Timeline
Studies on Japanese encephalitis:
2006: Japanese encephalitis (JE)- early warning system (EWS) was developed on a Geographical Information System (GIS) based platform. The model would forecast time of outbreak (week), High, medium and low risk areas (villages) for JE during the ensuing year and size of the outbreak. These information were generated on a yearly basis preceding the JE season by 2-3 months. After validation of the model for 6 years, the model was handed over to Govt. of Assam for generation of yearly forecast and necessary control measures in May 2014 under ICMR’s Flagship Programme in Translation Research. (JE forecast by this model has been a yearly exercise since 2007 having a prediction precision of 70-85% (during the pre-vaccination period). However, accuracy has come down post JE vaccination. Actual JE vaccine coverage records are needed for incorporating the same in the model to get better results.)
2011: Documented age shift trend in JE cases from paediatric to adult population and observed significant clinical differences among both the groups.
2011: Intervention strategies for reducing Japanese encephalitis virus (JEV) transmission using Insecticide Treated Mosquito Nets (ITMN) for human as well as pigs showed sharp reduction in sero-conversion (humans and pigs) in the intervention localities.
2011: Pilot study on immunogenicity and safety of JE vaccine SA-14-14-2 in adults showed protective antibody titre in 95.5% of study participants up to 12 months post vaccination. Subsequently, National Technical Advisory Group on Immunization (NTAGI), GOI, recommended mass vaccination programme among adult population in JE endemic areas.
2013: Established temporal relationship of JEV transmission in pigs, mosquitoes and humans; that revealed sentinel pig sero-conversions to be significantly associated with human case occurrence at 4 weeks’ interval.
2013: JEV incriminated from Cx. vishnui, Cx. pseudovishnui and Cx. tritaeniorhynchus mosquito species
2015: Established circulating JE virus genotype III in North east (NE) India evidenced by virus isolation
2016: Kanamycin and Doxycycline were documented to have potential antiviral activity capable of inhibiting JEV induced pathogenesis both on in-vivo and in-vitro models.
2021: The effectiveness of a single dose of JE vaccine over the 7-year period was found to be 77.0 (95% CI: 67.0–83.0). Vaccine effectiveness decreased from 91% (95% CI: 73.0–97.0) in first year of vaccination to 71% (95% CI: 21.0–90.0) at six years post-vaccination. The incidence of adults JE cases declined from 10.5 per 100,000 in the pre-vaccination period to 5.7 per 100,000 in the years following vaccination. The coverage of vaccine among adults in two districts was 40.1% (36.8–43.5). A single dose of JE vaccine offered adequate protection for at least six years.
Impact and importance:
The work of the Epidemiology and Nutrition Division is instrumental in shaping a healthier future for the NE region. By focusing on the region's unique epidemiological and nutritional challenges, the division not only contributes to the well-being of local communities but also provides valuable insights that can inform national and global public health efforts. Through its research, interventions, and capacity-building activities, the division plays a pivotal role in enhancing the health landscape of one of India's most diverse and dynamic regions.
Studies on JE/Acute encephalitis syndrome (AES):
2018: Developed an algorithm for identification of AES causing aetiologies for the NE states. JE, West Nile, rickettsial diseases and Leptospira were been found to be major contributors towards AES case burden in the NE region.
2018: In view of maximum AES cases being reported during May-Oct, suggestion for inclusion of Doxycycline and Azithromycin in the empirical treatment of AES was made to the Directorate of Health services, Assam. Following this, National Vector Borne Disease Control Programme (NVBDCP) in line with recommendation from ICMR-RMRC, Dibrugarh issued a guideline on empirical use of Doxycycline and Azithromycin for management of AES during May-Oct, to be followed at different levels of health facilities.
Studies on West Nile:
2011: Documented first evidence of West Nile virus (WNV) from Northeast (NE) India as an etiological agent (besides JE) causing AES.
2014: Isolated and documented circulation of two WNV lineage V strains. In-vivo study revealed higher pathogenicity in comparison to archival lineage V Indian strains.
2016: First report of WNV incrimination from Cx. vishnui, Cx. tritaeniorhynchus, Cx. pseudovishnui, Cx. quinquefasciatus, Cx. whitmorei and Ma. Uniformis mosquito species in NE India.
Studies on Scrub typhus & rickettsial diseases:
2012: Reported re-emergence of Scrub typhus in NE region after a gap of 67 years since its maiden report in 1944 during WWII.
2016: Recorded first evidence of Spotted fever and typhus group Rickettsiae and their potential vectors in NE region.
2017: Established scrub typhus as potential aetiology leading to AES in Assam
2018: Presence of multiple strains of Orientia (causative agent of scrub typhus) documented to circulate in NE region, with Karp being the dominant strain.
2020: Documented the first human case of Rickettsia felis infection in the Indian sub-continent
Studies on Chikungunya:
2011: Documented first evidence of Chikungunya virus activity in NE India.
2017: Identified the Chikungunya virus strain circulating in NE as East/Central/South African genotype.
Studies on Dengue:
2018: Documented Ae. aegypti as vectors of DENV-1 and DENV-2 in Assam
2019: Documented all four serotypes of Dengue in NE states and characterized the circulating genotype of Dengue viruses-DENV-1 (Genotype III), DENV-2 (Genotype V), DENV-3 (Genotype III)
2024: Identified Ae. albopictus as a potential vector of dengue in Tripura. The study gave important insights on the preferred larval habitats and provides information on the indication of displacement of Ae. albopictus from rural to urban and semi-urban areas.
Studies on Malaria:
2017: First documentation in India of a novel mutation in dihydropteroate synthetase (Pfdhps) gene in field collected Plasmodium falciparum from Assam and Arunachal Pradesh
2019: Documented An. baimaii, An. minimus and An. nivipes/philippinensis (the established vectors of malaria in North East India) susceptible to different insecticides under organochlorine, organophosphate and pyrethroid groups. Vectors of secondary importance such as An. annularis and An. aconitus were also susceptible to those insecticides. The findings were incorporated in the consolidated report prepared by ICMR, New Delhi and communicated to National Vector Borne Disease Control Program (NVBDCP).
2024:Anopheles culicifacies was reported in four districts of Assam namely Goalpara, Kamrup (R), Kokrajhar and Sonitpur. An. culicifacies samples collected from Goalpara and Sonitpur districts belong to Species B and Species E. The identification of sibling species B and E has important epidemiological implications, as these two species vary in their vectorial capacity for malaria transmission. Species E has a greater susceptibility to Plasmodium parasites and is anthropophilic. In contrast, species B has low susceptibility to malaria parasites and is zoophilic. Therefore, the presence of species E in Goalpara and Sonitpur districts signifies increased receptivity and a greater risk of malaria transmission by this species.
Studies on Wolbachia:
2017: First evidence of natural Wolbachia infection was documented from colonised Anopheles stephensi species.
Ongoing Projects
Completed Projects
Publications
Recent 2021-August 2024
2011-2020
2000-2010
1999-1993
_logo.svg.png){kind=logo}
