Geographical Distribution of Arboviruses, Aedes aegypti and Aedes albopictus Vectors and Their Resistance to Insecticides in Africa: A Systematic Review

Background & Objectives: Epidemics of arboviruses such as Dengue, Chikungunya and Zika have been recorded in recent years indicating that Aedes aegypti and Aedes albopictus are both important and very active vectors in Africa. For vector control, insecticides are on the front line, unfortunately, reported resistance jeopardizes the effectiveness of this strategy. The objective of this review was to determine the geographical distribution and insecticide resistance mechanisms of Ae. aegypti and Ae. Albopictus in Africa. Methods: A systematic review of the literature in scientific databases (PubMed, Google Scholar, ScienceDirect, Hinari) allowed us to identify relevant articles on the geographical distribution of Aedes aegypti, Aedes albopictus and arboviral diseases. On the other hand, studies related to insecticides used in vector control against Aedes, associated resistances and their molecular and metabolic mechanisms. Results: A total of 94 studies met the inclusion criteria for this search. Aedes aegypti is reported in most of Africa, and Aedes albopictus in part. There is a re-emergence and outbreak of Arbovirus epidemics in West and Central Africa. The insecticides used were organochlorines, carbamates, organophosphates and pyrethroids. In Aedes, target site insensitivity and metabolic resistance would be the 2 main mechanisms of resistance to these insecticides. Interpretation & Conclusion: Resistance has been recorded in all four major classes of insecticides recommended by WHO for vector control and eradication. New vector control methods such as the use of plant extracts with larvicidal and adulticidal activities, advanced modern biotechnology techniques, and nanobiotechnology need to be developed.

Larvicidal and repellent activities of Sida acuta Burm.F.(Family:Malvaceae) against three important vector mosquitoes

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 LC50 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/cm2 under the laboratory conditions.Results:Results showed varying degree of larvicidal activity of crude extract of Sida acuta against three important mosquitoes with LC50 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.

Phlebotomus papatasi and Meriones libycus as the vector and reservoir host of cutaneous leishmaniasis in Qomrood District,Qom Province,central Iran

Objective:To determine the sand flies species responsible for most transmission of Leishmania major(L major) to human,as well as to determine the main reservoir hosts of the disease. Methods:Sand flies were collected using sticky papers and mounted in Puri’s medium for species identification.Rodents were trapped by live Sherman traps.Both sand flies and rodents were subjected to molecular methods for detection of leishmanial parasite.Results:Phlebotomus papatasi(P.papatasi) was the common species in outdoor and indoor resting places.Employing PCR technique only three specimens of 150 P.papatasi(2%) were found naturally infected by parasites with a band of 350 bp which is equal to the L major parasite.Forty six rodents were captured by Sherman traps and identified.Microscopic investigation on blood smear of the animals for amastigote parasites revealed 1(3.22%) infected Meriones libycus(M.libycus). Infection of this animal to L.major was confirmed by PCR against rDNA loci of the parasite. Conclusions:This is the first molecular report of parasite infection of both vector(P.papatasi) and reservoir(M.libycus) to L major in the region.The results indicated that P.papatasi was the primary vector of the disease and circulating the parasite between human and reservoirs and M. libycus was the most important host reservoir for maintenance of the parasite source in the area.

Real-time traffic information extraction based on compressed video with interframe motion vector

Extraction of traffic information from image or video sequence is a hot research topic in intelligenttransportation system and computer vision. A real-time traffic information extraction method based on com-pressed video with interframe motion vectors for speed, density and flow detection, has been proposed for ex-traction of traffic information under fixed camera setting and well-defined environment. The motion vectors arefirst separated from the compressed video streams, and then filtered to eliminate incorrect and noisy vectors u-sing the well-defined environmental knowledge. By applying the projective transform and using the filtered mo-tion vectors, speed can be calculated from motion vector statistics, density can be estimated using the motionvector occupancy, and flow can be detected using the combination of speed and density. The embodiment of aprototype system for sky camera traffic monitoring using the MPEG video has been implemented, and experi-mental results proved the effectiveness of the method proposed.

