NK cell-induced damage to P.falciparum-infected erythrocytes requires ligand-specific recognition and releases parasitophorous vacuoles that are phagocytosed by monocytes in the presence of immune IgG.

Natural killer (NK) cells lyse virus-infected cells and transformed cells through polarized delivery of lytic effector molecules into target cells. We have shown that NK cells lyse Plasmodium falciparum-infected red blood cells (iRBC) via antibody-dependent cellular cytotoxicity (ADCC). A high frequency of adaptive NK cells, with elevated intrinsic ADCC activity, in people chronically exposed to malaria transmission is associated with reduced parasitemia and resistance to disease. How NK cells bind to iRBC and the outcome of iRBC lysis by NK cells has not been investigated. We applied gene ablation in inducible erythrocyte precursors and antibody-blocking experiments with iRBC to demonstrate a central role of CD58 and ICAM-4 as ligands for adhesion by NK cells via CD2 and integrin αMß2, respectively. Adhesion was dependent on opsonization of iRBC by IgG. Live imaging and quantitative flow cytometry of NK-mediated ADCC toward iRBC revealed that damage to the iRBC plasma membrane preceded damage to P. falciparum within parasitophorous vacuoles (PV). PV were identified and tracked with a P.falciparum strain that expresses the PV membrane-associated protein EXP2 tagged with GFP. After NK-mediated ADCC, PV were either found inside iRBC ghosts or released intact and devoid of RBC plasma membrane. Electron microscopy images of ADCC cultures revealed tight NK-iRBC synapses and free vesicles similar in size to GFP+ PV isolated from iRBC lysates by cell sorting. The titer of IgG in plasma of malaria-exposed individuals that bound PV was two orders of magnitude higher than IgG that bound iRBC. This immune IgG stimulated efficient phagocytosis of PV by primary monocytes. The selective NK-mediated damage to iRBC, resulting in release of PV, and subsequent phagocytosis of PV by monocytes may combine for efficient killing and removal of intra-erythrocytic P.falciparum parasite. This mechanism may mitigate the inflammation and malaria symptoms during blood-stage P. falciparum infection.

Structure of Plasmodium falciparum Rh5-CyRPA-Ripr invasion complex.

Plasmodium falciparum causes the severe form of malaria that has high levels of mortality in humans. Blood-stage merozoites of P. falciparum invade erythrocytes, and this requires interactions between multiple ligands from the parasite and receptors in hosts. These interactions include the binding of the Rh5-CyRPA-Ripr complex with the erythrocyte receptor basigin1,2, which is an essential step for entry into human erythrocytes. Here we show that the Rh5-CyRPA-Ripr complex binds the erythrocyte cell line JK-1 significantly better than does Rh5 alone, and that this binding occurs through the insertion of Rh5 and Ripr into host membranes as a complex with high molecular weight. We report a cryo-electron microscopy structure of the Rh5-CyRPA-Ripr complex at subnanometre resolution, which reveals the organization of this essential invasion complex and the mode of interactions between members of the complex, and shows that CyRPA is a critical mediator of complex assembly. Our structure identifies blades 4-6 of the ß-propeller of CyRPA as contact sites for Rh5 and Ripr. The limited contacts between Rh5-CyRPA and CyRPA-Ripr are consistent with the dissociation of Rh5 and Ripr from CyRPA for membrane insertion. A comparision of the crystal structure of Rh5-basigin with the cryo-electron microscopy structure of Rh5-CyRPA-Ripr suggests that Rh5 and Ripr are positioned parallel to the erythrocyte membrane before membrane insertion. This provides information on the function of this complex, and thereby provides insights into invasion by P. falciparum.

Development of a Plasmodium vivax biobank for functional ex vivo assays.

