Less is more: Validating a single method for comprehensive rh-insulin analysis

The objective of this current study is to establish a single method for potency and related proteins analysis of human insulin formulations using reverse-phase high performance liquid (RP-HPLC) chromatography technique which was validated and verified for the potency analysis in insulin formulations. Chromatographic separation was achieved using an octadecylsilane (C-18) stationary phase and a mobile phase composed of 55% (v/v) buffer (0.2 M sodium sulfate in water, {pH 2.3}) and 45% (v/v) acetonitrile. Detection was performed by UV detector at 214 nm with a flow rate of 1 ml/min and an injection volume of 20 µL, at 40°C. Currently there are separate methods available in Indian Pharmacopoeia for analysis of Potency and Related proteins in human insulin. We have validated a single method where quantitation of potency and related proteins can be performed in the same run. The method validation exhibited linearity over the concentration range of 0.08-4.5 mg/ml (r2=0.999) with limit of detection of 0.094 mg/ml The accuracy of the method was 99-102.8%. Thus, it is proposed that both potency and related proteins in insulin formulations can be precisely evaluated using a single run thus saving the time and cost for quality analysis of insulin preparations both at manufacturing and regulatory laboratories which in turn will increase the market availability of such standard quality insulin preparations for public health use.

SARS-CoV-2 spike protein expression as an identification in quality control testing for Adenovector based COVID-19 vaccine

AIM

Quality control testing of the vaccine for lot release is of paramount importance in public health. A recent pandemic caused by the SARS-CoV-2 virus brought together all spheres of vaccine to combat the virus. The scientific advancement in the development of vaccines facilitated the scientists to develop the vaccine against SARS-CoV-2 in a record time. Thus, these vaccines should be stringently monitored for their safety and efficacy as per the latest WHO and national regulatory guidelines, and quality control evaluation of the product should be done at national control laboratories before releasing the product into the market as it assures the quality and safety of the vaccine.

METHODS

The SARS-CoV-2 exploited the ACE2 (Angiotensin Converting Enzyme 2) receptor, a surface protein on mammalian cells to gain entry into the host cells. The viral surface protein that interacted with the ACE2 receptor is the Spike protein of SARS-CoV-2. Thus, in the development of the vaccine and assessing its quality, the Spike protein of SARS-CoV-2 became an attractive immunodominant antigen. In National Institute of Biologicals, an apex body in the testing of biologicals in India, received the Adenovector (Adenovirus + vector) based COVID-19 vaccine, a finished product for quality evaluation. Due to the lack of a pharmacopeial monograph, the testing of the vaccine was done as per the manufacturer's specifications and methods. The routine assays of identification employed by the manufacturer do not reflect the expression of Spike protein which is required for the immune system to get activated. In this report, we showed the determination of Spike protein expression by immunoblotting and immunofluorescence for identification parameters in the quality testing of the COVID-19 vaccine. We determined the translation of the SARS-CoV-2 Spike gene cloned into an Adenovector.

RESULTS

The results from these experiments indicated the expression of Spike protein upon infection of mammalian cells with viral particles suggested that the expression of immunodominant Spike protein of SARS-CoV-2 may be employed by quality control laboratories as a parameter for identification.

CONCLUSION

The study suggested that the determination of the expression of Spike protein is pertinent to identifying the Adenovector based vaccines against COVID-19.

Does acute malnutrition in young children increase the risk of treatment failure following artemisinin-based combination therapy? A WWARN individual patient data meta-analysis

BACKGROUND

The geographical, demographic, and socioeconomic distributions of malaria and malnutrition largely overlap. It remains unknown whether malnutrition affects the efficacy of WHO-recommended artemisinin-based combination therapies (ACTs). A previous systematic review was inconclusive as data were sparse and heterogeneous, indicating that other methodological approaches, such as individual patient data meta-analysis, should be considered. The objective of this study was to conduct such a meta-analysis to assess the effect of malnutrition (wasting and stunting) on treatment outcomes in children younger than 5 years treated with an ACT for uncomplicated falciparum malaria.

METHODS

We conducted a meta-analysis of individual patient data from studies identified through a systematic review of literature published between 1980 and 2018 in PubMed, Global Health, and Cochrane Libraries (PROSPERO CRD42017056934) and inspection of the WorldWide Antimalarial Resistance Network (WWARN) repository for ACT efficacy studies, including children younger than 5 years with uncomplicated falciparum malaria. The association of either acute (wasting) or chronic (stunting) malnutrition with day 42 PCR-adjusted risk of recrudescence (ie, return of the same infection) or reinfection after therapy was investigated using Cox regression, and with day 2 parasite positivity using logistic regression.

FINDINGS

Data were included from all 36 studies targeted, 31 from Africa. Of 11 301 eligible children in 75 study sites, 11·5% were wasted (weight-for-height Z score [WHZ] <-2), and 31·8% were stunted (height-for-age Z score [HAZ] <-2). Decrease in WHZ was associated with increased risk of day 2 positivity (adjusted odds ratio 1·12, 95% CI 1·05-1·18 per unit; p=0·0002), treatment failure (adjusted hazard ratio [AHR] 1·14, 95% CI 1·02-1·26, p=0·016), and reinfection after therapy (AHR 1·09, 1·04-1·13, p=0·0003). Children with milder wasting (WHZ -2 to -1) also had a higher risk of recrudescence (AHR 1·85, 1·29-2·65, p=0·0008 vs WHZ ≥0). Stunting was not associated with reduced ACT efficacy.

INTERPRETATION

Children younger than 5 years with acute malnutrition and presenting with uncomplicated falciparum malaria were at higher risk of delayed parasite clearance, ACT treatment failure, and reinfections. Stunting was more prevalent, but not associated with changes in ACT efficacy. Acute malnutrition is known to impact medicine absorption and metabolism. Further study to inform dose optimisation of ACTs in wasted children is urgently needed.

FUNDING

Bill & Melinda Gates Foundation.

TRANSLATION

For the French translation of the abstract see Supplementary Materials section.

Impact of climate change on temperature variations and extrinsic incubation period of malaria parasites in Chennai, India: implications for its disease transmission potential

BACKGROUND

The global temperature has significantly risen in the past century. Studies have indicated that higher temperature intensifies malaria transmission in tropical and temperate countries. Temperature fluctuations will have a potential impact on parasite development in the vector Anopheles mosquito.

METHODS

Year-long microclimate temperatures were recorded from a malaria-endemic area, Chennai, India, from September 2021 to August 2022. HOBO data loggers were placed in different vector resting sites including indoor and outdoor roof types. Downloaded temperatures were categorised by season, and the mean temperature was compared with data from the same study area recorded from November 2012 to October 2013. The extrinsic incubation period for Plasmodium falciparum and P. vivax was calculated from longitudinal temperatures recorded during both periods. Vector surveillance was also carried out in the area during the summer season.

RESULTS

In general, temperature and daily temperature range (DTR) have increased significantly compared to the 2012-2013 data, especially the DTR of indoor asbestos structures, from 4.30 ℃ to 12.62 ℃ in 2021-2022, unlike the marginal increase observed in thatched and concrete structures. Likewise, the average DTR of outdoor asbestos structures increased from 5.02 ℃ (2012-2013) to 8.76 ℃ (2021-2022) although the increase was marginal in thatched structures and, surprisingly, showed no such changes in concrete structures. The key finding of the extrinsic incubation period (EIP) is that a decreasing trend was observed in 2021-2022 compared to 2012-2013, mainly in indoor asbestos structures from 7.01 to 6.35 days, which negatively correlated with the current observation of an increase in temperature. Vector surveillance undertaken in the summer season revealed the presence of Anopheles breeding in various habitats. Anopheles stephensi could be collected using CDC light traps along with other mosquito species.

CONCLUSION

The microclimate temperature has increased significantly over the years, and mosquitoes are gradually adapting to this rising temperature. Temperature negatively correlates with the extrinsic incubation period of the parasite. As the temperature increases, the development of the parasite in An. stephensi will be faster because of a decrease in EIP, thus requiring relatively fewer days, posing a risk for disease transmission and a hindrance to malaria elimination efforts.

Benefits of Lot Testing to Improve the Quality of Malaria Rapid Diagnostic Tests in India

Since 2010, malaria rapid diagnostic tests (RDTs) are widely used to detect malaria. The Indian Council of Medical Research-National Institute of Malaria Research performed lot testing (LT) according to WHO procedures since 2016. Lot testing is performed to evaluate the lot-to-lot variation in performance of malaria RDTs. Four sets of positive quality control (QC) panels for P. falciparum (Pf) and P. vivax (Pv) and 10 negative panels tested RDTs. RDTs were reported as pass, failed, or deferred on the basis of WHO criteria. In the past 5 years, 275 lots containing 15,488 RDT kits for malaria diagnosis were subjected to LT. The monovalent RDTs (n = 1,216), based on either Pf histidine rich protein 2 (HRP2) or Pan-Plasmodium lactate dehydrogenase (Pan-pLDH) antigens, showed 90.4% sensitivity and 100% specificity, whereas RDTs based on HRP2 + Pan-pLDH or HRP2 + pLDH (n = 13,924) had sensitivity 95.6% and specificity 99.5%, respectively. RDTs based on PfHRP2 + Pv-pLDH + Pan-pLDH (n = 348) had 100% sensitivity and specificity. In a comparison between HRP2 + pLDH or HRP2 + Pan-pLDH to HRP2 + pLDH + Pan-pLDH RDTs, it was found that the sensitivity of PfHRP2 with Pan-pLDH RDTs (n = 2,382) was only 83%. Of the 275 lots analyzed, 15 lots of PfHRP2 with Pan-pLDH were deferred. The QC panel for Pf revealed a faint Pan band in the tested lots, which is a cause for concern. The results of deferred lots were reported to concerned government agencies. Quality-compromised RDTs may lead to an incorrect diagnosis. It is critical to have a QC system in place for effective malaria management.

Monkeypox virus: insights into pathogenesis and laboratory testing methods

The monkeypox virus (MPXV) is a zoonotic pathogen that transmits between monkeys and humans, exhibiting clinical similarities with the smallpox virus. Studies on the immunopathogenesis of MPXV revealed that an initial strong innate immune response is elicited on viral infection that subsequently helps in circumventing the host defense. Once the World Health Organization (WHO) declared it a global public health emergency in July 2022, it became essential to clearly demarcate the MPXV-induced symptoms from other viral infections. We have exhaustively searched the various databases involving Google Scholar, PubMed, and Medline to extract the information comprehensively compiled in this review. The primary focus of this review is to describe the diagnostic methods for MPXV such as polymerase chain reaction (PCR), and serological assays, along with developments in viral isolation, imaging techniques, and next-generation sequencing. These innovative technologies have the potential to greatly enhance the accuracy of diagnostic procedures. Significant discoveries involving MPXV immunopathogenesis have also been highlighted. Overall, this will be a knowledge repertoire that will be crucial for the development of efficient monitoring and control strategies in response to the MPXV infection helping clinicians and researchers in formulating healthcare strategies.

