Reappraisal on anopheline mosquitoes of Garhwal region, Uttarakhand, India

Background & objectives: The study examines occurrence of anopheline mosquitoes in seven districts— Dehradun, Pauri, New Tehri, Hardwar, Rudraprayag, Chamoli and Uttarkashi of Garhwal region in Uttarakhand state, India. Methods: The methodological approach comprised sampling and processing of adult/immature mosquitoes, data compilation, meteorological information and parasitological survey.Results: A total of 87 localities covering 24 tehsils/blocks were surveyed during January 2000 to December 2005 for mosquito sampling. The study encountered 18 species of anophelines including three malaria vectors namely Anopheles culicifacies, An. fluviatilis and An. stephensi collected from Kalsi, Dehradun City, Sahaspur, Hardwar town, Roorkee, New Tehri town and Kotdwar localities. An. pallidus has been recorded for the first time from the Garhwal region. All the collected species have been presented with particular reference to their both adult and immature distribution, brief account of bionomics and some ecological notes.Interpretation & conclusion: Out of 18 collected anopheline species, 15 were non-vectors and they were found to create nuisance to the inhabitants. As far as the species distribution was concerned the diversity was more at elevation between 150 and 1000 m above the mean sea level, while the immature of some species were not recovered from those localities where their adults were collected. Certain species of Anopheles were climate determined and their distribution was localized while some others were cosmopolitan

Altitudinal distribution of mosquitoes in mountainous area of Garhwal region : Part–I

Background & objectives : Mosquito fauna diversity in mountainous areas of Garhwal region wasstudied during November 2000 to October 2002 to correlate the altitudinal vegetation and distributionof mosquitoes.Methods : Adult mosquitoes and mosquito immatures were collected using WHO methods and identifiedusing standard keys and catalogues. Altitude of mosquito habitat was measured using portablealtimeter and also by GPS.Results : Altogether 34 species in five genera — Aedes, Anopheles, Armigeres, Culex and Uranotaeniawere encountered in the present study in the altitude range of 300 to 2000 m. Majority of themosquitoes were found in between 300 to 900 m altitude except Culex vagus and Anopheles maculatus,which were found throughout the range.Interpretation & conclusion : The mosquitoes were categorised into six groups based on their altitudinaldistribution. The areas at lowest elevation were having the greatest number of species but notthe corresponding greater number of specimens in the present study

Study on digestive tract contents of fish : Preliminary step for identification of indigenous species in mosquito larval control

The present study is based on screening of food preference by the indigenous fish under its natural condition. The gastrointestinal contents as an indicative of effective bioregulatory activity envisage the selection of a larvivorous fish. As many as 32 species of fishes were collected from their natural habitats at Imphal and Bishenpur districts in Manipur State between August 2007 to February 2008. Faecal drops of active fishes revealed remains of larvae / pupae of mosquitoes. However, the food types in 26 species of fish comprised larvae / pupae of mosquito, algae, weeds, tadepole fishes, crustaceans, insects, gastropods, worms and detritus / debris. On the basis of food preference Aplocheilus panchax, Polyacanthus fasciatus and Puntius manipurensis have been considered as most potent larvivorous fish of the study area

Studies on the Survivorship of Aedes albopictus (Diptera: Culicidae) in vitro in differentiated breeding water from some parts of district Dehradun, Uttarakhand

Survival of arthropod vectors is one of the most important components of transmission of a vector-borne pathogen. In general, any influence on the vector that increases female longevity will increase the likelihood of survival through the extrinsic incubation period of the virus and the risk of disease transmission. Survivability rate of Aedes albopictus was determined during the month of April 2015 based on the breeding success on 03 experimental parameters viz., aged tap water, natural water and distilled water, by constructing a cohort (horizontal) life table. Survivability rate of Aedes albopictus was higher where eggs were emerged in natural water resources, followed by aged tap water. Basic reproductive rate (Ro) of natural water resources accounted highest followed by aged tap water and distilled water. On performing the single way ANOVA, p value found higher than 0.001 concluding the fact that survivability was not independent of water resources. However, while performing Kaplan-Meier survivability test over age dependent parameters no such determining variation was registered. The value of Log rank test (Mantel Cox) abolish the null hypothesis suggesting the fact that there was significant difference in overall survival distribution among the three experimental parameters. Aedes mosquitoes are known to use their olfaction and visual cues to judge the chemical and physical factors present in the breeding water prior to egg laying. Thus, there must be some steps taken in order to analyse the chemicals released by these household deterrents so as to actively utilizing them in the Aedes management strategy

Mosquito Species Associated Within Some Western Himalayas Phytogeographic Zones in the Garhwal Region of India

