Objective:To determine the prevalence of mosquito larvae in campus areas and the infection rate of endosymbiotic bacteria,Wolbachia in mosquito larvae.Method:The mosquito larvae samples were collected in residential a...Objective:To determine the prevalence of mosquito larvae in campus areas and the infection rate of endosymbiotic bacteria,Wolbachia in mosquito larvae.Method:The mosquito larvae samples were collected in residential areas and academic buildings of Suranaree University of Technology located in Northeastern Thailand during 2017-2018.Mosquito species identification was performed using GLOBE mosquito protocols and Rattanarithikul&Panthusiri’s keys.The gene encoding for the surface protein of Wolbachia was amplified by PCR and confirmed by DNA sequencing.Results:Armigeres sp.is the highest proportion of mosquito larvae followed by Culex spp.,Aedes albopictus,Aedes aegypti,and Toxorynchites spp.,respectively.Aedes aegypti have breeding sites mostly in the containers found indoors,whereas the main breeding sites of Aedes albopictus were found in both outdoors and indoors.The House Index and Breteau Index for Aedes spp.was more than 5%and 20%,respectively,in both areas,indicating that these areas are dengue sensitive.The highest proportion of Wolbachia infection was found in the larvae of Culex spp.(86.21%),followed by Aedes albopictus(69.23%)and rarely detected in Aedes aegypti(9.09%).Conclusion:The present study reported the first natural infection of Wolbachia in mosquito larvae in Thailand.Our result suggested that the mosquito species containing higher proportion of Wolbachia are less likely to be vectors for dengue.Therefore,Wolbachia transfection in mosquito larvae could be applied as a biocontrol for dengue and other mosquito-borne disease prevention.展开更多
Objective:To evaluate the larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri endocarp against Aedes aegypti,Aedes albopictus,Culex quinquefasciatus,and Anopheles minimus mosquitos.Methods:Larv...Objective:To evaluate the larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri endocarp against Aedes aegypti,Aedes albopictus,Culex quinquefasciatus,and Anopheles minimus mosquitos.Methods:Larvicidal activity was tested according to World Health Organization standard protocol.The third-stage larvae of each mosquito species were exposed to various concentrations of Dracaena loureiri crude extract and six groups of Dracaena loureiri fractionated extracts(RC-DT 009-014).Larval mortality rates were observed after 24 h and48 h of exposure.Then,a computerized probit analysis of the mortality data was performed to determine lethal concentration 50(LC_(50))and lethal concentration 90 values.Results:Anopheles minimus larvae(24-h LC_(50)77.88 mg/L)had the highest susceptibility to crude extract,whereas others(Aedes aegypti,24-h LC_(50)224.73 mg/L;Aedes albopictus,24-h LC_(50)261.75 mg/L;and Culex quinquefasciatus,24-h LC_(50)282.86 mg/L)were significantly less susceptible.The most effective groups of fractionated extracts were RC-DT 012 and RC-DT 013.The mosquito species most susceptible to fractionated extracts was Culex quinquefasciatus,with 24-h LC_(50)values of 0.66 and 0.94 mg/L for RC-DT 012 and RC-DT 013,respectively.Conclusions:The larvicidal activity of fractionated extracts is more effective than that of crude extract against all tested mosquito species.For the most effective alternative larvicide,purification and a phytochemical constituent analysis must be performed.展开更多
The role of Typha spp. on water loss and public health has been uncertained and relatively poorly reported in Hadejia Nguru wetlands. This study investigated the extent to which Typha spp. contributed to evapotranspir...The role of Typha spp. on water loss and public health has been uncertained and relatively poorly reported in Hadejia Nguru wetlands. This study investigated the extent to which Typha spp. contributed to evapotranspirative water loss and the level at which it provides suitable habitat for mosquito breeding. A comparative analysis between Typha swamp and open water was made to determine the evapotranspiration water loss and mosquito larva