Joint Involvement Can Predict Chikungunya in a Dengue Syndemic Setting in India

Dengue and chikungunya have been endemic in India but have the tendency to cause periodic epidemics, often together, wherein they are termed 'syndemic'. Such a syndemic was observed in 2016 in India which resulted in a further scarcity of already resource-poor specific diagnostic infrastructure even in many urban conglomerates. A cross-sectional study was thus conducted, on 978 fever patients that consulted the ICMR-NIMR fever clinic, New Delhi, in September 2016, with an objective to identify symptom/s that could predict chikungunya with certainty. The overall aim was to rationally channelize the most clinically suitable patients for the required specific diagnosis of chikungunya. Based on their clinical profile, febrile patients attending NIMR's clinic, appropriate laboratory tests and their association analyses were performed. Bivariate analysis on 34 clinical parameters revealed that joint pain, joint swelling, rashes, red spots, weakness, itching, loss of taste, red eyes, and bleeding gums were found to be statistically significantly associated predictors of chikungunya as compared to dengue. While, in multivariate analysis, only four symptoms (joint pain in elbows, joint swelling, itching and bleeding gums) were found in statistically significant association with chikungunya. Hence, based on the results, a clinician may preferably channelize febrile patients with one or more of these four symptoms for chikungunya-specific diagnosis and divert the rest for dengue lab diagnosis in a dengue-chikungunya syndemic setting.

Artemisinin-based combination therapy successfully treated two hyperparasitaemic Plasmodium falciparum cases

Hyperparasitaemia is an important event in the cascade of Plasmodium falciparum severe malaria (SM), and may also lead to SM associated complications and death, if left untreated. Here, we report two hyperparasitaemic patients with no life-threatening complications. Malaria diagnosis was performed using thick and thin blood smears and immunochromatographic-based rapid diagnostic tests (RDTs) purchased from three different manufacturers. Parasitaemia was calculated following the World Health Organization (WHO) guidelines. Haematological and biochemical investigations were also performed. Weekly follow-up of blood smear examination, blood pressure and temperature were recorded up to day 63. The first patient had 42% parasitaemia (100% asexual parasites). The second patient had 9.5% parasitaemia, comprising 46% asexual and 54% sexual stages, with a 1:1 male to female ratio. On the day of admission, both had presented abnormal haematological and biochemical parameters compared to the reference values. Remarkably, both the patients recovered successfully with oral artemisinin-based combination therapy (ACT) and a single dose of primaquine on day 1. Weekly follow-up did not show any parasite suggesting successful treatment with ACT without any side effects. The presence of hypergametocytaemia may hinder malaria elimination efforts, if not treated immediately.

Design and validation of multiplex polymerase chain reaction as a diagnostic tool for Plasmodium species

BACKGROUND & OBJECTIVES

The highly sensitive method for a true understanding of malaria prevalence is of utmost importance for India's elimination strategy. The PCR reaction type with rapid detection, cost-effectiveness, and less workforce should be preferable. Multiplex PCR type accomplishes the present requirement by saving time and resources to find true surveillance data for malaria, especially in low-parasitemia/asymptomatic groups or populations.

METHODS

The present study focuses on designing multiplex PCR (mPCR) to detect simultaneously Plasmodium genus (PAN) and two common Plasmodium species found in India. It is compared to standard nested PCR on 195 clinical samples to diagnose malaria. The mPCR was designed with a minimum number of primers, leading to less clogging and effective and enhanced detection. It contains one common reverse primer and three forward primers amplifying three targeted genes corresponding to P. falciparum, P. vivax, and Plasmodium genus.

RESULTS

The sensitivity and specificity for mPCR were 94.06 and 95.74, respectively. The limit of detection for mPCR was 0.1 parasites/µl. The study has shown a ROC curve area for the mPCR of 0.949 for Plasmodium genus and P. falciparum and 0.897 for P. vivax with standard nPCR.

INTERPRETATION & CONCLUSION

The mPCR is rapid in detecting species together, cost-effective, and requires fewer human resources than the standard nPCR. Therefore, the mPCR can be used as an alternative technique for the higher sensitive detection of the malaria parasite. It could also become a vital tool for determining malaria prevalence, facilitating the application of the most effective measures.

Quality assurance of malaria rapid diagnostic tests: An aid in malaria elimination

Background & objectives

India targets malaria elimination by 2030 in a phased manner, so malaria's assured diagnosis is crucial. Introduction of rapid diagnostic kits in India in 2010 has revolutionized malaria surveillance. The storage temperature of rapid diagnostic tests (RDTs), kit components and handling in transportations impact the results of RDTs. Therefore, quality assurance (QA) is required before it reaches end-users. The Indian Council of Medical Research-National Institute of Malaria Research (ICMR-NIMR) has a World Health Organization (WHO) recognized lot-testing laboratory facility to assure the quality of RDTs.

Methods

The ICMR-NIMR receives RDTs from different manufacturing companies as well as various agencies such as National and State Programmes and Central Medical Services Society. The WHO standard protocol is followed to conduct all the tests, including long-term and post-dispatch testing.

Results

A total of 323 lots tested during January 2014-March 2021 were received from different agencies. Amongst them, 299 lots passed the quality of test and 24 failed. In long-term testing, 179 lots were tested and only nine failed. A total of 7741 RDTs were received from end-users for post-dispatch testing of which 7540 qualified the QA test with a score of 97.4 per cent.

Interpretation & conclusions

RDTs received for quality testing showed compliance with QA evaluation of malaria RDTs based on the protocol recommended by the WHO. However, continuous monitoring of the quality of RDTs is required under QA programme. Quality-assured RDTs have a major role, especially in areas where low parasitaemia of parasites persists.

Cost effective and reliable cell based ELISA as an alternative method of flow cytometry for assessment of binding activity of Vedolizumab

Vedolizumab is a humanized monoclonal antibody used for inflammatory bowel disease treatment. Vedolizumab binds to the α4β7 integrin complex and inhibits its binding to mucosal addressin cell adhesion molecule-1 (MAdCAM-1). To evaluate the binding efficacy and quality control check of Vedolizumab, flow cytometry is performed by using HuT78 cells. As we know, flow cytometer is costly and require high equipment maintenance with a designated technical manpower to handle it. In this regard, the aim of study was to develop and validate an economical, simple and efficient cell based ELISA assay for potency estimation of Vedolizumab which has not been reported in any pharmacopoeia. The proposed bioassay method was optimized by investigating Vedolizumab binding to α4β7 integrin which is expressed by HuT78 cells. The validation of this method was done at different parameters including specificity, linearity, range, repeatability, precision, and accuracy. The Vedolizumab binding by ELISA results were found specific for Vedolizumab with linearity (R² = 0.99) and precision (%Geometric Coefficient of variance) observed for repeatability and intermediate precision were 3.38% and 2.6% respectively. The relative bias was calculated as 8.68% for repeated performances by different analysts and found in accordance with parameter of accuracy as per various pharmacopoeial guidelines. The developed method is established as robust, effective, and less expensive than high maintenance setup like flow cytometry based assay.

Cancer informatics analysis indicates high CHAC2 associated with unfavorable prognosis in breast cancer

Breast cancer remains the most commonly diagnosed cancer worldwide and exhibits a poor prognosis. The induction of genetic changes deregulates several genes that increase the disposal towards this life-threatening disease. CHAC2, a member of the glutathione degrading enzyme family has been shown to suppress gastric and colorectal cancer progression, however, the expression of CHAC2 in breast cancer has not been reported. We did an analysis of CHAC2 expression in breast cancer patients from various online tools like UALCAN, GEPIA2, GENT2, TIMER2, and bcGenExminer v4.8. Further, we used the Kaplan-Meier plotter to establish the significance of CHAC2 in BC patient survival and prognosis while TISIDB and TIMER databases were used to investigate the filtration of immune cells. The results showed that CHAC2 levels were high in breast cancer patients and elevated CHAC2 was associated with low overall survival. Taken together, the results of the present study show that like its paralog CHAC1, CHAC2 may also be an important biomarker and could have a potential therapeutic implication in breast cancer.

Advances in Basic and Translational Research as Part of the Center for the Study of Complex Malaria in India

The Center for the Study of Complex Malaria in India (CSCMi) is one of 10 International Centers of Excellence in Malaria Research funded by the National Institutes of Health since 2010. The Center combines innovative research with capacity building and technology transfer to undertake studies with clinical and translational impact that will move malaria control in India toward the ultimate goal of malaria elimination/eradication. A key element of each research site in the four states of India (Tamil Nadu, Gujarat, Odisha, and Meghalaya) has been undertaking community- and clinic-based epidemiology projects to characterize the burden of malaria in the region. Demographic and clinical data and samples collected during these studies have been used in downstream projects on, for example, the widespread use of mosquito repellants, the population genomics of Plasmodium vivax, and the serological responses to P. vivax and Plasmodium falciparum antigens that reflect past or present exposure. A focus has been studying the pathogenesis of severe malaria caused by P. falciparum through magnetic resonance imaging of cerebral malaria patients. Here we provide a snapshot of some of the basic and applied research the CSCMi has undertaken over the past 12 years and indicate the further research and/or clinical and translational impact these studies have had.

Comparative Assessment of Diagnostic Performance of Cytochrome Oxidase Multiplex PCR and 18S rRNA Nested PCR

Malaria elimination and control require prompt and accurate diagnosis for treatment plan. Since microscopy and rapid diagnostic test (RDT) are not sensitive particularly for diagnosing low parasitemia, highly sensitive diagnostic tools are required for accurate treatment. Molecular diagnosis of malaria is commonly carried out by nested polymerase chain reaction (PCR) targeting 18S rRNA gene, while this technique involves long turnaround time and multiple steps leading to false positive results. To overcome these drawbacks, we compared highly sensitive cytochrome oxidase gene-based single-step multiplex reaction with 18S rRNA nested PCR. Cytochrome oxidase (cox) genes of P. falciparum (cox-III) and P. vivax (cox-I) were compared with 18S rRNA gene nested PCR and microscopy. Cox gene multiplex PCR was found to be highly specific and sensitive, enhancing the detection limit of mixed infections. Cox gene multiplex PCR showed a sensitivity of 100% and a specificity of 97%. This approach can be used as an alternative diagnostic method as it offers higher diagnostic performance and is amenable to high throughput scaling up for a larger sample size at low cost.