Thirty four species of mosquitoes (Diptera: Culicidae) were collected across three phytogeographic zones; tropical (300 to 1000 m), sub tropical (1000 to 2000 m) and temperate (2000 to 3000 m) in the Garhwal region of India. They included 5 genera: Aedes, Anopheles, Armigeres, Culex and Uranotaenia. Of these, the immature forms of 23 species were recovered from different breeding habitats. The larval habitats were seepage pools, river beds, rice fields, tanks, forest pools, ditches, streams, rock holes, tree holes, intradomestic containers and shallow pits. Three groups and two separate individual species were associated, based on breeding habitat similarity by means of cluster analysis. The characters taken into consideration for classification were natural/artificial, temporary/permanent, shady/lighted, vegetation, movement and turbidity. Breeding habitats such as streams and rock holes were the richest habitats shared by 18 mosquito species followed by seepage pools harboring 16 species of mosquitoes. The lowest species diversity (6 species) was recorded from shallow pits. Generally, all the collected species were found in natural habitats in quiet/stagnant conditions at a depth of 0.1–0.5 m. Generally, the maximum number of species preferred partially shady and temporary water habitats. Moderate vegetation and clear water habitats also had a diversity of mosquito species. Culex mimeticus Noe and Anopheles maculatus Theobald had the highest association coefficient (0.941) followed by Anopheles stephensi Liston and Anopheles vagus Donitz (0.884). The highest negative association (-0.30) was found between the species of Culex vishnui Theobald and Culex brevipalpis (Giles). There were a few species of mosquitoes for which only immatures were collected. Phytogeographically, the zones of lower elevation shared higher species abundance than the higher elevation

Studies on Symptomatic Profiles of Dengue Fever (DF) vis- -vis Non-Dengue Fever (NDF) in District Dehradun, Uttarakhand

AbstractDengue is considered to be common in most tropical and subtropical regions. The unplanned development of Dehradun city along with increasing circumference of slum areas has resulted in proportional increase of dengue prevalence. Dengue detection by conducting molecular and virological tests is complex, tedious to perform, and is less feasible for routine laboratory practices. Hence, this study was sought to describe the clinical, laboratory and ultrasonic manifestation of dengue fever based on two year’s (2013 and 2014) record in order to classify the features between DF and NDF. Out of a total of 15,556 cases (8253 cases in 2013 and 7303 cases in 2014) of suspected dengue fever, 242 cases (122 in 2013 and 120 in 2014) were reported positive confirming 1.56% serologically by ELISA, which were classified as DF cases and rest as NDF cases. The significant features in DF cases were myalgia, body ache, nausea, retro-orbital pain, skin rash, leukopenia, ALT <50, splenomegaly and hepatomegaly.The sensitivity was found highest in myalgia (91.32%), followed by body ache (88.02%) and nausea (81.82%), whereas highest specificity was found in skin rash (97.56%), trailed by leukopenia (96.63%) and hepatomegaly (96.06%). These predictive values can help the clinician to be more confident that a patient lacking these features does have the disease because of high negative prediction values. Changing characteristics of the disease deserve serious research attention, especially in shifts in modal age, rural spread, social and biological determinants of race; and sex related susceptibility have major implications for health service planning and control strategies

Food preference of Aplocheilus panchax (Cyprinidontiformes: Aplocheilidae) with special reference towards

Abstract: As there is a lack of study on food intake by larvivorous fish in general and Aplocheilus panchax (Cyprinidontiformes: Aplocheilidae) in particular, henceforth a study on food preference by the fish with special reference to Anopheline mosquito larvae has been taken up with aims of its application in field conditions in controlling mosquito population. The test fishes were collected from water fragments of Loktak lake in Manipur state, India. Two experiments were designed -first experiment on the size range food preference between live and artificial food when supplied separately while the second one is based on size range specific preference towards different food items when supplied together. The consumption rate of fish was found higher towards mosquito larvae than chironomids larvae and artificial food. The consumption rate of fish increases on increasing size range. Two-way ANOVA was followed for 2 source of variance i.e., size of fish and food types. A comparison has been made using F-test at 1% level of significance. The fish Aplocheilus panchax showed higher preference to live food and that too on Anopheline larvae; it is presumed that this fish could be one of the efficient biocontrol agents in fields and thus in reducing mosquito borne diseases

Landmark-based geometric morphometric analysis of wing shape among certain species of Aedes mosquitoes in District Dehradun (Uttarakhand), India

