Objective:To evaluate the mosquito larvicidal activity of plant extracts.Methods:The hexane,chloroform,ethyl acetate,acetone,and methanol leaf,flower and seed extracts of Abrus precatorius（A.precatorius）,Croton bonp...Objective:To evaluate the mosquito larvicidal activity of plant extracts.Methods:The hexane,chloroform,ethyl acetate,acetone,and methanol leaf,flower and seed extracts of Abrus precatorius（A.precatorius）,Croton bonplandianum（C.bonplandianum）,Cynodon dactylon （C.dactylon）,Musa paradisiaca（M.paradisiaca） and Syzygium aromaticum（S.aromaticum） were tested against fourth instar larvae of Anopheles vagus（An.vagus）,Armigeres subalbatus （Ar.subalbatus） and Culex vishnui（Cx.vishnui）.Results:The highest larval mortality was found in seed ethyl acetate extracts of A.precatorius and leaf extracts of C.bonplandianum, flower chloroform and methanol extracts of M.paradisiaca,and flower bud hexane extract of S. aromaticum against An.vagus with LC<sub>50</sub> values of 19.31,39.96,35.18,79.90 and 85.90μg/mL;leaf ethyl acetate and methanol extracts of C.dactylon,flower methanol extract of M.paradisiaca, flower bud methanol extract of S.aromaticum against Ar.subalbatus with LC<sub>50</sub> values of 21.67, 32.62,48.90 and 78.28μg/mL,and seed methanol of A.precatorius,flower methanol extract of M.paradisiaca,flower bud hexane extract of S.aromaticum against Cx.vishnui with LC<sub>50</sub> values of 136.84,103.36 and 149.56μg/mL,respectively.Conclusions:These results suggest that the effective plant crude extracts have the potential to be used as an ideal ecofriendly approach for the control of disease vectors.This study provides the first report on the larvicidal activity of crude solvent extracts of different mosquitoes.展开更多
Objective:To establish an efficacious and efficient surveillance method of Armigeres(Ar.)subalbatus,a known filarial vector,surviving in forest habitats to estimate realistic population density and assess the impact o...Objective:To establish an efficacious and efficient surveillance method of Armigeres(Ar.)subalbatus,a known filarial vector,surviving in forest habitats to estimate realistic population density and assess the impact of altitudinal variations on the efficacy of the trap.Methods:In the study,12 locations in areas with an altitudinal range from 82 m to 920 m were selected in three reserve forests for night sampling of adult Ar.subalbatus mosquito using standard chemical lure based BG-Sentinel traps and CDC-light traps in pairs.Effects of locations and time were estimated on the efficacy of traps as mosquito density using multifactor analysis of variance for significant differences.Impact of altitudinal variations on the efficacy of traps was assessed using multiple regression with slope comparison.Results:BG-Sentinel trap collected significantly more adult Ar.subalbatus,4.43 folds in Gorumara NP,5.19 folds in Neora Valley NP and 12.10 folds in Mahananda WLS than the CDC-light trap irrespective to locations.BG-Sentinel traps were tolerant of altitudinal variations(80 m-170 m)and showed no significant relationship between density and altitudes in contrast to CDC-light traps which showed a significant negative impact on capturing efficacy with increase in altitudes(P<0.001).Conclusions:The study suggests that BG-Sentinel traps can be used effectively and efficiently to collect more Ar.subalbatus mosquitoes during night time in comparison to CDC-light trap under complex climatic conditions of forest and variable altitudes.展开更多