Pfhrp2/3 gene deletion and genetic variation in PfHRP2-based RDTs with P. falciparum positive samples from India and its implication on malaria control

BACKGROUND

Recent studies have documented Pfhrp2/3 gene deletion globally as one of the biological threats in the fight against malaria. For malaria diagnosis, PfHRP2 based RDTs are most widely used in India, and performance of these RDTs are affected by deleted Pfhrp2/3 gene in Plasmodium falciparum. This study was planned to confirm Pfhrp2/3 gene deletion incidences and genetic variation in PfHRP2-based RDT positive with P.falciparum malaria cases from India.

METHODOLOGY

Confirmed positive samples by PfHRP2-based RDTs as P. falciparum (n = 240) from six different endemic regions of India were validated by PCR to assure the actual infection. Two hundred forty samples qualified for DNA intactness by single-copy genes were subjected to amplification for the Pfhrp2/3 gene and its neighbouring gene (downstream and upstream) by PCR genotyping. Genetic variation in samples was analysed post-sequencing using Mega X software. Statistical analysis was performed to validate the genetic variation using Mann-Whitney Test.

RESULTS

RDT target region of Pfhrp2 gene (exon2) was found deleted in a single sample with presence of the Pfhrp3 exon2. Complete gene deletion of 4.2% was observed in the Pfhrp3 gene. Partial gene deletion was recorded for both pfhrp2 gene (exon2-0.4%, upstream 25.8% and downstream -9.1%) and Pfhrp3 gene (exon2-18.75%, upstream - 22.08% and downstream 13.3%). Eleven new unique types of amino acid repeat sequence and earlier reported amino acid repeat type was found in the Pfhrp2 gene, prompting high genetic variation.

CONCLUSIONS

This study suggests that parasites lacking Pfhrp2/3 gene and its neighbouring gene (downstream and upstream) are present in malaria endemic areas of India, resulting in false positive results by RDT. Systematic countrywide monitoring for malaria control and elimination of malaria is warranted in this regard.

Impact of the malaria comprehensive case management programme in Odisha, India

Background

The Comprehensive Case Management Project (CCMP), was a collaborative implementation research initiative to strengthen malaria early detection and complete treatment in Odisha State, India.

Methods

A two-arm quasi-experimental design was deployed across four districts in Odisha, representing a range of malaria endemicity: Bolangir (low), Dhenkanal (moderate), Angul (high), and Kandhamal (hyper). In each district, a control block received routine malaria control measures, whereas a CCMP block received a range of interventions to intensify surveillance, diagnosis, and case management. Impact was evaluated by difference-in-difference (DID) analysis and interrupted time-series (ITS) analysis of monthly blood examination rate (MBER) and monthly parasite index (MPI) over three phases: phase 1 pre-CCMP (2009–2012) phase 2 CCMP intervention (2013–2015), and phase 3 post-CCMP (2016–2017).

Results

During CCMP implementation, adjusting for control blocks, DID and ITS analysis indicated a 25% increase in MBER and a 96% increase in MPI, followed by a –47% decline in MPI post-CCMP, though MBER was maintained. Level changes in MPI between phases 1 and 2 were most marked in Dhenkanal and Angul with increases of 976% and 287%, respectively, but declines in Bolangir (−57%) and Kandhamal (−22%). Between phase 2 and phase 3, despite the MBER remaining relatively constant, substantial decreases in MPI were observed in Dhenkanal (−78%), and Angul (−59%), with a more modest decline in Bolangir (−13%), and an increase in Kandhamal (14%).

Conclusions

Overall, CCMP improved malaria early detection and treatment through the enhancement of the existing network of malaria services which positively impacted case incidence in three districts. In Kandhamal, which is hyperendemic, the impact was not evident. However, in Dhenkanal and Angul, areas of moderate-to-high malaria endemicity, CCMP interventions precipitated a dramatic increase in case detection and a subsequent decline in malaria incidence, particularly in previously difficult-to-reach communities.

Haematological consequences of acute uncomplicated falciparum malaria: a WorldWide Antimalarial Resistance Network pooled analysis of individual patient data

BACKGROUND

Plasmodium falciparum malaria is associated with anaemia-related morbidity, attributable to host, parasite and drug factors. We quantified the haematological response following treatment of uncomplicated P. falciparum malaria to identify the factors associated with malarial anaemia.

METHODS

Individual patient data from eligible antimalarial efficacy studies of uncomplicated P. falciparum malaria, available through the WorldWide Antimalarial Resistance Network data repository prior to August 2015, were pooled using standardised methodology. The haematological response over time was quantified using a multivariable linear mixed effects model with nonlinear terms for time, and the model was then used to estimate the mean haemoglobin at day of nadir and day 7. Multivariable logistic regression quantified risk factors for moderately severe anaemia (haemoglobin < 7 g/dL) at day 0, day 3 and day 7 as well as a fractional fall ≥ 25% at day 3 and day 7.

RESULTS

A total of 70,226 patients, recruited into 200 studies between 1991 and 2013, were included in the analysis: 50,859 (72.4%) enrolled in Africa, 18,451 (26.3%) in Asia and 916 (1.3%) in South America. The median haemoglobin concentration at presentation was 9.9 g/dL (range 5.0-19.7 g/dL) in Africa, 11.6 g/dL (range 5.0-20.0 g/dL) in Asia and 12.3 g/dL (range 6.9-17.9 g/dL) in South America. Moderately severe anaemia (Hb < 7g/dl) was present in 8.4% (4284/50,859) of patients from Africa, 3.3% (606/18,451) from Asia and 0.1% (1/916) from South America. The nadir haemoglobin occurred on day 2 post treatment with a mean fall from baseline of 0.57 g/dL in Africa and 1.13 g/dL in Asia. Independent risk factors for moderately severe anaemia on day 7, in both Africa and Asia, included moderately severe anaemia at baseline (adjusted odds ratio (AOR) = 16.10 and AOR = 23.00, respectively), young age (age < 1 compared to ≥ 12 years AOR = 12.81 and AOR = 6.79, respectively), high parasitaemia (AOR = 1.78 and AOR = 1.58, respectively) and delayed parasite clearance (AOR = 2.44 and AOR = 2.59, respectively). In Asia, patients treated with an artemisinin-based regimen were at significantly greater risk of moderately severe anaemia on day 7 compared to those treated with a non-artemisinin-based regimen (AOR = 2.06 [95%CI 1.39-3.05], p < 0.001).

CONCLUSIONS

In patients with uncomplicated P. falciparum malaria, the nadir haemoglobin occurs 2 days after starting treatment. Although artemisinin-based treatments increase the rate of parasite clearance, in Asia they are associated with a greater risk of anaemia during recovery.

Active Pharmacovigilance for Primaquine Radical Cure of Plasmodium vivax Malaria in Odisha, India

Plasmodium vivax malaria elimination requires radical cure with chloroquine/primaquine. However, primaquine causes hemolysis in glucose-6-phosphate dehydrogenase-deficient (G6PDd) individuals. Between February 2016 and July 2017 in Odisha State, India, a prospective, observational, active pharmacovigilance study assessed the hematologic safety of directly observed 25 mg/kg chloroquine over 3 days plus primaquine 0.25 mg/kg/day for 14 days in 100 P. vivax patients (≥ 1 year old) with hemoglobin (Hb) ≥ 7 g/dL. Pretreatment G6PDd screening was not done, but patients were advised on hemolysis signs and symptoms using a visual aid. For evaluable patients, the mean absolute change in Hb between day 0 and day 7 was −0.62 g/dL (95% confidence interval [CI]: −0.93, −0.31) for males (N = 53) versus −0.24 g/dL (95%CI: −0.59, 0.10) for females (N = 45; P = 0.034). Hemoglobin declines ≥ 3 g/dL occurred in 5/99 (5.1%) patients (three males, two females); none had concurrent clinical symptoms of hemolysis. Based on G6PD qualitative testing after study completion, three had a G6PD-normal phenotype, one female was confirmed by genotyping as G6PDd heterozygous, and one male had an unknown phenotype. A G6PDd prevalence survey was conducted between August 2017 and March 2018 in the same region using qualitative G6PD testing, confirmed by genotyping. G6PDd prevalence was 12.0% (14/117) in tribal versus 3.1% (16/509) in nontribal populations, with G6PD Orissa identified in 29/30 (96.7%) of G6PDd samples. Following chloroquine/primaquine, notable Hb declines were observed in this population that were not recognized by patients based on clinical signs and symptoms.

Advanced Multiplex Loop Mediated Isothermal Amplification (mLAMP) Combined with Lateral Flow Detection (LFD) for Rapid Detection of Two Prevalent Malaria Species in India and Melting Curve Analysis

Isothermal techniques with lateral flow detection have emerged as a point of care (POC) technique for malaria, a major parasitic disease in tropical countries such as India. Plasmodium falciparum and Plasmodium vivax are the two most prevalent malaria species found in the country. An advanced multiplex loop-mediated isothermal amplification (mLAMP) combined with a lateral flow dipstick (LFD) technique was developed for the swift and accurate detection of P. falciparum and P. vivax, overcoming the challenges of the existing RDTs (rapid diagnostic tests). A single set of LAMP primers with a biotinylated backward inner primer (BIP primer) was used for DNA amplification of both malaria species in a single tube. The amplified DNA was hybridized with fluorescein isothiocyanate (FITC) and digoxigenin-labelled DNA probes, having a complemented sequence for the P. falciparum and P. vivax genomes, respectively. A colour band appeared on two separate LFDs for P. falciparum and P. vivax upon running the hybridized solution over them. In total, 39 clinical samples were collected from ICMR-NIMR, New Delhi. Melting curve analysis, with cross primers for both species, was used to ascertain specificity, and the sensitivity was equated with a polymerase chain reaction (PCR). The results were visualized on the LFD for both species within 60 min. We found 100% sensitivity and specificity, when compared with a traditional PCR. Melting curve analysis of mLAMP revealed the lowest detection limit of 0.15 pg/μL from sample genomic DNA. The mLAMP-LFD assays could be a potential point of care (POC) tool for early diagnosis in non-laboratory conditions, with the convenience of a reduced assay time and the simple interpretation of results.

Magnetic Multiplex Loop Mediated Isothermal Amplification (MM-LAMP) technique for simultaneous detection of dengue and chikungunya virus

Dengue and chikungunya viruses are arthropod borne virus spread through common vector instigating infection in human. There has been an increased recognition that more attention needs to be paid to similar sympotoms caused by both of the virus as they spread in the same region at same time. It warrants need of cost effective, user friendly and rapid multiplex diagnostic technique which could simultaneously diagnose and identify between two virus diseases in resource poor setting. A magnetic multiplex loop mediated isothermal amplification (MM-LAMP) technique was developed by coupling multiplex LAMP with magnetic particle-based naked eye visualization to overcome the shortcoming of simultaneous detection of both diseases. In recent years this technology has emerged as a particularly attractive candidate as amplification reaction process completes within 45 min. The first step involves multiplexing biotin and digoxigenin coated dengue and chikungunya primers respectively in LAMP reaction followed by precipitation of the amplified DNA with polyethylene glycol (PEG) buffer and finally clumping with streptavidin and anti-digoxigenin coated magnetic particle for virus discrimination and naked eye visualization. The DNA detection limit of MM LAMP visualization was 51.65 ng/μl which is comparable to the electrophoresis base UV light visualization. The results showed potential superiority over standard methods polymerase chain reaction (PCR). This current advancement empowers multiplex LAMP utility in resource limited setting without using any of the florescent dyes, turbidimeter, or the sophisticated quantitative PCR machine etc which restrict multiplex LAMP technique to laboratorial use only. We have proposed a novel method without such limitations. This technique has potential as a point of care technique for simultaneous detection of two diseases.

