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 Table of Contents  
ORIGINAL RESEARCH
Year : 2014  |  Volume : 3  |  Issue : 1  |  Page : 51-59

Dengue vectors in urban and suburban Assam, India: entomological observations


1 National Institute of Malaria Research (Field Station), Guwahati, Assam, India
2 National Vector Borne Disease Control Programme, Government of Assam, Guwahati, Assam, India

Date of Web Publication24-May-2017

Correspondence Address:
V Dev
National Institute of Malaria Research (Field Station), Guwahati – 781022, Assam
India
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DOI: 10.4103/2224-3151.206885

PMID: 28607255

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  Abstract 

Background:Dengue is rapidly becoming established in north-east India and spreading, on account of rapid urbanization and population movement, with reported morbidity and attributable death cases. This study aims to determine the seasonal abundance of Aedes (Stegomyia) albopictus and Aedes (Stegomyia) aegypti in Guwahati metropolis and suburban settlements; to characterize the breeding resources for these mosquitoes; and to ascertain the status of their susceptibility to adulticides and larvicides.
Methods:Mosquito larval surveys were carried out in different localities in both Guwahati city and adjoining suburbs from January to December 2013, to determine the seasonal abundance of disease vectors and their breeding preferences. The insecticide susceptibility status of mosquito adults and larval populations of both Aedes aegypti and Aedes albopictus was ascertained, using World Health Organization standard diagnostic concentrations and test procedures.
Results:The study revealed that both Aedes aegypti and Aedes albopictus are widely abundant in Guwahati city and suburbs, and breeding in a wide variety of resources. Aedes albopictus, however, was the predominant mosquito species in suburbs, breeding preferentially in flower vases, cut-bamboo stumps and leaf axils. Aedes aegypti was the most common in the city, breeding predominantly in discarded tyres, cement tanks and used battery boxes. Both Aedes aegypti and Aedes albopictus were resistant to dichlorodiphenyltrichloroethane (DDT; 4%), but susceptible to malathion (5%), and exhibited a varied response to pyrethroids. However, larval populations of both these mosquito species were susceptible to larvicides, including malathion (1.0 mg/L), temephos (0.02 mg/L) and fenthion (0.05 mg/L), at much lower dosages than diagnostic concentrations.
Conclusion:Given the seasonal abundance and case incidence in city areas, it is highly probable that Aedes aegypti is the predominant mosquito vector transmitting dengue virus. The study results have direct relevance for the state dengue-control programme, for targeting interventions and averting outbreaks and spread of disease.

Keywords: Aedes aegypti, Aedes albopictus, Assam, dengue, insecticide susceptibility status, mosquito breeding habitats, north-east India, seasonal abundance


How to cite this article:
Dev V, Khound K, Tewari G G. Dengue vectors in urban and suburban Assam, India: entomological observations. WHO South-East Asia J Public Health 2014;3:51-9

How to cite this URL:
Dev V, Khound K, Tewari G G. Dengue vectors in urban and suburban Assam, India: entomological observations. WHO South-East Asia J Public Health [serial online] 2014 [cited 2019 Sep 17];3:51-9. Available from: http://www.who-seajph.org/text.asp?2014/3/1/51/206885


  Introduction Top


There has been dramatic increase in dengue cases globally and nearly half of the world’s population is estimated to be living at risk of the disease.[1] The World Health Organization (WHO) estimates that there are 50 to 100 million cases every year in tropical and subtropical countries.[1] Dengue is endemic in India, with reported disease outbreaks in large metropolis cities.[2],[3],[4] However, with increased urbanization and population movement, the disease is reportedly spreading to other metropolitan areas or cities that were hitherto free from disease.[5],[7] The state of Assam, situated in north-east India, reported 237 confirmed cases of dengue for the first time in 2010, and subsequently there was a significant increase in 2012 and 2013, with 1058 and 4526 cases recorded, respectively.[3] Of the total confirmed cases for each year in the state, the majority (70–90%) were recorded in the largest metropolitan area, Guwahati city. The actual disease burden is estimated to be much higher, with many cases undiagnosed and additional cases reported in public/private sectors.

