Lead Institution: London School of Hygiene & Tropical Medicine
Research Areas
Despite a significant reduction in malaria morbidity and mortality in India, Plasmodium cases persist in the State of Odisha, hindering malaria control and elimination efforts locally and statewide. Through a community-based prospective cohort study, the India ICEMR investigates factors driving this maintenance of Plasmodium infections and reservoirs across three of the state's districts with diverse malaria endemicity: Keonjhar, a low malaria risk/transmission area in the north, Boudh, an area of unstable malaria risk/transmission with P. vivax foci in the middle of the state, and Malkangiri, a high malaria risk/transmission area and the most southern district in the state. In parallel, biomarkers associated with infection are being evaluated to inform the design and implementation of new interventions and diagnostic tools. The India ICEMR objectives are to be achieved through the following assessments:
- Comparison of different diagnostic methods (microscopy vs. rapid diagnostic tests (RDT) vs. polymerase chain reaction (PCR)) to determine the frequency, distribution, and overall importance of false negatives, RDT failure / diagnostic evasion, and misdiagnosis across the state
- Surveillance for non-P. falciparum species in Odisha to assess the possible rise of historically minor malaria parasite species in the niche vacated by P. falciparum
- Longitudinal evaluation of anti-Plasmodium antibody profiles to detect asymptomatic gametocyte carriers and better understand origins of persistent human-to-mosquito transmission
- Detection of Plasmodium-infected individuals using novel circulating host and parasite infection biomarkers identified by the India ICEMR
The overarching aim of the India ICEMR is to generate scientific evidence that can be used both locally and nationally to continue making strides toward malaria elimination across India.
Key Achievements
The India ICEMR builds upon and expands the research undertaken during the past 14 years as part of CSCMi 1 and CSCMi 2 led by New York University. Key achievements that informed the design and research questions of the current India ICEMR include:
Leveraging epidemiological and entomological surveillance studies to develop our understanding of malaria across different settings in India
Projects at four eco-epidemiologically different field sites in Gujarat, Meghalaya, Odisha, and Tamil Nadu elucidated the baseline epidemiology of malaria through census, cross-sectional, cohort, and clinic-based studies, using PCR as the gold standard for parasite detection. Researchers identified a considerable burden of asymptomatic and submicroscopic infections. For example, 71% of infections in cross-sectional surveys in Chennai, Tamil Nadu were asymptomatic and 71% submicroscopic. More recent surveys in the northeastern state of Meghalaya, where malaria prevalence has decreased dramatically over the past five years, presented a similar picture, with 97% of all infections asymptomatic and all submicroscopic. As transmission declines across India, Plasmodium infections are increasingly associated with no symptoms and low parasite biomass, making diagnosis challenging and underscoring the need for more sensitive diagnostic tests at the point of care.
Given the diversity of Anopheles mosquitoes in India, an important component of the India ICEMR has been capturing Anopheles adults using Centers for Disease Control and Prevention light traps and aspirators, accompanied by morphological and molecular classification, salivary gland and midgut dissections for malaria parasite detection, and blood meal analysis. A surveillance study in 15 villages in Odisha confirmed An. culicifacies and An. fluviatilis as the major vectors in this area, with greater densities found in cattle sheds compared with human dwellings. Researchers found a shift from the strongly anthropophilic An. fluviatilis S-type, to the more zoophilic T-type with a preference of cattle sheds over human dwellings; such a shift in zoophilic behavior could be a response to the intensified use of indoor residual spraying (IRS) and long-lasting insecticide-treated nets (LLINs) in the area. Blood meal analysis indicated possible frequent switching of feeding between humans and animals, and modeling studies suggested that such a zoophilic cycle was unlikely to be affected by scaling up conventional tools such as IRS or LLINs. Other studies have included determining the molecular mechanisms of insecticide resistance in Indian Anopheles, e.g., alternate point mutations in An. subpictus, mapping the distribution of two kdr mutations in An. stephensi and An. culicifacies in different Indian populations, and studying the evolution of the DDT-resistance mechanism in An. stephensi under laboratory conditions.
The establishment of high throughput ‘omics: a game changer for malaria research
A next generation sequencing facility was set up at the ICMR-National Institute for Malaria Research in Delhi as part of the India ICEMR and was used to develop the first amplicon sequencing protocols for deep sequencing of full-length P. falciparum drug resistance genes Pfmdr1, Pfcrt, PfDHFR, PfDHPS, PfK13, and Pfmrp1. This allowed known and novel mutations of these genes to be detected in patient samples collected through epidemiology studies in Tamil Nadu, Gujarat, and Odisha, revealing allele frequencies indicative of drug resistance across the sites. A major achievement has been the generation of the first P. vivax and P. falciparum reference genomes from India. The population genomic analysis of six P. vivax strains from India, Latin America, North Korea, and Mauritania with six comparator P. falciparum lines revealed twice as much genetic diversity in P. vivax, suggesting a more stable and older association of this species with humans than for P. falciparum, and that vivax malaria will likely be the more difficult parasite to eliminate. Subsequent generation and analysis of ~180 P. vivax whole genome sequences directly from patients at five ICEMRs identified diversity hotspots in the genome and the first P. vivax selective sweeps of two drug resistance-associated genes PvDHR and PvDHPS. Other signals of natural selection suggested that P. vivax is adapting to regional differences in the human host and mosquito vector. Several Indian P. vivax genomes from Chennai showed significant admixture with isolates from Africa and support the hypothesis that contemporary African and South Asian P. vivax populations are genetically similar, suggesting that the latter may have genetically mingled with European lineages during the colonial era.