Genetic surveillance in the Greater Mekong subregion and South Asia to support malaria control and elimination

Background

National Malaria Control Programmes (NMCPs) currently make limited use of parasite genetic data. We have developed GenRe-Mekong, a platform for genetic surveillance of malaria in the Greater Mekong Subregion (GMS) that enables NMCPs to implement large-scale surveillance projects by integrating simple sample collection procedures in routine public health procedures.

Methods

Samples from symptomatic patients are processed by SpotMalaria, a high-throughput system that produces a comprehensive set of genotypes comprising several drug resistance markers, species markers and a genomic barcode. GenRe-Mekong delivers Genetic Report Cards, a compendium of genotypes and phenotype predictions used to map prevalence of resistance to multiple drugs.

Results

GenRe-Mekong has worked with NMCPs and research projects in eight countries, processing 9623 samples from clinical cases. Monitoring resistance markers has been valuable for tracking the rapid spread of parasites resistant to the dihydroartemisinin-piperaquine combination therapy. In Vietnam and Laos, GenRe-Mekong data have provided novel knowledge about the spread of these resistant strains into previously unaffected provinces, informing decision-making by NMCPs.

Conclusions

GenRe-Mekong provides detailed knowledge about drug resistance at a local level, and facilitates data sharing at a regional level, enabling cross-border resistance monitoring and providing the public health community with valuable insights. The project provides a rich open data resource to benefit the entire malaria community.

Funding

The GenRe-Mekong project is funded by the Bill and Melinda Gates Foundation (OPP11188166, OPP1204268). Genotyping and sequencing were funded by the Wellcome Trust (098051, 206194, 203141, 090770, 204911, 106698/B/14/Z) and Medical Research Council (G0600718). A proportion of samples were collected with the support of the UK Department for International Development (201900, M006212), and Intramural Research Program of the National Institute of Allergy and Infectious Diseases.

Prevalence of Pfhrp2/3 gene deletions among false negative rapid antigen test results in central India

Background &objectives: The diagnosis of Plasmodium falciparum malaria is widely dependent on the P. falciparum histidine rich protein 2 (PfHRP2) antigens based rapid diagnostic tests. There are few possible factors like Pfhrp2 polymorphism, Pfhrp2 deletion and density of malaria parasite which can affect the sensitivity of the Pf-HRP2-based RDT. The primary objective of the investigation was to check whether the Pfhrp2 gene deletion is the primary cause of RDT false negative cases.

METHODS

Febrile patients from three districts of Chhattisgarh, India were screened for malaria during 2016-2017 by microscopy and RDT. All microscopy P. falciparum positive samples were validated by PCR. Microscopy positive and RDT negative samples were analyzed for the presence of Exon 2, across Exon 1-2, upstream and downstream of both the Pfhrp2 and Pfhrp3 genes fragment by PCR.

RESULTS

Out of 203 screened samples, 85 were detected positive for P. falciparum malaria based on microscopy and PCR. Among these 85 P. falciparum positive samples, 4 samples were observed Pf-HRP2 RDT negative. Although, it signified that the RDTs used were reliable with sensitivity of 95.3% (81/85). 3/4 PfHRP2-RDT negative samples of the P. falciparum isolates exhibited complete deletion of Pfhrp2 and Pfhrp3 genes and one sample was found RDT false negative due to high parasite density.

INTERPRETATION & CONCLUSION

Pfhrp2 and Pfhrp3 deletions that result in false negative RDTs were uncommon in our setting. The continued monitoring of RDTS which results in false negative tests due to Pfhrp2/3 gene deletion is the need of the hour for an effective malaria elimination strategy.

Optimization of Plasmodium vivax sporozoite production from Anopheles stephensi in South West India

BACKGROUND

Efforts to study the biology of Plasmodium vivax liver stages, particularly the latent hypnozoites, have been hampered by the limited availability of P. vivax sporozoites. Anopheles stephensi is a major urban malaria vector in Goa and elsewhere in South Asia. Using P. vivax patient blood samples, a series of standard membrane-feeding experiments were performed with An. stephensi under the US NIH International Center of Excellence for Malaria Research (ICEMR) for Malaria Evolution in South Asia (MESA). The goal was to understand the dynamics of parasite development in mosquitoes as well as the production of P. vivax sporozoites. To obtain a robust supply of P. vivax sporozoites, mosquito-rearing and mosquito membrane-feeding techniques were optimized, which are described here.

METHODS

Membrane-feeding experiments were conducted using both wild and laboratory-colonized An. stephensi mosquitoes and patient-derived P. vivax collected at the Goa Medical College and Hospital. Parasite development to midgut oocysts and salivary gland sporozoites was assessed on days 7 and 14 post-feeding, respectively. The optimal conditions for mosquito rearing and feeding were evaluated to produce high-quality mosquitoes and to yield a high sporozoite rate, respectively.

RESULTS

Laboratory-colonized mosquitoes could be starved for a shorter time before successful blood feeding compared with wild-caught mosquitoes. Optimizing the mosquito-rearing methods significantly increased mosquito survival. For mosquito feeding, replacing patient plasma with naïve serum increased sporozoite production > two-fold. With these changes, the sporozoite infection rate was high (> 85%) and resulted in an average of ~ 22,000 sporozoites per mosquito. Some mosquitoes reached up to 73,000 sporozoites. Sporozoite production could not be predicted from gametocyte density but could be predicted by measuring oocyst infection and oocyst load.

CONCLUSIONS

Optimized conditions for the production of high-quality P. vivax sporozoite-infected An. stephensi were established at a field site in South West India. This report describes techniques for producing a ready resource of P. vivax sporozoites. The improved protocols can help in future research on the biology of P. vivax liver stages, including hypnozoites, in India, as well as the development of anti-relapse interventions for vivax malaria.

Advanced Lyophilised Loop Mediated Isothermal Amplification (L-LAMP) based point of care technique for the detection of dengue virus

Dengue virus infects millions of the people globally each year and its diagnosis remains a challenge. Conventionally used diagnostic methods are complex and time consuming. LAMP technique is a potential alternative for diagnosis of dengue virus. The benefits of LAMP are its ease and ability, as it does not require an expensive equipment and results are effortlessly visualized by the naked eye. However, it does not aid as point of care technique owing to need of contamination free area, deep freezer for chemical storage and primer self amplification. Each small modification in LAMP method bring it towards an ideal point of care technique. An advanced lyophilized loop mediated isothermal amplification (L-LAMP) was developed in which the dye was dried on the cap and reaction reagents was lyophilized at the bottom of the tube to overcome the common hurdles of LAMP technique. The technique was able to diagnose disease within 35 min with 4U of Bst polymerase. The least concentration of dye required was 1000×. Result given by the seminested reverse transcriptase polymerase chain reaction (RT-PCR) and L-LAMP with enzyme linked immuno sorbent assay (ELISA) were compared using Chi square test. The L-LAMP showed 100 % specificity and 92 % sensitivity with respect ELISA and was found better than RT-PCR which showed 100 % specificity and 88 % sensitivity. There was no cross reactivity of primers with other disease like malaria caused by Plasmodium falciparum and P. vivax and with viral disease chikungunya. L-LAMP has dynamic potential as point of care technique.

Functional Food for the Stimulation of the Immune System Against Malaria

Drug resistance has become a threat to global health, and new interventions are needed to control major infectious diseases. The composition of gut microbiota has been linked to human health and has been associated with severity of malaria. Fermented foods contribute to the community of healthy gut bacteria. Despite the studies connecting gut microbiota to the prevention of malaria transmission and severity, research on developing functional foods for the purpose of manipulating the gut microbiota for malaria control is limited. This review summarizes recent knowledge on the role of the gut microbiota in malaria prevention and treatment. This information should encourage the search for lactic acid bacteria expressing α-Gal and those that exhibit the desired immune stimulating properties for the development of functional food and probiotics for malaria control.

A model for malaria elimination based on learnings from the Malaria Elimination Demonstration Project, Mandla district, Madhya Pradesh

Background

Malaria Elimination Demonstration Project (MEDP) was started as a Public-Private-Partnership between the Indian Council of Medical Research through National Institute of Research in Tribal Health, Govt. of Madhya Pradesh and Foundation of Disease Elimination and Control of India, which is a Corporate Social Responsibility (CSR) initiative of the Sun Pharmaceutical Industries Limited. The project’s goal was to demonstrate that malaria can be eliminated from a high malaria endemic district along with prevention of re-establishment of malaria and to develop a model for malaria elimination using the lessons learned and knowledge acquired from the demonstration project.

Methods

The project employed tested protocols of robust surveillance, case management, vector control, and capacity building through continuous evaluation and training.  The model was developed using the learnings from the operational plan, surveillance and case management, monitoring and feedback, entomological investigations and vector control, IEC and capacity building, supply chain management, mobile application (SOCH), and independent reviews of MEDP.

Results

The MEDP has been operational since April 2017 with field operations from August 2017, and has observed: (1) reduction in indigenous cases of malaria by about 91 %; (2) need for training and capacity building of field staff for diagnosis and treatment of malaria; (3) need for improvement insecticide spraying and for distribution and usage of bed-nets; (4) need for robust surveillance system that captures and documents information on febrile cases, RDT positive individuals, and treatments provided; (5) need for effective supervision of field staff based on advance tour plan; (6) accountability and controls from the highest level to field workers; and (7) need for context-specific IEC.

Conclusions

Malaria elimination is a high-priority public health goal of the Indian Government with a committed deadline of 2030. In order to achieve this goal, built-in systems of accountability, ownership, effective management, operational, technical, and financial controls will be crucial components for malaria elimination in India. This manuscript presents a model for malaria elimination with district as an operational unit, which may be considered for malaria elimination in India and other countries with similar geography, topography, climate, endemicity, health infrastructure, and socio-economic characteristics.