BACKGROUND: Plasmodium vivax is the second most prevalent cause of malaria yet remains challenging to study due to the lack of a continuous in vitro culture system, highlighting the need to establish a biobank of clinical isolates with multiple freezes per sample for use in functional assays. Different methods for cryopreserving parasite isolates were compared and subsequently the most promising one was validated. Enrichment of early- and late-stage parasites and parasite maturation were quantified to facilitate assay planning. METHODS: In order to compare cryopreservation protocols, nine clinical P. vivax isolates were frozen with four glycerolyte-based mixtures. Parasite recovery post thaw, post KCl-Percoll enrichment and in short-term in vitro culture was measured via slide microscopy. Enrichment of late-stage parasites by magnetic activated cell sorting (MACS) was measured. Short and long-term storage of parasites at either - 80 °C or liquid nitrogen were also compared. RESULTS: Of the four cryopreservation mixtures, one mixture (glycerolyte:serum:RBC at a 2.5:1.5:1 ratio) resulted in improved parasite recovery and statistically significant (P < 0.05) enhancement in parasite survival in short-term in vitro culture. A parasite biobank was subsequently generated using this protocol resulting in a collection of 106 clinical isolates, each with 8 vials. The quality of the biobank was validated by measuring several factors from 47 thaws: the average reduction in parasitaemia post-thaw (25.3%); the average fold enrichment post KCl-Percoll (6.65-fold); and the average percent recovery of parasites (22.0%, measured from 30 isolates). During short-term in vitro culture, robust maturation of ring stage parasites to later stages (> 20% trophozoites, schizonts and gametocytes) was observed in 60.0% of isolates by 48 h. Enrichment of mature parasite stages via MACS showed good reproducibility, with an average of 30.0% post-MACS parasitaemia and an average of 5.30 × 105 parasites/vial. Finally, the effect of storage temperature was tested, and no large impacts from short-term (7 days) or long-term (7-10 years) storage at - 80 °C on parasite recovery, enrichment or viability was observed. CONCLUSIONS: Here, an optimized freezing method for P. vivax clinical isolates is demonstrated as a template for the generation and validation of a parasite biobank for use in functional assays.

Plasmodium vivax Strains Use Alternative Pathways for Invasion.

Plasmodium vivax has 2 invasion ligand/host receptor pathways (P. vivax Duffy-binding protein/Duffy antigen receptor for chemokines [DARC] and P. vivax reticulocyte binding protein 2b/transferrin receptor [TfR1]) that are promising targets for therapeutic intervention. We optimized invasion assays with isogenic cultured reticulocytes. Using a receptor blockade approach with multiple P. vivax isolates, we found that all strains utilized both DARC and TfR1, but with significant variation in receptor usage. This suggests that P. vivax, like Plasmodium falciparum, uses alternative invasion pathways, with implications for pathogenesis and vaccine development.

CRISPR/Cas9 knockouts reveal genetic interaction between strain-transcendent erythrocyte determinants of Plasmodium falciparum invasion.

During malaria blood-stage infections, Plasmodium parasites interact with the RBC surface to enable invasion followed by intracellular proliferation. Critical factors involved in invasion have been identified using biochemical and genetic approaches including specific knockdowns of genes of interest from primary CD34+ hematopoietic stem cells (cRBCs). Here we report the development of a robust in vitro culture system to produce RBCs that allow the generation of gene knockouts via CRISPR/Cas9 using the immortal JK-1 erythroleukemia line. JK-1 cells spontaneously differentiate, generating cells at different stages of erythropoiesis, including terminally differentiated nucleated RBCs that we term "jkRBCs." A screen of small-molecule epigenetic regulators identified several bromodomain-specific inhibitors that promote differentiation and enable production of synchronous populations of jkRBCs. Global surface proteomic profiling revealed that jkRBCs express all known Pfalciparum host receptors in a similar fashion to cRBCs and that multiple Pfalciparum strains invade jkRBCs at comparable levels to cRBCs and RBCs. Using CRISPR/Cas9, we deleted two host factors, basigin (BSG) and CD44, for which no natural nulls exist. BSG interacts with the parasite ligand Rh5, a prominent vaccine candidate. A BSG knockout was completely refractory to parasite invasion in a strain-transcendent manner, confirming the essential role for BSG during invasion. CD44 was recently identified in an RNAi screen of blood group genes as a host factor for invasion, and we show that CD44 knockout results in strain-transcendent reduction in invasion. Furthermore, we demonstrate a functional interaction between these two determinants in mediating Pfalciparum erythrocyte invasion.