Aedes aegypti (renamed as Stegomyia aegypti) and Aedes albopictus (renamed as Stegomyia albopicta) are reportedly prevalent in the north-east region of India, which offers ideal conditions for proliferation of these mosquito vectors and the spread of disease.[5] Recent occurrences and increased case incidence of dengue in north-eastern states warrant detailed investigations of the seasonal prevalence of these two mosquito species, to improve understanding of their bionomics, for formulation of suitable interventions at specific places and times. There have been sporadic informal reports of mosquito surveys in north-eastern states, but no data on the relationship of seasonal abundance and the member species composition of the Aedes albopictus subgroup.[8],[9],[10]

This study aims to determine the seasonal abundance of Aedes albopictus and Aedes aegypti in Guwahati metropolis and suburban settlements; to characterize the breeding resources for respective species; and to ascertain their susceptibility to adulticides and larvicides.

Study site, topography and climate

Guwahati city (26°11’10? N, 91°45’3? E), situated on the southern bank of the mighty river Brahmaputra (54 m above sea level), is a fast-growing metropolis in Assam state and a gateway to the north-east of India for economic activities. It is the largest city in north-east India, spread over 264 km2, with a population of 1.5 million, and is a principal centre of social-cultural, political, industrial, trade and commerce for the entire north-east of India. The study site comprised Guwahati city and its adjoining suburban Sonapur block (see [Figure 1]). The city is densely populated, and grouped into four zones (East, West, South and Capital zone), under the jurisdiction of Guwahati Municipal Corporation for administrative purposes. Typically, the general population live in houses/apartment complexes made of brick and cement but drainage is still open in many areas. There is a piped water supply in most areas of the city, yet many households store potable water in cement tanks or plastic/tin containers for domestic use. In Sonapur block (population 0.19 million), however, housing is mixed, with many structures made of split bamboo with thatched roofing, often with an attached cattle shed. This block is sparsely populated, with large tribal concentrations and vast forest cover. In this region, most of the year is hot and humid and, during the summer (April to September), the monthly mean maximum and minimum temperatures range from 30°C to 34°C and 20°C to 25°C respectively. For rest of the year (October to March), the monthly mean maximum and minimum temperatures range from 24°C to 32°C and 9°C to 22°C respectively. The rainy season is extended, with pre-monsoon showers during April to June, followed by heavy downpours during July to September; in the post-monsoon months (October to March), the rainfall is comparatively less. The relative humidity is high (>70%) for most of the year and the total annual rainfall ranges from 1.5 m to 2 m and many areas get inundated due to flash flooding.
Figure 1: Diagrammatic sketch map of Guwahati city and adjoining suburban Sonapur block, showing mosquito larval survey locations (yellow circles) in different zones. Aedes aegypti is the predominant mosquito species in the city (total cases = 4121) and Aedes albopictus in the suburban Sonapur block (total cases = 2). Inset is the map of India showing location of the study site, and table giving distribution of dengue cases in different zones and corresponding entomological indices of disease vectors. HI:House/premise Index, CI: Container Index; BI: Breteau Index.

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  Methods Top


The study protocol was approved by the Institutional Scientific Advisory Committee and bears the project ID No. NIMR/ IDVC/2011/139; household heads provided informed verbal consent.

Entomological sampling techniques

Larval breeding surveys

To determine the seasonal abundance of Aedes albopictus and Aedes aegypti and species-specific breeding habitats, mosquito larval surveys were conducted in different localities in both Guwahati city and the adjoining suburban Sonapur block, during January to December 2013 (see [Figure 1]). Dflferent breeding resources were searched in various localities, including market places, houses (exterior premises only), nurseries, industrial areas and other landmark locations, such as the railway yard, city zoo and airport. All possible mosquito breeding resources, namely discarded tyres, flower vases, coconut shells, cut-bamboo stumps, and plastic/tin/earthenware containers were searched for larval/pupal breeding, in both urban and suburban settings. Larval collections were made, aided by a dipper (200 mL capacity) in tyres and cement tanks, and by direct pipetting of larvae and pupae from cut-bamboo stumps, leaf axils and small plastic/tin/earthenware containers of <200 mL capacity. Collections of immature populations, including larvae and pupae, from each type of container were kept separately in small water-filled containers, until emergence, for accurate species identification. Adult mosquitoes were identified using available taxonomic keys and related publications, and seasonal abundance was monitored by conventional indices, i.e. the House/premise Index (HI), Container Index (CI) and Breteau Index BI).{Figure 1}

