Epidemiology and Surveillance

Disease Burden of Rotavirus Diarrhea

Children in urban neighbourhoods in Delhi were followed up for 1 year to estimate the incidence of rotavirus gastroenteritis and common genotypes. Infants aged £1 week were enrolled in cohort 1 and infants aged 12 months (up to +14 days) in cohort 2. 40% (30/210) gastroenteritis episodes were positive for rotavirus. Incidence rates of rotavirus gastroenteritis episodes in the first and second year were 0.18 [95% confidence interval (CI) 0.10–0.27] and 0.14 (95% CI 0.07–0.21) episodes/child-year, respectively. The incidence rate of severe rotavirus gastroenteritis in the first year of life was 0.05 (95% CI 0.01–0.10) episodes/child-year. There were no cases in the second year. The common genotypes detected were G1P[8] (27%) and G9P[4] (23%). That severe rotavirus gastroenteritis is common in the first year of life is relevant for planning efficacy trials (Epidemiol Infect. 2013 Oct;141(10):2094-100)

The Effects of Human Intestinal Microbiota on Immune Responses

The bacterial species living in the gut mediate many aspects of biological processes such as nutrition and activation of adaptive immunity. Also, commensal fungi residing in the intestine also influence host health. Although the interaction of bacterium and fungus has been shown, its precise mechanism during colonization of the human intestine remains largely unknown. Next generation sequencing of fecal samples from Japanese and Indian adults revealed differential patterns of bacterial and fungal composition. In particular, Indians, who consume more plant polysaccharides than Japanese, harbored increased numbers of Prevotella and Candida. Candida spp. showed strong growth responses to the plant polysaccharide arabinoxylan in vitro. The findings of this study demonstrate a proof of concept that fungal members of gut microbiota can facilitate a colonization of the intestine by their bacterial counterparts, potentially mediated by a dietary metabolite.

National Surveillance System for Enteric Fever in India

The Surveillance for Enteric Fever in India (SEFI) programme was established in 2017 to determine the current burden of typhoid and paratyphoid fever. It includes community cohorts, hospital surveillance combined with local health-seeking surveys and expansion of blood-culture testing to tertiary care hospitals. We established a community cohort; eligible children aged between 6 months and 13 years of age were identified. We enrolled a cohort of 6000 children aged 6 months to <14 years in South Delhi and followed them weekly for 24 months or till 15 completed years of child-age. Blood culture to confirm enteric fever was done in children with ≥3 consecutive days of fever. A total of 14650 episodes of fever  were recorded in the 11510 person-years (PY) of follow up; 81 fever episodes were positive for enteric fever. Despite a 35% reduction in incidence compared to the 1995-96 cohort, the study suggested a substantial incidence of enteric fever in the population i.e. 703.7 (560.5-874.7) per 100,000 PY; incidence was highest in children aged 10-15 years.

Establishment of a New Demographic and Health Surveillance Site in an Urban Resettlement Colony in Delhi to Study Disease-specific Epidemiology and Conduct Future Vaccine Trials

We aim to establish a model urban Demographic and Health Surveillance (DHS) site and estimate age-specific incidence and seroprevalence of Dengue and Chikungunya and be a site for future vaccine trials.

We will also estimate prevalence of other conditions of public health importance, build capacity in utilizing the data generated and to strengthen and impart new skills to the team.

The DHS will be established in Dakshinpuri, South Delhi, which is a low-middle-income setting with a population of around 2 lacs. Status: Study Ongoing

A Multicentre, Prospective, Community-based Cohort Study to Estimate the Incidence of Dengue Infection in India (INDEN Study)

We are part of the ICMR-NIE surveillance network for estimating the incidence of laboratory confirmed dengue fever and incidence of asymptomatic or sub clinical dengue infection in the community. We will also estimate the incidence of Chikungunya, malaria, leptospirosis and scrub typhus.

A cohort of 850 children and adults between 2-50 years will be followed for 2 years and contacted weekly for ascertaining fever

Fever episodes ≥2 days will be tested for Dengue, Chikungunya, scrub typhus and leptospirosis

Baseline and yearly samples will be collected for dengue IgG ELISA. Our partner lab is the Molecular Virology laboratory, Department of Microbiology, AIIMS. Status: Preparatory work ongoing.

Optimizing Place of Treatment and Antibiotic Regimens for Young Infants Presenting with Signs of Possible Serious Bacterial Infection

We are part of a WHO coordinated multi-country, open-label, individually randomized controlled trial, in Himachal Pradesh. In this study, we aim to generate knowledge that will allow us to hospitalize only those young infants with PSBI who need hospitalization and treat the others on an outpatient basis. We will randomize 1000 young infants with low-mortality risk signs: temp. ≥38 deg C, severe chest indrawing, fast breathing (≥60 breaths/min) in infants 0-6 d, to receive hospital treatment with Injection Ampicillin, gentamicin and supportive care for 7d or outpatient treatment with Injection Gentamicin OD for 2d and oral amoxicillin BD for 7d.

In another study, we also aim to generate knowledge to allow us to assess if young infants with PSBI who need hospitalization but improve after 48 hours can be discharged early and continue to be treated at home. We will randomize 750 young infants with high-mortality risk signs: movement only when stimulated, not feeding well/stopped feeding well, ≥2 signs including low risk signs, who clinically improve after 48 hours of hospital treatment and have a negative CRP, to continue hospitalization for 5 d or be discharged from the hospital on oral amoxicillin BD for 5 d. Status: Preparatory work ongoing