hours,respectively,while more than 80% reduction was observed after 3 weeks.Conclusions:In the present study spinosad effectively caused mortality of mosquito larvae in both the laboratory and field trial.It is predicted that spinosad is likely to be an effective larvicide for treatment of mosquito breeding sites.展开更多
Extracts and constituents of medicinal plants have proven to be biodegradable, had low mammalian toxicity and induction of resistance, and comparable activities to the standard drugs. Therefore, methanolic extracts of...Extracts and constituents of medicinal plants have proven to be biodegradable, had low mammalian toxicity and induction of resistance, and comparable activities to the standard drugs. Therefore, methanolic extracts of some plants that are termite resistant or used ethnomedically as antimalarial and febrifuge were evaluated for activities against 4th-instar larvae of Aedes aegypti. A 61 % of these plants with these properties demonstrated larvicidal activities and may confirm the usefulness of these properties in choosing plant larvicides. This is the first report of larvicidal activities of stem barks and leaves of Blighia sapida and Baphia nitida, stem barks of Markhamia tomentosa and Newboldia laevis, and whole plants of Euphorbia macrophylla. Extracts of B. sapida stem bark, Costus specious root and Xylopia aethiopica seed, with LC50 1.71, 1.47 and 1.49 mg/ml at 48 h, respectively, were the most active and had significant activities that were comparable to Endosulphan. Hence, they may be used as plant larvicides in the control of dengue and yellow fever.展开更多
Objective:To evaluate the larvicidal and pupicidal potential of the methanolic extracts from Moringa oleifera(M.oleifera) plant seeds against malarial vector Anopheles stephensi(A.stephensi) mosquitoes at different co...Objective:To evaluate the larvicidal and pupicidal potential of the methanolic extracts from Moringa oleifera(M.oleifera) plant seeds against malarial vector Anopheles stephensi(A.stephensi) mosquitoes at different concentrations(20,40,60,80 and 100 ppm).Methods:M.oleifera was collected from the area of around Bharathiar University,Coimbatore.The dried plant materials were powdered by an electrical blender.From each sample,100 g of the plant material were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus.The extracts were evaporated to dryness in rotary vacuum evaporator to yield 122 mg and 110 mg of dark greenish material(residue) from Arcang amara and Ocimum basilicum,respectively.One gram of the each plant residue was dissolved separately in 100 mL of acetone(stock solution) from which different concentrations, i.e.,20,40,60,80 and 100 ppm were prepared.Results:Larvicidal activity of M.oleifera exhibited in the first to fourth instar larvae of the A.stephensi,and the LC_(50) and LC_(90) values were 57.79 ppm and 125.93 ppm for the first instar,63.90 ppm and 133.07 ppm for the second inslar,72.45 ppm and 139.82 ppm for the third instar,78.93 ppm and 143.20 ppm for the fourth instar,respectively. During the pupal stage the methanolic extract of M.oleifera showed that the LC_(50),and LC_(90) values were 67.77 ppm and 141.00 ppm,respectively.Conclusions:The present study indicates that the phytochemicals derived from M.oleifera seeds extracts are effective mosquito vector control agents and the plant extracts may be used for further integrated pest management programs.展开更多
Objective:The present study deals with the investigation of larvicidal and ovicidal activities of benzene,hexane,ethyl acetate,methanol and chloroform leaf extract of Eclipta alba（E.alba） against dengue vector,Aedes...Objective:The present study deals with the investigation of larvicidal and ovicidal activities of benzene,hexane,ethyl acetate,methanol and chloroform leaf extract of Eclipta alba（E.alba） against dengue vector,Aedes aegypti（Ae.Aegypti）.Methods:Twenty five earlyⅢinstar larvae of Ae.aegypti was exposed to various concentrations（50-300 ppm） and was assayed in the laboratory by using the protocol of WHO 2005;the 24 h LC<sub>50</sub> values of the E.alba leaf extract was determined by Probit analysis.For ovicidal activity,slightly modified method of Su and Mulla was performed.The ovicidal activity was determined against Ae.aegypti to various concentrations ranging from 100-350 ppm under the laboratory conditions.The egg hatch rates were assessed 48 h post treatment.Results:The LC<sub>50</sub> values of benzene,hexane,ethyl acetate,methanol and chloroform extract of E.alba against early third instar larvae of Ae.aegypti were 151.38,165.10, 154.88,127.64 and 146.28 ppm,respectively.Maximum larvicidal activity was observed in the methanol extract followed by chloroform,benzene,ethyl acetate and hexane extract.No mortality was observed in control.Among five solvent tested the methanol extract was found to be most effective for ovicidal activity against Ae.aegypti.The methanol extracts exerted 100%mortality （zero hatchability） at 300 ppm.Conclusions:From the results it can be concluded the crude extract of E.alba was an excellent potential for controlling Ae.aegypti mosquito.