Species composition of the Aedes (Stegomyia) albopictus subgroup

Aedes (Stegomyia) albopictus is a species subgroup, members of which are known to coexist in south-east Asia, and are implicated in transmission of dengue and chikungunya/ arboviruses.”These include Aedes albopictus (Skuse), Aedes downsi (Bohart and Ingram), Aedes flavopictus (Yamada), Aedes novalbopictus (Barraud), Aedes patriciae (Mattingly), Aedes pseudalbopictus (Borel), Aedes seatoi (Huang) and Aedes subalbopictus (Barraud). Some of these member species flmt not all) have been recorded in India; however, there are no data on the abundance of member species of this subgroup specific to north-eastern states. Mosquitoes were identified using taxonomic keys primarily based on male genitalia for claspette, a species-specific diagnostic character.[12]

Insecticide susceptibility status

The insecticide susceptibility status of mosquito adults as well as larval populations of both Aedes aegypti and Aedes albopictus was ascertained using WHO standard diagnostic dosages and test procedures.[13],[14] Batches of unfed, 2–3-day-old female mosquitoes (emerged from field-collected larval populations) were introduced into holding tubes for 1 h and then transferred into the exposure tube and placed vertically for 1 h to the test insecticides, namely organochlorine (4 % dichlorodiphenyltrichloroethane [DDT]), organophosphorous (5% malathion), and synthetic pyrethroids (0.75% permethrin, 0.05% deltamethrin). Knocked-down and dead mosquitoes were recorded after this time (1 hKD) before being transferred into the holding tubes. A mosquito was recorded as knock-down if it was lying on its back or side and was unable to maintain flight after a gentle tap. Mortality was recorded 24 h after exposure (24 hM). Each test was replicated five to eight times (10–20) mosquitoes per replicate. Appropriate controls were tested as described above, with a batch of 10 unfed females per replicate against each insecticide. The experiments were completed at ambient room temperature of 27 ± 2°C and relative humidity of 70–80%. Ten per cent sugar-soaked cotton was provided to the females during the 24-h holding period.

Following the WHO test protocol,[14] two to four batches of third- or fourth-instar larvae (20–40 per replicate) were evaluated against larvicides, namely fenthion (0.05 mg/L), malathion (1.0 mg/L) and temephos (0.02 mg/L). The first filial generation of each mosquito species was exposed to serial dilutions of discriminating dosages. The number of dead/ moribund and alive mosquito larvae post 24-h exposure was recorded, keeping appropriate control for corrected percentage mortality. Data from larval bioassays were subject to probit analysis, using SPSS software version 22 for determining the 50% and 95% lethal concentrations (LC50 and LC95), with 95% confidence intervals.


