Objective: To investigate the efficacies of 12 essential oil(EO) formulations from three Zingiberaceae plants(Alpinia galanga, Curcuma zedoaria, and Zingiber cassumunar) individually and in combination with an augment...Objective: To investigate the efficacies of 12 essential oil(EO) formulations from three Zingiberaceae plants(Alpinia galanga, Curcuma zedoaria, and Zingiber cassumunar) individually and in combination with an augmenting Eucalyptus globulus(E. globulus) EO against females of Aedes albopictus(Ae. albopictus) and Anopheles minimus(An. minimus). Methods: These formulations were evaluated for their ovicidal, oviposition deterrent and adulticidal activities against Ae. albopictus and An. minimus by a topical method, a double-choice method and a WHO susceptibility test, respectively. Results: It was found that all formulations of Zingiberaceae plants EOs augmented with E. globulus EO were more effective in oviposition deterrent, ovicidal, and adulticidal activities against the two mosquito species than all of the formulations used without E. globulus EO. Their oviposition deterrent, ovicidal and adulticidal activities were equivalent to those of 10% w/v cypermethrin. In contrast, 70% v/v ethyl alcohol as a control alone was not effective at all. The highest synergistic effect in effective repellency against Ae. albopictus was achieved by 5% Alpinia galanga EO + 5% E. globulus EO and against An. minimus was 5% Zingiber cassumunar EO + 5% E. globulus EO. Moreover, the highest synergistic effects in ovicidal activities against Ae. albopictus and An. minimus were achieved by 10% Zingiber cassumunar EO + 10% E. globulus EO and 5% Curcuma zedoaria EO + 5% E. globulus EO, respectively. For the adulticidal activities, the highest synergistic effect against two mosquitoes was achieved by 5% Curcuma zedoaria EO + 5% E. globulus EO. Conclusions: These results suggest that Zingiberaceae plant EOs augmented with E. globulus EO have a high potential to be developed into oviposition deterrent, ovicidal, and adulticidal agents for controlling populations of Ae. albopictus and An. minimus.展开更多
Objective: To record the human cases of dengue fever(DF) and investigate the Aedes mosquito species circulating during the Hanoi 2011 DF epidemics. Methods: 24 different outbreak points were recorded in 8 districts be...Objective: To record the human cases of dengue fever(DF) and investigate the Aedes mosquito species circulating during the Hanoi 2011 DF epidemics. Methods: 24 different outbreak points were recorded in 8 districts between August and December 2011. Results: 140 patients were hospitalized following dengue diagnostic with a predominance of males(59.3%) and the 15-34 age class. Only DENV-1(11.27%) and DENV-2(88.73%) serotypes were detected in human samples. Mosquito sampling performed in and around patients households revealed the predominance of Aedes aegypti(95.15%) versus Aedes albopictus(4.85%). There is a positive correlation between the population density of Aedes aegypti and the number of human cases and duration of outbreaks. Conclusions: This was not observed for Aedes albopictus. 3 pools of Aedes aegypti were positive with dengue virus, two with DENV-1 and one with DENV-2.展开更多
Objective:To generate life table characteristics for the dengue vector Aedes albopictus(A. albopictus) under uncontrolled conditions,incorporating both the aquatic and the adult stages. Methods:Ten females derived fro...Objective:To generate life table characteristics for the dengue vector Aedes albopictus(A. albopictus) under uncontrolled conditions,incorporating both the aquatic and the adult stages. Methods:Ten females derived from wild pupae were allowed to fully blood-feed on restrained mice.774 eggs were hatched in seasoned water.F1 larvae were followed for development until their F2 counterparts emerged as adults.Some population parameters were monitored(Fl) or estimated(F2).Results:A.albopictus exhibited increased fecundity and egg hatch success. Immature development was quick.Immature survival was high,with lowest rate in the pupal stage.Adult emergence was about 81%and sex ratio was close to 1:1.Generational mortality(K) was about 28%.A high proportion of females completed a reproductive cycle and the obtained parity rate was predicted to lead to higher fecundity in the next generation.Conclusios:It can be concluded that natural A.albopictus populations in Penang seem largely determined by quick development in combination with low immature loss and increased oviposition.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