Astrodaucus persicus as a new source of bioinsectisides against malaria vector, Anopheles stephensi

Objective: To determine the larvicidal activities of petroleum ether, chloroform, ethyl acetate and methanol fractions of roots and fruits extracts of Astrodaucus persicus from Apiaceae family against malaria vector, Anopheles stephensi(An. stephensi).Methods: Twenty five third instar larvae of An. stephensi were exposed to various concentrations(10–160 g/L) of fractions and were assayed according to World Health Organization protocol. The larval mortality was calculated after 24 h treatment.Results: Among tested fractions, the highest larvicidal efficacy was observed from ethyl acetate fraction of fruits extract with 50% and 90% mortality values(LC_(50) and LC_(90)) of34.49 g/L and 108.61 g/L, respectively. Chloroform fraction of fruits extract was the second larvicidal sample with LC_(50) of 45.11 g/L and LC_(90) of 139.36 g/L. Petroleum ether fractions of fruits and roots and methanol fraction of fruits showed moderate toxicity against An. stephensi.Conclusions: Astrodaucus persicus is a potential source of valuable and natural larvicidal compounds against malaria vector, An. stephensi and can be used in mosquitoes control programs as an alternative to synthetic insecticides.

Application of Auto-regressive Linear Model in Understanding the Effect of Climate on Malaria Vectors Dynamics in the Three Gorges Reservoir

It is important to understand the dynamics of malaria vectors in implementing malaria control strategies. Six villages were selected from different sections in the Three Gorges Reservoir fc,r exploring the relationship between the climatic ｜：actors and its malaria vector density from 1997 to 2007 using the auto-regressive linear model regressi^n method. The result indicated that both temperature and precipitation were better modeled as quadratic rather than linearly related to the density of Anopheles sinensis.

In vitro effect of p2l^(WAF-1/CIP1) gene on growth of human glioma cells mediated by EGFR targeted non-viral vector GE7 system

Objective: To construct the EGFR targeted non-viral vector GE7 system and explore the in vitro effect of p21WAF-1/CIPI gene on growth of human glioma cells mediated by the GE7 system. Methods: The EGFR targeted non-viral vector GE7 gene delivery system was constructed. The malignant human glioma cell line U251MG was transfected in vitro with β-galactosidase gene ( reporter gene) and p21WAF-1/CIPI gee (therapeutic gene) using the GE7 system. By means of X-gal staining, MTS and FACS, the transfection efficiency of exogenous gene and apoptosis rate of tumor cells were examined. The expression of p21WAF-1/ CIPI gene in transfected U251MG cell was examined by immunohistochemis-try staining. Results: The highest transfer rate of exogenous gene was 70% . After transfection with p21WAF-1/CIPI gene, the expression of WAF-1 increased remarkably and steadily; the growth of U251MG cells were inhibited evidently. FACS examination showed G1 arrest. The average apoptosis rate was 25.2%. Conclusion: GE7 system has the ability to transfer exogenous gene to targeted cells efficiently, and expression of p21WAF-1/CIPI gene can induce apoptosis of glioma cell and inhibit its growth.

Mosquito larvicidal and ovicidal properties of Eclipta alba(L.) Hassk(Asteraceae) against chikungunya vector,Aedes aegypti(Linn.)(Diptera:Culicidae)

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 LC50 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 LC50 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.