Background:Zika virus (ZIKV) and dengue virus (DENV) are closely related flaviviruses primarily transmitted by Aedes mosquitoes. Armigeres subalbatus is an emerging and widely distributed mosquito, and ZIKV has been d...Background:Zika virus (ZIKV) and dengue virus (DENV) are closely related flaviviruses primarily transmitted by Aedes mosquitoes. Armigeres subalbatus is an emerging and widely distributed mosquito, and ZIKV has been detected and isolated from it. However, it is not clear whether Ar. subalbatus could be a vector for ZIKV and DENV or not. In this study, we investigated the infection and transmission of Ar. subalbatus to ZIKV and DENV.Methods:A line of Ar. subalbatus was isolated from Guangdong, China, and further identified by the mitochondrial cytochrome oxidase subunit 1 (COI) gene. The adults of Ar. subalbatus were fed with blood meal containing ZIKV or DENV-2. At 4, 7, 10, 14, and 21 days post-inoculation (dpi), the infections of ZIKV or DENV-2 in the midguts, ovaries and salivary glands were detected and quantified by RT-PCR and RT-qPCR. To assess the transmissibility, suckling mice were exposed to bites of ZIKV-infected mosquitoes, and ZIKV was detected in brain tissue by RT-qPCR and plaque assays. Furthermore, the larvae of Ar. subalbatus were reared in artificial urine containing ZIKV or DENV-2. The infection rates and viral titers of larvae and adults were analyzed by RT-PCR and RT-qPCR, and the viral distribution in larval tissues was observed by immunohistochemistry. Chi-square test and one-way ANOVA analysis were used for assessing the infection rate and viral titer in varied tissues and different time points, respectively.Results:Following oral inoculation, ZIKV but not DENV-2 could be detected in Ar. subalbatus midguts at 4 dpi, ovaries at 7 dpi and salivary glands at 10 dpi. The highest infection rate (IR) of ZIKV was 27.8% in midgut at 7 dpi, 9.7% in ovary and 5.6% in salivary gland at 21 dpi. Eight days after being bitten by ZIKV-positive mosquitoes, ZIKV was detected in three brain tissues out of four suckling mice exposed to bites. ZIKV could be detected in the larvae reared in artificial urine contained ZIKV at a high concentration of 105 pfu/ml and various tissues of adults with a low infection rate (0.70–1.35%). ZIKV could be observed in anal papillae and midgut of larvae at 4 dpi under laboratory conditions.Conclusions:ZIKV but not DENV-2 can infect Ar. subalbatus by blood meal and artificial urine, and the infected mosquitoes can transmit ZIKV to suckling mice by bite. From these findings, we can conclude that the Ar. subalbatus isolated from Guangdong province, China, is a potential vector for ZIKV and should therefore be considered in vector control programs to prevent and control of Zika virus disease.展开更多
文摘Objective:To evaluate the mosquito larvicidal activity of plant extracts.Methods:The hexane,chloroform,ethyl acetate,acetone,and methanol leaf,flower and seed extracts of Abrus precatorius（A.precatorius）,Croton bonplandianum（C.bonplandianum）,Cynodon dactylon （C.dactylon）,Musa paradisiaca（M.paradisiaca） and Syzygium aromaticum（S.aromaticum） were tested against fourth instar larvae of Anopheles vagus（An.vagus）,Armigeres subalbatus （Ar.subalbatus） and Culex vishnui（Cx.vishnui）.Results:The highest larval mortality was found in seed ethyl acetate extracts of A.precatorius and leaf extracts of C.bonplandianum, flower chloroform and methanol extracts of M.paradisiaca,and flower bud hexane extract of S. aromaticum against An.vagus with LC<sub>50</sub> values of 19.31,39.96,35.18,79.90 and 85.90μg/mL;leaf ethyl acetate and methanol extracts of C.dactylon,flower methanol extract of M.paradisiaca, flower bud methanol extract of S.aromaticum against Ar.subalbatus with LC<sub>50</sub> values of 21.67, 32.62,48.90 and 78.28μg/mL,and seed methanol of A.precatorius,flower methanol extract of M.paradisiaca,flower bud hexane extract of S.aromaticum against Cx.vishnui with LC<sub>50</sub> values of 136.84,103.36 and 149.56μg/mL,respectively.Conclusions:These results suggest that the effective plant crude extracts have the potential to be used as an ideal ecofriendly approach for the control of disease vectors.This study provides the first report on the larvicidal activity of crude solvent extracts of different mosquitoes.
基金Dr.Kailash Chandra,Director,Zoological Survey of India(ZSI),Ministry of Environment,Forest and Climate Change(MoEFCC),Govt.of India,for providing funding and logistic support.