Prevalence of Asymptomatic Malaria Parasitemia in Odisha, India: A Challenge to Malaria Elimination

The prevalence of malaria in India is decreasing, but it remains a major concern for public health administration. The role of submicroscopic malaria and asymptomatic malaria parasitemia and their persistence is being explored. A cross-sectional survey was conducted in the Kandhamal district of Odisha (India) during May-June 2017. Blood samples were collected from 1897 individuals for screening of asymptomatic parasitemia. Samples were screened using rapid diagnostic tests (RDTs) and examined microscopically for Plasmodium species. Approximately 30% of randomly selected samples (n = 586) were analyzed using real-time PCR (qPCR), and the genetic diversity of Plasmodium falciparum was analyzed. The prevalence of Plasmodium species among asymptomatic individuals detected using qPCR was 18%, which was significantly higher than that detected by microscopy examination (5.5%) or RDT (7.3%). Of these, 37% had submicroscopic malaria. The species-specific prevalence among asymptomatic malaria-positive cases for P. falciparum, Plasmodium vivax, and mixed infection (P. falciparum and P. vivax) by qPCR was 57%, 29%, and 14%, respectively. The multiplicity of infection was 1.6 and 1.2 for the merozoite surface protein-1 gene (msp1) and (msp2), respectively. Expected heterozygosity was 0.64 and 0.47 for msp1 and msp2, respectively. A significant proportion of the study population, 105/586 (18%), was found to be a reservoir for malaria infection, and identification of this group will help in the development of elimination strategies.

The risk of Plasmodium vivax parasitaemia after P. falciparum malaria: An individual patient data meta-analysis from the WorldWide Antimalarial Resistance Network

BACKGROUND

There is a high risk of Plasmodium vivax parasitaemia following treatment of falciparum malaria. Our study aimed to quantify this risk and the associated determinants using an individual patient data meta-analysis in order to identify populations in which a policy of universal radical cure, combining artemisinin-based combination therapy (ACT) with a hypnozoitocidal antimalarial drug, would be beneficial.

METHODS AND FINDINGS

A systematic review of Medline, Embase, Web of Science, and the Cochrane Database of Systematic Reviews identified efficacy studies of uncomplicated falciparum malaria treated with ACT that were undertaken in regions coendemic for P. vivax between 1 January 1960 and 5 January 2018. Data from eligible studies were pooled using standardised methodology. The risk of P. vivax parasitaemia at days 42 and 63 and associated risk factors were investigated by multivariable Cox regression analyses. Study quality was assessed using a tool developed by the Joanna Briggs Institute. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42018097400). In total, 42 studies enrolling 15,341 patients were included in the analysis, including 30 randomised controlled trials and 12 cohort studies. Overall, 14,146 (92.2%) patients had P. falciparum monoinfection and 1,195 (7.8%) mixed infection with P. falciparum and P. vivax. The median age was 17.0 years (interquartile range [IQR] = 9.0-29.0 years; range = 0-80 years), with 1,584 (10.3%) patients younger than 5 years. 2,711 (17.7%) patients were treated with artemether-lumefantrine (AL, 13 studies), 651 (4.2%) with artesunate-amodiaquine (AA, 6 studies), 7,340 (47.8%) with artesunate-mefloquine (AM, 25 studies), and 4,639 (30.2%) with dihydroartemisinin-piperaquine (DP, 16 studies). 14,537 patients (94.8%) were enrolled from the Asia-Pacific region, 684 (4.5%) from the Americas, and 120 (0.8%) from Africa. At day 42, the cumulative risk of vivax parasitaemia following treatment of P. falciparum was 31.1% (95% CI 28.9-33.4) after AL, 14.1% (95% CI 10.8-18.3) after AA, 7.4% (95% CI 6.7-8.1) after AM, and 4.5% (95% CI 3.9-5.3) after DP. By day 63, the risks had risen to 39.9% (95% CI 36.6-43.3), 42.4% (95% CI 34.7-51.2), 22.8% (95% CI 21.2-24.4), and 12.8% (95% CI 11.4-14.5), respectively. In multivariable analyses, the highest rate of P. vivax parasitaemia over 42 days of follow-up was in patients residing in areas of short relapse periodicity (adjusted hazard ratio [AHR] = 6.2, 95% CI 2.0-19.5; p = 0.002); patients treated with AL (AHR = 6.2, 95% CI 4.6-8.5; p < 0.001), AA (AHR = 2.3, 95% CI 1.4-3.7; p = 0.001), or AM (AHR = 1.4, 95% CI 1.0-1.9; p = 0.028) compared with DP; and patients who did not clear their initial parasitaemia within 2 days (AHR = 1.8, 95% CI 1.4-2.3; p < 0.001). The analysis was limited by heterogeneity between study populations and lack of data from very low transmission settings. Study quality was high.

CONCLUSIONS

In this meta-analysis, we found a high risk of P. vivax parasitaemia after treatment of P. falciparum malaria that varied significantly between studies. These P. vivax infections are likely attributable to relapses that could be prevented with radical cure including a hypnozoitocidal agent; however, the benefits of such a novel strategy will vary considerably between geographical areas.

Haplotype of RNASE 3 polymorphisms is associated with severe malaria in an Indian population

Severe malaria (SM) caused by Plasmodium falciparum (Pf) infection has been associated with life-threatening anemia, metabolic acidosis, cerebral malaria and multiorgan dysfunction. It may lead to death if not treated promptly. RNASE 3 has been linked to Pf growth inhibition and its polymorphisms found associated with SM and cerebral malaria in African populations. This study aimed to assess the association of RNASE 3 polymorphisms with SM in an Indian population. RNASE 3 gene and flanking regions were amplified followed by direct DNA sequencing in 151 Indian patients who visited Wenlock District Government Hospital, Mangalore, Karnataka, India. Allele, genotype and haplotype frequencies were compared between patients with SM (n = 47) and uncomplicated malaria (UM; n = 104). Homozygous mutant genotype was only found for rs2233860 (+ 499G > C) polymorphism (< 1% frequency). No significant genetic associations were found for RNASE 3 polymorphism genotypes and alleles in Indian SM patients using the Fisher's exact test. C-G-G haplotype of rs2233859 (− 38C > A), rs2073342 (+ 371C > G) and rs2233860 (+ 499G > C) polymorphisms was correlated significantly with SM patients (OR = 3.03; p = 0.008) after Bonferroni correction. A haplotype of RNASE 3 gene was found associated with an increased risk of SM and confirming that RNASE 3 gene plays a role in susceptibility to SM.

Evaluation of Implementation of Intermittent Screening and Treatment for Control of Malaria in Pregnancy in Jharkhand, India

This study evaluated intermittent screening and treatment during pregnancy (ISTp) for malaria using rapid diagnostic tests (RDTs) at antenatal care (ANC) compared with passive case detection within the routine health system. The mixed-method evaluation included two cross-sectional household surveys (pre- and post-implementation of ISTp), in-depth interviews with health workers, and focus group discussions (FGDs) with pregnant women. Differences in proportions between surveys for a number of outcomes were tested; 553 and 534 current and recently pregnant women were surveyed (pre- and post-implementation, respectively). In-depth interviews were conducted with 29 health providers, and 13 FGDs were held with pregnant women. The proportion of pregnant women who received an RDT for malaria at ANC at least once during their pregnancy increased from pre- to post-implementation (19.2%; 95% CI: 14.9, 24.3 versus 42.5%; 95% CI: 36.6, 48.7; P < 0.0001), and the proportion of women who had more than one RDT also increased (16.5%; 95% CI: 13.1, 20.5 versus 27.7%; 95% CI: 23.0, 33.0; P = 0.0008). Post-implementation, however, only 8% of women who had completed their pregnancy received an RDT on three visits to ANC. Health workers were positive about ISTp mainly because of their perception that many pregnant women with malaria were asymptomatic. Health workers perceived pregnant women to have reservations about ISTp because of their dislike of frequent blood withdrawal, but pregnant women themselves were more positive. Intermittent screening and treatment during pregnancy was not sufficiently adopted by health workers to ensure the increased detection of malaria infections achievable with this strategy in this setting.

Efficacy and tolerability of artemisinin-based and quinine-based treatments for uncomplicated falciparum malaria in pregnancy: a systematic review and individual patient data meta-analysis

BACKGROUND

Malaria in pregnancy affects both the mother and the fetus. However, evidence supporting treatment guidelines for uncomplicated (including asymptomatic) falciparum malaria in pregnant women is scarce and assessed in varied ways. We did a systematic literature review and individual patient data (IPD) meta-analysis to compare the efficacy and tolerability of different artemisinin-based or quinine-based treatments for malaria in pregnant women.

METHODS

We did a systematic review of interventional or observational cohort studies assessing the efficacy of artemisinin-based or quinine-based treatments in pregnancy. Seven databases (MEDLINE, Embase, Global Health, Cochrane Library, Scopus, Web of Science, and Literatura Latino Americana em Ciencias da Saude) and two clinical trial registries (International Clinical Trials Registry Platform and ClinicalTrials.gov) were searched. The final search was done on April 26, 2019. Studies that assessed PCR-corrected treatment efficacy in pregnancy with follow-up of 28 days or more were included. Investigators of identified studies were invited to share data from individual patients. The outcomes assessed included PCR-corrected efficacy, PCR-uncorrected efficacy, parasite clearance, fever clearance, gametocyte development, and acute adverse events. One-stage IPD meta-analysis using Cox and logistic regression with random-effects was done to estimate the risk factors associated with PCR-corrected treatment failure, using artemether-lumefantrine as the reference. This study is registered with PROSPERO, CRD42018104013.

FINDINGS

Of the 30 studies assessed, 19 were included, representing 92% of patients in the literature (4968 of 5360 episodes). Risk of PCR-corrected treatment failure was higher for the quinine monotherapy (n=244, adjusted hazard ratio [aHR] 6·11, 95% CI 2·57-14·54, p<0·0001) but lower for artesunate-amodiaquine (n=840, 0·27, 95% 0·14-0·52, p<0·0001), artesunate-mefloquine (n=1028, 0·56, 95% 0·34-0·94, p=0·03), and dihydroartemisinin-piperaquine (n=872, 0·35, 95% CI 0·18-0·68, p=0·002) than artemether-lumefantrine (n=1278) after adjustment for baseline asexual parasitaemia and parity. The risk of gametocyte carriage on day 7 was higher after quinine-based therapy than artemisinin-based treatment (adjusted odds ratio [OR] 7·38, 95% CI 2·29-23·82).

INTERPRETATION

Efficacy and tolerability of artemisinin-based combination therapies (ACTs) in pregnant women are better than quinine. The lower efficacy of artemether-lumefantrine compared with other ACTs might require dose optimisation.

FUNDING

The Bill & Melinda Gates Foundation, ExxonMobil Foundation, and the University of Oxford Clarendon Fund.

Efficacy and safety of fixed dose combination of arterolane maleate and piperaquine phosphate in comparison with chloroquine phosphate in children with acute uncomplicated Plasmodium vivax malaria: A phase III, randomised, multicentric study

BACKGROUND & OBJECTIVES

In India, the burden of Plasmodium vivax malaria has been projected to be highest in some areas. This study investigated the efficacy and safety of fixed dose combination (FDC) of arterolane maleate (AM) 37.5 mg and piperaquine phosphate 187.5 mg (PQP) dispersible tablets and (not with) chloroquine in the treatment of uncomplicated vivax malaria in pediatric patients.