The use of magnetic resonance imaging (MRI) to study the impact of falciparum malaria on the brain
A main objective of the India ICEMR has been to better understand the mechanisms that lead to cerebral malaria during P. falciparum infection and assess whether these differ in children and adults. Leveraging the availability of a 1.5 Tesla MRI scanner at Ispat General Hospital, Rourkela, researchers carried out serial imaging comparisons between pediatric and adult patients, and demonstrated that posterior reversible encephalopathy syndrome (PRES) frequently occurs in non-fatal cerebral malaria across all age groups, with concurrent and age-dependent patterns of reversible cytotoxic edema. In contrast, fatal cerebral malaria was associated with severe brain swelling in children, and with profound and global hypoxic injury in adults. These results support the hypothesis that both endothelial dysfunction and microvascular obstruction make independent contributions to the pathogenesis of cerebral malaria, and that different adjunct therapies need to be considered according to the patient age. Researchers then demonstrated that the brain is frequently affected in P. falciparum infection, irrespective of disease severity or presence of coma. Intriguingly, adult patients with severe malaria had patterns of brain changes similar to cerebral malaria despite the absence of coma, which were strongly associated with their degree of renal dysfunction. This not only indicates a kidney-brain pathogenic crosstalk, but also that severe malaria leads to a spectrum of neurological findings, where cerebral malaria is only defined by the presence of coma. India ICEMR researchers also highlighted the need to revise the existing definition of “cerebral” malaria, as severity syndromes are overlapping and the current Glasgow Coma Score (GCS) cut-off is not optimal to identify all cases with acute brain alterations.
The identification of biomarkers associated with brain changes on MRI
A key focus of the work of the India ICEMR has been to identify diagnostic and prognostic tools that can be deployed in malaria endemic areas to identify patients with brain involvement where neuroimaging is not an option. These findings have revealed a broader and unrecognized spectrum of cerebral disease in falciparum malaria, as well as inadequacies of the current World Health Organization criteria to diagnose it. Over the course of the last 14 years, researchers have discovered promising plasma biomarkers that strongly correlate with MRI findings and could therefore be developed for diagnostic and prognostic approaches. These include lipocalin-2, S100 calcium-binding protein B (S100B), and miR-150 and miR-3158, two microRNAs involved in hypoxia-related processes. In parallel, the extensive metabolomic and lipidomic analysis of the plasma from patients scanned as part of the CSCMi cohort has revealed specific profiles of elevated neurosteroids associated with brain alterations, and studies are currently underway to validate their diagnostic value in different cohorts.
Assessing the effectiveness of Malaria Camps as part of the DAMaN program in Odisha
Together with state and district level malaria control programs, India ICEMR researchers are working to evaluate the effectiveness of a multi-component, state-sponsored intervention called “Durgama Anchalare Malaria Nirakaran” (DAMaN) in reducing malaria in Odisha. A key activity of the DAMaN program is the implementation of ‘Malaria Camps’ (MCs) where teams of health workers visit villages to provide the intervention, and include seven key activities in each cycle:
- one round of mass screen and treat (MSAT) before the monsoon season conducted with point-of-care RDTs;
- 1-2 rounds of fever screen and treat (FSAT) during or after the monsoon season;
- IRS;
- other vector control methods;
- LLIN distribution (not on an annual basis);
- educational programming; and
- maternal and child health visits and screenings.
In 2019-2021, India ICEMR researchers undertook an initial quasi-experimental cluster-assigned stepped-wedge study with a pretest-posttest control group design to assess the effectiveness of the MCs against local standard of care. Results suggest that the DAMaN intervention is associated with reduced Plasmodium infections in the study villages and thus is a promising, financially feasible approach for malaria control in rural settings. Plans are in place to scale up assessment of the intervention's effectiveness in a state-wide RCT.
Regional Impact
The CSCMi has forged strong links with Indian and international academic partners to promote capacity exchange, training, and transfer of technology to field sites and provided insights that support evidence-based policy making and program implementation. A key approach undertaken is to hold stakeholder meetings to discuss the overall goal, aims, and progress of the India ICEMR, provide a forum for stakeholders to be involved in operations, and undertake assessment of progress for mid-stage study adjustments.
Study Sites
View Sites for The Center for the Study of Complex Malaria in India in a larger map
Staff
Co-Principal Investigators: Sam Wassmer, Ph.D., and Sanjib Mohanty, M.D.
Project Leads
- Sanghamitra Pati, Indian Council of Medical Research - Regional Medical Research Centre Bhubaneshwar
- Praveen Sahu, Community Welfare Society Hospital
- Sanjib Mohanty, Community Welfare Society Hospital
- Jane Carlton, Johns Hopkins Malaria Research Institute
Collaborating Institutions
- Community Welfare Society Hospital, Rourkela, Odisha, India
- Indian Council of Medical Research Regional Medical Research Centre, Bhubaneswar, Odisha, India
- Indian Council of Medical Research National Institute of Research in Tribal Health, Jabalpur, Madhya Pradesh, India
- GLA University, Mathura, Uttar Pradesh, India
- Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Baltimore, MD, USA