Epidemiology of malaria and anemia in high and low malaria-endemic North-Eastern districts of India

Anemia and malaria are the two major public health problems that lead to substantial morbidity and mortality. Malaria infection destroys erythrocytes, resulting in low hemoglobin (Hb) levels known as anemia. Here we report the determinants of anemia in high and low malaria-endemic areas that would help understand which parasite densities, age, and gender-associated low Hb levels. Therefore, a cross-sectional mass survey (n = 8,233) was conducted to screen anemia and malaria in high and low malaria-endemic districts (HMED and LMED) of North-East India. Axillary body temperature was measured using a digital thermometer. The prevalence of anemia was found to be 55.3% (4,547/8,233), of which 45.1% had mild (2,049/4,547), 52.1% moderate (2,367/4,547) and 2.9% had severe anemia (131/4,547). Among anemic, 70.8% (3,219/4,547) resided in LMED and the rest in HMED. The median age of the anemic population was 12 years (IQR: 7–30). Overall, malaria positivity was 8.9% (734/8,233), of which HMED shared 79.6% (584/734) and LMED 20.4% (150/734) malaria burden. The village-wise malaria frequency was concordant to asymptomatic malaria (10–20%), which showed that apparently all of the malaria cases were asymptomatic in HMED. LMED population had significantly lower Hb than HMED [standardized beta (β) = −0.067, p < 0.0001] and low-density Plasmodium infections had higher Hb levels than high-density infections (β = 0.113; p = 0.031). Women of reproductive age had higher odds for malaria (OR: 1.42; 95% CI: 1.00–2.05; p = 0.04). Females (β = −0.193; p < 0.0001) and febrile individuals (β = −0.029; p = 0.008) have shown lower Hb levels, but malaria positivity did not show any effect on Hb. Young children and women of reproductive age are prone to anemia and malaria. Although there was no relation between malaria with the occurrence of anemia, we found low-density Plasmodium infections, female gender, and LMED were potential determinants of Hb.

AB0042 OPTIMAL CONDITIONS FOR THE DETECTION OF INFLAMMASOME ACTIVATION IN CD14+ CD16- MONOCYTES FROM HUMAN BLOOD BY FLOW CYTOMETRY

Background

The inflammasome activation is linked to the aggregation of the adaptor protein ASC into a multimeric structure, known as the ASC speck. The aggregation of cytosolic ASC into ASC specks is therefore used as a readout parameter for inflammasome activity. The direct detection of ASC speck formation on a single cell basis through flow cytometry, can analyze inflammasome activated cells. This allows the investigation of inflammasome activity in a clinical setting.

Objectives

Investigating the optimal conditions for a reliable identification of inflammasome activated ASC speck positive cells ex vivo using flow cytometry.

Methods

Freshly donated blood from five different healthy donors was used for all experiments. The choice of anticoagulant, storage time and storage temperature were examined. PBMCs were isolated from blood collecting tubes with ethylenediaminetetraacetic acid (EDTA) or lithium heparin (LH). PBMCs were also isolated from LH blood stored at 4 °C, room temperature (RT), 37 °C and after different storage times. After isolation, PBMCs were fixed immediately and stained for flow cytometric analysis. ASC speck positive CD14+ CD16- monocytes and THP-1 cells can be generated through incubation with nigericin in PBS.

Results

We adapted a method for flow cytometric analysis of ASC specks, with was previously described by Sester et al. [1]. As expected, we observed ASC speck formation after inflammasome activation, in CD14+ CD16-monocytes through a decrease in ASC fluorescent pulse width and an increase in ASC fluorescent pulse area. Monocytes in PBMCs collected from tubes with EDTA compared with LH showed significantly higher numbers of unspecific ASC speck positive cells. Blood storage at RT for 24 h can lead to an unspecific ASC speck formation. Storage at 37 °C resulted in contamination of the PBMC interface with erythrocytes, while blood stored at 4 °C resulted in severe cell clumping. Since storing LH blood for 24 h at RT lead to unspecific ASC speck formation in CD14+ CD16- cells, but not monocytes from freshly isolated PBMCs, the determination of the time until unspecific ASC speck signals occur was investigated. A significant increase in ASC speck positive CD14+CD16- monocytes was detected after 4 h storage at RT compared to directly processed samples and the number of ASC speck positive monocytes further accumulated over time. The incubation with nigericin in PBS leads to a significant increase in ASC speck positive CD14+ CD16- monocytes and THP-1 cells compared to incubation in RPMI media.