METHODS

This multicentric, open-label trial was carried out at 12 sites in India. A total of 164 patients aged 6 months to 12 years with P. vivax malaria were randomized in a ratio of 2:1 to AM-PQP (111 patients) or chloroquine (53 patients) arms. The duration of follow up was 42 days.

RESULTS

At 72 hours, the proportion of a parasitaemic and afebrile patients was 100% in both treatment arms in per protocol (PP) population, and 98.2% and 100% [95% CI: -1.8 (-6.33 to 5.08)] in AM-PQP and chloroquine arms, respectively, in intent to treat (ITT) population. The efficacy and safety of AM-PQP was found to be comparable to chloroquine in the treatment of uncomplicated P. vivax malaria in pediatric patients. Overall, the cure rate at Day 28 and 42 was >95% for both AM-PQP or CQ. The commonly reported clinical adverse event was vomiting. No patient was discontinued for any QTc abnormality.

INTERPRETATION & CONCLUSION

The efficacy and safety of FDC of arterolane maleate and piperaquine phosphate was found to be comparable to chloroquine for treatment of uncomplicated P. vivax malaria in pediatric patients.

Plasmodium vivax liver stage assay platforms using Indian clinical isolates

Background

Vivax malaria is associated with significant morbidity and economic loss, and constitutes the bulk of malaria cases in large parts of Asia and South America as well as recent case reports in Africa. The widespread prevalence of vivax is a challenge to global malaria elimination programmes. Vivax malaria control is particularly challenged by existence of dormant liver stage forms that are difficult to treat and are responsible for multiple relapses, growing drug resistance to the asexual blood stages and host-genetic factors that preclude use of specific drugs like primaquine capable of targeting Plasmodium vivax liver stages. Despite an obligatory liver-stage in the Plasmodium life cycle, both the difficulty in obtaining P. vivax sporozoites and the limited availability of robust host cell models permissive to P. vivax infection are responsible for the limited knowledge of hypnozoite formation biology and relapse mechanisms, as well as the limited capability to do drug screening. Although India accounts for about half of vivax malaria cases world-wide, very little is known about the vivax liver stage forms in the context of Indian clinical isolates.

Methods

To address this, methods were established to obtain infective P. vivax sporozoites from an endemic region in India and multiple assay platforms set up to detect and characterize vivax liver stage forms. Different hepatoma cell lines, including the widely used HCO4 cells, primary human hepatocytes as well as hepatocytes obtained from iPSC’s generated from vivax patients and healthy donors were tested for infectivity with P. vivax sporozoites.

Results

Both large and small forms of vivax liver stage are detected in these assays, although the infectivity obtained in these platforms are low.

Conclusions

This study provides a proof of concept for detecting liver stage P. vivax and provide the first characterization of P. vivax liver stage forms from an endemic region in India.

Pregnancy outcomes and risk of placental malaria after artemisinin-based and quinine-based treatment for uncomplicated falciparum malaria in pregnancy: a WorldWide Antimalarial Resistance Network systematic review and individual patient data meta-analysis

BACKGROUND

Malaria in pregnancy, including asymptomatic infection, has a detrimental impact on foetal development. Individual patient data (IPD) meta-analysis was conducted to compare the association between antimalarial treatments and adverse pregnancy outcomes, including placental malaria, accompanied with the gestational age at diagnosis of uncomplicated falciparum malaria infection.

METHODS

A systematic review and one-stage IPD meta-analysis of studies assessing the efficacy of artemisinin-based and quinine-based treatments for patent microscopic uncomplicated falciparum malaria infection (hereinafter uncomplicated falciparum malaria) in pregnancy was conducted. The risks of stillbirth (pregnancy loss at ≥ 28.0 weeks of gestation), moderate to late preterm birth (PTB, live birth between 32.0 and < 37.0 weeks), small for gestational age (SGA, birthweight of < 10th percentile), and placental malaria (defined as deposition of malaria pigment in the placenta with or without parasites) after different treatments of uncomplicated falciparum malaria were assessed by mixed-effects logistic regression, using artemether-lumefantrine, the most used antimalarial, as the reference standard. Registration PROSPERO: CRD42018104013.

RESULTS

Of the 22 eligible studies (n = 5015), IPD from16 studies were shared, representing 95.0% (n = 4765) of the women enrolled in literature. Malaria treatment in this pooled analysis mostly occurred in the second (68.4%, 3064/4501) or third trimester (31.6%, 1421/4501), with gestational age confirmed by ultrasound in 91.5% (4120/4503). Quinine (n = 184) and five commonly used artemisinin-based combination therapies (ACTs) were included: artemether-lumefantrine (n = 1087), artesunate-amodiaquine (n = 775), artesunate-mefloquine (n = 965), and dihydroartemisinin-piperaquine (n = 837). The overall pooled proportion of stillbirth was 1.1% (84/4361), PTB 10.0% (619/4131), SGA 32.3% (1007/3707), and placental malaria 80.1% (2543/3035), and there were no significant differences of considered outcomes by ACT. Higher parasitaemia before treatment was associated with a higher risk of SGA (adjusted odds ratio [aOR] 1.14 per 10-fold increase, 95% confidence interval [CI] 1.03 to 1.26, p = 0.009) and deposition of malaria pigment in the placenta (aOR 1.67 per 10-fold increase, 95% CI 1.42 to 1.96, p < 0.001).

CONCLUSIONS

The risks of stillbirth, PTB, SGA, and placental malaria were not different between the commonly used ACTs. The risk of SGA was high among pregnant women infected with falciparum malaria despite treatment with highly effective drugs. Reduction of malaria-associated adverse birth outcomes requires effective prevention in pregnant women.

Triple artemisinin-based combination therapies versus artemisinin-based combination therapies for uncomplicated Plasmodium falciparum malaria: a multicentre, open-label, randomised clinical trial

BACKGROUND

Artemisinin and partner-drug resistance in Plasmodium falciparum are major threats to malaria control and elimination. Triple artemisinin-based combination therapies (TACTs), which combine existing co-formulated ACTs with a second partner drug that is slowly eliminated, might provide effective treatment and delay emergence of antimalarial drug resistance.

METHODS

In this multicentre, open-label, randomised trial, we recruited patients with uncomplicated P falciparum malaria at 18 hospitals and health clinics in eight countries. Eligible patients were aged 2-65 years, with acute, uncomplicated P falciparum malaria alone or mixed with non-falciparum species, and a temperature of 37·5°C or higher, or a history of fever in the past 24 h. Patients were randomly assigned (1:1) to one of two treatments using block randomisation, depending on their location: in Thailand, Cambodia, Vietnam, and Myanmar patients were assigned to either dihydroartemisinin-piperaquine or dihydroartemisinin-piperaquine plus mefloquine; at three sites in Cambodia they were assigned to either artesunate-mefloquine or dihydroartemisinin-piperaquine plus mefloquine; and in Laos, Myanmar, Bangladesh, India, and the Democratic Republic of the Congo they were assigned to either artemether-lumefantrine or artemether-lumefantrine plus amodiaquine. All drugs were administered orally and doses varied by drug combination and site. Patients were followed-up weekly for 42 days. The primary endpoint was efficacy, defined by 42-day PCR-corrected adequate clinical and parasitological response. Primary analysis was by intention to treat. A detailed assessment of safety and tolerability of the study drugs was done in all patients randomly assigned to treatment. This study is registered at ClinicalTrials.gov, NCT02453308, and is complete.

FINDINGS

Between Aug 7, 2015, and Feb 8, 2018, 1100 patients were given either dihydroartemisinin-piperaquine (183 [17%]), dihydroartemisinin-piperaquine plus mefloquine (269 [24%]), artesunate-mefloquine (73 [7%]), artemether-lumefantrine (289 [26%]), or artemether-lumefantrine plus amodiaquine (286 [26%]). The median age was 23 years (IQR 13 to 34) and 854 (78%) of 1100 patients were male. In Cambodia, Thailand, and Vietnam the 42-day PCR-corrected efficacy after dihydroartemisinin-piperaquine plus mefloquine was 98% (149 of 152; 95% CI 94 to 100) and after dihydroartemisinin-piperaquine was 48% (67 of 141; 95% CI 39 to 56; risk difference 51%, 95% CI 42 to 59; p<0·0001). Efficacy of dihydroartemisinin-piperaquine plus mefloquine in the three sites in Myanmar was 91% (42 of 46; 95% CI 79 to 98) versus 100% (42 of 42; 95% CI 92 to 100) after dihydroartemisinin-piperaquine (risk difference 9%, 95% CI 1 to 17; p=0·12). The 42-day PCR corrected efficacy of dihydroartemisinin-piperaquine plus mefloquine (96% [68 of 71; 95% CI 88 to 99]) was non-inferior to that of artesunate-mefloquine (95% [69 of 73; 95% CI 87 to 99]) in three sites in Cambodia (risk difference 1%; 95% CI -6 to 8; p=1·00). The overall 42-day PCR-corrected efficacy of artemether-lumefantrine plus amodiaquine (98% [281 of 286; 95% CI 97 to 99]) was similar to that of artemether-lumefantrine (97% [279 of 289; 95% CI 94 to 98]; risk difference 2%, 95% CI -1 to 4; p=0·30). Both TACTs were well tolerated, although early vomiting (within 1 h) was more frequent after dihydroartemisinin-piperaquine plus mefloquine (30 [3·8%] of 794) than after dihydroartemisinin-piperaquine (eight [1·5%] of 543; p=0·012). Vomiting after artemether-lumefantrine plus amodiaquine (22 [1·3%] of 1703) and artemether-lumefantrine (11 [0·6%] of 1721) was infrequent. Adding amodiaquine to artemether-lumefantrine extended the electrocardiogram corrected QT interval (mean increase at 52 h compared with baseline of 8·8 ms [SD 18·6] vs 0·9 ms [16·1]; p<0·01) but adding mefloquine to dihydroartemisinin-piperaquine did not (mean increase of 22·1 ms [SD 19·2] for dihydroartemisinin-piperaquine vs 20·8 ms [SD 17·8] for dihydroartemisinin-piperaquine plus mefloquine; p=0·50).

INTERPRETATION

Dihydroartemisinin-piperaquine plus mefloquine and artemether-lumefantrine plus amodiaquine TACTs are efficacious, well tolerated, and safe treatments of uncomplicated P falciparum malaria, including in areas with artemisinin and ACT partner-drug resistance.

FUNDING

UK Department for International Development, Wellcome Trust, Bill & Melinda Gates Foundation, UK Medical Research Council, and US National Institutes of Health.