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 mosquito larvicidal activity of leaf essential oil and their chemical constituents from Clausena anisata（C.anisata）（Willd.） Hook.f.ex Benth.against Culex quinquefasciatus,Aedes aegypti a...Objective:To determine the mosquito larvicidal activity of leaf essential oil and their chemical constituents from Clausena anisata（C.anisata）（Willd.） Hook.f.ex Benth.against Culex quinquefasciatus,Aedes aegypti and Anopheles Stephensi.Methods:Essential oil was obtained by hydro-distillation and the chemical composition of the leaf essential oil was analyzed using gas chromatography—mass spectrometry.The mosquitoes were reared in the vector control laboratory and twenty lateⅢinstar larvae of three mosquito species were exposed to based on the wide range and narrow range tests,essential oil was tested at 50.100.150,200 and 250 ppm and each compound was tested at various concentration（5-75 ppm） and were assayed in the laboratory by using the protocol of WHO 2005:the 24 h LC<sub>50</sub> values of the C.anisata leaf essential oil and their major compounds were determined following Probit analysis.Results:The oil contained were mainlyβ-pinene（32.8%）,sabinene（28.3%）,germacrene-D（12.7%）,estragole （6.4%） and linalool（5.9%）.The essential oil from the leaves of C.anisata exhibited significant larvicidal activity,with 24 h LC<sub>50</sub> values of 140.96,130.19 and 119.59 ppm.respectively.The five pure constituents extracted from the C.anisata leaf essential oil were also tested individually against three mosquito larvae.The LC<sub>50</sub> values ofβ-pinene,sabinene,germacrene-D,estragole and linalool appeared to be most effective against Anopheles stephensi(LC<sub>50</sub>-23.17,19.67,16.95. 11.01,35.17 ppm) followed by Aedes aegypti(LC<sub>50</sub>-27.69,21.20,18.76,12.70,38.64 ppm) and Culex quinquefasciatus(LC<sub>50</sub>-32.23,25.01.21.28,14.01,42.28).Conclusions:The essential oil of C. anisata contains five major compounds and has remarkable larvicidal properties,which may be considered as a potent source for the production of natural larvicides.展开更多
Objective:To determine the larvicidal and adult emergence inhibition activities of castor （Ricinus communis） seed extract against three potential mosquito vectors Anopheles stephensi（An. slephensi）,Culex quinquefa...Objective:To determine the larvicidal and adult emergence inhibition activities of castor （Ricinus communis） seed extract against three potential mosquito vectors Anopheles stephensi（An. slephensi）,Culex quinquefasciatus（Cx.quinquefasciatus） and Aedes albopictus（Ae.albopictus） in India.Methods:The R.communis seed extract was tested,employing WHO procedure,against fourth larval instars of the three mosquito species for 24 h and larval mortalities were recorded at various concentrations（2-64μg/mL）:the 24 h LC<sub>50</sub> values of the R.communis seed extract were determined following Probit analysis.The larval killing,antipupation and adult emergence inhibition rates of the test extract,using a single concentration of 2μLC<sub>50</sub>,were studied at different time periods（24-72 h）:the extract toxicity was tested against a fish.Oreochromis niloticus（O.niloticus）.Results:The R.communis seed extract exhibited larvicidal effects with 100%killing activities at concentrations 32-64μg/mL,and with LC<sub>50</sub> values 7.10.11.64 and 16.84μg/mL for Cx.quinquefasciatus,An.stephensi and Ae.albopictus larvae,respectively. When the larvae were treated with the extract at a single concentration of 2×LC<sub>50</sub>,significant differences were observed,compared to control groups,in rate of pupation（P【0.001） as well as in adult formation（P【0.001）.Conclusions:The present findings suggest that the R.communis seed extract provided an excellent potential for controlling An.stephensi,Cx.quinquefasciatus and Ae. albopictus mosquito vectors.展开更多
Clove(Syzygium aromaticum) is one of the most valuable spices that has been used for centuries as food preservative and Tor many medicinal purposes.Clove is native of Indonesia but nowadays is cultured in several part...Clove(Syzygium aromaticum) is one of the most valuable spices that has been used for centuries as food preservative and Tor many medicinal purposes.Clove is native of Indonesia but nowadays is cultured in several parts of the world including Brazil in the slate of Bahia.This plant represents one of the richest source of phenolic compounds such as eugenol,eugenol acetate and gallic acid and posses great potential for pharmaceutical,cosmetic,food and agricultural applications.This review includes the main studies reporting the biological activities of clove and eugennl.The antioxidant and antimicrobial activity of clove is higher than many fruits,vegetables and other spices and should deserve special attention.A new application of clove as larvicidal agent is an interesting strategy to combat dengue which is a serious health problem in Brazil and other tropical countries.Pharmacokinetics and lexicological studies were also mentioned.The different studies reviewed in this work confirm the traditional use of clove as food preservative and medicinal plant standing out the importance of this plant for different applications.展开更多