Generation of an immortalized erythroid progenitor cell line from peripheral blood: A model system for the functional analysis of Plasmodium spp. invasion.

Malaria pathogenesis is caused by the replication of Plasmodium parasites within the red blood cells (RBCs) of the vertebrate host. This selective pressure has favored the evolution of protective polymorphisms in erythrocyte proteins, a subset of which serve as cognate receptors for parasite invasion ligands. Recently, the generation of RBCs from immortalized hematopoietic stem cells (HSCs) has offered a more tractable system for genetic manipulation and long-term in vitro culture, enabling elucidation of the functional determinants of host susceptibility in vitro. Here we report the generation of an immortalized erythroid progenitor cell line (EJ cells) from as few as 100 000 peripheral blood mononuclear cells. It offers a robust method for the creation of customized model systems from small volumes of peripheral blood. The EJ cell differentiation mirrored erythropoiesis of primary HSCs, yielding orthochromatic erythroblasts and enucleated RBCs after eight days (ejRBCs). The ejRBCs supported invasion by both P. vivax and P. falciparum. To demonstrate the genetic tractability of this system, we used CRISPR/Cas9 to disrupt the Duffy Antigen/Receptor for Chemokines (DARC) gene, which encodes the canonical receptor of P. vivax in humans. Invasion of P. vivax into this DARC-knockout cell line was strongly inhibited providing direct genetic evidence that P. vivax requires DARC for RBC invasion. Further, genetic complementation of DARC restored P. vivax invasion. Taken together, the peripheral blood immortalization method presented here offers the capacity to generate biologically representative model systems for studies of blood-stage malaria invasion from the peripheral blood of donors harboring unique genetic backgrounds, or rare polymorphisms.

Enhanced Ex Vivo Plasmodium vivax Intraerythrocytic Enrichment and Maturation for Rapid and Sensitive Parasite Growth Assays.

Plasmodium vivax chloroquine resistance has been documented in nearly every region where this malaria-causing parasite is endemic. Unfortunately, P. vivax resistance surveillance and drug discovery are challenging due to the low parasitemias of patient isolates and poor parasite survival through ex vivo maturation that reduce the sensitivity and scalability of current P. vivax antimalarial assays. Using cryopreserved patient isolates from Brazil and fresh patient isolates from India, we established a robust enrichment method for P. vivax parasites. We next performed a medium screen for formulations that enhance ex vivo survival. Finally, we optimized an isotopic metabolic labeling assay for measuring P. vivax maturation and its sensitivity to antimalarials. A KCl Percoll density gradient enrichment method increased parasitemias from small-volume ex vivo isolates by an average of >40-fold. The use of Iscove's modified Dulbecco's medium for P. vivax ex vivo culture approximately doubled the parasite survival through maturation. Coupling these with [3H]hypoxanthine metabolic labeling permitted sensitive and robust measurements of parasite maturation, which was used to measure the sensitivities of Brazilian P. vivax isolates to chloroquine and several novel antimalarials. These techniques can be applied to rapidly and robustly assess the P. vivax isolate sensitivities to antimalarials for resistance surveillance and drug discovery.

Mechanisms of acid resistance in Escherichia coli.