Delayed haemolysis after treatment with intravenous artesunate in patients with severe malaria in India

Background

Parenteral artesunate is the treatment of choice for severe malaria. It is safe, efficacious and well tolerated anti-malarial. However, delayed haemolysis has been reported in travellers, non-immune individuals and in African children.

Methods

A prospective, observational study was carried out in admitted severe malaria patients receiving parenteral artesunate. The patients were followed up until day 28 for monitoring clinical as well as laboratory parameters for haemolytic anaemia.

Results

Twenty-four patients with severe malaria receiving injection artesunate were enrolled in the study. Post-artesunate delayed haemolysis following parenteral artesunate therapy was observed in three of 24 patients (12.5%, 95% confidence interval 4.5–31.2%). Haemolysis was observed in two more patients possibly due to other reasons. The haemoglobin fall ranged from 13.6 to 38.3% from day 7 to day 28 in these patients.

Conclusion

The possibility of delayed haemolysis should be considered while treating the severe malaria patients with parenteral artesunate. The study highlights the need for further studies in different epidemiological settings.

Clinical and epidemiological characterization of severe Plasmodium vivax malaria in Gujarat, India

The mounting evidence supporting the capacity of Plasmodium vivax to cause severe disease has prompted the need for a better characterization of the resulting clinical complications. India is making progress with reducing malaria, but epidemics of severe vivax malaria in Gujarat, one of the main contributors to the vivax malaria burden in the country, have been reported recently and may be the result of a decrease in transmission and immune development. Over a period of one year, we enrolled severe malaria patients admitted at the Civil Hospital in Ahmedabad, the largest city in Gujarat, to investigate the morbidity of severe vivax malaria compared to severe falciparum malaria. Patients were submitted to standard thorough clinical and laboratory investigations and only PCR-confirmed infections were selected for the present study. Severevivax malaria (30 patients) was more frequent than severe falciparum malaria (8 patients) in our setting, and it predominantly affected adults (median age 32 years, interquartile range 22.5 years). This suggests a potential age shift in anti-malarial immunity, likely to result from the recent decrease in transmission across India. The clinical presentation of severe vivax patients was in line with previous reports, with jaundice as the most common complication. Our findings further support the need for epidemiological studies combining clinical characterization of severe vivax malaria and serological evaluation of exposure markers to monitor the impact of elimination programmes.

C-reactive protein as a prognostic marker of Plasmodiumfalciparum malaria severity

Background & objectives

Plasmodiumfalciparum malaria causes wide variety of clinical symptoms ranging from a mild febrile illness to life-threatening complications. For prevention of the severity and early diagnosis, evaluation of potential biomarkers is much needed. C-reactive protein (CRP) is an acute phase protein and well-recognized marker of inflammation in the body. It is synthesized by liver in response to pro-inflammatory responses and has correlation with complications associated with malaria. The study was aimed to assess, if it could serve as a predictive marker for malaria disease severity.

Methods

In the present study, 74 P. falciparum patients and 22 healthy controls were enrolled. Turbidimetric immunoassay was used to measure the CRP in serum samples of all the study participants. Mann-Whitney U-test for continuous data and chi-square test for categorical data were used to compare all malaria cases vs. healthy control group and uncomplicated vs. severe malaria groups. Using receiver operating characteristic (ROC) analysis, best threshold value was determined for CRP in severe malaria patients.

Results

CRP level was significantly elevated in all malaria case groups (1.6 mg/dl IQ 1-2.6) as compared to healthy controls (0.10 mg/dl IQ 0.1-0.20), with p-value <0.0001. Further, CRP level was significantly higher in the severe malaria group (2 mg/dl IQ 1.8-3.9) as compared to the uncomplicated malaria group (1.4 mg/dl IQ 1-2.47) and healthy control group (0.10 mg/dl IQ 0.10-0.20), with p-value <0.05.

Interpretation & conclusion

The present study findings suggest that CRP level can be used to differentiate severe malaria from uncomplicated malaria. Elevated CRP level could be helpful in early prediction of the disease severity in patients infected with P. falciparum and may play an important role in diagnosis of falciparum malaria where improper initial test and clinical manifestations like fever may be absent even with a high load of parasite.

Effectiveness of intermittent screening and treatment for the control of malaria in pregnancy: a cluster randomised trial in India

Background

The control of malaria in pregnancy (MiP) in India relies on testing women who present with symptoms or signs suggestive of malaria. We hypothesised that intermittent screening and treatment for malaria at each antenatal care visit (ISTp) would improve on this approach and reduce the adverse effects of MiP.

Methods

A cluster randomised controlled trial comparing ISTp versus passive case detection (PCD) was conducted in Jharkhand state. Pregnant women of all parities with a gestational age of 18–28 weeks were enrolled. Women in the ISTp group were screened with a rapid diagnostic test (RDT) for malaria at each antenatal clinic visit and those in the PCD group were screened only if they had symptoms or signs suggestive of malaria. All RDT positive women were treated with artesunate/sulfadoxine–pyrimethamine. The primary endpoint was placental malaria, determined by placental histology, and the key secondary endpoints were birth weight, gestational age, vital status of the newborn baby and maternal anaemia.

Results

Between April 2012 and September 2015, 6868 women were enrolled; 3300 in 46 ISTp clusters and 3568 in 41 PCD clusters. In the ISTp arm, 4.9% of women were tested malaria positive and 0.6% in the PCD arm. There was no difference in the prevalence of placental malaria in the ISTp (87/1454, 6.0%) and PCD (65/1560, 4.2%) groups (6.0% vs 4.2%; OR 1.34, 95% CI 0.78 to 2.29, p=0.29) or in any of the secondary endpoints.

Conclusion

ISTp detected more infections than PCD, but monthly ISTp with the current generation of RDT is unlikely to reduce placental malaria or impact on pregnancy outcomes. ISTp trials with more sensitive point-of-care diagnostic tests are needed.

Targeting Asexual and Sexual Blood Stages of the Human Malaria Parasite P. falciparum with 7-Chloroquinoline-Based 1,2,3-Triazoles

Novel 4-amino-7-chloroquinoline-based 1,2,3-triazole hybrids were synthesised in good yields by Cu^I -catalysed Huisgen 1,3-dipolar cycloaddition reactions of 2-azido-N-(7-chloroquinolin-4-ylaminoalkyl)acetamides with various terminal alkynes. These new hybrids were screened in vitro against asexual blood stages of the chloroquine-sensitive 3D7 strain of P. falciparum. The most active compounds were further screened against asexual and sexual stages (gametocytes) of the chloroquine-resistant RKL-9 strain of P. falciparum. Although all compounds were less potent than chloroquine against the 3D7 strain, the three best compounds were appreciably more active than chloroquine against the RKL-9 strain, displaying IC₅₀ values of <100 nm, with one of them having an IC₅₀ of 2.94 nm. Further, the lead compounds were gametocytocidal with IC₅₀ values in the micromolar range, and were observed to induce morphological deformations in mature gametocytes. Most compounds demonstrated little or no cytotoxicity and exhibited good selectivity indices. The most active compounds represent promising candidates for further evaluation of their schizonticidal and gametocytocidal potential.

Improved access to early diagnosis and complete treatment of malaria in Odisha, India

Background

In 2013, the Comprehensive Case Management Programme (CCMP) was initiated to assess the impact of universal access to diagnosis and treatment and improved surveillance on malaria transmission in different settings in Odisha state, India.

Methods

Pairs of intervention and control sub-districts (blocks), matched on malaria incidence were selected in four districts with different transmission intensities. CCMP activities included training and supervision, ensuring no stock-outs of malaria tests and drugs, analysing verified surveillance data, stratifying areas based on risk factors, and appointing alternative providers to underserved areas. Composite risk scores were calculated for each sub-centre using principal component analysis. Post−pre changes (2013–2015 versus 2011–2012) for annual blood examination rates (ABER) and annual parasite incidence (API) across intervention and control groups were assessed using difference-in-difference (DID) estimates, adjusted for malaria transmission risk.

Results

In the intervention sub-centres, the mean increase in ABER was 6.41 tests/sub-centre (95%CI 4.69, 8.14; p<0.01) and in API was 9.2 cases diagnosed/sub-centre (95%CI 5.18, 13.21; p<0.01). The control sub-centres reported lower increases in ABER (2.84 [95%CI 0.35, 5.34]; p<0.05) and API (3.68 [95%CI 0.45, 6.90]; p<0.05). The control-adjusted post–pre changes in API showed that 5.52 more cases (95%CI 0.34, 10.70; p<0.05) were diagnosed, and a 3.6 more cases (95%CI 0.58, 6.56; p<0.05) were tested per sub-centre in the intervention versus control areas. Larger differences in post–pre changes in API between intervention and control sub-centres were registered in the higher transmission-risk areas compared with the lower risk areas. All the changes were statistically significant.

Conclusions

Intensive intervention activities targeted at improved access to malaria diagnosis and treatment produced a substantial increase in blood examination and case notification, especially in inaccessible, hard-to-reach pockets. CCMP provides insights into how to achieve universal coverage of malaria services through a routine, state-run programme.

Insights into the early liver stage biology of Plasmodium

Even though malaria is preventable and curable, it has become a serious threat to mankind. In 2016, there were an estimated 216 million cases of malaria across the world. The biology of its causative agent, i.e. Plasmodium parasite is full of complex mechanisms. There are five Plasmodium species responsible for malaria in humans, viz. Plasmodium falciparum, P. vivax, P. malariae, P. ovale and recently identified P. knowlesi that normally infect apes. In humans, malaria is spread by the injection of Plasmodium sporozoites through the bite of infectious Anopheles' female mosquito during their blood meal. From the time of entry into human skin till the development into the asexual forms, the parasite undergoes several transformations. This review attempts to understand the science behind the pre-erythrocytic liver stage of Plasmodium. Research articles explaining parasite biology, cell-traversal, transformation stages, cell-egress process, etc. were retrieved from PubMed and google scholar database. Various known and unknown mechanisms and strategies used by the malaria parasite P. berghei in rodent models have been discussed in this review. Limited or no information was available for humans, due to technical feasibility and complexity of parasite's life cycle. Hence, it was concluded that there is an urgent need to investigate the hepatic invasion, traversal and egress mechanism of P. falciparum and P. vivax for developing novel therapeutics to fight against malaria.

Influence of midgut microbiota in Anopheles stephensi on Plasmodium berghei infections

Background

The native gut microbiota of Anopheles mosquitoes is known to play a key role in the physiological function of its host. Interestingly, this microbiota can also influence the development of Plasmodium in its host mosquitoes. In recent years, much interest has been shown in the employment of gut symbionts derived from vectors in the control of vector-borne disease transmission. In this study, the midgut microbial diversity has been characterized among laboratory-reared adult Anopheles stephensi mosquitoes, from the colony created by rearing progeny of wild-caught mosquitoes (obtained from three different locations in southern India) for multiple generations, using 16S ribosomal RNA (rRNA) gene sequencing approach. Further, the influence of native midgut microbiota of mosquitoes on the development of rodent malaria parasite Plasmodium berghei in its host has been studied.