Objective:To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant,Mentha piperita(M.piperita) against the larval and adult stages of Aedes aegypti(Ae.Aegypti...Objective:To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant,Mentha piperita(M.piperita) against the larval and adult stages of Aedes aegypti(Ae.Aegypti).Methods:The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae.aegypti using WHO protocol.The mortality counts were made after 24 and 48 h,and LC_(50) and LC_(90) values were calculated.The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique.The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol.The mosquito bites on both the arms were recorded for 3 min after every 15 min.The experiment continued for 3 h and the percent protection was calculated.Results:The essential oil extracted from M.piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC_(50) and LC_(90) value of 111.9 and 295.18 ppm,respectively after 24 h of exposure.The toxicity of the oil increased 11.8%when the larvae were exposed to the oil for 48 h.The remarkable repellent properties of M.piperita essential oil were established against adults Ae.aegypti.The application of oil resulted in 100%protection till 150 min.After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm.Conclusions:The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide,oviposilion deterrent and ovicidal agent.The isolation of active ingredient from the oil could help in formulating strategies for mosquito control.展开更多
Objective:To determine the larvicidal and repellent activities of Sida acuta Burm.F.（Family: Malvaceae）extract against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi. Methods:Twenty five late III insta...Objective:To determine the larvicidal and repellent activities of Sida acuta Burm.F.（Family: Malvaceae）extract against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi. Methods:Twenty five late III instar larve of three mosquito species were exposed to various concentrations（15-90 mg/L） and were assayed in the laboratory by using the protocol of WHO 2005:the 24 h LC<sub>50</sub> values of the Sida acuta leaf extract was determined following Probit analysis. The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm<sup>2</sup> under the laboratory conditions.Results:Results showed varying degree of larvicidal activity of crude extract of Sida acuta against three important mosquitoes with LC<sub>50</sub> values ranging between 38 to 48 mg/L.The crude extract had strong repellent action against three species of mosquitoes as it provided 100%protection against Anopheles stephensi for 180 min followed by Aedes aegypti（150 min） and Culex quinquefasciatus（120 min）.Conclusions: From the results it can be concluded the crude extract of Sida acuta was an excellent potential for controlling Culex quinquefasciatus,Aedes aegypti and Anopleles stephensi mosquitoes.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 evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts of Acacia concinna（A.concinna）,Cassia siamea（C.siamea）.Conundrum sativum（C. sativum）,Cuminum cyminum（C.cyminu...Objective:To evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts of Acacia concinna（A.concinna）,Cassia siamea（C.siamea）.Conundrum sativum（C. sativum）,Cuminum cyminum（C.cyminum）,Lantana camma（L.camara）,Nelumbo nucifera （N.nucifera） Phyllanlhus amarus（P.amarus）.Piper nigrum（P.nigrum） and Trachyspermum ammi（T.ammi） against Anopheles stephensi（An.stephensi） and Culex quinquefasciatus（Cx. quinquefasciatus）.Methods:The larvicidal activity of medicinal plant extracts were tested against earl) fourth-instar larvae of malaria and filariasis vectors.The mortality was observed 24 h and 48 h after treatment,data were subjected to probit analysis to determine the lethal concentrations(LC<sub>50</sub> and LC<sub>90</sub>) to kill 50 and 90 per cent of the treated larvae of the tested species. The repellent efficacy was determined against two mosquito species at five concentrations（31.25. 62.50.125.00.250.00,and 500.00 ppm） under the laboratory conditions.Results:All plant extracts showed moderate effects after 24 h and 48 h of exposure;however,the highest activity was observed after 24 h in the leaf methanol extract ol N.nucifera.seed ethyl acetate and methanol extract of P.nigrum against the larvae of An.Stephensi(LC<sub>50</sub> = 34.76.24.54 and 30.20 ppm) and against Cx.quinquefasciatus(LC<sub>50</sub>= 37.49.43.94 and 57.39 ppm),respectively.The toxic effect of leaf methanol extract of C.siamea,seed methanol extract of C.cyminum,leaf ethyl acetate extract of N.nucifera.leaf ethyl acetate and methanol extract of P.amarus and seed methanol extract of T.ammi were showed 100%mortality against An.stephensi and Cx.quinquefasciatus alter 48 h exposer.The maximum repellent activity was observed at 500 ppm in methanol extracts of N. nucifera.ethyl acetate and methanol extract of P.nigrum and methanol extract of T.ammi and the mean complete protection time ranged from 30 to 150 min with the different extracts tested. Conclusions:These results suggest that the leaf and seed extracts of C.siamea.N.nucifera.P. amarus.P.nigrum and T.ammi have the potential to be used as an ideal ecofriendly approach for the control of the An.stephensi and Cx.quinquefasciatus.展开更多
文摘In this paper,we analyze a stage structured mathematical model for the transmission of malaria and its control by killing mosquitoes in larvae(immature)stage.Both the Mosquito and human populations are divided into susceptible and infective class.Sus-ceptible class of mosquito population is further divided into mature and immature.The model is analyzed by using stability theory of nonlinear ordinary differential equations.Basic reproduction ratio is derived which is found to be the decreasing function of maturation delay and larvicidal activity.In addition,it is observed that biting rate of mosquito,transmission efficiency of parasitic infection from infective human to mosquito and critical value of maturation delay are the key parameters determining the stability switch in the system.Numerical simulation is also carried out to confirm the analytical results obtained in the paper.