Conclusion

The flow cytometric detection of ASC specks is adapted for practical clinical usability. To reduce background signals, LH- instead of EDTA blood collecting tubes are recommended. The LH blood should be processed within 2 h after blood collection and be stored at RT. To avoid nonspecific activation and formation of ASC specks, the PBMCs should be isolated directly after venipuncture and fixed immediately. It is also possible to freeze the PBMCs until further usage. However, this will cause some loss of ASC speck positive cells. With these settings, clinical samples can now be examined.

References

[1]Sester, D.P et al. A novel flow cytometric method to assess inflammasome formation. J. Immunol. 2015, 194, 455–462.

Acknowledgements

We thank all healthy donors who participated in this study. The authors thank Jana Gramenz (University Medicine Greifswald, Pediatric Rheumatology and Immunology, Greifswald, Germany) for excellent technical assistance.

Disclosure of Interests

None declared

Association of Mucormycosis in Covid-19 and its Epidemiologic Study

Mucormycosis, also known as Zygomycosis or Black Fungus, is an infection caused in humans via various causative agents from the Zygomycetes class. Several countries including India is afflicted by the covid-19 virus, which has infected approximately 3.7 million people across the country. Some of the corona-positive patients suffer from another fatal infection, Mucormycosis, commonly known as Black Fungus. The strategy should be to administer an effective antifungal drug as soon as possible at the optimum dose. However, India being an epicenter of Diabetes with enormous 80 million diabetics, is of particular importance in the present scenario of the COVID pandemic. COVID therapy with Steroids and immune suppressants has increased the chances of infection in various individuals within the country with weaker immune system responses. The main purpose of this paper is to enlighten the community about the involvement of mucormycosis in covid-19 affected population and basic insights of its invasion. Keywords Mucormycosis, Black Fungus, Covid-19, Diabetes Mellitus, Amphotericin B, Immunosuppression, Apophysomyces, Renal Failure, Corticosteroids

Mutations in Pfcrt and Pfmdr1 genes of Plasmodium falciparum isolates from two sites in Northcentral and Southwest Nigeria

The ability of malaria parasites to develop resistance to antimalarial drugs has made it necessary to continuously survey malaria parasite populations for resistance markers. Mutations in specific malaria parasite genes confer resistance to antimalarial drugs. The study compared mutations in Pfcrt and Pfmdr1 genes of P. falciparum from two ecologically different areas of Nigeria. Plasmodium falciparum dried blood spots collected from New Bussa (Northcentral Nigeria) and Ijede (Southwest Nigeria) were analysed by PCR-RFLP for Pfcrt, K76 T, Pfmdr1, N86Y and Y184F mutations. Pfmdr1 copy number was determined by quantitative-PCR. A total of 145 blood spots [Ijede = 55; New Bussa = 90 blood spots] were analysed, but Pfcrt gene was successfully amplified in 144 samples while Pfmdr1 was amplified in 132 samples. Overall, prevalence of mutant forms of Pfcrt 76 T,Pfmdr1 86Y and 184F were 74.3% (95% CI: 66.4-81.2%), 18.2% (95% CI: 12.0-25.8%) and 35.6% (95% CI: 27.5-44.4%). The frequency of Pfcrt 76 T was similar in both study sites [Ijede: 81.8% (95%CI: 69.1-90.9%); New Bussa: 69.7% (95%CI: 59.0-79.0), p = 0.105]. However, the frequencies of Pfmdr1 86Y and 184F were significantly higher in Ijede (28.3% and 62.3%) than in New Bussa (11.4% and 17.7%), respectively (P < 0.05). Eight parasite genotypes based on three codons of the two genes were identified. The most frequent genotype was TNY 53(40.5%) while the least was KYF 1 (0.8%). The most frequent genotype in Ijede and New Bussa were TNF 18(34.0%) and TNY 40 (51.3%) respectively. The frequency of wild strain KNF in Ijede and New Bussa were 3 (5.7%) and 18 (23.1%), respectively. The distribution of the genotypes differed significantly by location. The genotypes with more than two or more mutations were more in Ijede 32 (60.4%) than in New Bussa 16 (20.5%) (p < 0.001). Amplification of Pfmdr1 copy number was not observed in the two study sites. The prevalence of Pfcrt 76 T was similar in both locations while Pfmdr1 86Y and 184F differed in both locations. Single nucleotide polymorphisms in the three codons assessed were more in Ijede than in New Bussa.