  Results Top


Entomological observations

Seasonal abundance of Aedes aegypti and Aedes albopictus

Monthly data on the houses/premises inspected and containers searched for seasonal changes in breeding indices, including HI, CI and BI are given in [Table 1]. Based on monthly breeding surveys, it was observed that during the winter season (January to March), the majority of the containers searched were dry (82.4%), and of those recorded wet (17.6%, 532/3013), all were devoid of mosquito breeding. During the remainder of the season (April to December), 27% (2039/7651) of wetcontainers searched were positive for Aedes immature stages; however, monthly entomological indices, i.e. HI, CI and BI ranged from 3.4 to 21.5,2.910 33.8, and 5.0 to 61.0 respectively (see [Figure 2]). At the onset of the rainy season in April, the HI was observed rising gradually and peaked during November and December (post-monsoon season). Similarly, the CI combined for both Aedes aegypti and Aedes albopictus was observed rising from 2.9 in April and then fluctuated between 13.1 and 33.8 for rest of the season. There was a parallel rise in BI, from 5.0 in April to 61.0 in May and it then varied between 25.9 and 58.1 during June to December. During April to December, of a total of 2039 breeding sources searched in both urban and suburban areas, 408 (20%) containers were positive for mosquito breeding. Of these, 172 (8.43%) and 167 (8.19%) containers were positive for Aedes albopictus and Aedes aegypti respectively, and the remaining 69 (3.38%) were positive for mixed breeding comprising both species (see [Table 2]). Aedes albopictus, however, was first detected at the beginning of April and Aedes aegypti was first recorded in May. The CI, however, for each mosquito species, and the extent of mixed breeding, varied during the months investigated. The CI ranged from 1.70 to 28.12 and 0.52 to 26.67 for Aedes albopictus and Aedes aegypti respectively, and for mixed breeding it varied from 1.05 t0 9.78 for the months observed. Both these mosquito species are morphologically separated by the presence of a distinct lyre marking covered with white scales on the scutum (Aedes aegypti)or a prominent median stripe of white scales on the scutum (Aedes albopictus). Both varieties of Aedes aegypti, i.e. mosquitoes with dark scales (type form) and pale scaled mosquitoes (variety queenslandensis)were recorded breeding in Guwahati city; the latter was the predominant collection in pre-monsoon and monsoon months (April to September), and the former was the exclusive collection during post-monsoon months (October to December).
Table 1: Monitoring seasonal abundance of Aedes albopictus and Aedes aegypti mosquito breeding, dengue vector mosquito species in Guwahati metropolis and suburbs, Assam, India

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Table 2: Seasonal container positivity of Aedes albopictus and Aedes aegypti, dengue vector mosquito species in Guwahati metropolis and adjoining suburbs, Assam, India

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Figure 2: Seasonal cumulative larval breeding indices of Aedes aegypti and Aedes albopictus mosquito species in Guwahati city and adjoining suburbs, Assam, India. HI: House/premise Index, CI: Container Index; BI: Breteau Index

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Breeding habitat surveys

During April to December 2013, of a total 2039 containers searched for mosquito breeding, 17.95% (260/1448) and 25.04% (148/591) were positive in urban and semi-urban areas respectively. Both Aedes aegypti and Aedes albopictus were observed breeding in a variety of natural and artificial habitats (see [Figure 3]). Aedes albopictus was recorded breeding in tyres, cut-bamboo stumps, plastic/tin containers, flower vases and leaf axils, in both urban and suburban areas but the CI varied between habitats and ecotype (see [Table 3]). It was relatively less abundant in city areas in all habitats, and in Coconut shells it was observed only in suburbs. It was, however, the exclusive collection in flower vases and leaf axils in both in urban and suburban areas, and was predominant in plastic/tin containers (CI = 8.7) in urban areas, compared to Aedes aegypti (CI = 3.9). Aedes aegypti, on the Other hand, was the most common species in the city, predominantly breeding in discarded tyres (CI = 15.3), and was the exclusive collection in cement tanks (CI = 43.7) and used battery boxes (CI = 14.3). Mixed breeding of both mosquito species was largely recorded in tyres in both urban and suburban areas, in which Aedes aegypti and Aedes albopictus occurred in approximately 60:40 proportions, and occasionally in cut-bamboo stumps, plastic/tin containers and coconut shells, during the months investigated.
Table 3: Major breeding habitats and relative abundance of Aedes albopictus and Aedes aegypti in Guwahati metropolis and adjoining suburbs, Assam, India, April to December 2013

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Figure 3: Breeding habitats of Aedes aegypti and Aedes albopictus in Guwahati city and adjoining suburbs, Assam, India. Upper left: a discarded tyre, a preferred breeding source for Aedes aegypti in urban areas (written permission to reproduce this image was provided by the individual portrayed); upper right: a cut bamboo stump, a breeding source for Aedes albopictus in rural areas; lower left, a leaf axil, a breeding source for Aedes albopictus; lower right: a flower vase, a preferred breeding habitat for Aedes albopictus

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Species composition of the Aedes (Stegomyia) albopictus subgroup

Mosquito adult males that emerged from larval collections from various breeding resources in different localities were dissected for male terminalia/claspette, a species-specific diagnostic characteristic of the Aedes albopictus subgroup. During April to December, 290 male mosquitoes were dissected for male genitalia, all of which were confirmed to be true morphotype Aedes (Stegomyia) albopictus (Skuse), as they possess (i) a claspette – mushroom like with numerous scales and several widened specialized setae on the mesal aspect, and a few widened specialized curved setae on an apical angle of the expanded distal part; and (ii) a tergum IX, with a conspicuous horn-like median projection. Thus, it is concluded that Aedes albopictus is the only member species of the Aedes albopictus subgroup that is prevalent in Guwahati and suburbs.