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 monitor the current duration of the application rates in vector programme and the level of Aedes albopictus larvae susceptibility from three selected areas in northeast district of Penang on two selected ...Objective:To monitor the current duration of the application rates in vector programme and the level of Aedes albopictus larvae susceptibility from three selected areas in northeast district of Penang on two selected larvicides,temephos and Bacillus thuringiensis subsp.israelensis(Bti) which are commonly used by Penang Health Department for vector control.Methods:The mosquito larvae were tested against two types of larvicides:(1) temephos(Abate®) with diagnostic dosage(0.012 mg/L) and operational dosage(1 mg/L) and(2)Bacillus thuringiensis subsp.israelensis(Vecto Bac®WG) with operational dosage ranging from 6 000 international toxic units per L to 24 000 international toxic unit per L.A total of 20 late third and early forth instar larvae were selected and transferred into paper cup sized 300 m L using wide-mouthed pipette.The larvae were distributed into each 300 m L paper cup containing 50 m L of aged tap water.The experiment was replicated five times for each concentration tested.Each test was repeated three times.The mortality was recorded after 24 h of exposure and recorded lethal time was based on 2 h for temephos and 6 h for Bti.The control consisted of ethanol for temephos and only seasoned water for Bti.Results:The result showed that Aedes albopictus from Flat Hamna,Kampung Sungai Gelugor and Kampung Tanjung Tokong were still susceptible to Bti and temephos.However,higher lethal time and resistance ratio were detected in strain from Flat Hamna which was a known dengue hot spot area in northeast of Penang.Conclusions:The application of temephos and Bti in vector control activity in these selected localities is still relevant in the control of Aedes larvae populations.展开更多
Objective: To obtain the complete β-actin gene from Aedes albopictus. Methods: Total RNA was extracted from C6/36 cells. Degenerate primers were designed based on the β-actin sequences of An. gambiae, Ae. aegypti,...Objective: To obtain the complete β-actin gene from Aedes albopictus. Methods: Total RNA was extracted from C6/36 cells. Degenerate primers were designed based on the β-actin sequences of An. gambiae, Ae. aegypti, Cx. pipiens pallens and D. melanogaster. By RT-PCR, the product was amplified, purified, cloned into the pGT vector and sequenced. The β-actin sequence was aligned and phylogenetically analyzed by the BLAST program and the CLUSTAL W program. Results: A sequence of 1132 bp including an open reading frame of 1131 bp was obtained (GenBank DQ657949). The deduced protein had 376 amino acids. Aligned to SWISS-PROT, it exhibited a high level of identity with β-actins from Anopheles, Drosophila and Culex at the amino acid sequence level. Phylogenetic analysis indicated that Ae. albopictus β-acfin was much more homologous with invertebrate β- actin than with vertebrate β-actin. Conclusion: The gene may be used as the internal control in the experiments of Ae. albopictus.展开更多
Objective:To evaluate the growth inhibition activity of the crude extract of Cyperus aromaticus(C.aromaticus)cultured cells against the 3rd instar larvae of Aedes aegypti(Linn.)and Aedes albopictus Skuse(Ae.albopictus...Objective:To evaluate the growth inhibition activity of the crude extract of Cyperus aromaticus(C.aromaticus)cultured cells against the 3rd instar larvae of Aedes aegypti(Linn.)and Aedes albopictus Skuse(Ae.albopictus)under laboratory conditions,and determine the sublethal effects(EI_(50))of the crude extract of C.aromaticus cultured cells on some biological and morphological parameters of both Aedes mosquito species during two generations as well.Methods:The cell suspension cultures of C.aromaticus were activated from five callus lines(P4,Pa,Z1,Z6 and Ml)derived from the root explants of in vitro plantlets.The cultured cells were extracted in chloroform and used as plant material for the present study.For detection of juvenile hormone III.the crude extracts were analyzed by HPLC.Then the crude extracts of the three C.aromaticus cultured cell lines which contained varied amounts of juvenile hormone III[high level(P4 cell line),medium level(Z1 cell line)and low level(Ml cell line)]were tested against Aedes mosquito species.Laboratory evaluation was performed against late third instar larvae of the Vector Control Research Unit strains of Ae.aegypti and Ae.albopictus using the standard WHO method.The effects of EI_(50)of the C.aromaticus cultured P4 cells on fecundity,fertility,growth period,sex ratio,adult size and longevity of Aedes mosquitoes were assessed.Results:Bioassay tests presented the remarkable growth inhibition activity of the crude extracts of C.aromaticus cultured cells against the two Aedes mosquitoes.Between the two mosquito species,Ae.albopictus was more susceptible to the crude extracts with lower EI_(50)values.EI_(50)of the crude extract of C.aromaticus cultured cells(P4)increased the sterility indices in the parental generation females in both Aedes mosquito species.A significant delay in the pupal formation and adult emergence were observed in the parental generation of the both mosquito species.The sex ratio of the adult population either parental or F1 generation of the Aedes mosquito species was not significantly affected by the EI_(50)dosage of the crude extract of C.aromaticus cultured P4 cells.A significant decrease in the wing length of the treated adult(female and male)of Aedes aegypti as well as the treated female of Ae.albopictus were observed.Longevity of the adult female of the parental generation of both Aedes mosquitoes as well as females of F1 generation of Ae.albopictus were significantly decreased.Conclusions:The present study revealed the potential of the crude extract of C.aromaticus cultured cells in controlling vector mosquito populations in the effort to reduce the transmission of vector borne diseases.展开更多