Adaptation to acid stress is an important factor in the transmission of intestinal microbes. The enterobacterium Escherichia coli uses a range of physiological, metabolic, and proton-consuming acid resistance mechanisms in order to survive acid stresses as low as pH 2.0. The physiological adaptations include membrane modifications and outer membrane porins to reduce proton influx and periplasmic and cytoplasmic chaperones to manage the effects of acid damage. The metabolic acid resistance systems couple proton efflux to energy generation via select components of the electron transport chain, including cytochrome bo oxidase, NADH dehydrogenase I, NADH dehydrogenase II, and succinate dehydrogenase. Under anaerobic conditions the formate hydrogen lyase complex catalyzes conversion of cytoplasmic protons to hydrogen gas. Finally, each major proton-consuming acid resistance system has a pyridoxal-5'-phosphate-dependent amino acid decarboxylase that catalyzes proton-dependent decarboxylation of a substrate amino acid to product and CO2, and an inner membrane antiporter that exchanges external substrate for internal product.

Genetic Evidence for Erythrocyte Receptor Glycophorin B Expression Levels Defining a Dominant Plasmodium falciparum Invasion Pathway into Human Erythrocytes.

Plasmodium falciparum, the parasite that causes the deadliest form of malaria, has evolved multiple proteins known as invasion ligands that bind to specific erythrocyte receptors to facilitate invasion of human erythrocytes. The EBA-175/glycophorin A (GPA) and Rh5/basigin ligand-receptor interactions, referred to as invasion pathways, have been the subject of intense study. In this study, we focused on the less-characterized sialic acid-containing receptors glycophorin B (GPB) and glycophorin C (GPC). Through bioinformatic analysis, we identified extensive variation in glycophorin B (GYPB) transcript levels in individuals from Benin, suggesting selection from malaria pressure. To elucidate the importance of the GPB and GPC receptors relative to the well-described EBA-175/GPA invasion pathway, we used an ex vivo erythrocyte culture system to decrease expression of GPA, GPB, or GPC via lentiviral short hairpin RNA transduction of erythroid progenitor cells, with global surface proteomic profiling. We assessed the efficiency of parasite invasion into knockdown cells using a panel of wild-type P. falciparum laboratory strains and invasion ligand knockout lines, as well as P. falciparum Senegalese clinical isolates and a short-term-culture-adapted strain. For this, we optimized an invasion assay suitable for use with small numbers of erythrocytes. We found that all laboratory strains and the majority of field strains tested were dependent on GPB expression level for invasion. The collective data suggest that the GPA and GPB receptors are of greater importance than the GPC receptor, supporting a hierarchy of erythrocyte receptor usage in P. falciparum.

Demographic and clinical profiles of Plasmodium falciparum and Plasmodium vivax patients at a tertiary care centre in southwestern India.

BACKGROUND: Malaria remains an important cause of morbidity and mortality in India. Though many comprehensive studies have been carried out in Africa and Southeast Asia to characterize and examine determinants of Plasmodium falciparum and Plasmodium vivax malaria pathogenesis, fewer have been conducted in India. METHODS: A prospective study of malaria-positive individuals was conducted at Goa Medical College and Hospital (GMC) from 2012 to 2015 to identify demographic, diagnostic and clinical indicators associated with P. falciparum and P. vivax infection on univariate analysis. RESULTS: Between 2012 and 2015, 74,571 febrile individuals, 6287 (8.4%) of whom were malaria positive, presented to GMC. The total number of malaria cases at GMC increased more than two-fold over four years, with both P. vivax and P. falciparum cases present year-round. Some 1116 malaria-positive individuals (mean age = 27, 91% male), 88.2% of whom were born outside of Goa and 51% of whom were construction workers, were enroled in the study. Of 1088 confirmed malaria-positive patients, 77.0% had P. vivax, 21.0% had P. falciparum and 2.0% had mixed malaria. Patients over 40 years of age and with P. falciparum infection were significantly (p < 0.001) more likely to be hospitalised than younger and P. vivax patients, respectively. While approximately equal percentages of hospitalised P. falciparum (76.6%) and P. vivax (78.9%) cases presented with at least one WHO severity indicator, a greater percentage of P. falciparum inpatients presented with at least two (43.9%, p < 0.05) and at least three (29.9%, p < 0.01) severity features. There were six deaths among the 182 hospitalised malaria positive patients, all of whom had P. falciparum. CONCLUSION: During the four year study period at GMC, the number of malaria cases increased substantially and the greatest burden of severe disease was contributed by P. falciparum.