Background & objectives: Insect wing morphology has been used in many studies to describe variations among species and populations using traditional morphometrics, and more recently geometric morphometrics. A landmark-based geometric morphometric analysis of the wings of three species of Aedes (Diptera: Culicidae), viz. Ae. aegypti, Ae. albopictus and Ae. pseudotaeniatus, at District Dehradun was conducted belling on the fact that it can provide insight into the population structure, ecology and taxonomic identification. Methods: Adult Aedes mosquito specimens were randomly collected using aerial nets and morphologically examined and identified. The landmarks were identified on the basis of landmark based geometric morphometric analysis thin-plate spline (mainly the software tps-Util 1.28; tps-Dig 1.40; tps-Relw 1.53; and tps-Spline 1.20) and integrated morphometrics programme (mainly twogroup win8 and PCA win8) were utilized. Results: In relative warp (RW) analysis, the first two RW of Ae. aegypti accounted for the highest value (95.82%), followed by Ae. pseudotaeniatus (90.89%), while the lowest (90.12%) being recorded for Ae. albopictus. The bending energies of Ae. aegypti and Ae. pseudotaeniatus were quite identical being 0.1882 and 0.1858 respectively, while Ae. albopictus recorded the highest value of 0.9774. The mean difference values of the distances among Aedes species performing Hotelling′s T 2 test were significantly high, predicting major differences among the taxa. In PCA analysis, the horizontal and vertical axis summarized 52.41 and 23.30% of variances respectively. The centroid size exhibited significant differences among populations (non-parametric Kruskal-Wallis test, H = 10.56, p < 0.01). Interpretation & conclusion: It has been marked out that the geometric morphometrics utilizes powerful and comprehensive statistical procedures to analyze the shape differences of a morphological feature, assuming that the studied mosquitoes may represent different genotypes and probably come from one diverse gene pool

Physico-Chemical Assessment of Natural Breeding Habitats of Mosquito Larvae in Outskirts of Dehradun City, Uttarakhand

Mosquitoes have been an important group of insect vectors causing maximum nuisance and public health problems to human beings. This study was planned to determine the physico-chemical characteristics of breeding habitats of mosquito larvae having emphasis on distribution and abundance of potential vectors from March 2013-Feb 2014 covering all the 4 seasons in selected habitats viz., H-1 (Fresh Water Ponds), H-2 (Swamp Marshy areas), H-3 (Irrigational drains) and H-4 (Grassy Ditches) in outskirts of Dehradun city. Data was statistically analysed, in one way ANOVA p value ≤ 0.001; in Pearson Correlation -0.5 ≥ r ≤ 0.5 and in multiple regression coefficient -1.0 ≥ slope ≤ 1.0 were considered statistically significant. Among the 4 genera of mosquito larvae collected during the study period Anopheles accounted the highest abundance (87.2 ± 7.19) from H-4 in post monsoon period, however in winter season H-4 site dried up and hence no mosquito larvae were found. Water temperature, pH, fluoride concentration, TDS and DO were found to vary significantly with mosquito larval abundance. The correlation (r) between Armigeres and Anopheles was found highest (0.82) while lowest was recorded between Aedes and Culex (0.33). In multiple regression analysis, temperature and dissolved oxygen were observed as positive predictor variables, whereas pH and concentration of fluoride as for negative predictor variables for all the genera of mosquito larvae. The results obtained from the present study would certainly be helpful in designing and implementing control program based on environmental modifications and manipulation

Mark-Release-Recapture (MRR) Study to Determine the Dispersal of Aedes aegypti and Aedes albopictus in Dehradun City, Uttarakhand

Background and Objectives: Knowledge about the movement of adult mosquito vectors in endemic and epidemic areas is valuable for understanding disease transmission dynamics providing a phenomenon of the behaviour, biology, demography, ethology and patterns of disease transmission. Methods: With this respect, the dispersal range of Ae. aegypti and Ae. albopictus had been conducted based on mark-release-recapture method in the campus periphery of Dayanand Anglo Vedic Post Graduate College, Dehradun, Uttarakhand, in the month of June 2015. Results: Aedes recaptured from various distances consist of 21.21% within 20 m, 45.45% within 50 m and 72.72% within 80 m distance from the release point. However, mean dispersion distances of Ae. aegypti and Ae. albopictus were found to be 31.78 m and 97.36 m respectively. The R2 value was found higher in case of Ae. aegypti (0.6795) than Ae. albopictus (0.3597), indicating that Ae. albopictus dispersed more than Ae. aegypti. Using the non-parametric test, Mann-Whitney test for two independent samples, the results showed there is no significant difference (p ≤0.05) of flight range of the two species (z=−0.7181, p=0.47152 ). Interpretation and Conclusion: Less recapture rate of male than female justified the fact that mosquitoes will be forced to fly greater distances than they normally would if released at a point distance from any of the enumerated ovipositing items. From the present study, it was suggested that adulticiding should be intensified up to 100 m in and around the periphery of the reported dengue incidences for a week. Busy roads or unshaded areas may serve as barriers to movement of Aedes species and thus water holding containers should be targeted for more intensive adulticiding