Epidemio-entomological survey of Japanese encephalitis in Korea.

In order to determine the seasonal prevalence and population dynamics of Culex tritaeniorhynchus in relation to the epidemics of Japanese encephalitis, and ecology of these vector mosquito in Kyungpook Province, Korea, studies were conducted during the period of 7 years from 1984 to 1990. Cx. tritaeniorhynchus first collected in June between 4th and 28th, and trapped in large numbers during the period from mid-August to early September, showed a simple sharply pointed one-peaked curve. There was a gradual decrease from mid-September, with a very small number of them collected until early October in every year. The average number of Cx. tritaeniorhynchus rapidly decreased after 1985, and the number became particularly low in 1989. The highest population density, which was observed in August during the initial three years, was found to be delayed in the following years, accompanied by a decrease in the number of mosquitoes. In the trend of nocturnal activity of Cx. tritaeniorhynchus, with oncoming darkness they become very active, gradually decreasing in activity toward mid night, but slightly increasing toward dawn. The immature stages of Cx. tritaeniorhynchus were first found in rice fields contributing to peak adult densities in mid-July. The highest average densities of Cx. tritaeniorhynchus was 14,900 per m2 on mid-August 19th. The larval Cx. tritaeniorhynchus showed high resistance levels and resistance ratios against 5 organophosphorus compounds. In the adult horizontal life table characteristics of Kyungsan colonies of Cx. tritaeniorhynchus under insectary conditions, life expectancy was 28.3 days for males and 59.8 days for females. The net reproductive rate was 7.8 and generation time was 25.6 days.     

Seasonal population density and daily survival of anopheline mosquitoes (Diptera: Culicidae) in a malaria endemic area, Republic of Korea.

Mosquito surveillance was conducted near the Korean Demilitarized Zone (Paju County, Gyeonggi Province) from April to October, 1999, where malaria cases were reported. Adult mosquito surveillance, using black light and CDC UV light traps, was conducted at five and two sites, respectively. Weekly larval collections were made at five rice paddies located adjacent to the adult collection sites. Anopheles sinensis was the most abundant mosquito of 11 species collected throughout the surveillance period in 1999, comprising 47 - 48% of the total number of mosquitoes collected at cow sheds and residence. At all five sites surveyed by CDC UV light traps, anophelines appeared early in the year (May 3) and were most abundant in the cow sheds followed by the hillside forest, residence, stream/river bank, and were least abundant in rice fields. The population density of the larvae and the adults of An. sinensis increased steadily in June and reached their peaks during the second week of July (mean 112 females/trap/night). The parity rates were higher in July and September, when populations were highest. The probabilities of daily survival of An. sinensis were 0.804 in June to 0.895 in July. Cross-correlation showed a significant relationship between the number of adult anopheline mosquitoes and the number of larvae collected on the previous day, the same day, and also three and seven days later, which may be useful for determining treatment thresholds.     

Seasonal prevalence of mosquitoes, including vectors of Brugian filariasis, in southern islands of the Republic of Korea

A survey of mosquitoes, including the vector status of Brugia malayi filariasis and their relative larval density, was conducted from 2002 to 2005 at several southern remote islands of Jeollanam-do (province), Gyeongsangnam-do, and Jeju-do, Korea, where filariasis was previously endemic. Overall, a total of 9 species belonging to 7 genera were collected. Ochlerotatus togoi (formerly known as Aedes togoi), Anopheles (Hyrcanus) group, and Culex pipiens were the predominant species captured at all areas. Oc. togoi larvae were most frequently collected at salinity levels <0.5% during June and July, with densities decreasing sharply during the rainy season in August. The most likely explanation for the eradication of filariasis in these areas is suggested to be an aggressive treatment program executed during the 1970s and the 1990s. However, high prevalence of the vector mosquitoes may constitute a potential risk for reemerging of brugian filariasis in these areas.     