基金This work was supported by the National Institutes of Health(R01 A1050243,U19 AI129326 and D43 TW001505).
文摘The issues of pyrethroid resistance and outdoor malaria parasite transmission have prompted the WHO to call for the development and adoption of viable alternative vector control methods.Larval source management is one of the core malaria vector interventions recommended by the Ministry of Health in many African countries,but it is rarely implemented due to concerns on its cost-effectiveness.New long-lasting microbial larvicide can be a promising cost-effective supplement to current vector control and elimination methods because microbial larvicide uses killing mechanisms different from pyrethroids and other chemical insecticides.It has been shown to be effective in reducing the overall vector abundance and thus both indoor and outdoor transmission.In our opinion,the long-lasting formulation can potentially reduce the cost of larvicide field application,and should be evaluated for its cost-effectiveness,resistance development,and impact on non-target organisms when integrating with other malaria vector control measures.In this opinion,we highlight that long-lasting microbial larvicide can be a potential cost-effective product that complements current front-line long-lasting insecticidal nets(LLINs)and indoor residual spraying(IRS)programs for malaria control and elimination.Microbial larviciding targets immature mosquitoes,reduces both indoor and outdoor transmission and is not affected by vector resistance to synthetic insecticides.This control method is a shift from the conventional LLINs and IRS programs that mainly target indoor-biting and resting adult mosquitoes.
文摘Background:Plants are known to produce a diverse group of natural metabolites with different biological activities.Centaurea ensiformis P.H.Davis,Origanum hypericifolium O.Schwartz&P.H.Davis,and Paeonia turcica Davis&Cullen are endemic plant species that grow on mountains in select regions in Türkiye and have been used in traditional Turkish medicine for various ailments.Methods:As first,we evaluated the larvicidal and antibiofilm activities of ethanol,ethyl acetate,acetone,and water extracts obtained from these plants.Antioxidant activities of the extracts were also investigated.Results:All tested extracts were effective at concentrations>25 ppm on Aedes aegypti larval mortality with the lethal concentration 50(LC_(50))values ranging between 32.82-48.35 ppm and LC90 between 46.26-63.2 ppm.O.hypericifolium was the most effective plant,ethanol extracts presented LC50 values of 32.82 ppm.Extracts demonstrated varying degrees of antibiofilm activity depending on the dose and bacterial species.Origanum hypericifolium extracts notably inhibited biofilms of Staphylococcus aureus(up to 98%inhibition),while P.turcica showed moderate efficacy against the same bacterial species.Pseudomonas aeruginosa biofilms displayed high resistance to all extracts.Conclusion:The results indicated that these endemic Turkish plants possess promising larvicidal and antibiofilm potential,particularly Origanum hypericifolium.Extracts analyzed by liquid chromatography-tandem mass spectrometry contained caffeic acid,myricetin,cinnamic acid,quercetin,gallic acid,epicatechin,and ascorbic acid.Further research should explore their potential applications in mosquito control and biofilm-related infections.
基金Logistic support from the Management of Osun State University Osogbo through grant support number UNIOSUN/SET/010
文摘Objective:To assess the chemical composition and mosquito larvicidal potentials of essential oils of locally sourced Pinus sylvestris(P.sylvestris)and Syzygium aromatkum(S.aromaticum)against Aedes aegypti(A.aegypti)and Culex quinquefasciatus(C.quinquefasciatus).Method:The chemical composition of the essential oils of both plants was determined using GCMS while the larvicidal bioassay was carried out using different concentrations of the oils against the larvae of A.aegypti and C.quinquefasciatus in accordance with the standard protocol.Results:The results as determined by GC-MS showed that oil of S.aromaticum has eugenol(80.5%)as its principal constituent while P.sylvestris has 3-Cyclohexene-1-methanol,.alpha.,.alpha.4-trimethyl(27.1%)as its dominant constituent.Both oils achieved over 85%larval mortality within24 h.The larvae of A.aegypti were more susceptible to the oils[LC_(50)(S.aromaticum)=92.56 mg/L,LC_(50)(P.sylvestris)=100.39 mg/L]than C.quinquefasciatus[LC_(50)(S.aromaticum)=124.42 mg/L;LC_(50)(P.sylvestris)=128.00 mg/L].S.aromaticum oil was more toxic to the mosquito larvae than oil of P.sylvatris but the difference in lethal concentrations was insignificant(P>0.05).Condusioii:The results justify the larvicidal potentials of both essential oils and the need to incorporate them in vector management and control.