Isolation and efficacy of entomopathogenic fungus(Metarhizium anisopliae)for the control of Aedes albopictus Skuse larvae:suspected dengue vector in Pakistan

Objective:To isolate the entomopathogenic fungus Metarhixium anisopliae(M.anisopliae) in the local environment,and evaluate its efficacy against the suspected dengue vector Aedes albopictus in Pakistan.Methods:According to the standard procedure,M.anisopliae was isolated from the dead mosquitoes which were collected from the field or dead after the collection.Bioassay was performed to determine its efficacy.Results:The results indicated that M.anisopliae had larvicidal effect with LC,value 1.09×10~5 and LC_(50) value 1.90×10^(13) while it took 45.41 h to kill 50% of tested population.Conclusions:Taking long time to kill 50%population when compare with the synthetic insecticides,is the only drawback for the use of entomopathogenic fungus but these bio-pesticides are safe for the use.

Mosquito adulticidal and repellent activities of botanical extracts against malarial vector,Anopheles stephensi Liston(Diptera:Culicidae)

ObjectiveTo determine the adulticidal and repellent activities of different solvent leaf extracts of Eclipta alba (E. alba) and Andrographis paniculata (A. paniculata) against malarial vector, Anopheles stephensi (An. stephensi).MethodsAdulticidal efficacy of the crude leaf extracts of E. alba and A. paniculata with five different solvents like benzene, hexane, ethyl acetate, methanol and chloroform was tested against the five to six day old adult female mosquitoes of An. stephensi. The adult mortality was observed after 24 h under the laboratory conditions. The repellent efficacy was determined against An. stephensi mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm2 under laboratory conditions.ResultsAmong the tested solvents the maximum efficacy was observed in the methanol extract. The LC50 and LC90 values of E. alba and A. paniculata against adults of An. stephensi were 150.36, 130.19 ppm and 285.22, 244.16 ppm, respectively. No mortality was observed in controls. The chi-square values were significant at P<0.05 level. Methanol extract of E. alba and A. paniculata was produce maximum repellency against An. stephensi.ConclusionsFrom the results it can be concluded the crude extract of E. alba and A. paniculata was an excellent potential for controlling An. stephensi mosquitoes.

Spatio-temporal distribution of malaria vectors(Diptera:Culicidae) across different climatic zones of Iran

Malaria is a main vector-borne public health problem in Iran.The last studies on Iranian mosquitoes show 31 Anopheles species including different sibling species and genotypes,eight of them are reported to play role in malaria transmission.The objective of this study is to provide a reference for malaria vectors of Iran and to map their spatial and temporal distribution in different climatic zones.Shape files of administrative boundaries and climates of Iran were provided by National Cartographic Center.Data on distribution and seasonal activity of malaria vectors were obtained from different sources and a databank in district level was created in Excel 2003, inserted to the shape files and analyzed by ArcGIS 9.2 to provide the maps.Anopheles culicifacies Giles s.l.,Anopheles dthali Patton,Anopheles fluviatilis James s.L,Anopheles maculipennis Meigen s.L,Anopheles sacharovi Favre,Anopheles stephensi IJston,and Anopheles superpictus Grassi have been introduced as primary and secondary malaria vectors and Anopheles puicherrimus Theobald as a suspected vector in Iran.Temporal distribution of anopheline mosquitoes is restricted to April_December in northern Iran,however mosquitoes can be found during the year in southern region.Spatial distribution of malaria vectors is different based on species,thus six of them(except for Anopheles maculipennis s.l.and Anopheles sacharovi) are reported from endemic malarious area in southern and southeastern areas of Iran.The climate of this part is usually warm and humid,which makes it favorable for mosquito rearing and malaria transmission.Correlation between climate conditions and vector distribution can help to predict the potential range of activity for each species and preparedness for malaria epidemics.