长江湖口段春夏季仔稚鱼群落结构研究

湖口江段连通长江与鄱阳湖, 是诸多鱼类的洄游通道, 在长江鱼类的繁衍生息中发挥重要功能。研究于2016年5月—8月在长江中下游鱼类繁殖期内对湖口江段系统开展鱼类仔稚鱼资源的调查, 研究分析了该江段仔稚鱼群落组成、优势种、密度变化、时间空间分布及其与环境因子的关系。结果表明:88d连续采样共鉴定出隶属于8目12科39个仔稚鱼类群, 其中37个类群鉴定到种, 1个类群鉴定到亚科, 1个类群鉴定到科。贝氏?(Hemiculter bleekeri)为该江段仔稚鱼的第一优势种, 其余优势种有虾虎鱼科(Gobiidae)、鳊(Parabramis pekinensis)和飘鱼(Pseudolaubuca sinensis)。仔稚鱼密度在7月1日达到峰值, 峰值为1230.77 ind./100 m3; 7月1日至8月15日仔稚鱼密度整体呈波动性下降的趋势。时间尺度的聚类将6个时期分为5月下旬—7月上旬与7月下旬—8月上旬2个群组, 贝氏?、翘嘴鲌和刀鲚等在6月下旬达到峰值; 鳊、四大家鱼和鳜等在7月上旬达到峰值。江段断面上南北近岸采样点仔稚鱼密度高于断面中心。使用冗余分析方法(RDA)分析了仔稚鱼密度与环境因子的关系, 发现水温、透明度、流量均为影响仔稚鱼群落结构的主要环境因子。水位与仔稚鱼密度相关性分析表明, 两者呈极显著相关(P<0.01)。研究表明, 湖口江段鱼类早期资源较为丰富, 仔稚鱼群落结构主要以中小型鱼类为主, 且江湖洄游性鱼类占比较高; 仔稚鱼对各环境条件有着不同适应特点, 仔稚鱼与水温、透明度、流量均呈现出不同程度的相关关系。研究结果补充了湖口江段鱼类早期资源的基础资料, 为长江中下游鱼类资源保护策略的制定提供了科学依据。     

Distributions of larval mosquitoes among bamboo-stump pools which vary in persistence and resource input

We studied the seasonal occurrence and the distribution patterns of larval mosquitoes in a bamboo grove in northern Kyushu, Japan. The number of pools was large from June to August and was small in winter. Deep stumps and semi-closed-type stumps held water more persistently than shallow and open-type stumps, respectively. Open-type stumps trapped more leaves than semi-closed-type stumps and the number of leaves trapped in the open-type stump was positively correlated with the area of the pool. The incidences ofTripteroides bambusa andAedes albopictus were low early in their breeding season and gradually increased thereafter. In August, the density ofT. bambusa larvae per pool was higher in the old (>2 months) pools than in the new pools and was positively correlated with the depth of the stumps. In contrast, the density ofA. albopictus did not differ significantly between the new-and old pools and was not significantly correlated with the depth of the stump. The density ofA. albopictus was positively correlated with the number of leaves that had been trapped in the stump, whereas the density ofT. bambusa was not. In addition to the seasonal fluctuation in habitat-patch availability, the variations in habitat persistence and resource input among bamboo stumps may facilitate the coexistence of the two mosquitoes that were differentially limited by these factors.     

Is the Mbita trap a reliable tool for evaluating the density of anopheline vectors in the highlands of Madagascar?

BACKGROUND: One method of collecting mosquitoes is to use human beings as bait. This is called human landing collection and is a reference method for evaluating mosquito density per person. The Mbita trap, described by Mathenge et al in the literature, consists of an entry-no return device whereby humans are used as bait but cannot be bitten. We compared the Mbita trap and human landing collection in field conditions to estimate mosquito density and malaria transmission. METHODS: Our study was carried out in the highlands of Madagascar in three traditional villages, for 28 nights distributed over six months, with a final comparison between 448 men-nights for human landing and 84 men-nights for Mbita trap, resulting in 6,881 and 85 collected mosquitoes, respectively. RESULTS: The number of mosquitoes collected was 15.4 per human-night and 1.0 per trap-night, i.e. an efficiency of 0.066 for Mbita trap vs. human landing. The number of anophelines was 10.30 per human-night and 0.55 per trap-night, i.e. an efficiency of 0.053. This efficiency was 0.10 for indoor Anopheles funestus, 0.24 for outdoor An. funestus, and 0.03 for Anopheles arabiensis. Large and unexplained variations in efficiency were observed between villages and months. CONCLUSION: In the highlands of Madagascar with its unique, highly zoophilic malaria vectors, Mbita trap collection was poor and unreliable compared to human landing collections, which remains the reference method for evaluating mosquito density and malaria transmission. This conclusion, however, should not be extrapolated directly to other areas such as tropical Africa, where malaria vectors are consistently endophilic.     