文摘Objective: To investigate the larvicidal activity of Syzygium guineense(Myrtaceae)(S. guineense), Monodora myristica and Zanthoxylum heitzii(Rutaceae)(Z. heitzii) extracts against Aedes albopictus(Ae. albopictus).Methods: The larvicidal activity of the hydro-ethanolic extracts from these plant species was assessed at three different concentrations(50, 100 and 200 mg/L) on first-instar of Ae. albopictus larvae in comparison with untreated controls. Mortality rate was recorded daily for a period of 12 days. The values of LC_(50) and lethal time killing 50% of the tested individuals(LT_(50)) were calculated using the log-probit analysis.Results: The root extract of S. guineense exhibited the best activity with 100% mortality after 8 days of treatment at 200 mg/L, followed by the fruit extract of Z. heitzii with83.33% mortality at the same concentration. Nonetheless, larvae were most susceptible to the fruit extract of Z. heitzii both in terms of LC_(50)(39.89 mg/L) and LT_(50)(145.68 h). A statistically significant difference between the control and the group treated at 200 mg/L was noticed in all the extracts.Conclusions: The present study shows that the hydro-ethanolic extracts of S. guineense,Monodora myristica and Z. heitzii tested have significant larvicidal activity. These preliminary results are of great interest and some of these plant species can be proposed for the formulation of new bioinsecticides to control Ae. albopictus populations.
基金Entomology and Toxicology Unit,University of Tabuk,Saudi Arabia with Grant No.1/1/11/1435
文摘Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L.(Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia.Methods: The tested conventional insecticides were Actikil and Pesgard, while the nonconventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photomicroscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains.Results: Cx. pipiens were more susceptible to Pesgard(LC50: 0.045 and 0.032 mg/L)than Actikil(0.052 and 0.038 mg/L) and Bacilod(0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin synthesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained(concentration which to inhibit the emergence of 50% of mosquito adults), the compound Dudim(0.000 3 and 0.000 1 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal(0.000 4 and 0.000 3 mg/L) for both the field and laboratory strains, respectively.Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia.
基金Supported by Ministry of Environment and Forest[Grant No.D.O.NO.3/2/2004 CS(M)-11.12.2006]
文摘Objective:To identify the larvieidal activity of the seagrass extracts.Methods:Seagrass extracts,Syringodium isoelifolium(.S.isoetifolium),Cymodocea serrulata and Hulophila beccarii,were dissolved in DMSO to prepare a graded series of concentration.Batches of 25 early 4th instars larvae of Aedes aegypti(Ae.aegypti) were transferred to 250 ml.enamel bowl containing199 mL of distilled water and 1 mL of plant extracts(0.01 mg- 0.1 mg).After 24 h the mortality rate was identified with the formulae[(%of lest mortality-%of control mortality)/(100-%of control morlality)]× 100.Each experiment was conducted with three replicates and a concurrent control group.A control group consisted of 1 mL of DMSO and 199 mL of distilled water only.Results:The root extract of S.isoelifolium showed maximum larvicidal activity with minimum concentration of extract of LC_(50)= 0.0604 ± 0.0040)μg/mL with lower confidence limit(LCL)-upper confidence limit(UCL) =(0.051-0.071) and LC_(90)=0.0972 μg/mL followed by leaf extract of S.isoelifolium showed LC_(50)=(0.062 ± 0.005)μ'g/mL.The regression equation of pool and leaf extract of S.isoelifolium for4th instar larvae were Y =4.909- 1.32x(R^2= 0.909) and Y= 2.066+ 1.2x(R^2 =0.897) respectively.The results of the preliminary photochemical constituents shows the presence of saponin,steroids,terpenoid,phenols,protein and sugars.Conclusions:from the present study the ethanolic extracts of seagrass of S.isoelifolium possesses lead compound for development of larvieidal activity.
基金financially supported by Univeresiry Grants Commission. New Post Doctoral Fellowship(2009-2011)the University Grants Conuuission, New Delhi of Major Research Projcct for the financial support 2010-2012 to DST-FIST program (2003-2008)for providing laboratory facilities. G.Singh is indebted to UGC, New Delhi, for an award of Post Doctoral Fellowship (2009-2011)
文摘Objective:To investigate lethal effect of culture filtrates of Streptomyces citreofluorescens （S.citreofluorescens） against Anopheles stephensi（An.stephensi）,Culex quinquefasciatus（Cx. quinquefasciatus）,and Aedes aegypti（Ae.aegypti） larvae vectors for malaria,filarial and dengue. Methods:The culture filtrates obtained from S.cilreofluorescens 2528 was grown in Potato Dextrose Broth（PDB）,filtrated and used for the bioassay after a growth of 15 days.Results:The results demonstrated that the An.stephensi shows mortalities with LC<sub>50</sub>,LG<sub>40</sub> values of first instar 46.8μL/mL,79.5μL/mL,second instar 79.0μL/mL,95.6μL/mL,third instar 79.0μL/mL,136.9μL/mL,and fourth instar 122.6μL/mL,174.5μL/mL Whereas,The Cx.quinquefasciatus were found effective on first instar 40.0μL/mL,138.03μL/mL,second instar 80.0μL/ml,181.97μL/ mL,third instar 100.0μL/mL,309.2μL/mL,and fourth instar 60.0μL/ml,169.82μL/mL.The Ae.aegypti were successfully achieved susceptible with higher concentrations in comparisons of An.stephensi and Cx.quinquefasciatus larvae.These outcomes of the investigations have compared with the Chitinase of Streptomyces griseus（S.griseus） C6137 that shows 90%-95% mortality.Conclusions:These new findings significantly permitted that the culture filtrates of S. citreofluorescens can be used as bacterial larvicides.This is an environmentally safe approach to control the vectors of malaria,dengue and filariasis of tropical areas.