Some ecological attributes of malarial vector Anopheles superpictus Grassi in endemic foci in southeastern Iran

Objective:To determine the bionomics and susceptibility status of the malarial vector Anopheles superpictus(An.superpictus)to different insecticides in the Sistan-Baluchestan province which has the highest malarial prevalence in Iran.Methods:Different sampling methods,in addition to scoring abdominal conditions,were used to define the seasonal activity and endo/exophilic behavior of this species.In addition,the standard WHO susceptibility tests were applied on adult field strains.Results:Most adult mosquitoes were collected from outdoor shelters.The peak of seasonal activity of An.superpictus occurred at the end of autumn.Most larvae were collected from natural and permanent breeding places with full sunlight and no vegetation.Blood feeding activities occurred around midnight.Compared with the abdominal conditions of adult mosquitoes collected indoors,the abdominal conditions of adult mosquitoes collected outdoors were gravid and seniigravid.This species was suspected to be resistant to DDT,but was susceptible to other insecticides.Conclusions:An.superpictus was present in almost all outdoor shelters,and the ratios of gravid,semigravid/unfed,and freshly fed confirmed that this species had a higher tendency to rest outdoors than indoors.This behavior can protect An.superpictus from indoor residual spraying in this malarious area.To the best of our knowledge,this is the first report on the susceptibility status of An.superpictus in Southeastern Iran.We do not suggest the use of DDT for indoor residual spraying in southeast Iran.

Comparative efficacy of neem and dimethyl phthalate (DMP) against malaria vector,Anopheles stephensi (diptera:culicidae)

Malaria is one of the most important parasitic diseases in the world which is transmitted by the Anopheles mosquitoes. There are several methods for malaria control.One of them is application of repellents on skin in malarious area as an intergrated vectro management measures.This study evaluated two repellents of DMP as a synthtic and locally product of neem oil as a botanical repellent against Anopheles stephensi.The modified method of K & D was used for the tests.Probing/biting rates on the shaved belly of white rabbits were counted. ED50 and ED95 values were calculated by probit statistic software.Calculation of effective dose(ED50, ED90 ) on human volunteer and white rabbit was performed using regression line.Protection and failure time of DMP and neem oil was also determined.ED50 value of DMP and neem oil was determined as 0.0076 and 0. 159 mg/cm respectively on white rabit.The figures of ED90 value of DMP and neem oil was determined as 0. 046 and 1.388 mg/cm^2.DMP and neem oil showed repellency effects against An.stephensi on human volunteers with ED50 value of 0.0037 and 0.127 mg/cm^2 respectively.ED90 value of DMP was determined as 0. 032 mg/cm^2.neem oil exhibited a ED90 value of 1.066 mg/cm^2 on human volunteer.The protection time of 6-7 hours for DMP and 31 minute for neem oil was determined.The failure times for DMP and Neem was 9 hours and 65 minutes rspectively on human bait.Our results exhibited that plant-based repellent is generally less effective than synthetic repellents.However,use of locally made botanical materials would be of great advantages for personal protection against mosquito biting.

Repellent properties of Cardiospermum,halicacabum Linn.(Family:Sapindaceae)plant leaf extracts against three important vector mosquitoes

Objective:To determine repellent activity of hexane,ethyl acetate,benzene,chloroform and methanol extract of Cardiospermum halicacabum,(C.halicacabum) against Culex quinque/ascialus(Cx.quinquefuscialus),Aedes aegypti(Ae.aegypli) and Anopheles slephensi(An.slephensi). Methods:Evaluation was carried out in a net cage(45 cm×30 cm×25 cm) containing 100 blood starved female mosquitoes of three mosquito species and were assayed in the laboratory condition by using the protocol of WHO 2005;The plant leaf crude extracts of C.halicacabum was applied at 1.0,2.5,and 5.0 me/cm^2 separately in the exposed area of the fore arm.Only ethanol served as control.Results:In this observation,the plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person,and also,the repellent activity was dependent on the strength of the plant extracts.The tested plant crude extracts had exerted promising repellent against all the three mosquitoes.Conclusions:From the results it can be concluded the crude extract of C.halicacabum was potential for controlling Cx.quinquefasciatus, Ae.aegypli and An.slephensi mosquitoes.