Detection of vivax malaria sporozoites naturally infected in Anopheline mosquitoes from endemic areas of northern parts of Gyeonggi-do (Province) in Korea

We investigated population densities of mosquitoes infected with sporozoites in three highly epidemic areas of Josan-ri and Jangpa-ri (Paju City) and Dongjung-ri (Yeoncheon County) in Korea. Anopheline mosquitoes were collected from both indoors and outdoors by human baiting collection method during the period of the first week of June to the second week of September 1999. Total 13,296 female mosquitoes were collected and 8,650 (65.1%) were Anophelines. Thirty seven percent (3,199) of the Anopheline mosquitoes were captured outdoors and 63.9% (5,531) indoors. Employing a sandwich enzyme-linked immunosorbent assay (ELISA), we analyzed a total of 7,820 Anopheline mosquitoes and found that 7 Anopheline mosquitoes were infected with sporozoites. The positive rate in Josan-ri was 0.14% (5/3,500) and 0.15% (2/1,370) in Jangpa-ri. The total positive rate in all three surveyed areas was 0.09% (7/7,820). The mosquitoes infected with the sporozoites were detected on June 28th (n = 2), July 5th (n = 1), July 19th (n = 1), August 9th (n = 1), September 6th (n = 1), and the last one on September 13th (n = 1). They were all classified as Anopheles sinensis, which showed positive reaction in ELISA test. Therefore it might be concluded that Anopheles sinensis plays an important role in re-emerging malaria transmission in Korea.     

The Identification of Plasmodium vivax Infected Anopheles sinensis by Enzyme-Linked Immunosorbent Assay, Republic of Korea, 1998

ABSTRACT To figure out how far spread the malaria parasite infected mosquitoes from Demilitarized Zone (DMZ). We investigated the sporozoite-infected mosquitoes in Chosan-ri and Hajiseok-ri of Paju-shi, Tonae-dong of Koyang-shi, Mudeung-ri of Yonchon-gun, Soyo-dong of Tongduchon-shi, and Tukjeong-ri of Yangju-gun, Kyonggi-do province in 1998. They were known as highly epidemic areas in the Republic of Korea. Anopheline mosquitoes were collected by human biting collection method from the 2nd week of June to the 5th week of August. A total of 3,256 anopheles mosquitoes were captured in these areas. A sandwich enzyme-linked immununosorbent assay (ELISA) for identifying Plasmodium vivax sporozoites in mosquitoes was used in this survey. Only one mosquito which was captured in Chosan-ri, on 2nd week of July showed positive reaction in this test. This mosquito was identified as Anopheles sinensis. This showed a 0.068% (1/1,465) positive rate in Chosan-ri on 2nd week of July. We could not detect positive mosquitoes the other areas. So we concluded the parasite infected mosquitoes may be highly limited near the DMZ.     

Biological Control of Anopheles sinensis with Native Fish Predators (Aplocheilus and Aphyocypris) and Herbivorous Fish, Tilapia in Natural Rice Fields in Korea

ABSTRACT A confined field experiment was conducted to investigate biological control of malaria and inland filariasis vector, Anopheles sinensis Wied. by combined use of larvivorous fishes, Aplocheilus latipes or Aphyocypris chinensis and herbivorous, Tilapia mossambicus niloticus in natural rice fields at Banwol near Suwon, Gyeonggi province from June through October, 1989. In the presence of naturally breeding Aplocheilus at the density of 0.8 fish/m² water surface, the natural control of Anopheles larvae ranged 34.4% to 51.6% from June through August; later supplemental introduction of herbivore (Tilapia) at the release rate of 1-pair per 10 m² resulted in 67.8% increased to 80.0% control of Anopheles sinensis in 3rd and 5th week respectively. In a combined fish release at the rate of 1.0 fish/m² of Aphyocypris and 1-pair/10 m² of Tilapia produced 67.3% and 82.1% mosquito larval reduction in 3rd and 5th week periods, respectively. The similar pattern of gradual but significant suppression of mosquitoes was also evident in separate rice paddy in 4-5 week period, maintaining ca. 75'82% for the subsequent mosquito breeding season in comparison with control plot.     