文摘Objective:To establish an efficacious and efficient surveillance method of Armigeres(Ar.)subalbatus,a known filarial vector,surviving in forest habitats to estimate realistic population density and assess the impact of altitudinal variations on the efficacy of the trap.Methods:In the study,12 locations in areas with an altitudinal range from 82 m to 920 m were selected in three reserve forests for night sampling of adult Ar.subalbatus mosquito using standard chemical lure based BG-Sentinel traps and CDC-light traps in pairs.Effects of locations and time were estimated on the efficacy of traps as mosquito density using multifactor analysis of variance for significant differences.Impact of altitudinal variations on the efficacy of traps was assessed using multiple regression with slope comparison.Results:BG-Sentinel trap collected significantly more adult Ar.subalbatus,4.43 folds in Gorumara NP,5.19 folds in Neora Valley NP and 12.10 folds in Mahananda WLS than the CDC-light trap irrespective to locations.BG-Sentinel traps were tolerant of altitudinal variations(80 m-170 m)and showed no significant relationship between density and altitudes in contrast to CDC-light traps which showed a significant negative impact on capturing efficacy with increase in altitudes(P<0.001).Conclusions:The study suggests that BG-Sentinel traps can be used effectively and efficiently to collect more Ar.subalbatus mosquitoes during night time in comparison to CDC-light trap under complex climatic conditions of forest and variable altitudes.
文摘Background:Zika virus (ZIKV) and dengue virus (DENV) are closely related flaviviruses primarily transmitted by Aedes mosquitoes. Armigeres subalbatus is an emerging and widely distributed mosquito, and ZIKV has been detected and isolated from it. However, it is not clear whether Ar. subalbatus could be a vector for ZIKV and DENV or not. In this study, we investigated the infection and transmission of Ar. subalbatus to ZIKV and DENV.Methods:A line of Ar. subalbatus was isolated from Guangdong, China, and further identified by the mitochondrial cytochrome oxidase subunit 1 (COI) gene. The adults of Ar. subalbatus were fed with blood meal containing ZIKV or DENV-2. At 4, 7, 10, 14, and 21 days post-inoculation (dpi), the infections of ZIKV or DENV-2 in the midguts, ovaries and salivary glands were detected and quantified by RT-PCR and RT-qPCR. To assess the transmissibility, suckling mice were exposed to bites of ZIKV-infected mosquitoes, and ZIKV was detected in brain tissue by RT-qPCR and plaque assays. Furthermore, the larvae of Ar. subalbatus were reared in artificial urine containing ZIKV or DENV-2. The infection rates and viral titers of larvae and adults were analyzed by RT-PCR and RT-qPCR, and the viral distribution in larval tissues was observed by immunohistochemistry. Chi-square test and one-way ANOVA analysis were used for assessing the infection rate and viral titer in varied tissues and different time points, respectively.Results:Following oral inoculation, ZIKV but not DENV-2 could be detected in Ar. subalbatus midguts at 4 dpi, ovaries at 7 dpi and salivary glands at 10 dpi. The highest infection rate (IR) of ZIKV was 27.8% in midgut at 7 dpi, 9.7% in ovary and 5.6% in salivary gland at 21 dpi. Eight days after being bitten by ZIKV-positive mosquitoes, ZIKV was detected in three brain tissues out of four suckling mice exposed to bites. ZIKV could be detected in the larvae reared in artificial urine contained ZIKV at a high concentration of 105 pfu/ml and various tissues of adults with a low infection rate (0.70–1.35%). ZIKV could be observed in anal papillae and midgut of larvae at 4 dpi under laboratory conditions.Conclusions:ZIKV but not DENV-2 can infect Ar. subalbatus by blood meal and artificial urine, and the infected mosquitoes can transmit ZIKV to suckling mice by bite. From these findings, we can conclude that the Ar. subalbatus isolated from Guangdong province, China, is a potential vector for ZIKV and should therefore be considered in vector control programs to prevent and control of Zika virus disease.