Linkage between the bacterial acid stress and stringent responses: the structure of the inducible lysine decarboxylase.

The Escherichia coli inducible lysine decarboxylase, LdcI/CadA, together with the inner-membrane lysine-cadaverine antiporter, CadB, provide cells with protection against mild acidic conditions (pH∼5). To gain a better understanding of the molecular processes underlying the acid stress response, the X-ray crystal structure of LdcI was determined. The structure revealed that the protein is an oligomer of five dimers that associate to form a decamer. Surprisingly, LdcI was found to co-crystallize with the stringent response effector molecule ppGpp, also known as the alarmone, with 10 ppGpp molecules in the decamer. ppGpp is known to mediate the stringent response, which occurs in response to nutrient deprivation. The alarmone strongly inhibited LdcI enzymatic activity. This inhibition is important for modulating the consumption of lysine in cells during acid stress under nutrient limiting conditions. Hence, our data provide direct evidence for a link between the bacterial acid stress and stringent responses.

Public health 101 nanocourse: a condensed educational tool for non-public health professionals.

Graduate students and postdoctoral fellows-including those at the Harvard School of Public Health (HSPH)-have somewhat limited opportunities outside of traditional coursework to learn holistically about public health. Because this lack of familiarity could be a barrier to fruitful collaboration across disciplines, HSPH postdocs sought to address this challenge. In response, the Public Health 101 Nanocourse was developed to provide an overview of five core areas of public health (biostatistics, environmental health sciences, epidemiology, health policy and management, and social and behavioral sciences) in a two half-day course format. We present our experiences with developing and launching this novel approach to acquainting wider multidisciplinary audiences with the field of public health.

Descriptive, Hospital-Based, 10-Year Study of Malaria Transmission in Goa, a Southwest Indian State in the Malaria Elimination Phase.

The South Asia International Center of Excellence for Malaria Research, an NIH-funded collaborative program, investigated the epidemiology of malaria in the Indian state of Goa through health facility-based data collected from the Goa Medical College and Hospital (GMC), the state's largest tertiary healthcare facility, between 2012 and 2021. Our study investigated region-specific spatial and temporal patterns of malaria transmission in Goa and the factors driving such patterns. Over the past decade, the number of malaria cases, inpatients, and deaths at the GMC decreased significantly after a peak in 2014-2015. However, the proportion of severe malaria cases increased over the study period. Also, a trend of decreasing average parasitemia and increasing average gametocyte density suggests a shift toward submicroscopic infections and an increase in transmission commitment characteristic of low-transmission regions. Although transmission occurred throughout the year, 75% of the cases occurred between June and December, overlapping with the monsoon (June-October), which featured rainfall above yearly average, minimal diurnal temperature variation, and high relative humidity. Sociodemographic factors also had a significant association with malaria cases, with cases being more frequent in the 15-50-year-old age group, men, construction workers, and people living in urban areas within the GMC catchment region. Our environmental model of malaria transmission projects almost negligible transmission at the beginning of 2025 (annual parasitic index: 0.0095, 95% CI: 0.0075-0.0114) if the current control measures continue undisrupted.

Direct binding targets of the stringent response alarmone (p)ppGpp.