Methods

The microbial diversity associated with the midgut of An. stephensi mosquitoes was studied by sequencing V3 region of 16S ribosomal RNA (rRNA) gene. The influence of native midgut microbiota of An. stephensi mosquitoes on the susceptibility of the mosquitoes to rodent malaria parasite P. berghei was studied by comparing the intensity and prevalence of P. berghei infection among the antibiotic treated and untreated cohorts of mosquitoes.

Results

The analysis of bacterial diversity from the midguts of An. stephensi showed Proteobacteria as the most dominant population among the three laboratory-reared strains of An. stephensi studied. Major genera identified among these mosquito strains were Acinetobacter, Pseudomonas, Prevotella, Corynebacterium, Veillonella, and Bacillus. The mosquito infectivity studies carried out to determine the implication of total midgut microbiota on P. berghei infection showed that mosquitoes whose native microbiota cleared with antibiotics had increased susceptibility to P. berghei infection compared to the antibiotic untreated mosquitoes with its natural native microbiota.

Conclusions

The use of microbial symbiont to reduce the competence of vectors involved in disease transmission has gained much importance in recent years as an emerging alternative approach towards disease control. In this context, the present study was aimed to identify the midgut microbiota composition of An. stephensi, and its effect on the development of P. berghei. Interestingly, the analysis of midgut microbiota from An. stephensi revealed the presence of genus Veillonella in Anopheles species for the first time. Importantly, the study also revealed the negative influence of total midgut microbiota on the development of P. berghei in three laboratory strains of An. stephensi, emphasizing the importance of understanding the gut microbiota in malaria vectors, and its relationship with parasite development in designing strategies to control malaria transmission.

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2535-7) contains supplementary material, which is available to authorized users.

In vitro susceptibility of Indian Plasmodium falciparum isolates to different antimalarial drugs & antibiotics

Background & objectives:

The in vitro assays for susceptibility of Plasmodium falciparum to antimalarial drugs are important tools for monitoring drug resistance. During the present study, efforts were made to establish long-term continuous in vitro culture of Indian field isolates of P. falciparum and to determine their sensitivity to standard antimalarial drugs and antibiotics.

Methods:

Four (MZR-I, -II, -III and -IV) P. falciparum isolates were obtained from four patients who showed artemisinin-based combination therapy (ACT) from Mizoram, a north-eastern State of India, and characterized for their in vitro susceptibility to chloroquine diphosphate (CQ), quinine hydrochloride dehydrate, mefloquine, piperaquine, artemether, arteether, dihydro-artemisinin (DHA), lumefantrine and atovaquone and antibiotics, azithromycin and doxycycline. These patients showed ACT treatment failure. Two-fold serial dilutions of each drug were tested and the effect was evaluated using the malaria SYBR Green I fluorescence assay. K1 (chloroquine-resistant) and 3D7 (chloroquine-sensitive) reference strains were used as controls.

Results:

Growth profile of all field isolates was identical to that of reference parasites. The IC₅₀ values of all the drugs were also similar against field isolates and reference parasite strains, except K1, exhibited high IC₅₀ value (275±12.5 nM) of CQ for which it was resistant. All field isolates exhibited higher IC₅₀ values of CQ, quinine hydrochloride dihydrate and DHA compared to reference strains. The resistance index of field isolates with respect to 3D7 ranged between 260.55 and 403.78 to CQ, 39.83 and 46.42 to quinine, and 2.98 and 4.16 to DHA, and with respect to K1 strain ranged between 6.51 and 10.08, 39.26 and 45.75, and 2.65 and 3.71. MZR-I isolate exhibited highest resistance index.

Interpretation & conclusions:

As the increase in IC₅₀ and IC₉₀ values of DHA against field isolates of P. falciparum was not significant, the tolerance to DHA-piperaquine (PPQ) combination might be because of PPQ only. Further study is required on more number of such isolates to generate data for a meaningful conclusion.

Efficacy of two artemisinin-based combinations for the treatment of malaria in pregnancy in India: a randomized controlled trial

Background

In India, the recommended first-line treatment for malaria in the second and third trimester of pregnancy is artesunate + sulfadoxine-pyrimethamine (AS+SP). However, data on safety and efficacy of artemisinin-based combination therapy (ACT) in pregnancy is limited. This study assessed the safety and efficacy of AS+SP and artesunate + mefloquine (AS+MQ) for treatment of Plasmodium falciparum in pregnancy in India.

Methods

This open-label, randomized clinical trial was conducted from October 2010 to December 2013 at three sites in India (Ranchi and Jamshedpur in Jharkhand state, and Rourkela in Odisha state). Pregnant women in the second or third trimester who had P. falciparum mono-infection of any parasite density with or without fever were randomized to receive AS+SP or AS+MQ. Blood slides and filter paper samples for Polymerase Chain Reaction (PCR) were collected on days 0, 1, 2, 3, 14, 21, 28, 42 and 63 post treatment. Women were followed up at delivery and at day 42 postpartum.

Findings

Two hundred and forty-eight women of 7064 pregnant women (3.5%) who were screened at monthly antenatal clinics had a P. falciparum mono-infection and were randomized to receive AS+SP (125) or AS+MQ (123) and all of these women were included in the intention to treat (ITT) analysis. The primary endpoint of an adequate clinical and parasite response (ACPR) on day 63 was not available for 9 women who were counted as treatment failure in the ITT analysis. In the ITT population, the ACPR was 121/125 (96.8%; 95% Confidence interval (CI) 92.0–99.1%) in the AS+SP group and 117/123 (95.1%; 95% CI 89.7–98.2) in the AS+MQ group. Among the 239 women (121 from the AS+SP arm and 118 from the AS+MQ arm) who completed the day 63 follow up (per protocol analysis) the ACPR was 100% in the AS+SP group and 99.2% (117/118) in the AS+MQ group. There were five serious adverse events (SAE) among pregnant women (4 in the AS+SP group and 1 in the AS+MQ group) and 13 fetal/neonatal SAEs (7 in the AS+SP group and 6 in the AS+MQ) but none of them were related to the study drugs. A higher proportion of women in the AS+MQ arm reported vomiting within 7 days post-treatment than did women in the AS+SP arm (6.9 vs. 1.6%; p = 0.001).

Conclusion

Both AS+SP and AS+MQ are safe and effective for treatment of uncomplicated falciparum malaria in pregnancy in India.

Trial registrationCTRI This study is registered with Clinical Trial Registry India (CTRI), number CTRI/2009/091/001055. Date of Registration 11 January 2010, http://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=1185&EncHid=&userName=anvikar

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2393-3) contains supplementary material, which is available to authorized users.

Assessment of Efficacy and Safety of Arterolane Maleate-Piperaquine Phosphate Dispersible Tablets in Comparison With Artemether-Lumefantrine Dispersible Tablets in Pediatric Patients With Acute Uncomplicated Plasmodium falciparum Malaria: A Phase 3, Randomized, Multicenter Trial in India and Africa

Background

Administration of artemisinin-based combination therapy (ACT) to infant and young children can be challenging. A formulation with accurate dose and ease of administration will improve adherence and compliance in children. The fixed-dose combination dispersible tablet of arterolane maleate (AM) 37.5 mg and piperaquine phosphate (PQP) 187.5 mg can make dosing convenient in children.

Methods

This multicenter (India and Africa), comparative, parallel-group trial enrolled 859 patients aged 6 months to 12 years with Plasmodium falciparum malaria. Patients were randomized in a ratio of 2:1 to AM-PQP (571 patients) once daily and artemether-lumefantrine (AL) (288 patients) twice daily for 3 days and followed for 42 days.

Results

The cure rate (ie, polymerase chain reaction-corrected adequate clinical and parasitological response) in the per-protocol population at day 28 was 100.0% and 98.5% (difference, 1.48% [95% confidence interval {CI}, .04%-2.91%]) in the AM-PQP and AL arms, respectively, and 96.0% and 95.8% (difference, 0.14% [95% CI, -2.68% to 2.95%]) in the intention-to-treat (ITT) population. The cure rate was comparable at day 42 in the ITT population (AM-PQP, 94.4% vs AL, 93.1%). The median parasite clearance time was 24 hours in both the arms. The median fever clearance time was 6 hours in AM-PQP and 12 hours in the AL arm. Both the treatments were found to be safe and well tolerated. Overall, safety profile of both the treatments was similar.

Conclusions

The efficacy and safety of fixed-dose combination of AM and PQP was comparable to AL for the treatment of uncomplicated P. falciparum malaria in pediatric patients.

Clinical Trials Registration

CTRI/2014/07/004764.

Methylene blue induced morphological deformations in Plasmodium falciparum gametocytes: implications for transmission-blocking

Background

Malaria remains a global health problem despite availability of effective tools. For malaria elimination, drugs targeting sexual stages of Plasmodium falciparum need to be incorporated in treatment regimen along with schizonticidal drugs to interrupt transmission. Primaquine is recommended as a transmission blocking drug for its effect on mature gametocytes but is not extensively utilized because of associated safety concerns among glucose-6-phosphate dehydrogenase (G6PD) deficient patients. In present work, methylene blue, which is proposed as an alternative to primaquine is investigated for its gametocytocidal activity amongst Indian field isolates. An effort has been made to establish Indian field isolates of P. falciparum as in vitro model for gametocytocidal drugs screening.

Methods

Plasmodium falciparum isolates were adapted to in vitro culture and induced to gametocyte production by hypoxanthine and culture was enriched for gametocyte stages using N-acetyl-glucosamine. Gametocytes were incubated with methylene blue for 48 h and stage specific gametocytocidal activity was evaluated by microscopic examination.

Results

Plasmodium falciparum field isolates RKL-9 and JDP-8 were able to reproducibly produce gametocytes in high yield and were used to screen gametocytocidal drugs. Methylene blue was found to target gametocytes in a concentration dependent manner by either completely eliminating gametocytes or rendering them morphologically deformed with mean IC₅₀ (early stages) as 424.1 nM and mean IC₅₀ (late stages) as 106.4 nM. These morphologically altered gametocytes appeared highly degenerated having shrinkage, distortions and membrane deformations.

Conclusions

Field isolates that produce gametocytes in high yield in vitro can be identified and used to screen gametocytocidal drugs. These isolates should be used for validation of gametocytocidal hits obtained previously by using lab adapted reference strains. Methylene blue was found to target gametocytes produced from Indian field isolates and is proposed to be used as a gametocytocidal adjunct with artemisinin-based combination therapy. Further exploration of methylene blue in clinical studies amongst Indian population, including G6PD deficient patients, is recommended.