Diagnostic performance of rapid diagnostic test, light microscopy and polymerase chain reaction during mass survey conducted in low and high malaria-endemic areas from two North-Eastern states of India

An early and accurate diagnosis followed by prompt treatment is pre-requisite for the management of any disease. Malaria diagnosis is routinely performed by microscopy and rapid diagnostic tests (RDTs) in the field settings; however, their performance may vary across regions, age and asymptomatic status. Owing to this, we assessed the diagnostic performance of conventional and advanced molecular tools for malaria detection in low and high malaria-endemic settings. We performed mass blood surveys in low and high endemic regions of two North-Eastern districts from the states of Assam and Meghalaya. A total of 3322 individuals were screened for malaria using RDT, microscopy and PCR and measures of diagnostic accuracy were estimated. Out of 3322 individuals, 649 (19.5%) were detected with malaria parasite. Asymptomatic were 86.4% (2872/3322), of which 19.4% (557/2872) had Plasmodium infection. The sensitivity and specificity of microscopy were 42.7% and 99.3%, and RDT showed 49.9% and 90.4%, respectively, considering PCR as standard. RDT (AUC: 0.65 vs 0.74; p = 0.001) and microscopy (AUC: 0.64 vs 0.76; p < 0.0001) performances were significantly lower in low compared to high endemic areas. True positive rate was lower in asymptomatics but true negative rate was found similar to symptomatic individuals. The conventional diagnostic tools (RDT and microscopy) had detected malaria in children with nearly twofold greater sensitivity than in the adults (p < 0.05). To conclude, asymptomatics, adults and low malaria-endemic regions require major attention due to mediocre performance of conventional diagnostic tools in malaria detection.

The nucleotide specificity of succinyl-CoA synthetase of Plasmodium falciparum is not determined by charged gatekeeper residues alone

Substrate specificity of an enzyme is an important characteristic of its mechanism of action. Investigation of the nucleotide specificity of Plasmodium falciparum succinyl‐CoA synthetase (SCS; PfSCS) would provide crucial insights of its substrate recognition. Charged gatekeeper residues have been shown to alter the substrate specificity via electrostatic interactions with approaching substrates. The enzyme kinetics of recombinant PfSCS (wild‐type), generated by refolding of the individual P. falciparum SCSβ and Blastocystis SCSα subunits, demonstrated ADP‐forming activity (K_mATP = 48 µm). Further, the introduction of charged gatekeeper residues, either positive (Lys and Lys) or negative (Glu and Asp), resulted in significant reductions in the ATP affinity of PfSCS. It is interesting to note that the recombinant PfSCSβ subunit can be refolded to a functional enzyme conformation using Blastocystis SCSα, indicating the possibility of subunits swapping among different organisms. These results concluded that electrostatic interactions at the gatekeeper region alone are insufficient to alter the substrate specificity of PfSCS, and further structural analysis with a particular focus on binding site architecture is required.

Asymptomatic low-density Plasmodium infection during non-transmission season: a community-based cross-sectional study in two districts of North Eastern Region, India

BACKGROUND

Malaria elimination requires targeting asymptomatic and low-density Plasmodium infections that largely remain undetected. Therefore we conducted a cross-sectional study to estimate the burden of asymptomatic and low-density Plasmodium infection using conventional and molecular diagnostics.

METHODS

A total of 9118 participants, irrespective of age and sex, were screened for malaria using rapid diagnostic tests (RDTs), microscopy and polymerase chain reaction.

RESULTS

Among the participants, 707 presented with symptoms and 8411 without symptoms, of which Plasmodium was present in 15.6% (110/707) and 8.1% (681/8411), respectively. Low-density infection was found in 5.1% (145/2818) of participants and 8327 of 9118 were Plasmodium negative. Endemicity was propotional to asymptomatic infections (high endemicity 11.1% [404/3633] vs low endemicity 5.8% [277/4778]; odds ratio [OR] 2.0 [95% confidence interval {CI} 1.7 to 2.4]) but inversely related to low-density infection (high endemicity 3.7% [57/1545] vs low endemicity 6.9% [88/1273]; OR 1.9 [95% CI 1.4 to 2.7]). The spleen rate in children 2-9 y of age was 17.9% (602/3368) and the enlarged spleen index was 1.6. Children between 8 and 14 y showed higher odds for asymptomatic (adjusted OR [aOR] 1.75 [95% CI 1.4 to 2.2]) and low-density infections (aOR 0.63 [95% CI 0.4 to 1.0)] than adults.