Insecticide susceptibility status of mosquito adult and larval populations

Adult bioassay

The results of the susceptibility test of Aedes aegypti and Aedes albopictus females to various insecticides are presented in [Table 4]. Both Aedes aegypti and Aedes albopictus were resistant to DDT (4%), with a mortality of <80%, but fully susceptible to malathion (5%) at the given diagnostic concentrations. However, both these species exhibited a varied response to pyrethroids (deltamethrin and permethrin). Aedes aegypti was observed to be resistant to deltamethrin (0.05%) as well as permethrin (0.75%), but Aedes albopictus was susceptible to deltamethrin: 1 hKD = 100%, and for permethrin 1 hKD ranged from 57% to 100% and 24 hM was <97%; thus, the susceptibility status was borderline (verification required) according to the given WHO criterion.
Table 4: Insecticide susceptibility status of Aedes aegypti and Aedes albopictus, dengue mosquito vector species in Assam, India, July to October 2013

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Larval bioassay

Larval samples of both Aedes aegypti and Aedes albopictus were susceptible to all three larvicides, including malathion (1.0 mg/L), temephos (0.02 mg/L) and fenthion (0.05 mg/L), at much lower dosages than given diagnostic concentrations, For larvicide assay of Aedes aegypti, the LC50 to LC95 values for malathion were 0.0199 ing, to 0.0707 mg/L, for temephos 0.000059 mg, to 0.000317 mg/L, and for fenthion 0.00226 mg/L to 0.00294 mg/L, respectively. For Aedes albopictus, the LC50 to LC95 values for malathion were 0.01747 mg, to 0.0518 mg/L, for temephos 0.000027 mg/L to 0.000058 mg/L, and for fenthion 0.00374 mg, to 0.00579 mg/L respectively (see [Table 5]).
Table 5: Summary statistics of susceptibility test results of mosquito larvae of Aedes aegypti and Aedes albopictus to various larvicides in Assam, India, June to July 2013

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  Discussion Top


Dengue is spreading rapidly and becoming established in north-east India, owing to socioeconomic and developmental changes, with a dramatic increase in urbanization and population movement, and an increase in reported morbidity and attributable death.[3],[5] In the state of Assam, although most cases have been recorded in Guwahati city itself, confirmed cases have also been reported from other district towns, supported by serological evidence for circulating strains of dengue virus.[5],[15],[16] In 2013, 91% (4121/4526) of the total reported dengue cases were recorded in Guwahati city alone and only two cases in the suburban Sonapur block. The cases were, however, unevenly distributed in different zones of the city, with large concentrations in the East zone, Capital zone, West zone and South zone, in decreasing order (see [Figure 1]).{Figure 1}