load accounted for by Typha swamp in the wetland. Maximum and minimum temperatures were measured and recorded daily for the months of January, March and June in 2013. Blaney-Criddle equation was used to estimate the evapotranspiration from Typha swamp (Site A) while piche evaporimeter was used to measure direct evaporation from the adjacent open water (Site B). Water samples were collected in Sites A and B using 100 ml beaker at random and the number of mosquito larvae in the sample was counted. T test was used to evaluate differences in water loss and larva load between open water and Typha swamp in the wetland. The findings revealed that there was no significant difference in water loss at p < 0.05 between Typha swamp and open water in the wetland. However, the Typha swamp was found to harbor more mosquito larvae than the open water at p < 0.05 which was considered a public health risk.展开更多
Dengue virus is an arthropod-borne pathogen that is transmitted to humans primarily by Aedes spp.mosquitos,causing the acute infectious disease,dengue fever(DF).Until 2019,no dengue outbreak had been reported in Haina...Dengue virus is an arthropod-borne pathogen that is transmitted to humans primarily by Aedes spp.mosquitos,causing the acute infectious disease,dengue fever(DF).Until 2019,no dengue outbreak had been reported in Hainan Province for over 20 years.However,in early September of 2019,an increasing number of infected cases appeared and the DF outbreak lasted for over one month in Haikou City,Hainan Province.In our study,we collected 97 plasma samples from DF patients at three hospitals,as well as 1585 mosquito larvae samples from puddles in different areas of Haikou.There were 49(50.5%)plasma samples found to be strongly positive and 9(9.3%)plasma samples were weakly positive against the NS1 antigen.We discovered DENV both in the patient's plasma samples and mosquito larvae samples,and isolated the virus from C6/36 cells inoculated with the acute phase serum of patients.Phylogenetic analysis revealed that the new strains were the most closely related to the epidemic strain in the southern regions of China,belonging to lineageⅣ,genotypeⅠ,DENV-1.Compared to the seven closest strains from neighboring countries and provinces,a total of 18 amino acid mutations occurred in the coding sequences(CDS)of the new isolated strain,DENV1 HMU-HKU-2.Our data shows that dengue virus is re-emerged in Hainan,and pose new threats for public health.Thus regular molecular epidemiological surveillance is necessary for control and prevention of DENV transmission.展开更多
文摘Objective:To determine the prevalence of mosquito larvae in campus areas and the infection rate of endosymbiotic bacteria,Wolbachia in mosquito larvae.Method:The mosquito larvae samples were collected in residential areas and academic buildings of Suranaree University of Technology located in Northeastern Thailand during 2017-2018.Mosquito species identification was performed using GLOBE mosquito protocols and Rattanarithikul&Panthusiri’s keys.The gene encoding for the surface protein of Wolbachia was amplified by PCR and confirmed by DNA sequencing.Results:Armigeres sp.is the highest proportion of mosquito larvae followed by Culex spp.,Aedes albopictus,Aedes aegypti,and Toxorynchites spp.,respectively.Aedes aegypti have breeding sites mostly in the containers found indoors,whereas the main breeding sites of Aedes albopictus were found in both outdoors and indoors.The House Index and Breteau Index for Aedes spp.was more than 5%and 20%,respectively,in both areas,indicating that these areas are dengue sensitive.The highest proportion of Wolbachia infection was found in the larvae of Culex spp.(86.21%),followed by Aedes albopictus(69.23%)and rarely detected in Aedes aegypti(9.09%).Conclusion:The present study reported the first natural infection of Wolbachia in mosquito larvae in Thailand.Our result suggested that the mosquito species containing higher proportion of Wolbachia are less likely to be vectors for dengue.Therefore,Wolbachia transfection in mosquito larvae could be applied as a biocontrol for dengue and other mosquito-borne disease prevention.