CONCLUSIONS

The prevalence of asymptomatic and low-density Plasmodium infection undermines the usefulness of standard diagnostic tools used by health agencies. This necessitates deploying molecular tools in areas where malaria microscopy/RDTs indicate a dearth of infection.

Redox interactome in malaria parasite Plasmodium falciparum

The malaria-causing parasite Plasmodium falciparum is a severe threat to human health across the globe. This parasite alone causes the highest morbidity and mortality than any other species of Plasmodium. The parasites dynamically multiply in the erythrocytes of the vertebrate hosts, a large number of reactive oxygen species that damage biological macromolecules are produced in the cell during parasite growth. To relieve this intense oxidative stress, the parasite employs an NADPH-dependent thioredoxin and glutathione system that acts as an antioxidant and maintains redox status in the parasite. The mutual interaction of both redox proteins is involved in various biological functions and the survival of the erythrocytic stage of the parasite. Since the Plasmodium species is deficient in catalase and classical glutathione peroxidase, so their redox balance relies on a complex set of five peroxiredoxins, differentially positioned in the cytosol, mitochondria, apicoplast, and nucleus with partly overlapping substrate preferences. Moreover, Plasmodium falciparum possesses a set of members belonging to the thioredoxin superfamily, such as three thioredoxins, two thioredoxin-like proteins, one dithiol, three monocysteine glutaredoxins, and one redox-active plasmoredoxin with largely redundant functions. This review paper aims to discuss and encapsulate the biological function and current knowledge of the functional redox network of Plasmodium falciparum.

Prevalence and spectrum of mutations causing G6PD deficiency in Indian populations

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common human erythroenzymopathy affecting around 10% of the world population. India is endemic for malaria and antimalarial drugs are known to induce haemolysis in G6PD deficient individuals. Here we report the prevalence as well as the molecular diversity of G6PD deficiency in geographical regions of India.

METHODS AND RESULTS

A total of 20,896 individuals (11,838 males and 9058 females) were screened by DPIP dye decolorisation method followed by quantitation of G6PD enzyme activity on the suspected samples. Molecular analysis was undertaken in a total of 350 G6PD deficient individuals by PCR-RFLP and DNA sequencing. A structural characteristic of the novel variant was deduced by using DynaMut web-server. The prevalence rate of G6PD deficiency varied between 0.8 and 6.3% with an overall prevalence of 1.9%. A total of twelve mutations were identified. Of the total deleterious alleles detected G6PD Orissa (56.5%) was found to be the most predominant variant followed by G6PD Mediterranean (23.6%). G6PD Mediterranean, G6PD Kaiping and G6PD Mahidol were found to be severely deficient variant and 14.1% of them showed undetectable activity. A novel mutation c.544C➔G (R182G) in exon 6 was identified in one tribal male where substitution of arginine by glycine, likely causes the alteration in the alpha helix leading to disruption of secondary structure of the protein.

CONCLUSION

There are large differences in the distribution of G6PD causal variants between Indian states, and this may have implications for the treatment in the malaria endemic areas.

Systems approach for assessment of maternal deaths in Rajasthan: A feasibility study

Background

High maternal mortality in the state like Rajasthan, which is at second rank in terms of high Maternal Mortality Ratio (MMR) in India, require concentrated efforts in this direction The objectives of this study were to assess the magnitude and trend of maternal death and underlying factors contributing to maternal deaths in Rajasthan and to identify barriers and challenges in reporting maternal deaths in Rajasthan.

Methods

Data related to maternal deaths, cause of deaths and live births were retrieved from official Government sources and MMR was calculated. To find out the underlying factors contributing to maternal deaths, Verbal Autopsies were conducted through household surveys. In-depth interviews of health care staff were conducted to carry out the 'SWOT' analysis in order to identify the barriers in reporting maternal deaths. Data was analysed using SPSS version 23.

Results

A total of 7185 maternal deaths were reported from Rajasthan in last five years. The mean age of mothers was 25.18±4.98 years. Haemorrhage were reported as most common cause of maternal death (17%) followed by Severe hypertension or fits (8%) and obstructed labour (2%). The median duration of hospital stay was 23 hours (IQR=7.5-70). Maximum deaths were reported during post-partum period (61%), while around one fourth of the deaths happened during delivery.

Conclusions

The discrepancies were observed in the reporting of number and causes of maternal deaths. The trend and forecasted figures were quite different from the published National and State level reports in this regard.

Key messages

need to streamline and strengthen the Maternal Deaths Surveillance and Response to track the number of deaths and get the exact information about the underlying factors contributing to them. Effective strategies can be developed to reduce the Maternal Deaths in the State.

