Vector Biology & Control

Ongoing Projects

• A pilot scale bio-ecological studies on Aedes aegypti population for developing alternate dengue control strategy
• APInetMap-A comprehensive database on Aedes pathogen interactions and network maps.
• Determining discriminating concentrations in bottle assays for insecticide compounds that are unstable on filter papers, and for some selected compounds suitable for filter paper impregnation.
• Field evaluation of Veeralin LN an alphacypermethrin long lasting insecticidal net against natural populations of Anopheles culicifacies s.l. in experimental huts in Odisha, East Central India.
• Assessment of entomological risk factors in terms of vector abundance and dusk index for JE transmission and vector susceptibility to conventional insecticides in three southern districts.
• Laboratory studies on Wolbachia based vector control strategy for the control of dengue/chikungunya transmitted by Aedes aegypti.

New Initiatives

• Epidemiological and entomological investigations of scrub typhus in different eco-epidemiological settings reported with acute encephalitis syndrome
• In-silico prediction and in vitro evaluation of diagnostic epitopes of outer membrane protein b (ompB) of Orientia tsutsugamushi.
• Phase III evaluation to compare insecticidal efficacy and household acceptability of MAGnet, an alphacypermethrin long lasting insecticidal net with DuraNet in India.
• Behavioural change in Anopheline vectors in areas of insecticidal nets (ITNs/LLINs) use in Odisha: A possible challenge to malaria elimination
• Studies on prevalence and spatial distribution of Ixodid tick populations, the vectors of Kyasanur forest disease and the KFD virus in the forest ranges of Eastern/Western Ghats, India
• Studies on vulnerability and receptivity of urban Puducherry in relation to malaria transmission and elimination.
• Tracking the elimination of malaria in Odisha state: Evidence to corroborate the decline of malaria to the status of zero transmission
• Studies on the prevalence of Anopheles sundaicus in Chilka lake, Odisha state, India
• Studies on persistent foci of Plasmodium falciparum malaria among Bonda tribes over three decades in Odisha state
• Population genetic structure and phylogeography of Asian tiger mosquito Aedes albopictus (Skuse) in India

• Stegomyia indices indicate that Ae.aegypti is well established in Lawspet PHC, Puducherry. Epidemiologically, cement tanks, discarded tyres, grinding stones, earthen pots facilitate DC determination test using 6 concentrations
• Predominance of Ae. aegypti suggests conducive environment for their population growth in terms of water holding containers in domestic/ peri-domestic locations. The information generated will serve as a baseline data prior to the implementation of alternate dengue control strategy.
• Step 1 (preliminary testing using 10-12 concentrations) and Step 2 (discriminating concentration test using 6 concentrations test results of three compounds viz., Alpha-cypermethrin, Pirimiphos-methyl, transfluthrin, pyriproxyfen and flupyradifurone have been accomplished. This enables to take these compounds for further validation (Step 3).
• A significant reduction was observed in vector abundance and malaria incidence in all the three arms (IRS alone, LLIN alone and combination of LLIN+IRS) irrespective of the combination, with the level of coverage observed
• The performance of MAGNet after 20/ 25 washes was comparable to unwashed MAGNet as well as to the reference net, DuraNet. Compared to the untreated net, the performance of unwashed or washed MAGNet was significantly higher than the untreated net (negative control) and comparable to/marginally better than the positive control (Duranet) in terms of mortality, deterrence effect, blood-feeding inhibition and induced exophily of the malaria vector, Anopheles fluviatilis in experimental huts.
• Assessment of development of insecticide resistance in malaria vectors based on the exposure of different insecticides - mortality was 74.8% with 1x, and 95.1% with 10x, confirming moderate resistance intensity of Anopheles culicifacies to deltamethrin
• Residual efficacy of DDT: Results of bio assays (before and after spraying DDT indoors), conducted at 1, 9, 16, 22, 31 and 37 days post-spraying showed a corrected mortality of 4.4% to 35.0% indicating that DDT spray was not effective against An. Culicifacies.
• Prevalence of G6PD deficiency among different tribes was studied in Odisha State. Out of 1,423 people from six tribes screened so far, 67 (4.7%) were found to have G6PD deficiency. Since, Plasmodium vivax is prevalent in tribal areas, the study results provide evidence that has implications on the treatment regimens to be used for the treatment of P. vivax patients in the area.
• Studies on “Prevalence of scrub typhus vectors/rodent hosts and the pathogen, Orientia tsutsugamushi in areas reporting human cases of AES in Gorakhpur district, Uttar Pradesh” showed high abundance of mite vectors species with an estimated Leptotrombidium deliense index of 13.8 per animal, which was well above the critical level (0.69 per animal), in the 13 villages surveyed. The study also demonstrated natural infection of O. tsutsugamushi in animal hosts and vector mites in the AES reporting villages of Gorakhpur district, which confirmed transmission of scrub typhus. The findings were useful in sensitization of Medical Officers for early diagnosis, treatment and case management to prevent severe complications and also for implementing appropriate preventive and control measures.
• ICMR- VCRC has initiated laboratory studies on Wolbachia based control of dengue and chikungunya. Wolbachia carrying Aedes aegypti eggs received from Monash University, Australia and cyclic colonies have been raised up to 24th generation. ICMR-VCRC has generated two new Indian Ae. Aegypti colonies by backcrossing Ae. Aegypti females infected with wMel and wAlbB Wolbachia (Aus) strains with wild type Ae. Aegypti (Pud) males and the newly generated wMel and wAlbB infected Ae. Aegypti (Pud) release lines are being maintained over 12 generations, successfully.
• Indoor residual spraying in two Blocks significantly reduced the risk of transmission of JE in Gorakhpur district and the impact of the LLIN distributed in another block was monitored. Similarly, in LLIN block the vector density was reduced with no JE cases compared to control block during post-LLIN distribution.
• Studies on Kyasanur Forest Disease virus (KFDV) in ticks and rodents in potential risk areas of adjoining states to Karnataka showed high abundance of Haemaphysalis vectors in the villages in the forest fringes of the six districts surveyed in Western Ghats of Tamil Nadu, Karanataka and Kerala with KFDV infection in the tick vector in two of the six districts. KFD risk maps created at the district level were provided to the Programme personnel for strengthening the ongoing preventive measures such as vaccination, supply of insect repellents to the high risk groups in particular to the Cholanaickan tribe living deep in the forest, Kattunaickan tribe engaged in the fire line works and other forest staff/workers and intensive health education.

Molecular Biology laboratory- Thermal cycler, Gel documentation Unit, Electrophoresis, Bench top Autoclave, Nanopure water system, Analytical weighing balance, refrigerated micro centrifuge, Label printer, -40° Freezer, High Performance Liquid Chromatography (HPLC), Microplate reader.

Insecticide testing facility (ITF)- Washing machine, Dish washer, Eye wash station, Refrigerator, Cone-bioassay desk, Adult susceptibility test kit, Electronic Weighing balance,

• Long lasting insecticidal nets storage facility
• Insecticide Impregnation Facility (IIF) –Filter paper and bottles.
• Insectary
• Animal House