文摘Objective:To investigate the larvicidal and pupicidal activity of spinosad against Anopheles stephensi Listen.Methods:Spinosad from the actinomycete,Saccharopolyspora spinosa was tested against Anopheles stephensi at different concentrations（0.01,0.02,0.04,0.06 and 0.08 ppm.）, and against first to fourth instar larvae and pupae.Results:The larval mortality ranged from 36.1±1.7 in（0.01 ppm） to 79.3±1.8（0.08 ppm） the first instar larva.The LC<sub>50</sub> and LC<sub>90</sub> values of first, second,third and fourth instar larva were 0.001,0.031,0.034,0.036 and 0.0113,0.102,0.111,0.113, respectively.The pupal mortality ranged from 33.0±2.0（0.01 ppm） to 80.0±0.9（0.08 ppm）.The LC<sub>50</sub> and LC<sub>90</sub> values were 0.028 and 0.1020,respectively.The reduction percentage of Anopheles larvae was 82.7%,91.4%and 96.0%after 24,48,72 hours,respectively,while more than 80% reduction was observed after 3 weeks.Conclusions:In the present study spinosad effectively caused mortality of mosquito larvae in both the laboratory and field trial.It is predicted that spinosad is likely to be an effective larvicide for treatment of mosquito breeding sites.
文摘Extracts and constituents of medicinal plants have proven to be biodegradable, had low mammalian toxicity and induction of resistance, and comparable activities to the standard drugs. Therefore, methanolic extracts of some plants that are termite resistant or used ethnomedically as antimalarial and febrifuge were evaluated for activities against 4th-instar larvae of Aedes aegypti. A 61 % of these plants with these properties demonstrated larvicidal activities and may confirm the usefulness of these properties in choosing plant larvicides. This is the first report of larvicidal activities of stem barks and leaves of Blighia sapida and Baphia nitida, stem barks of Markhamia tomentosa and Newboldia laevis, and whole plants of Euphorbia macrophylla. Extracts of B. sapida stem bark, Costus specious root and Xylopia aethiopica seed, with LC50 1.71, 1.47 and 1.49 mg/ml at 48 h, respectively, were the most active and had significant activities that were comparable to Endosulphan. Hence, they may be used as plant larvicides in the control of dengue and yellow fever.
文摘Objective:To evaluate the larvicidal and pupicidal potential of the methanolic extracts from Moringa oleifera(M.oleifera) plant seeds against malarial vector Anopheles stephensi(A.stephensi) mosquitoes at different concentrations(20,40,60,80 and 100 ppm).Methods:M.oleifera was collected from the area of around Bharathiar University,Coimbatore.The dried plant materials were powdered by an electrical blender.From each sample,100 g of the plant material were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus.The extracts were evaporated to dryness in rotary vacuum evaporator to yield 122 mg and 110 mg of dark greenish material(residue) from Arcang amara and Ocimum basilicum,respectively.One gram of the each plant residue was dissolved separately in 100 mL of acetone(stock solution) from which different concentrations, i.e.,20,40,60,80 and 100 ppm were prepared.Results:Larvicidal activity of M.oleifera exhibited in the first to fourth instar larvae of the A.stephensi,and the LC_(50) and LC_(90) values were 57.79 ppm and 125.93 ppm for the first instar,63.90 ppm and 133.07 ppm for the second inslar,72.45 ppm and 139.82 ppm for the third instar,78.93 ppm and 143.20 ppm for the fourth instar,respectively. During the pupal stage the methanolic extract of M.oleifera showed that the LC_(50),and LC_(90) values were 67.77 ppm and 141.00 ppm,respectively.Conclusions:The present study indicates that the phytochemicals derived from M.oleifera seeds extracts are effective mosquito vector control agents and the plant extracts may be used for further integrated pest management programs.
基金the Department of Science and Technology(DST),New Delhi,India for providing financial assistance for the present investigation
文摘Objective:The present study deals with the investigation of larvicidal and ovicidal activities of benzene,hexane,ethyl acetate,methanol and chloroform leaf extract of Eclipta alba（E.alba） against dengue vector,Aedes aegypti（Ae.Aegypti）.Methods:Twenty five earlyⅢinstar larvae of Ae.aegypti was exposed to various concentrations（50-300 ppm） and was assayed in the laboratory by using the protocol of WHO 2005;the 24 h LC<sub>50</sub> values of the E.alba leaf extract was determined by Probit analysis.For ovicidal activity,slightly modified method of Su and Mulla was performed.The ovicidal activity was determined against Ae.aegypti to various concentrations ranging from 100-350 ppm under the laboratory conditions.The egg hatch rates were assessed 48 h post treatment.Results:The LC<sub>50</sub> values of benzene,hexane,ethyl acetate,methanol and chloroform extract of E.alba against early third instar larvae of Ae.aegypti were 151.38,165.10, 154.88,127.64 and 146.28 ppm,respectively.Maximum larvicidal activity was observed in the methanol extract followed by chloroform,benzene,ethyl acetate and hexane extract.No mortality was observed in control.Among five solvent tested the methanol extract was found to be most effective for ovicidal activity against Ae.aegypti.The methanol extracts exerted 100%mortality （zero hatchability） at 300 ppm.Conclusions:From the results it can be concluded the crude extract of E.alba was an excellent potential for controlling Ae.aegypti mosquito.