The present study has revealed that both Aedes aegypti and Aedes albopictus (the only member species of the Aedes albopictus subgroup) are widely abundant in Guwahati city and suburbs, breeding in a wide variety of resources (see [Table 3]). The seasonal prevalence of both mosquito species occurs from the onset of rains in April until December, and the mosquito breeding indices varied between the months observed (see [Figure 2]). Aedes aegypti was the most common species in urban areas, breeding predominantly in discarded tyres; it seemingly outnumbered Aedes albopictus, evidenced by the CI, and was recorded exclusively in cement tanks and used battery boxes (see [Table 3]). Interestingly, a CI of 0.52 (for Aedes aegypti), and combined CI of 5.20, was associated with the first reported dengue case in May, and high values of CI for Aedes aegypti were maintained in the city premises during July to December, which corresponded with increased case incidence, although correlation with CI and the number of cases was very weak (r = 0.248, P = 0.455; see [Table 2]). Similarly, correlation of dengue cases with HI (r=0.348, P = 0.218) and BI (r = 0.230, P = 0.557) were also insignificant statistically. Given the variable distribution of confirmed dengue cases in different zones of the city, and the data analysed for mosquito breeding indices for respective zones, the CI was observed to be the highest in the East zone, corresponding to a record number of cases, but correlation was very weak (r = 0.43) and there was negative correlation for HI (r = –0.891) and BI (r = –0.90). Aedes albopictus, on the other hand, was the predominant mosquito species in the semi-urban area, breeding in variety of habitats, preferentially in flower vases, cut-bamboo stumps and leaf axils. With only two dengue cases recorded in the suburban Sonapur block, it is highly unlikely that Aedes albopictus is an efficient vector. Instead, it is argued that, with increased urbanization and depletion of forest cover, Aedes aegypti is reportedly invading the suburbs and other town areas in the state, competitively displacing Aedes albopictus, as evidenced by higher relative abundance in tyres in both urban and suburban areas (see [Table 3]).[5] Similar observations have also been documented in other countries of south-east Asia.[17]

Even though both Aedes aegypti and Aedes albopictus are the suspected vectors and implicated in dengue transmission in the north-east region of India, given the seasonal abundance and case incidence in city areas, it is highly probable that Aedes aegypti is the predominant mosquito vector transmitting dengue Virus. With the increasing distribution range of Aedes aegypti and evidence of virus activity, it is projected that dengue will emerge as a major public health issue in north-east India. However, the role of Aedes albopictus in dengue transmission in this region needs to be elucidated. Given the fact that populations of both mosquito species were resistant to DDT, and showed a variable response to pyrethroids, malathion should be the insecticide of choice for control. Similar study results have been reported in Thailand, where populations of Aedes aegypti have been found to be resistant to both deltamethrin and permethin, evidenced by underlying biochemical mechanisms.[18],[19] For anti-larval operations, even though larval populations of both species were susceptible to all three larvicides, malathion (1.0 mg/L), temephos (0.02 mg/L) and fenthion (0.05 mg/L), repeated applications seemed inappropriate given the diversity of breeding resources and selection pressure for resistance. Apart from the variable response of mosquito adults to pyrethroids, similar study results have been reported for mosquito adult and larval population in other regions of India, including Delhi and Jharkhand.[20],[21],[22] However, continuous monitoring of insecticide susceptibility against dengue vectors is imperative for effective control and containment of disease spread. To overcome insecticide resistance, an appropriate mix of technologies, including application of bio-larvicides, namely, Bacillus thuringiensis israelensis (Bti) and insect growth regulator compounds; sustained efforts for community awareness; and community participation to prevent mosquito breeding, enforced by civic bye-laws, should all be considered.[23]

This study has provided data on the prevalence of both disease vectors and some bionomic characteristics, but lack of data on the pupae-per-person index in the given locality remains the limitation of the study. The pupal/demographic survey has been proven to be an effective tool for assessing risk and targeting the most productive containers for reducing operational costs, and has been duly endorsed by WHO.[24],[25],[26] There is scope for further research on the subject to generate similar data for other districts/states of north-east India, with particular reference to identification of high-risk areas, vector incrimination and seasonal infectivity of dengue, as well as chikungunya virus infection and co-infection of various dengue serotypes.[27],[29] The study results have direct relevance for the state dengue-control programme, for targeting interventions and averting outbreaks and spread of disease.


  Acknowledgements Top


The authors are grateful to Dr BK Tyagi, Centre for Research in Medical Entomology, Madurai for confirmation of mosquito species identification” and DK Srivastava, NG Das and the project staff for technical assistance. Thanks are also due NR Choudhury, district officer for data access on reported cases and coordinated efforts for vector breeding surveillance, and to the India Meteorological Department, Guwahati, for providing meteorological data.

Source of Support: This study was funded by the Indian Council of Medical Research, New Delhi (File No.5/8-7 (306) V-2011-ECD-II). This submission has been reviewed by the Institute Publication Screening Committee and bears the approval No.03/2014.