Objective: To evaluate the efficacy of symbiotic bacteria, Xenorhabdus indica, Xenorhabdus stockiae, Photorhabdus luminescens subsp. akhurstii and Photorhabdus luminescens subsp. hainanensis as a larvicide against Aed...Objective: To evaluate the efficacy of symbiotic bacteria, Xenorhabdus indica, Xenorhabdus stockiae, Photorhabdus luminescens subsp. akhurstii and Photorhabdus luminescens subsp. hainanensis as a larvicide against Aedes aegypti and Aedes albopictus. Methods: Larvae(L3-L4) of Aedes aegypti and Aedes albopictus were given 2 m L of a suspension 107-108 CFU/m L of each symbiotic bacterium. Distilled water and Escherichia coli ATCC襅25922 were used as the control. The mortality rate of the larval mosquitoes was observed at 24, 48, 72 and 96 h. The experiment was performed in triplicates. Results: The larvae of both Aedes species started to die at 24 h exposure. Aedes aegypti showed the highest mortality rate(87%-99%), 96 h after exposure to Xenorhabdus stockiae(b NBP22.2_TH). The mortality rate of Aedes albopictus was between 82% and 96% at 96 h after exposure to Xenorhabdus indica(b KK26.2_TH). Low effectiveness of distilled water and Escherichia coli ATCC襅25922 were observed in both Aedes larvae, with a mortality rate of 2% to 12%. Conclusions: The study confirms the oral toxicity of Xenorhabdus and Photorhabdus bacteria against Aedes spp. Xenorhabdus stockiae and Xenorhabdus indica may be an alternative agent for control Aedes spp. This is basic information for further study on the mechanism of action on Aedes larvae or application to control mosquito larvae in the community.展开更多
Objective:To develop an artificial and modified Wolbaehia removal technique using tetracycline from naturally Wolbachia infected Aedes albopictus(Ae.albopictus)so as to be able to produce generations of Wolbaehia free...Objective:To develop an artificial and modified Wolbaehia removal technique using tetracycline from naturally Wolbachia infected Aedes albopictus(Ae.albopictus)so as to be able to produce generations of Wolbaehia free offsprings.Methods:In this study,seven different tetracycline treatment methods were conducted to obtain the best removal method.Four methods focused on larvae tetracycline treatment,one method on both larvae and adult tetracycline treatment and the last two methods on adult mosquito sucrose treatment.Results:All larval tetracycline treatments resulted in either high larvae mortality,sterile F_o adult mosquitoes or unsuccessful Wolbaehia removal.Treatment of both larvae and adults resulted in reduced larvae mortality,successful Wolbachia removal but slow mosquito fecundity.As for the adult treatment,1.0 mg/mL as previously published was not aisle to completely remove Wolbaehia in F,generation whereas 1.25 mg/mL successfully removed Wolbachia from F,and F,mosquitoes in 2 weeks.Conclusions:This method is different from the previously published methods as it provides an improved Watbachia removal technique from Ae.albopictus with high egg hatchability.low larvae mortality,increased fecundity and better Wolbaehia removal rate.展开更多
Objective:To determine the suitable ecological habitats of Aedes(Ae.)aegypti and Ae.albopictus in Iran due to climate change by the 2070s.Methods:All data relating to the spatial distribution of Ae.aegypti and Ae.albo...Objective:To determine the suitable ecological habitats of Aedes(Ae.)aegypti and Ae.albopictus in Iran due to climate change by the 2070s.Methods:All data relating to the spatial distribution of Ae.aegypti and Ae.albopictus worldwide,which indicated the geographical coordinates of the collection sites of these mosquitoes,were extracted from online scientific websites and entered into an Excel file.The effect of climatic and environmental variables on these mosquitoes was evaluated using the MaxEnt model in the current and future climatic conditions in the 2030s,2050s,and 2070s.Results:The most suitable areas for the establishment of Ae.aegypti are located in the southern and northern coastal areas of Iran,based on the model outputs.The modelling result for suitable ecological niches of Ae.albopictus shows that in the current climatic conditions,the southern half of Iran from east to west,and parts of the northern coasts are prone to the presence of this species.In the future,some regions,such as Gilan and Golestan provinces,will have more potential to exist/establish Ae.albopictus.Also,according to the different climate change scenarios,suitable habitats for this species will gradually change to the northwest and west of the country.The temperature of the wettest season of the year(Bio8)and average annual temperature(Bio1)were the most effective factors in predicting the model for Ae.aegypti and Ae.albopictus,respectively.Conclusions:It is required to focus on entomological studies using different collection methods in the vulnerable areas of Iran.The future modelling results can also be used for long-term planning to prevent the entry and establishment of these invasive Aedes vectors in the country.展开更多