Crop monitoring to assess the risk of slug damage to winter wheat in the United Kingdom

The percentage of winter wheat seeds killed by slugs was measured, together with various risk factors, at 93 sites throughout the UK from 1987 to 1990. Estimates of slug populations at each site were obtained from traps baited with methiocarb pellets. The peak number of slugs trapped during the period from July until just before cultivation accounted for 26% of the variability in seed damage, more than any other single risk factor. A combined function of the number of slugs trapped at drilling and the percentage of fine soil aggregates in the seed-bed accounted for 21% of the variability in seed damage. Both (i) the peak number of slugs trapped before drilling, and (ii) the combined function of number of slugs trapped at drilling and the percentage of fine soil aggregates in the seed-bed, have potential for identifying fields with a negligible risk of slug damage to wheat seeds. However, further research is needed to improve the accuracy of forecasting slug damage. In particular, other forms of trap should be tested for their potential use in providing more accurate estimates of slug numbers and biomass at drilling, and techniques of assessing seed-bed conditions should be improved. The percentage of seedlings grazed by slugs was correlated with the numbers of slugs trapped before drilling, at drilling and after crop emergence.     

The influence of weather and egg contamination on the development of third-stage larvae of Cooperia oncophora on pasture.

The influence of weather and egg contamination on the dynamics of herbage contamination with infective larave of Cooperia oncophora was investigated on artificially contaminated grass plots and in a grazing experiment with 24 first-year grazing calves from May to October 1987 in Lower Saxony, Germany. On the experimental plots the larval translation was highest at the beginning of July and in the second part of September, following high mean weekly temperatures. Between July and September peak recovery of larvae from herbage occurred 4 weeks after contamination. A seasonal pattern of larval translation similar to that on the experimental plots could be demonstrated on the grazed pastures when the number of larvae per m2 of pasture had been adjusted to the previous egg output by means of a contamination index. The resulting 'relative larval density' is regarded as a good indicator for larval development on pasture. From July to September the larval population on pasture resulted mainly from the egg contamination 2-3 weeks earlier. The short persistence of the infective larvae on herbage was probably due to the frequent and heavy rainfall throughout the season, causing a passive washout of larvae into the soil. On single pastures the larval density started to increase within 1 week after the calves had first contact with these fields. The impact of the calves on the distribution of larvae is discussed.     

Modeling the effects of Aedes aegypti’s larval environment on adult body mass at emergence

Mosquitoes vector harmful pathogens that infect millions of people every year, and developing approaches to effectively control mosquitoes is a topic of great interest. However, the success of many control measures is highly dependent upon ecological, physiological, and life history traits of mosquito species. The behavior of mosquitoes and their potential to vector pathogens can also be impacted by these traits. One trait of interest is mosquito body mass, which depends upon many factors associated with the environment in which juvenile mosquitoes develop. Our experiments examined the impact of larval density on the body mass of Aedes aegypti mosquitoes, which are important vectors of dengue, Zika, yellow fever, and other pathogens. To investigate the interactions between the larval environment and mosquito body mass, we built a discrete time mathematical model that incorporates body mass, larval density, and food availability and fit the model to our experimental data. We considered three categories of model complexity informed by data, and selected the best model within each category using Akaike’s Information Criterion. We found that the larval environment is an important determinant of the body mass of mosquitoes upon emergence. Furthermore, we found that larval density has greater impact on body mass of adults at emergence than on development time, and that inclusion of density dependence in the survival of female aquatic stages in models is important. We discuss the implications of our results for the control of Aedes mosquitoes and on their potential to spread disease.     

Biotic and abiotic parameters associated with an epizootic of Coelomomyces punctatus in a larval population of the mosquito Anopheles quadrimaculatus.

Biotic and abiotic parameters associated with an epizootic of the fungus Coelomomyces punctatus in larval populations of the mosquito Anopheles quadrimaculatus were investigated for three mosquito breeding seasons (1986-1988) in two adjacent farm ponds in North Carolina. In the first pond, the prevalence of infected larvae averaged 42% (range 0-85%) for collections made weekly from May 1 to November 20, 1986, but larvae did not occur in this pond in 1987. Infection rates in the adjacent pond, sampled during the mosquito breeding seasons of 1987 and 1988, declined from 10.9% (range 0-27.5%) in 1987 to 2.5% (range 0-14.2%) in 1988. Correlation analyses between the number of female copepods and fungal infection rates in sentinel mosquitoes were significant (P < 0.01) for Acanthocyclops robustus but insignificant for eight other species. Infections obtained in sentinel larvae placed in the ponds for 3 hr intervals indicated that C. punctatus infected larvae around sundown. Infection rates for field-collected larvae increased with the stage of larval development. However, experiments with sentinel larvae showed that early instars were more susceptible to infection than later instars, suggesting that the higher infection rates in late instars resulted from individual larvae being infected by two or more zygotes during larval development. Standard multiple regression analyses, used to determine the relationship between seasonal infection rates and water chemistry, weather variables, and the abundance of early and late instar larvae, showed that the abundance of late instars was the only independent variable common to linear models. The models only accounted for 20 and 9% of the variation in larval infection rates for 1987 and 1988, respectively. These results indicate that of the parameters examined, the seasonal abundance of the copepod, A. robustus, was the most important factor (or variable) correlated with the prevalence of mosquito infection.     