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 mosquito larvicidal activity of leaf essential oil and their chemical constituents from Clausena anisata（C.anisata）（Willd.） Hook.f.ex Benth.against Culex quinquefasciatus,Aedes aegypti and Anopheles Stephensi.Methods:Essential oil was obtained by hydro-distillation and the chemical composition of the leaf essential oil was analyzed using gas chromatography—mass spectrometry.The mosquitoes were reared in the vector control laboratory and twenty lateⅢinstar larvae of three mosquito species were exposed to based on the wide range and narrow range tests,essential oil was tested at 50.100.150,200 and 250 ppm and each compound was tested at various concentration（5-75 ppm） and were assayed in the laboratory by using the protocol of WHO 2005:the 24 h LC<sub>50</sub> values of the C.anisata leaf essential oil and their major compounds were determined following Probit analysis.Results:The oil contained were mainlyβ-pinene（32.8%）,sabinene（28.3%）,germacrene-D（12.7%）,estragole （6.4%） and linalool（5.9%）.The essential oil from the leaves of C.anisata exhibited significant larvicidal activity,with 24 h LC<sub>50</sub> values of 140.96,130.19 and 119.59 ppm.respectively.The five pure constituents extracted from the C.anisata leaf essential oil were also tested individually against three mosquito larvae.The LC<sub>50</sub> values ofβ-pinene,sabinene,germacrene-D,estragole and linalool appeared to be most effective against Anopheles stephensi(LC<sub>50</sub>-23.17,19.67,16.95. 11.01,35.17 ppm) followed by Aedes aegypti(LC<sub>50</sub>-27.69,21.20,18.76,12.70,38.64 ppm) and Culex quinquefasciatus(LC<sub>50</sub>-32.23,25.01.21.28,14.01,42.28).Conclusions:The essential oil of C. anisata contains five major compounds and has remarkable larvicidal properties,which may be considered as a potent source for the production of natural larvicides.
文摘Objective:To determine the larvicidal and adult emergence inhibition activities of castor （Ricinus communis） seed extract against three potential mosquito vectors Anopheles stephensi（An. slephensi）,Culex quinquefasciatus（Cx.quinquefasciatus） and Aedes albopictus（Ae.albopictus） in India.Methods:The R.communis seed extract was tested,employing WHO procedure,against fourth larval instars of the three mosquito species for 24 h and larval mortalities were recorded at various concentrations（2-64μg/mL）:the 24 h LC<sub>50</sub> values of the R.communis seed extract were determined following Probit analysis.The larval killing,antipupation and adult emergence inhibition rates of the test extract,using a single concentration of 2μLC<sub>50</sub>,were studied at different time periods（24-72 h）:the extract toxicity was tested against a fish.Oreochromis niloticus（O.niloticus）.Results:The R.communis seed extract exhibited larvicidal effects with 100%killing activities at concentrations 32-64μg/mL,and with LC<sub>50</sub> values 7.10.11.64 and 16.84μg/mL for Cx.quinquefasciatus,An.stephensi and Ae.albopictus larvae,respectively. When the larvae were treated with the extract at a single concentration of 2×LC<sub>50</sub>,significant differences were observed,compared to control groups,in rate of pupation（P【0.001） as well as in adult formation（P【0.001）.Conclusions:The present findings suggest that the R.communis seed extract provided an excellent potential for controlling An.stephensi,Cx.quinquefasciatus and Ae. albopictus mosquito vectors.
基金Supported by the So Paulo Research Foundation-FAPESP-Brazil(Grant No.2012/09890-6)
文摘Clove(Syzygium aromaticum) is one of the most valuable spices that has been used for centuries as food preservative and Tor many medicinal purposes.Clove is native of Indonesia but nowadays is cultured in several parts of the world including Brazil in the slate of Bahia.This plant represents one of the richest source of phenolic compounds such as eugenol,eugenol acetate and gallic acid and posses great potential for pharmaceutical,cosmetic,food and agricultural applications.This review includes the main studies reporting the biological activities of clove and eugennl.The antioxidant and antimicrobial activity of clove is higher than many fruits,vegetables and other spices and should deserve special attention.A new application of clove as larvicidal agent is an interesting strategy to combat dengue which is a serious health problem in Brazil and other tropical countries.Pharmacokinetics and lexicological studies were also mentioned.The different studies reviewed in this work confirm the traditional use of clove as food preservative and medicinal plant standing out the importance of this plant for different applications.