The frequent cases of dengue incidences are leading cause of illness and death in urban areas and Aedes albopictus (Skuse) is a primary vector for Dengue transmission in India. Synthesis of leaf mediated silver nanopa...The frequent cases of dengue incidences are leading cause of illness and death in urban areas and Aedes albopictus (Skuse) is a primary vector for Dengue transmission in India. Synthesis of leaf mediated silver nanoparticles especially with Pongamia pinnata is a potential substitute for the existing organophosphorus insecticides like Tenophos, malathion and fenthion etc., for mosquito control programme. The nanoparticles were characterized by UV-visible absorption spectrum, X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and Transmission Electron Microscopy (TEM). Analysis of TEM showed that the synthesized silver nanoparticles are in spherical shape with average size of 20 nm. Further the XRD analysis confirms the nano-crystalline phase of silver with face centred cubic (FCC) crystal structure. GC-MS analysis elucidated the presence of two active ingredients, such as 9-Octadecenoic acid (Z) and n-hexadecanoic acid, which are the prominent substances considered as larvicide. Larvae were exposed to varying concentrations of plant extracts and synthesized silver nanoparticles for 24 hours. From the results, it is found that plant extracts showed moderate larvicidal effects but, the synthesized silver nanoparticles had found to be toxic to larvae at LC50 (0.25 ppm) and LC90 (1 ppm).展开更多
Objective:To observe the effect of common salt(NaCl) on immature stages of laboratory reared Aedes aegypti(L).Methods:A laboratory colony of Aedes aegypti mosquitoes of Rajahmundry strain was established in the labora...Objective:To observe the effect of common salt(NaCl) on immature stages of laboratory reared Aedes aegypti(L).Methods:A laboratory colony of Aedes aegypti mosquitoes of Rajahmundry strain was established in the laboratory of National Institute for Communicable Disease(NICD), Rajahmundry unit at(26±2)℃with relative humidity of(70±10)%.1.00%,1.25%and 1.50% solutions of common salt(NaCl) were selected to observe the susceptibility status of immature stages of Aedes aegypti in laboratory.Results:Fifty percent larvae of Aedes aegypti died within 19,31 and 48 hours when exposed to 1.50%,1.25%and 1.00%common salt solution, respectively.Ninety percent of the larvae died within 29,57 and 108 hours when exposed to the same salt solutions,respectively.Very high pupal mortality was observed varying from 81.8% to 40.0%.Formation of pupae was found inversely proportional in the presence of concentration of common salt in breeding water.Conclusions:With easy availability,less toxicity and long lasting nature,common salt may be applied in unused containers,especially in junkyards where surveillance mechanism is poor along with other conventional vector control methods in order to control breeding of Aedes aegypti,the vector of dengue/ dengue hemorrhagic fever and chikungunya.展开更多
Mosquitoes belonging to the genus Aedes pose a significant threat to human health on a global scenario due to their role in transmission of dengue,chikungunya,zika,and yellow fever.In absence of specific medications a...Mosquitoes belonging to the genus Aedes pose a significant threat to human health on a global scenario due to their role in transmission of dengue,chikungunya,zika,and yellow fever.In absence of specific medications and vaccines against these diseases,disease prevention relies on vector control.However,in today’s world,vector control is facing major challenges due to the onset of insecticide resistance in mosquitoes.There are four main mechanisms of insecticide resistance,namely,behavioral resistance,reduced penetration/cuticular resistance,metabolic detoxification,and target site resistance;however,the latter two mechanisms have been studied widely in Aedes mosquitoes.Insecticide resistance in Aedes mosquitoes is widespread throughout the world.This review compiles the degree of insecticide resistance/susceptibility prevailing among different field populations of Aedes mosquitoes worldwide.In addition,the review has detailed the mechanisms providing the resistance phenomenon observed in nature in Aedes mosquitoes.展开更多
Objective: To evaluate the potential of local mosquitoes to act as vectors for dengue transmission in Japan.Methods: Serotype 2 Th NH28/93 was used to test the dengue susceptibility profiles of Aedes flavopictus miyar...Objective: To evaluate the potential of local mosquitoes to act as vectors for dengue transmission in Japan.Methods: Serotype 2 Th NH28/93 was used to test the dengue susceptibility profiles of Aedes flavopictus miyarai(Ae. f. miyarai), Aedes galloisi(Ae. galloisi) and Aedes albopictus(Ae.albopictus), which were collected in Japan. We used Aedes aegypti from Thailand as a positive control. The mosquitoes were infected with the virus intrathoracically or orally. At 10 or 14 days post infection, the mosquitoes were dissected and total RNA was extracted from their abdomens, thoraxes, heads and legs. Mosquito susceptibility to dengue virus was evaluated using RT-PCR with dengue virus-specific primers. Differences in the infection and mortality rates of the different mosquito species were tested using Fisher's exact probability test.Results: The infection rates for dengue virus administered intrathoracically to Ae. f. miyarai,Ae. galloisi and Aedes aegypti