Conflict of Interest: None declared.

Contributorship: VD developedthe conceptproposal, conducted overall supervision, data collation and analysis, and drafted the manuscript; KK coordinated the study, provided intermediate supervision and developed portions of the manuscript; GGT undertook data collection, intermediate supervision, data compilation, mosquito dissections and identification. All authors have read the final version and approved it for submission.

 
  References Top

1.
World Health Organization. Dengue and severe dengue. Fact sheet N° 117, updated September 2013. Geneva: WHO, 2013”http://www.who. int/ - accessed 30 December 2013.  Back to cited text no. 1
    
2.
Gupta N, Srivastava S, Jain A, Chaturvedi C. Dengue in India. Indian J Med Res. 2012;136: 373–390.  Back to cited text no. 2
    
3.
India, Ministry of Health and Family Welfare. National vector borne disease control programme. New Delhi: Directorate General of Health Services. http://www.nvbdcp.gov.in/ - accessed 28 February 2014.  Back to cited text no. 3
    
4.
Chaturvedi UC, Nagar R. Dengue and dengue haemorrhagic fever: Indianperspective. J. Biosci. 2008;33:429–441  Back to cited text no. 4
    
5.
Dutta P, Mahanta J. Potential vectors of dengue and the profile of dengue in the north-eastern region of India: an epidemiological perspective. Dengue Bulletin. 2006;30:234–242.  Back to cited text no. 5
    
6.
Das BP, Kabilan L, Sharma SN, Lal S, Ragu K, Saxena VK. Detection of dengue virus in wild caught Aedes albopictus (Skuse) around Calicut Airport, Maslapurum district, Kerala, India. Dengue Bulletin. 2004;28:210–212.  Back to cited text no. 6
    
7.
Thenmozhi V, Hiryan J, Tiwari SC, Samuel P. Natural and vertical transmission of dengue virus in Aedes albopictus in southern India, Kerala. Japanese J Infect Dis. 2007;60:245–249.  Back to cited text no. 7
    
8.
Nagpal BN, Sharma VP. Survey of mosquito fauna of northeastern region of India. Indian J Malariol. 1987;24:143–149.  Back to cited text no. 8
    
9.
Malhotra PR, Sarkar PK, Das NG, Hazarika S, John VM. Mosquito survey in Tirap and Subansiri districts of Arunachal Pradesh. Indian J Malariol. 1987;24:151–158.  Back to cited text no. 9
    
10.
Dutta P, Khan SA, Khan AM, Sharma CK, Mahanta J. Entomological observations on dengue vectors mosquitoes following a suspected outbreak of dengue in certain parts of Nagalnad with notes on susceptibility to insecticides. J Environ Biol. 2004;25:209–212.  Back to cited text no. 10
    
11.
Belkin JN. The Mosquitoes of the South Pacific (Diptera, Culicidae). Vol. l&2. Berkeley and Los Angles: University of California Press, 1962.pp. 608 and 412.  Back to cited text no. 11
    
12.
Huang YM. Contributions to the mosquito fauna of Southeast Asia, XIV The subgenus Stegomyia of Aedes in Southeast Asia. I- The Scutellaris group of species. Contrib Am Entomol Inst. 1972;9(1): 109.  Back to cited text no. 12
    
13.
World Health Organization. Instructions for determining the susceptibility or resistance of adult mosquitoes to organochlorines, organophosphates and carbamate insecticides diagnostic test. Geneva: WHO, 1981. Document No. WHO/VBC/81–806.  Back to cited text no. 13
    
14.
World Health Organization. Instructions for determining the susceptibility or resistance of mosquito larvae to insecticides. Geneva: WHO, 1981. Document No. WHO/VBC/81.807.  Back to cited text no. 14
    
15.
Barua HC, Mahanta J. Serologcial evidence of DEN-2 activity in Assam and Nagaland. J Commun Dis. 1996;28:56–58.  Back to cited text no. 15
    
16.
Barua HC, Mohapatra PK, Kire M, Pegu DK, Mahanta J. Hemorrhagic manifestations associated with dengue virus infection in Nagaland. J CommunDis. 1996;28:301–303.  Back to cited text no. 16
    
