ABSTRACT
Lymphatic filariasis is one of the major public health concern in India, and Bankura district of West Bengal is one of the main filaria prone area of the country. Wuchereria bancrofti is the causative organism and Culex quinquefasciatus is the main vector of lymphatic filariasis in India. In the present study, infection and infectivity rate of filarial vector C. quinquefasciatus were determined. The molecular characterization, DNA fingerprinting and phylogenetic analysis of W. bancrofti was done. In the study area, overall vector infection and infectivity rates were 4.83 and 0.97%, respectively. The infection and infectivity rate were found to be higher in rainy season and lower in summer season. The AT and GC content of W. bancrofti SNC Bankura (Accession No. JF930705) were 55.59 and 44.41%, respectively. The phylogenetic tree was prepared following neighbour joining, maximum parsimony, minimum evolutionary and UPGMA methods. The study revealed that W. bancrofti SNC Bankura (JF930705) showed 100% similarity with W. bancrofti (Accession No. EU370161). The cluster containing, W. bancrofti SNC Bankura (JF930705) and W. bancrofti (EU370161) branched with Brugia pahangi (M15309) with 62% bootstrap value. W. bancrofti SNC Bankura (JF930705), W. bancrofti (EU370161) and B. pahangi (M15309) branched with Dirofilaria immitis (AF188120) with 78% bootstrap value.
ABSTRACT
The bacterial isolate Bacillus thuringiensis TS110 was isolated from the rice field soil of Burdwan district, West Bengal, India. Bioassay test of the bacteria TS110 against 3rd, 4th and 5th instar larvae of Cnaphalocrocis medinalis was carried out. Cut leaf assay, potted plant assay and field assay were done. During filed assay, it has been observed that the LC50 (×107) values of TS110 against 3rd, 4th and 5th instar larvae of C. medinalis were 3.77, 5.29, 4.83 and 4.93, 4.42, 4.72 in dry and wet season, respectively. The morphological, biochemical and phylogenetic analysis of the isolate TS110 were done. TS110 was positive for catalase, nitrate reductase, methyl red, voges-proskauer, oxidase, urease, indole, citrate utilization, arginine dihydrolase test, starch, lipid, gelatin, casein, and lecithin hydrolysis test. TS110 showed fermentation test positive for glucose, fructose, mannose, arabinose and trehalose in nutrient broth medium. The antibiotic sensitivity test showed that the bacterial isolate was sensitive to kanamycin (30 µg/disc), nalidixic acid (30 µg/disc), rifampicin (5 µg/disc), doxycycline (30 µg/disc), gatifloxacin (10 µg/disc), vancomycin (30 µg/disc), gentamycin (10 µg/disc), ampicillin (10 µg/disc), ofloxacin (5 µg/disc), levofloxacin (5 µg/disc), streptomycin (10 µg/disc), gentamycin (10 µg/disc). The phylogenetic analysis revealed that TS110 was closely related to different species of B. thuringiensis submitted to the GenBank. On the basis of morpho-physiological and molecular characterization, the bacterial isolate was identified as B. thuringiensis.
ABSTRACT
In this present study the population dynamics of the soil bacteria of some coastal villages, namely Padima, Jatimati, Chanpabani, Palsandapur, Bhagibaharampur, Duttapur, Gangadharpur, Gobindabasan, Somaibasan of Digha, West Bengal, India, was determined. In these villages the aerobic heterotrophic, Gram-negative, spore-forming, starch-hydrolyzing, Pseudomonas, nitrate-reducing, denitrifying, asymbiotic N2 fixing, nitrifying, phosphate-solubilizing bacterial populations ranged from 1.22 to 2.67 × 106, 0.09-1.63 × 105, 1.53-3.68 × 105, 2.22-4.06 × 105, 0.02-0.04 × 105, 0.35-1.33 × 105, 0.07-0.82 × 105, 0.58-2.50 × 105, 0.13-2.35 × 105, 0.05-1.9 × 105 cfu/g dry soil, respectively. The organic carbon content of the soil samples ranged from 0.61 to 0.93 %. The available nitrogen and phosphate in the soils of the study area varied from 11.2 to 29.5 and 230.8-503.09 mg/kg, respectively. The one-way ANOVA revealed significant variations (p < 0.05) in the microbial diversity with respect to different locations of the study site. Shannon-Wiener and Simpson Index of the study areas ranged from 1.56 to 1.88 and 3.85-5.73, respectively. Jatimati showed comparatively higher diversity index among the villages of the study area. From principal component analysis, three components were extracted having the Eigen values of 3.541, 1.603 and 1.391, respectively. Agglometric hierarchial cluster analysis in respect of the number of different bacterial groups in different places of the study area showed that the denitrifying, nitrate reducing, asymbiotic nitrogen-fixing and spore-forming bacteria formed a cluster while Pseudomonas differed from them forming another cluster and nitrifying, Gram negative, phosphate-solubilising and starch-hydrolyzing bacteria formed another different cluster. This variation of the soil bacteria might be dependent on the microhabitat present in different locations of the study area.
ABSTRACT
BACKGROUND & OBJECTIVES: Filariasis is one of the major vector-borne diseases causing serious health problem in the tropics and subtropics. The coastal areas of Digha are known to be a filariasis prone region of West Bengal, India. The filarial parasite Wuchereria bancrofti is transmitted by Culex quinquefasciatus, the established filarial vector in West Bengal, India. The present work was aimed to determine the abundance of different mosquito species; and the frequency, distribution and blood meal analysis of Cx. quinquefasciatus in coastal areas of Digha. METHODS: During the present study, a total of 11,537 mosquitoes [Cx. quinquefasciatus, Armigeres subalbatus, Anopheles barbirostris, An. annularis, An. subpictus, An. sundaicus, Aedes albopictus, and Cx. vishnui (group)] were collected by hand collection method from human habitations and cattlesheds of 10 villages of Digha, West Bengal, India. The seasonal prevalence of Cx. quinquefasciatus was studied. In each season, blood meals of 300 Cx. quinquefasciatus collected from human habitations were analysed during the study period. RESULTS: Cx. quinquefasciatus was found to be the dominant species (88.44% of the total collection) in the study area. It was most frequently found in and around human habitations than cattlesheds. Total man hour density calculation revealed that this species was most prevalent during the rainy season. Two-way ANOVA revealed that the abundance of Cx. quinquefasciatus varied with different seasons. Blood meal analysis showed that the filarial vector preferred human blood than that of other animals. INTERPRETATION & CONCLUSION: This study suggested Cx. quinquefasciatus as the dominant mosquito species in the study area; and the anthropophilic nature of Cx. quinquefasciatus might be the reason of increase in the intensity of filarial transmission in coastal areas of Digha.