文摘Objective:To assess the larvicidal and repellent potential of the essential oil extracted from the leaves of peppermint plant,Mentha piperita(M.piperita) against the larval and adult stages of Aedes aegypti(Ae.Aegypti).Methods:The larvicidal potential of peppermint oil was evaluated against early fourth instar larvae of Ae.aegypti using WHO protocol.The mortality counts were made after 24 and 48 h,and LC_(50) and LC_(90) values were calculated.The efficacy of peppermint oil as mosquito repellent was assessed using the human-bait technique.The measured area of one arm of a human volunteer was applied with the oil and the other arm was applied with ethanol.The mosquito bites on both the arms were recorded for 3 min after every 15 min.The experiment continued for 3 h and the percent protection was calculated.Results:The essential oil extracted from M.piperita possessed excellent larvicidal efficiency against dengue vector. The bioassays showed an LC_(50) and LC_(90) value of 111.9 and 295.18 ppm,respectively after 24 h of exposure.The toxicity of the oil increased 11.8%when the larvae were exposed to the oil for 48 h.The remarkable repellent properties of M.piperita essential oil were established against adults Ae.aegypti.The application of oil resulted in 100%protection till 150 min.After next 30 min, only 1-2 bites were recorded as compared with 8-9 bites on the control arm.Conclusions:The peppermint essential oil is proved to be efficient larvicide and repellent against dengue vector. Further studies are needed to identify the possible role of oil as adulticide,oviposilion deterrent and ovicidal agent.The isolation of active ingredient from the oil could help in formulating strategies for mosquito control.
文摘Objective:To determine the larvicidal and repellent activities of Sida acuta Burm.F.（Family: Malvaceae）extract against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi. Methods:Twenty five late III instar larve of three mosquito species were exposed to various concentrations（15-90 mg/L） and were assayed in the laboratory by using the protocol of WHO 2005:the 24 h LC<sub>50</sub> values of the Sida acuta leaf extract was determined following Probit analysis. The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm<sup>2</sup> under the laboratory conditions.Results:Results showed varying degree of larvicidal activity of crude extract of Sida acuta against three important mosquitoes with LC<sub>50</sub> values ranging between 38 to 48 mg/L.The crude extract had strong repellent action against three species of mosquitoes as it provided 100%protection against Anopheles stephensi for 180 min followed by Aedes aegypti（150 min） and Culex quinquefasciatus（120 min）.Conclusions: From the results it can be concluded the crude extract of Sida acuta was an excellent potential for controlling Culex quinquefasciatus,Aedes aegypti and Anopleles stephensi mosquitoes.
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 evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts of Acacia concinna（A.concinna）,Cassia siamea（C.siamea）.Conundrum sativum（C. sativum）,Cuminum cyminum（C.cyminum）,Lantana camma（L.camara）,Nelumbo nucifera （N.nucifera） Phyllanlhus amarus（P.amarus）.Piper nigrum（P.nigrum） and Trachyspermum ammi（T.ammi） against Anopheles stephensi（An.stephensi） and Culex quinquefasciatus（Cx. quinquefasciatus）.Methods:The larvicidal activity of medicinal plant extracts were tested against earl) fourth-instar larvae of malaria and filariasis vectors.The mortality was observed 24 h and 48 h after treatment,data were subjected to probit analysis to determine the lethal concentrations(LC<sub>50</sub> and LC<sub>90</sub>) to kill 50 and 90 per cent of the treated larvae of the tested species. The repellent efficacy was determined against two mosquito species at five concentrations（31.25. 62.50.125.00.250.00,and 500.00 ppm） under the laboratory conditions.Results:All plant extracts showed moderate effects after 24 h and 48 h of exposure;however,the highest activity was observed after 24 h in the leaf methanol extract ol N.nucifera.seed ethyl acetate and methanol extract of P.nigrum against the larvae of An.Stephensi(LC<sub>50</sub> = 34.76.24.54 and 30.20 ppm) and against Cx.quinquefasciatus(LC<sub>50</sub>= 37.49.43.94 and 57.39 ppm),respectively.The toxic effect of leaf methanol extract of C.siamea,seed methanol extract of C.cyminum,leaf ethyl acetate extract of N.nucifera.leaf ethyl acetate and methanol extract of P.amarus and seed methanol extract of T.ammi were showed 100%mortality against An.stephensi and Cx.quinquefasciatus alter 48 h exposer.The maximum repellent activity was observed at 500 ppm in methanol extracts of N. nucifera.ethyl acetate and methanol extract of P.nigrum and methanol extract of T.ammi and the mean complete protection time ranged from 30 to 150 min with the different extracts tested. Conclusions:These results suggest that the leaf and seed extracts of C.siamea.N.nucifera.P. amarus.P.nigrum and T.ammi have the potential to be used as an ideal ecofriendly approach for the control of the An.stephensi and Cx.quinquefasciatus.