mosquitoes were identical by RT-PCR on Day 10 post infection.All of the body parts we tested were RT-PCR-positive for dengue virus. For the orally administered virus, the infection rates in the different body parts of the Ae. f. miyarai mosquitoes were slightly higher than those of Ae. albopictus mosquitoes, but were similar to the control mosquitoes(P > 0.05). The mortality rates for Ae. f. miyarai and Ae. albopictus mosquitoes were similar(P = 0.19). Our data indicated that dengue virus was able to replicate and disseminate to secondary infection sites in all of the four mosquito species(Japanese and Thai).Conclusions: Ae. albopictus is a well-known candidate for dengue transmission in Japan. However, our data suggest that Ae. f. miyarai from Ishigaki Island(near Okinawa Island) and Ae. galloisi from Hokkaido(Northern Japan) should also be regarded as potential vectors for dengue transmission in these regions. Further studies on these mosquitoes should be conducted.展开更多
基金supported by Faculty of Agricultural Technology,KMITL,Bangkok,Thailand(Grant no 01-04-002)the National Research Council of Thailand(GRAD 6007KMITL)
文摘Objective: To investigate the efficacies of 12 essential oil(EO) formulations from three Zingiberaceae plants(Alpinia galanga, Curcuma zedoaria, and Zingiber cassumunar) individually and in combination with an augmenting Eucalyptus globulus(E. globulus) EO against females of Aedes albopictus(Ae. albopictus) and Anopheles minimus(An. minimus). Methods: These formulations were evaluated for their ovicidal, oviposition deterrent and adulticidal activities against Ae. albopictus and An. minimus by a topical method, a double-choice method and a WHO susceptibility test, respectively. Results: It was found that all formulations of Zingiberaceae plants EOs augmented with E. globulus EO were more effective in oviposition deterrent, ovicidal, and adulticidal activities against the two mosquito species than all of the formulations used without E. globulus EO. Their oviposition deterrent, ovicidal and adulticidal activities were equivalent to those of 10% w/v cypermethrin. In contrast, 70% v/v ethyl alcohol as a control alone was not effective at all. The highest synergistic effect in effective repellency against Ae. albopictus was achieved by 5% Alpinia galanga EO + 5% E. globulus EO and against An. minimus was 5% Zingiber cassumunar EO + 5% E. globulus EO. Moreover, the highest synergistic effects in ovicidal activities against Ae. albopictus and An. minimus were achieved by 10% Zingiber cassumunar EO + 10% E. globulus EO and 5% Curcuma zedoaria EO + 5% E. globulus EO, respectively. For the adulticidal activities, the highest synergistic effect against two mosquitoes was achieved by 5% Curcuma zedoaria EO + 5% E. globulus EO. Conclusions: These results suggest that Zingiberaceae plant EOs augmented with E. globulus EO have a high potential to be developed into oviposition deterrent, ovicidal, and adulticidal agents for controlling populations of Ae. albopictus and An. minimus.
基金supported in part by the Erasmus Mundus project MAHEVAthe CNRS-UM1-UM2 PEPS project MoD yCAsupported by the Entomology department, National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
文摘Objective: To record the human cases of dengue fever(DF) and investigate the Aedes mosquito species circulating during the Hanoi 2011 DF epidemics. Methods: 24 different outbreak points were recorded in 8 districts between August and December 2011. Results: 140 patients were hospitalized following dengue diagnostic with a predominance of males(59.3%) and the 15-34 age class. Only DENV-1(11.27%) and DENV-2(88.73%) serotypes were detected in human samples. Mosquito sampling performed in and around patients households revealed the predominance of Aedes aegypti(95.15%) versus Aedes albopictus(4.85%). There is a positive correlation between the population density of Aedes aegypti and the number of human cases and duration of outbreaks. Conclusions: This was not observed for Aedes albopictus. 3 pools of Aedes aegypti were positive with dengue virus, two with DENV-1 and one with DENV-2.
基金Supported by grants from Universiti Sains Malaysi(No:#07-05-16-MG1-GM15,#1001/PBIOLOGI/842004)
文摘Objective:To generate life table characteristics for the dengue vector Aedes albopictus(A. albopictus) under uncontrolled conditions,incorporating both the aquatic and the adult stages. Methods:Ten females derived from wild pupae were allowed to fully blood-feed on restrained mice.774 eggs were hatched in seasoned water.F1 larvae were followed for development until their F2 counterparts emerged as adults.Some population parameters were monitored(Fl) or estimated(F2).Results:A.albopictus exhibited increased fecundity and egg hatch success. Immature development was quick.Immature survival was high,with lowest rate in the pupal stage.Adult emergence was about 81%and sex ratio was close to 1:1.Generational mortality(K) was about 28%.A high proportion of females completed a reproductive cycle and the obtained parity rate was predicted to lead to higher fecundity in the next generation.Conclusios:It can be concluded that natural A.albopictus populations in Penang seem largely determined by quick development in combination with low immature loss and increased oviposition.