17.
Wongkoon S, Jaroensutasinee M, Jaroensutasinee K. Distribution, seasonal variation & dengue transmission prediction in Sisaket, Thailand. Indian J Med Res. 2013;138:347–353.  Back to cited text no. 17
    
18.
Paeporn P, Ya-umphan P, Supaphathom K, Savanpanyalert p Wattanachai P, Patimaprakorn R. Insecticide susceptibility and selection for resistance in a population of Aedes aegypti from Ratchaburi Province, Thailand. Tropical Biomedicine. 2004;21:1–6).  Back to cited text no. 18
    
19.
Paeporn P, Supaphathom K, Srisawat R, Komalamisra N, Deesin V, Ya-umphan P, Sawat SL. Biochemical detection of pyrethroid resistance mechanism in Aedes aegypti in Ratchaburi province, Thailand. Tropical Biomedicine. 2004;21:145–151.  Back to cited text no. 19
    
20.
Mourya DT, Gokhale MD, Chakraborti S, Mahadev PVM, Banerjee K. Insectcide susceptibility status of certain populations of Aedes aegypti mosquito from rural areas of Maharashtra state. Indian J Med Res. 1993;97:87–91.  Back to cited text no. 20
    
21.
Katyal R, Tewari P, Rahman SJ, Pajni HR, Kumar K, Gill KS. Susceptibility status of immature and adult stages of Aedes aegypti against conventional insecticides in Delhi, India. Dengue Bulletin. 2001;25:84–87.  Back to cited text no. 21
    
22.
Singh RK, Dhiman RC, Mittal PK, Dua VK. Susceptibility status of dengue vectors against various insecticides in Koderma (Jharkhand), India. J Vector Borne Dis.2011;48:116–118.  Back to cited text no. 22
    
23.
Arunachalam N, Tana S, Espino Fe, Kittayapong P, Abeyewickreme W, Wai KT, Tyagi BK, Kroeger A, Sommerfeld J, Petzold M. Eco-bio-social determinants of dengue vector breeding: a multicountry study in urban and periurban Asia. Bull World Health Organ. 2010;88:173–184.  Back to cited text no. 23
    
24.
Tun-Lin W, Lenhart A, Nam VS, Rebollar-Téllez E, Morrison AC, Barbazan P, Cote M, Midega J, Sanchez F, Manrique-Saide P, Kroeger A, Nathan MB, Meheus F, Petzold M. Reducing costs and operational constraints of dengue vector control by targeting productive breeding places: a multi-country non-inferiority cluster randomized trial. Trop Med Int Health. 2009;14(9):1143–1153.  Back to cited text no. 24
    
25.
Fock DA. A review of entomological sampling methods and indicators for dengue vectors. Geneva: World Health Organization, 2003. Document No. TDR/IDE/Den/03.1. http://whqlibdoc.who.int/ hq/2003/TDR_IDE_DEN_03.1.pdf - accessed 28 February 2014.  Back to cited text no. 25
    
26.
Fock DA, Alexander N. Multicountry study of Aedes aegypti pupal productivity survey methodology: findings and recommendations. Geneva: World Health Organization, 2006” Document No.TDR/IDE/ DEN/06.1.  Back to cited text no. 26
    
27.
Mourya DT, Thakare JP, Gokhale MD, Powers AM, Hundekar S1, Jaykumar PC. Isolation of chikungunya virus from Aedes aegypti mosquitoes collected in the town of Yawar, Pune district, Maharashtra state, India. Acta Virol. 2001;45:305–309.  Back to cited text no. 27
    
28.
Chandrakant L, Pradhan SK. Emergence of chikungunya virus in Indian subcontinent after 32 years: a review. J Vector Borne Dis. 2006;43:151–160.  Back to cited text no. 28
    
29.
Dutta P, Khan SA, Khan AM, Borah J, Chowdhury P, Mahanta J. First evidence of chikungunya virus infection in Assam, Northeast India. Trans R Soc Trop Med Hyg. 2011;105:355–357.  Back to cited text no. 29
    


    Figures

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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


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