Phytochemistry and larvicidal activity of Eucalyptus camaldulensis against malaria vector,Anopheles stephensi

Objective:To determine phytochemistry and larvicidal activity of Eucalyptus eamaldulensis against Anopheles stephensi.Methods:The chemical compositions of the leaf essential oils were analyzed using gas chromatography/mass spectrometry（GC/MS）.The larvicidal activity of essential oils and extract of leaf were tested against 4th instar larvae of laboratory-reared Anopheles stephensi.Results:GC/MS analyses identified the presence of 28 compounds corresponding to 99.60%of the total oil.The main constituents in the leaf essential oil were 1,8-cineole（69.46%）,γ-Terpinene（15.10%）,α-Pinene（5.47%） and Globulol（2%）.The leaf extract and volatile oil exerted significant larvicidal activity with LC50 values of 89.85 and 397.75 ppm,respectively.Clear dose-response relationships were established with the highest dose of 320 ppm essential oil extract resulted almost 100%mortality in the population.Conclusions:The larvicidal properties suggest that the essential oil of plant is a potential source of valuable larvicidal compounds against malaria vector and can be used as an alternative to synthetic insecticides.

Indication of pyrethroid resistance in the main malaria vector Anopheles stephensi from Iran

ObjectiveTo investiagte insecticide resistance in target species for better insecticide resistance managemnet in malaria control programs.MethodsThe status of insecticide resistance to different imagicides in Anopheles stephensi (An. stephensi) including DDT 4%, lambdacyhalothrin 0.50%, deltamethrin 0.05%, permethrin 0.75%, cyfluthrin 0.15% and etofenprox 0.50% was performed according to WHO standard method.ResultsThe mortality rate to lambdacyhalothrin, permethrin, cyfluthrin, deltamethrin, etofenprox and DDT was (88.0±3.2), (92.0±2.7), (52.0±5.0), (96.0±2.2), (90.0±3.0) and (41.0±5.7) percent, respectively at diagnostic dose for one hour exposure time followed by 24 h recovery period.ConclusionsThese results showed first indication of pyrethroid resistance in An. stephensi in a malarious area, from southern Iran. There is widespread, multiple resistances in the country in An. stephensi to organochlorine and some report of tolerance to organophosphate insecticides and recently to pyrethroids. However, results of this paper will provide a clue for monitoring and mapping of insecticide resistance in the main malaria vector for implementation of any vector control.

Bio-ecology of malaria vectors in an endemic area,Southeast of Iran

Objective:To determine some bio-ecological aspects of malaria vectors in Jask County,where is targeted for malaria elimination in the national program.Methods:Mosquitoes were collected monthly during 2013-2014 using different collection methods.Subsequently,ELISA test was used to detect the human blood index of mosquitoes.The susceptibility status of Anopheles stephensi was evaluated against the diagnostic dosages of seven WHO recommended insecticides.Results:A total of 3 650 female and 4 736 Anopheles larvae were collected including Anopheles stephensi,Anopheles culicifacies s.l.,Anopheles dthali.Anopheles fluviatilis s.l.,Anopheles moghulensis and Anopheles turkhodi species.Anopheles stephensi was the dominant collected species on human baits and indoors with high rate of unfed and gravid specimens in internal and external window traps.Human blood index was calculated as 14.3%for this species.It was also found to be resistant to DDT and Dieldrin.Conclusions:The collected species had a wide range of habitats,and resting behaviors.With regarding to the presence of most important malaria vectors in Jask.control of the disease may be so complicated;as based on the weather condition it can be transmitted during the whole year,except for cold months.With this strong potential of transmission,existing population movements in the area may lead to imported cases of malaria and local outbreak(s).So,more specific studies on malaria vectors in high risk areas of Jask County are recommended.