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Funded by FGRS Grant by Ministry of Education and Universiti Sains Malaysia(203/PBIOLOGI/6711359)
文摘Objective:To monitor the current duration of the application rates in vector programme and the level of Aedes albopictus larvae susceptibility from three selected areas in northeast district of Penang on two selected larvicides,temephos and Bacillus thuringiensis subsp.israelensis(Bti) which are commonly used by Penang Health Department for vector control.Methods:The mosquito larvae were tested against two types of larvicides:(1) temephos(Abate®) with diagnostic dosage(0.012 mg/L) and operational dosage(1 mg/L) and(2)Bacillus thuringiensis subsp.israelensis(Vecto Bac®WG) with operational dosage ranging from 6 000 international toxic units per L to 24 000 international toxic unit per L.A total of 20 late third and early forth instar larvae were selected and transferred into paper cup sized 300 m L using wide-mouthed pipette.The larvae were distributed into each 300 m L paper cup containing 50 m L of aged tap water.The experiment was replicated five times for each concentration tested.Each test was repeated three times.The mortality was recorded after 24 h of exposure and recorded lethal time was based on 2 h for temephos and 6 h for Bti.The control consisted of ethanol for temephos and only seasoned water for Bti.Results:The result showed that Aedes albopictus from Flat Hamna,Kampung Sungai Gelugor and Kampung Tanjung Tokong were still susceptible to Bti and temephos.However,higher lethal time and resistance ratio were detected in strain from Flat Hamna which was a known dengue hot spot area in northeast of Penang.Conclusions:The application of temephos and Bti in vector control activity in these selected localities is still relevant in the control of Aedes larvae populations.
基金This work was supported by the National Natural Science Foundationof China(No.30628022 and No.30671827)
文摘Objective: To obtain the complete β-actin gene from Aedes albopictus. Methods: Total RNA was extracted from C6/36 cells. Degenerate primers were designed based on the β-actin sequences of An. gambiae, Ae. aegypti, Cx. pipiens pallens and D. melanogaster. By RT-PCR, the product was amplified, purified, cloned into the pGT vector and sequenced. The β-actin sequence was aligned and phylogenetically analyzed by the BLAST program and the CLUSTAL W program. Results: A sequence of 1132 bp including an open reading frame of 1131 bp was obtained (GenBank DQ657949). The deduced protein had 376 amino acids. Aligned to SWISS-PROT, it exhibited a high level of identity with β-actins from Anopheles, Drosophila and Culex at the amino acid sequence level. Phylogenetic analysis indicated that Ae. albopictus β-acfin was much more homologous with invertebrate β- actin than with vertebrate β-actin. Conclusion: The gene may be used as the internal control in the experiments of Ae. albopictus.
基金supported by University Sains Malaysia(USM)with the grant No 304.PBIOLOGI.650272.C112
文摘Objective:To evaluate the growth inhibition activity of the crude extract of Cyperus aromaticus(C.aromaticus)cultured cells against the 3rd instar larvae of Aedes aegypti(Linn.)and Aedes albopictus Skuse(Ae.albopictus)under laboratory conditions,and determine the sublethal effects(EI_(50))of the crude extract of C.aromaticus cultured cells on some biological and morphological parameters of both Aedes mosquito species during two generations as well.Methods:The cell suspension cultures of C.aromaticus were activated from five callus lines(P4,Pa,Z1,Z6 and Ml)derived from the root explants of in vitro plantlets.The cultured cells were extracted in chloroform and used as plant material for the present study.For detection of juvenile hormone III.the crude extracts were analyzed by HPLC.Then the crude extracts of the three C.aromaticus cultured cell lines which contained varied amounts of juvenile hormone III[high level(P4 cell line),medium level(Z1 cell line)and low level(Ml cell line)]were tested against Aedes mosquito species.Laboratory evaluation was performed against late third instar larvae of the Vector Control Research Unit strains of Ae.aegypti and Ae.albopictus using the standard WHO method.The effects of EI_(50)of the C.aromaticus cultured P4 cells on fecundity,fertility,growth period,sex ratio,adult size and longevity of Aedes mosquitoes were assessed.Results:Bioassay tests presented the remarkable growth inhibition activity of the crude extracts of C.aromaticus cultured cells against the two Aedes mosquitoes.Between the two mosquito species,Ae.albopictus was more susceptible to the crude extracts with lower EI_(50)values.EI_(50)of the crude extract of C.aromaticus cultured cells(P4)increased the sterility indices in the parental generation females in both Aedes mosquito species.A significant delay in the pupal formation and adult emergence were observed in the parental generation of the both mosquito species.The sex ratio of the adult population either parental or F1 generation of the Aedes mosquito species was not significantly affected by the EI_(50)dosage of the crude extract of C.aromaticus cultured P4 cells.A significant decrease in the wing length of the treated adult(female and male)of Aedes aegypti as well as the treated female of Ae.albopictus were observed.Longevity of the adult female of the parental generation of both Aedes mosquitoes as well as females of F1 generation of Ae.albopictus were significantly decreased.Conclusions:The present study revealed the potential of the crude extract of C.aromaticus cultured cells in controlling vector mosquito populations in the effort to reduce the transmission of vector borne diseases.