基金supported by the Naresuan University Research Fund(Reference Number:R2560B057)
文摘Objective:To evaluate the larvicidal efficacy of crude and fractionated extracts of Dracaena loureiri endocarp against Aedes aegypti,Aedes albopictus,Culex quinquefasciatus,and Anopheles minimus mosquitos.Methods:Larvicidal activity was tested according to World Health Organization standard protocol.The third-stage larvae of each mosquito species were exposed to various concentrations of Dracaena loureiri crude extract and six groups of Dracaena loureiri fractionated extracts(RC-DT 009-014).Larval mortality rates were observed after 24 h and48 h of exposure.Then,a computerized probit analysis of the mortality data was performed to determine lethal concentration 50(LC_(50))and lethal concentration 90 values.Results:Anopheles minimus larvae(24-h LC_(50)77.88 mg/L)had the highest susceptibility to crude extract,whereas others(Aedes aegypti,24-h LC_(50)224.73 mg/L;Aedes albopictus,24-h LC_(50)261.75 mg/L;and Culex quinquefasciatus,24-h LC_(50)282.86 mg/L)were significantly less susceptible.The most effective groups of fractionated extracts were RC-DT 012 and RC-DT 013.The mosquito species most susceptible to fractionated extracts was Culex quinquefasciatus,with 24-h LC_(50)values of 0.66 and 0.94 mg/L for RC-DT 012 and RC-DT 013,respectively.Conclusions:The larvicidal activity of fractionated extracts is more effective than that of crude extract against all tested mosquito species.For the most effective alternative larvicide,purification and a phytochemical constituent analysis must be performed.
文摘The role of Typha spp. on water loss and public health has been uncertained and relatively poorly reported in Hadejia Nguru wetlands. This study investigated the extent to which Typha spp. contributed to evapotranspirative water loss and the level at which it provides suitable habitat for mosquito breeding. A comparative analysis between Typha swamp and open water was made to determine the evapotranspiration water loss and mosquito larva load accounted for by Typha swamp in the wetland. Maximum and minimum temperatures were measured and recorded daily for the months of January, March and June in 2013. Blaney-Criddle equation was used to estimate the evapotranspiration from Typha swamp (Site A) while piche evaporimeter was used to measure direct evaporation from the adjacent open water (Site B). Water samples were collected in Sites A and B using 100 ml beaker at random and the number of mosquito larvae in the sample was counted. T test was used to evaluate differences in water loss and larva load between open water and Typha swamp in the wetland. The findings revealed that there was no significant difference in water loss at p < 0.05 between Typha swamp and open water in the wetland. However, the Typha swamp was found to harbor more mosquito larvae than the open water at p < 0.05 which was considered a public health risk.
基金This work was supported by the Hainan Provincial Natural Science Foundation of China(Grant No.2019RC218)the National Natural Science Foundation of China(grant No.81860367,31460017)+5 种基金the Scientific Research Foundation of the Higher Education Institutions of Hainan Province,China(Grant No.Hnky2020-33)the Hainan Medical University novel coronavirus pneumonia project(Grant No.XGZX2020005)the Hainan Provincial Natural Science Foundation of China(Grant No.819QN360)State Key Laboratory of Virology 2018 Open Fund Project(2018IOV002)the National S&T Major Project"China Mega-Project for Infectious Disease"(Grant No.2018ZX10711001)the CAMS Innovation Fund for Medical Sciences(Grant No.2017-I2M-3-017).
文摘Dengue virus is an arthropod-borne pathogen that is transmitted to humans primarily by Aedes spp.mosquitos,causing the acute infectious disease,dengue fever(DF).Until 2019,no dengue outbreak had been reported in Hainan Province for over 20 years.However,in early September of 2019,an increasing number of infected cases appeared and the DF outbreak lasted for over one month in Haikou City,Hainan Province.In our study,we collected 97 plasma samples from DF patients at three hospitals,as well as 1585 mosquito larvae samples from puddles in different areas of Haikou.There were 49(50.5%)plasma samples found to be strongly positive and 9(9.3%)plasma samples were weakly positive against the NS1 antigen.We discovered DENV both in the patient's plasma samples and mosquito larvae samples,and isolated the virus from C6/36 cells inoculated with the acute phase serum of patients.Phylogenetic analysis revealed that the new strains were the most closely related to the epidemic strain in the southern regions of China,belonging to lineageⅣ,genotypeⅠ,DENV-1.Compared to the seven closest strains from neighboring countries and provinces,a total of 18 amino acid mutations occurred in the coding sequences(CDS)of the new isolated strain,DENV1 HMU-HKU-2.Our data shows that dengue virus is re-emerged in Hainan,and pose new threats for public health.Thus regular molecular epidemiological surveillance is necessary for control and prevention of DENV transmission.