Contribution of public places in proliferation of dengue vectors in Penang Island,Malaysia

Objective: To determine abundance, distribution and diversity of potential breeding container habitats of the dengue vectors in public places including schools, restaurants,mosques and parks in southwest areas of Penang Island, Malaysia.Methods: Premises at restaurants, schools, parks and mosques were surveyed simultaneously and inspected visually for container habitats and production of immature mosquitoes from March 2015 to March 2016. Abundance(mean ± SE) of breeding containers between sites was compared using One-way ANOVA. Independent sample ttest was used to compare total number of Aedes albopictus(Ae. albopictus) and Aedes aegypti(Ae. aegypti) surveyed.Results: The surveyed locations yielded a total of 3 741 breeding containers and 19 537 immature mosquitoes from four areas. Concurrent artificial and natural containers produced 78.4% immature Ae. albopictus and 6.3% Ae. aegypti mosquitoes in wet season,with 14.2% Ae. albopictus and 1.1% Ae. aegypti mosquitoes in dry season. Artificial containers accounted for 98.1% of the total containers recorded, with restaurants being the most productive locations(8 012) and schools being the least productive(2 234).Conclusions: It was concluded that public places are good sources of potential container habitats of Aedes mosquitoes in Penang Island, Malaysia and Ae. albopictus has exclusively replaced the home-grown Ae. aegypti even in urban areas. Therefore, treatment of artificial containers in such locations is critical in Aedes mosquito control campaigns during dengue outbreaks.

Resistance status of main malaria vector, Liston (Diptera:Culicidae) to insecticides in a malaria Endemic Area,Southern Iran

Objective: To evaluate the susceptibility of Anopheles stephensi(An. stephensi) Liston, the main malaria vector in southern Iran, to WHO recommended insecticides. Methods: Larvae of An. stephensi were collected from three different larval habitats in both urban and rural area of Bandar Abbas city and one rural area in Rudan county southern Iran. WHO standard method was used for evaluation of adult and larval mosquito susceptibility. Bendiocarb, permethrin, lambda-cyhalothrin, deltamethrin as insecticide and temephos and chlorpyriphos as larvicide were used at the diagnostic dosages recommended by WHO. Results: Findings of this study showed all larval populations of An. stephensi were completely susceptible to temephos and candidate for resistance to chlorpyriphos. Adult mosquitoes in rural areas of Bandar Abbas city were resistant to pyrethroid and carbamate insecticides. Conclusion: Comparison of the results of this survey with previous studies indicates that the resistance to pyrethroids and carbamates in this malaria endemic region is increasing. Wide use of pesticides in agriculture is certainly effective in increasing resistance. The inter-sectoral coordination and collaboration in health and agriculture seem to be necessary to manage insecticide resistance in malaria vectors.

Irritability of malaria vector,Anopheles sacharovi to different insecticides in a malaria-prone area

Objective:To determine the susceptibility and irritability level of malaria vector Anopheles sacharovi(An.sachrovi) to different insecticides in a malaria-prone area.Methods:Susceptibility and irritability levels of field collected strain of An.sacharovi to WHO standard papers of DDT 4%,dieldrin 0.4%,malathion 5%,fenitrothion 1%,permethrin 0.75%,and deltamethrin 0.05% were determined in East Azerbaijan of Iran during reemerging of malaria as described by WHO.Results:Results showed that at the diagnostic dose of insecticides this species exhibited resistance to DDT,tolerant to dieldrin and but somehow susceptible to fenitrothion,malathion, permethrin and deltamethrin.The results of irritability of this species to DDT,lambdacyhalothrin. permethrin cyfluthrin and deltamethrin revealed that DDT had had the most and deltamethrin the least irritancy effect.The average number of take offs/fly/minules for DDT was 0.8±0.2.The order of irritability for permethrin,lambdacyhalothrin,cyfluthrin and deltamethrin were 0.7±0.2,0.5±0.2, 0.5±0.3,and 0.2±0.1,respectively.Conclusions:Results of this study reveals the responsiveness of the main malaria vector to different insecticides.This phenomenon is depending on several factors such as type and background of insecticide used previously,insecticide properties,and physiology of the species.Careful monitoring of insecticide resistance and irritability level of species could provide a clue for appropriate selection of insecticide for malaria control.