基金supported by Higher Education Research Promotion,The Commission on Higher Education,Thailand(Grant No.R2558A008)Naresuan University(Grant No.R2557B013)
文摘Objective: To evaluate the efficacy of symbiotic bacteria, Xenorhabdus indica, Xenorhabdus stockiae, Photorhabdus luminescens subsp. akhurstii and Photorhabdus luminescens subsp. hainanensis as a larvicide against Aedes aegypti and Aedes albopictus. Methods: Larvae(L3-L4) of Aedes aegypti and Aedes albopictus were given 2 m L of a suspension 107-108 CFU/m L of each symbiotic bacterium. Distilled water and Escherichia coli ATCC襅25922 were used as the control. The mortality rate of the larval mosquitoes was observed at 24, 48, 72 and 96 h. The experiment was performed in triplicates. Results: The larvae of both Aedes species started to die at 24 h exposure. Aedes aegypti showed the highest mortality rate(87%-99%), 96 h after exposure to Xenorhabdus stockiae(b NBP22.2_TH). The mortality rate of Aedes albopictus was between 82% and 96% at 96 h after exposure to Xenorhabdus indica(b KK26.2_TH). Low effectiveness of distilled water and Escherichia coli ATCC襅25922 were observed in both Aedes larvae, with a mortality rate of 2% to 12%. Conclusions: The study confirms the oral toxicity of Xenorhabdus and Photorhabdus bacteria against Aedes spp. Xenorhabdus stockiae and Xenorhabdus indica may be an alternative agent for control Aedes spp. This is basic information for further study on the mechanism of action on Aedes larvae or application to control mosquito larvae in the community.
基金Supported by University Malaya liesearch Grant of (MRG) with grant NO:RG372/11HTM
文摘Objective:To develop an artificial and modified Wolbaehia removal technique using tetracycline from naturally Wolbachia infected Aedes albopictus(Ae.albopictus)so as to be able to produce generations of Wolbaehia free offsprings.Methods:In this study,seven different tetracycline treatment methods were conducted to obtain the best removal method.Four methods focused on larvae tetracycline treatment,one method on both larvae and adult tetracycline treatment and the last two methods on adult mosquito sucrose treatment.Results:All larval tetracycline treatments resulted in either high larvae mortality,sterile F_o adult mosquitoes or unsuccessful Wolbaehia removal.Treatment of both larvae and adults resulted in reduced larvae mortality,successful Wolbachia removal but slow mosquito fecundity.As for the adult treatment,1.0 mg/mL as previously published was not aisle to completely remove Wolbaehia in F,generation whereas 1.25 mg/mL successfully removed Wolbachia from F,and F,mosquitoes in 2 weeks.Conclusions:This method is different from the previously published methods as it provides an improved Watbachia removal technique from Ae.albopictus with high egg hatchability.low larvae mortality,increased fecundity and better Wolbaehia removal rate.
基金Research Deputy,Tehran University of Medical Sciences,grant No.46857。
文摘Objective:To determine the suitable ecological habitats of Aedes(Ae.)aegypti and Ae.albopictus in Iran due to climate change by the 2070s.Methods:All data relating to the spatial distribution of Ae.aegypti and Ae.albopictus worldwide,which indicated the geographical coordinates of the collection sites of these mosquitoes,were extracted from online scientific websites and entered into an Excel file.The effect of climatic and environmental variables on these mosquitoes was evaluated using the MaxEnt model in the current and future climatic conditions in the 2030s,2050s,and 2070s.Results:The most suitable areas for the establishment of Ae.aegypti are located in the southern and northern coastal areas of Iran,based on the model outputs.The modelling result for suitable ecological niches of Ae.albopictus shows that in the current climatic conditions,the southern half of Iran from east to west,and parts of the northern coasts are prone to the presence of this species.In the future,some regions,such as Gilan and Golestan provinces,will have more potential to exist/establish Ae.albopictus.Also,according to the different climate change scenarios,suitable habitats for this species will gradually change to the northwest and west of the country.The temperature of the wettest season of the year(Bio8)and average annual temperature(Bio1)were the most effective factors in predicting the model for Ae.aegypti and Ae.albopictus,respectively.Conclusions:It is required to focus on entomological studies using different collection methods in the vulnerable areas of Iran.The future modelling results can also be used for long-term planning to prevent the entry and establishment of these invasive Aedes vectors in the country.
文摘The frequent cases of dengue incidences are leading cause of illness and death in urban areas and Aedes albopictus (Skuse) is a primary vector for Dengue transmission in India. Synthesis of leaf mediated silver nanoparticles especially with Pongamia pinnata is a potential substitute for the existing organophosphorus insecticides like Tenophos, malathion and fenthion etc., for mosquito control programme. The nanoparticles were characterized by UV-visible absorption spectrum, X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and Transmission Electron Microscopy (TEM). Analysis of TEM showed that the synthesized silver nanoparticles are in spherical shape with average size of 20 nm. Further the XRD analysis confirms the nano-crystalline phase of silver with face centred cubic (FCC) crystal structure. GC-MS analysis elucidated the presence of two active ingredients, such as 9-Octadecenoic acid (Z) and n-hexadecanoic acid, which are the prominent substances considered as larvicide. Larvae were exposed to varying concentrations of plant extracts and synthesized silver nanoparticles for 24 hours. From the results, it is found that plant extracts showed moderate larvicidal effects but, the synthesized silver nanoparticles had found to be toxic to larvae at LC50 (0.25 ppm) and LC90 (1 ppm).