The Escherichia coli stringent response, mediated by the alarmone ppGpp, is responsible for the reorganization of cellular transcription upon nutritional starvation and other stresses. These transcriptional changes occur mainly as a result of the direct effects of ppGpp and its partner transcription factor DksA on RNA polymerase. An often overlooked feature of the stringent response is the direct targeting of other proteins by ppGpp. Here we review the literature on proteins that are known to bind ppGpp and, based on sequence homology, X-ray crystal structures and in silico docking, we propose new potential protein binding targets for ppGpp. These proteins were found to fall into five main categories: (i) cellular GTPases, (ii) proteins involved in nucleotide metabolism, (iii) proteins involved in lipid metabolism, (iv) general metabolic proteins and (v) PLP-dependent basic aliphatic amino acid decarboxylases. Bioinformatic rationale is provided for expanding the role of ppGpp in regulating the activities of the cellular GTPases. Proteins involved in nucleotide and lipid metabolism and general metabolic proteins provide an interesting set of structurally varied stringent response targets. While the inhibition of some PLP-dependent decarboxylases by ppGpp suggests the existence of cross-talk between the acid stress and stringent response systems.

Structure of RavA MoxR AAA+ protein reveals the design principles of a molecular cage modulating the inducible lysine decarboxylase activity.

The MoxR family of AAA+ ATPases is widespread throughout bacteria and archaea but remains poorly characterized. We recently found that the Escherichia coli MoxR protein, RavA (Regulatory ATPase variant A), tightly interacts with the inducible lysine decarboxylase, LdcI/CadA, to form a unique cage-like structure. Here, we present the X-ray structure of RavA and show that the αßα and all-α subdomains in the RavA AAA+ module are arranged as in magnesium chelatases rather than as in classical AAA+ proteins. RavA structure also contains a discontinuous triple-helical domain as well as a ß-barrel-like domain forming a unique fold, which we termed the LARA domain. The LARA domain was found to mediate the interaction between RavA and LdcI. The RavA structure provides insights into how five RavA hexamers interact with two LdcI decamers to form the RavA-LdcI cage-like structure.

Development of a Plasmodium vivax biobank for functional ex vivo assays.

Background: Plasmodium vivax is the second most prevalent cause of malaria yet remains challenging to study due to the lack of a continuous in vitro culture system, highlighting the need to establish a biobank of clinical isolates with multiple freezes per sample for use in functional assays. Different methods for cryopreserving parasite isolates were compared and subsequently the most promising one was validated. Enrichment of early- and late-stage parasites and parasite maturation were quantified to facilitate assay planning. Methods: In order to compare cryopreservation protocols, nine clinical P. vivax isolates were frozen with four glycerolyte-based mixtures. Parasite recovery post thaw, post KCl-Percoll enrichment and in short-term in vitro culture was measured via slide microscopy. Enrichment of late-stage parasites by magnetic activated cell sorting (MACS) was measured. Short and long-term storage of parasites at either -80°C or liquid nitrogen were also compared. Results: Of the four cryopreservation mixtures, one mixture (glycerolyte:serum:RBC at a 2.5:1.5:1 ratio) resulted in improved parasite recovery and statistically significant (P<0.05) enhancement in parasite survival in short-term in vitro culture. A parasite biobank was subsequently generated using this protocol resulting in a collection with 106 clinical isolates, each with 8 vials. The quality of the biobank was validated by measuring several factors from 47 thaws: the average reduction in parasitemia post-thaw (25.3%); the average fold enrichment post KCl-Percoll (6.65-fold); and the average percent recovery of parasites (22.0%, measured from 30 isolates). During short-term in vitro culture, robust maturation of ring stage parasites to later stages (>20% trophozoites, schizonts and gametocytes) was observed in 60.0% of isolates by 48 hours. Enrichment of mature parasite stages via MACS showed good reproducibility, with an average 30.0% post-MACS parasitemia and an average 5.30 × 10 5 parasites/vial. Finally, the effect of storage temperature was tested, and no large impacts from short-term (7 day) or long term (7 - 10 year) storage at -80°C on parasite recovery, enrichment or viability was observed. Conclusions: Here, an optimized freezing method for P. vivax clinical isolates is demonstrated as a template for the generation and validation of a parasite biobank for use in functional assays.