Size variation and reproductive success in the mosquito Aedes cantans

Abstract. A link between density-dependent larval competition and adult size of the mosquito Aedes cantans was demonstrated in northern England. Ponds containing high larval densities produced smaller larvae which, in turn, resulted in smaller adults at emergence.
In both 1989 and 1990, parous mosquitoes caught at human bait were larger than nulliparous ones, suggesting that larger mosquitoes are more successful at host location and egg-laying and also that they may be longer lived.
Larger mosquitoes produced larger egg clutches than smaller females: however, there was no difference in the size of eggs laid by large and small females.     

Synchronous peaks in trap catches of malaria-infected mosquito species at Daeseongdong, a border village between North and South Korea

Malaria continues to be a major health threat near the Demilitarized Zone (DMZ) that separates North and South Korea. Adult mosquitoes were collected from 20 July through 21 October, 2010 at Daeseongdong, a small village within the DMZ. Molecular techniques were used to identify Anopheles to species and for detection of Plasmodium vivax sporozoites in their head and thorax. Trap catches showed concordant peaks of Anopheles belenrae and An. kleini early in the study period and concordant peaks of An. pullus and An. sinensis later in the season. Three well defined peaks of the 107 sporozoite positive mosquitoes were observed: 34.6% were An. kleini, 23.4% were An. belenrae, 21.5% were An. sinensis, 19.6% were An. pullus, and 0.9% were An. lesteri. Estimation of the extrinsic incubation period from daily temperatures did not help identify preceding biting peaks of An. pullus and An. sinensis, when infection should have been acquired. We explore possible reasons for the sudden appearance and disappearance of sporozoite-infected mosquitoes, including the influx of infected mosquitoes from adjoining areas, and weather patterns. Regular surveillance for infected mosquitoes near border areas of the Republic of Korea may provide advance warning of increased malaria risk potential.     

中华按蚊和白纹伊蚊接种马来丝虫微丝蚴后酚氧化酶活性的变化(英文)

酚氧化酶在昆虫抵抗外来异物黑化和成囊的免疫反应中起重要作用。中华按蚊和白纹伊蚊分别经胸内接种马来丝虫微丝蚴和生理盐水后,测定蚊血淋巴中酚氧化酶活性。结果表明:未接种的两种蚊,其1日龄蚊的酚氧化酶活性显著高于3、12和16日龄蚊。1日龄中华按蚊接种微丝蚴24h后,其酚氧化酶活性比未接种蚊和接种生理盐水蚊高2—3倍。1日龄白纹伊蚊接种微丝蚴24h后,其酚氧化酶活性是未接种蚊的7倍。白纹伊蚊酚氧化酶活性的免疫激活水平显著高于中华按蚊。讨论了中华按蚊和白纹伊蚊酚氧化酶活性的差异与其免疫力差异的关系。     

Failure to identify alveolar echinococcosis in trappers from South Dakota in spite of high prevalence of Echinococcus multilocularis in wild canids

Echinococcus multilocularis causes a rare but potentially lethal zoonotic disease in humans. This tapeworm has been known to be endemic in foxes (Vulpes vulpes) and coyotes (Canis latrans) within the northern United States since the 1960s. One purpose of this study was to provide recent data on the prevalence of E. multilocularis in foxes and coyotes from eastern South Dakota. In a survey conducted from 1987 to 1991 and involving 137 foxes and 9 coyotes from this area, 74.5% of the foxes and 4 of the coyotes were infected. To assess the possible prevalence of alveolar echinococcosis in a group at presumptive high risk, we also conducted a serological survey of members of the South Dakota Trappers Association in 1990 and 1991. Serum samples from 115 trappers were evaluated for the presence of E. multilocularis antibodies using enzyme-linked immunosorbent assay tests involving a purified antigen called Em2, a crude E. multilocularis antigen, and a recombinant E. multilocularis antigen called II/3-10. None of the trappers showed antibody evidence for the presence of E. multilocularis. Roughly half of the surveyed individuals had trapped more than 50 foxes during their life, and almost one-fourth had trapped more than 1,000 foxes.     