文摘Objective:To observe the effect of common salt(NaCl) on immature stages of laboratory reared Aedes aegypti(L).Methods:A laboratory colony of Aedes aegypti mosquitoes of Rajahmundry strain was established in the laboratory of National Institute for Communicable Disease(NICD), Rajahmundry unit at(26±2)℃with relative humidity of(70±10)%.1.00%,1.25%and 1.50% solutions of common salt(NaCl) were selected to observe the susceptibility status of immature stages of Aedes aegypti in laboratory.Results:Fifty percent larvae of Aedes aegypti died within 19,31 and 48 hours when exposed to 1.50%,1.25%and 1.00%common salt solution, respectively.Ninety percent of the larvae died within 29,57 and 108 hours when exposed to the same salt solutions,respectively.Very high pupal mortality was observed varying from 81.8% to 40.0%.Formation of pupae was found inversely proportional in the presence of concentration of common salt in breeding water.Conclusions:With easy availability,less toxicity and long lasting nature,common salt may be applied in unused containers,especially in junkyards where surveillance mechanism is poor along with other conventional vector control methods in order to control breeding of Aedes aegypti,the vector of dengue/ dengue hemorrhagic fever and chikungunya.
基金University Grants Commission,New Delhi,India for providing financial assistance throughout this work through Junior Research Fellowship[award letter Sr.No.2121430414,Ref No.21/12/2014(ii)EU-V,Dated 03/06/2015]
文摘Mosquitoes belonging to the genus Aedes pose a significant threat to human health on a global scenario due to their role in transmission of dengue,chikungunya,zika,and yellow fever.In absence of specific medications and vaccines against these diseases,disease prevention relies on vector control.However,in today’s world,vector control is facing major challenges due to the onset of insecticide resistance in mosquitoes.There are four main mechanisms of insecticide resistance,namely,behavioral resistance,reduced penetration/cuticular resistance,metabolic detoxification,and target site resistance;however,the latter two mechanisms have been studied widely in Aedes mosquitoes.Insecticide resistance in Aedes mosquitoes is widespread throughout the world.This review compiles the degree of insecticide resistance/susceptibility prevailing among different field populations of Aedes mosquitoes worldwide.In addition,the review has detailed the mechanisms providing the resistance phenomenon observed in nature in Aedes mosquitoes.
基金Supported by the Matsumae International Foundation in Japan for Raweewan Srisawat,Faculty of Tropical Medicine grant,Grants-in-Aid(Kiban-B,#25300053)from Japan Society for the Promotion of Science(JSPS)Research Program on Emerging and Re-emerging Infectious Diseases(H26-shinkou-jitsuyouka-007)from the Japan Agency for Medical Research and Development(AMED)
文摘Objective: To evaluate the potential of local mosquitoes to act as vectors for dengue transmission in Japan.Methods: Serotype 2 Th NH28/93 was used to test the dengue susceptibility profiles of Aedes flavopictus miyarai(Ae. f. miyarai), Aedes galloisi(Ae. galloisi) and Aedes albopictus(Ae.albopictus), which were collected in Japan. We used Aedes aegypti from Thailand as a positive control. The mosquitoes were infected with the virus intrathoracically or orally. At 10 or 14 days post infection, the mosquitoes were dissected and total RNA was extracted from their abdomens, thoraxes, heads and legs. Mosquito susceptibility to dengue virus was evaluated using RT-PCR with dengue virus-specific primers. Differences in the infection and mortality rates of the different mosquito species were tested using Fisher's exact probability test.Results: The infection rates for dengue virus administered intrathoracically to Ae. f. miyarai,Ae. galloisi and Aedes aegypti mosquitoes were identical by RT-PCR on Day 10 post infection.All of the body parts we tested were RT-PCR-positive for dengue virus. For the orally administered virus, the infection rates in the different body parts of the Ae. f. miyarai mosquitoes were slightly higher than those of Ae. albopictus mosquitoes, but were similar to the control mosquitoes(P > 0.05). The mortality rates for Ae. f. miyarai and Ae. albopictus mosquitoes were similar(P = 0.19). Our data indicated that dengue virus was able to replicate and disseminate to secondary infection sites in all of the four mosquito species(Japanese and Thai).Conclusions: Ae. albopictus is a well-known candidate for dengue transmission in Japan. However, our data suggest that Ae. f. miyarai from Ishigaki Island(near Okinawa Island) and Ae. galloisi from Hokkaido(Northern Japan) should also be regarded as potential vectors for dengue transmission in these regions. Further studies on these mosquitoes should be conducted.