The structure of a Plasmodium vivax Tryptophan Rich Antigen domain suggests a lipid binding function for a pan-Plasmodium multi-gene family.

Tryptophan Rich Antigens (TRAgs) are encoded by a multi-gene family found in all Plasmodium species, but are significantly expanded in P. vivax and closely related parasites. We show that multiple P. vivax TRAgs are expressed on the merozoite surface and that one, PVP01_0000100 binds red blood cells with a strong preference for reticulocytes. Using X-ray crystallography, we solved the structure of the PVP01_0000100 C-terminal tryptophan rich domain, which defines the TRAg family, revealing a three-helical bundle that is conserved across Plasmodium and has structural homology with lipid-binding BAR domains involved in membrane remodelling. Biochemical assays confirm that the PVP01_0000100 C-terminal domain has lipid binding activity with preference for sulfatide, a glycosphingolipid present in the outer leaflet of plasma membranes. Deletion of the putative orthologue in P. knowlesi, PKNH_1300500, impacts invasion in reticulocytes, suggesting a role during this essential process. Together, this work defines an emerging molecular function for the Plasmodium TRAg family.

RBC membrane biomechanics and Plasmodium falciparum invasion: probing beyond ligand-receptor interactions.

A critical step in malaria blood-stage infections is the invasion of red blood cells (RBCs) by merozoite forms of the Plasmodium parasite. Much progress has been made in defining the parasite ligands and host receptors that mediate this critical step. However, less well understood are the RBC biophysical determinants that influence parasite invasion. In this review we explore how Plasmodium falciparum merozoites interact with the RBC membrane during invasion to modulate RBC deformability and facilitate invasion. We further highlight RBC biomechanics-related polymorphisms that might have been selected for in human populations due to their ability to reduce parasite invasion. Such an understanding will reveal the translational potential of targeting host pathways affecting RBC biomechanical properties for the treatment of malaria.

International Center of Excellence for Malaria Research for South Asia and Broader Malaria Research in India.

The Malaria Evolution in South Asia (MESA) International Center of Excellence for Malaria Research (ICEMR) conducted research studies at multiple sites in India to record blood-slide positivity over time, but also to study broader aspects of the disease. From the Southwest of India (Goa) to the Northeast (Assam), the MESA-ICEMR invested in research equipment, operational capacity, and trained personnel to observe frequencies of Plasmodium falciparum and Plasmodium vivax infections, clinical presentations, treatment effectiveness, vector transmission, and reinfections. With Government of India partners, Indian and U.S. academics, and trained researchers on the ground, the MESA-ICEMR team contributes information on malaria in selected parts of India.

Diverse Malaria Presentations across National Institutes of Health South Asia International Center for Excellence in Malaria Research Sites in India.

The Malaria Evolution in South Asia (MESA) International Center for Excellence in Malaria Research (ICEMR) was established by the US National Institutes of Health (US NIH) as one of 10 malaria research centers in endemic countries. In 10 years of hospital-based and field-based work in India, the MESA-ICEMR has documented the changing epidemiology and transmission of malaria in four different parts of India. Malaria Evolution in South Asia-ICEMR activities, in collaboration with Indian partners, are carried out in the broad thematic areas of malaria case surveillance, vector biology and transmission, antimalarial resistance, pathogenesis, and host response. The program integrates insights from surveillance and field studies with novel basic science studies. This is a two-pronged approach determining the biology behind the disease patterns seen in the field, and generating new relevant biological questions about malaria to be tested in the field. Malaria Evolution in South Asia-ICEMR activities inform local and international stakeholders on the current status of malaria transmission in select parts of South Asia including updates on regional vectors of transmission of local parasites. The community surveys and new laboratory tools help monitor ongoing efforts to control and eliminate malaria in key regions of South Asia including the state of evolving antimalarial resistance in different parts of India, new host biomarkers of recent infection, and molecular markers of pathogenesis from uncomplicated and severe malaria.