Abundance, sizes and developmental stages of larval krill, Euphausia superba, during winter in ice-covered seas west of the Antarctic Peninsula

Larval krill were sampled west of the Antarctic Peninsula duringthree winter cruises: September 1991, June 1993 and September1993. Larval abundances were estimated from net catches andcompared directly to visual counts (made by a SCUBA diver) oflarvae occupying the ice habitat at the same sampling stations.The number of larvae per square meter sampled with nets wasmore often greater than that observed by the diver, irrespectiveof the sampling period. However, comparisons of larval abundancewithin sampling periods were not statistically significant.Larval krill collected by divers were significantly larger thanthose collected with nets for each of the three cruises. Thestage composition of larval krill also depended on the collectionmethod: net-collected samples contained a disproportionatelyhigh number of early furcilia larvae in June 1993 (early winter),and a disproportionately low number of early juveniles duringSeptember 1991 and 1993 (late winter). These results lead usto suggest that larval/juvenile krill occupy both the watercolumn and sea ice habitat during the austral winter, and thatthere are often differences in the sizes and developmental stagesof the two groups. For larval krill that occupied the sea icehabitat, aggregations were larger and more numerous during latewinter than in early winter. In addition, larvae within aggregationsoccupied structurally complex microhabitats, provided by over-raftedice floes, more often than they occupied smooth, downward-facingice surfaces where ice was not over-rafted.     

Emergence of Zika Virus in Culex tritaeniorhynchus and Anopheles sinensis Mosquitoes in China

Zika virus(ZIKV) has been isolated from mosquitoes such as Aedes, Mansonia uniformis, and Culex perfuscus; However,the isolation of ZIKV from Anopheles sinensis and Culex tritaeniorhynchus has not yet been reported. In June and July2018, 22,985 mosquitoes and 57,500 midges were collected in Jiangxi Province in southeastern China. Among them, six strains of ZIKV were isolated from mosquitoes: four from An. sinensis and two from Cx. tritaeniorhynchus. Molecular genetic analysis showed that the ZIKV isolated from An. sinensis and Cx. tritaeniorhynchus belonged to genotype 2 in the Asian evolutionary branch of ZIKV. In addition, the ZIKV strains isolated from An. sinensis and Cx. tritaeniorhynchus had amino acid substitutions identical to ZIKV strains prevalent in South America since 2015. This study is the first to isolate ZIKV from mosquito specimens collected in the wild of Jiangxi Province, China; This is also the first time that ZIKV has been isolated from An. sinensis and Cx. tritaeniorhynchus. Given that An. sinensis and Cx. tritaeniorhynchus have a very wide geographical distribution in China and even in eastern and southern Asia, the isolation of several strains of ZIKV from these two mosquitoes poses new challenges for the prevention and control of ZIKV infection in the mainland of China and countries and regions with the same distribution of mosquitoes.     

Multiple Cytochrome P450 genes: their constitutive overexpression and permethrin induction in insecticide resistant mosquitoes, Culex quinquefasciatus

Four cytochrome P450 cDNAs, CYP6AA7, CYP9J40, CYP9J34, and CYP9M10, were isolated from mosquitoes, Culex quinquefasciatus. The P450 gene expression and induction by permethrin were compared for three different mosquito populations bearing different resistance phenotypes, ranging from susceptible (S-Lab), through intermediate (HAmCq(G0), the field parental population) to highly resistant (HAmCq(G8), the 8(th) generation of permethrin selected offspring of HAmCq(G0)). A strong correlation was found for P450 gene expression with the levels of resistance and following permethrin selection at the larval stage of mosquitoes, with the highest expression levels identified in HAmCq(G8), suggesting the importance of CYP6AA7, CYP9J40, CYP9J34, and CYP9M10 in the permethrin resistance of larva mosquitoes. Only CYP6AA7 showed a significant overexpression in HAmCq(G8) adult mosquitoes. Other P450 genes had similar expression levels among the mosquito populations tested, suggesting different P450 genes may be involved in the response to insecticide pressure in different developmental stages. The expression of CYP6AA7, CYP9J34, and CYP9M10 was further induced by permethrin in resistant mosquitoes. Taken together, these results indicate that multiple P450 genes are up-regulated in insecticide resistant mosquitoes through both constitutive overexpression and induction mechanisms, thus increasing the overall expression levels of P450 genes.