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.

Novel molecular diagnostic technique for detecting the different species of Plasmodium

BACKGROUND

Sensitive diagnostic techniques are needed for timely detection of malaria parasite and disease control. Molecular diagnostic techniques involving Polymerase chain reaction (PCR) with 18 s rRNA as a known diagnostic target with an overall sensitivity of 10 parasites per microliter is used as a gold standard. Till date, no attempt has been undertaken to develop a technique for the identification of four Plasmodium species in a single step PCR combined with restriction digestion with enzymes.

METHOD

Plasmodium species-specific polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assays have been developed, based on RFLP of amplified PCR product of mitochondrial gene as a target. This approach identifies Plasmodium species in two steps involving amplification of mitochondrial (Mt) gene by PCR followed by digestion with restriction enzymes.

RESULT

A total of 36 clinical samples were subjected to PCR-RFLP for the diagnosis and detection of malaria parasites targeting mitochondrial gene (Mt). The findings of the method were compared with gold standard methods (Microscopy, RDTs and Nested PCR) and was able to detect mixed infection with a sensitivity of 100% and specificity of 93.8% with respect to nested PCR. The results obtained by PCR-RFLP were validated with Sanger sequencing (n = 32) and were found to be consistent with the method.

CONCLUSION

This method identifies and distinguishes four species of human malaria parasite namely P. falciparum (Pf), P. vivax (Pv), P. malariae (Pm) and P. ovale (Po) in approximately 4 h. To overcome and address PCR difficulties, continuous efforts are needed for the development of newer diagnostic techniques.

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.

Effect of homoeopathic treatment on filariasis

A single blind follow-up study was undertaken to assess the effect of homeopathic treatment on microfilarial clearance and frequency of filarial fevers in an endemic village, India, State of Orissa. Homoeopathic treatment effectively reduced the frequency of filarial fevers by 20 per cent (P<0.05) among amicrofilaraemic cases, with a higher reduction in cases with genital involvement (36%) and mastitis (57%). However, among symptomatic microfilaraemia cases, the frequency of filarial fever (attack) had doubled (p<0.05) following treatment. There was no additional effect on microfilaria clearance in asymptomatic carriers.

Homœopathic treatment of filariasis

A single-blind study was conducted to assess the effect of homœopathic treatment on cases of bancroftian filariasis. Based on the predominant symptom, the filariasis cases were grouped as adenitis, genitalia involvement, lymphoedema and mastitis. Effect of treatment with homœopathic drugs were assessed by comparing with groups treated with placebo. Filiariasis cases treated with homœopathic medicines showed a better improved/not improved ratio (2.0) compared with cases treated with placebo (0.46). The results indicate that the improvements derived from homœopathic medicines are statistically highly significant (p<0.001).

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.

Quantifying primaquine effectiveness and improving adherence: a round table discussion of the APMEN Vivax Working Group

The goal to eliminate malaria from the Asia-Pacific by 2030 will require the safe and widespread delivery of effective radical cure of malaria. In October 2017, the Asia Pacific Malaria Elimination Network Vivax Working Group met to discuss the impediments to primaquine (PQ) radical cure, how these can be overcome and the methodological difficulties in assessing clinical effectiveness of radical cure. The salient discussions of this meeting which involved 110 representatives from 18 partner countries and 21 institutional partner organizations are reported. Context specific strategies to improve adherence are needed to increase understanding and awareness of PQ within affected communities; these must include education and health promotion programs. Lessons learned from other disease programs highlight that a package of approaches has the greatest potential to change patient and prescriber habits, however optimizing the components of this approach and quantifying their effectiveness is challenging. In a trial setting, the reactivity of participants results in patients altering their behaviour and creates inherent bias. Although bias can be reduced by integrating data collection into the routine health care and surveillance systems, this comes at a cost of decreasing the detection of clinical outcomes. Measuring adherence and the factors that relate to it, also requires an in-depth understanding of the context and the underlying sociocultural logic that supports it. Reaching the elimination goal will require innovative approaches to improve radical cure for vivax malaria, as well as the methods to evaluate its effectiveness.

Spatio-temporal distribution of PfMDR1 polymorphism among uncomplicated Plasmodium falciparum malaria cases along international border of north east India

PfMDR1 single nucleotide polymorphisms (SNP) are good correlate markers for antimalarial drug resistance worldwide. Present study is a comprehensive view of screening of PfMDR1 polymorphism to antimalarials practiced with geography and time. Study sites Mizoram, Tripura, Meghalaya chosen are at multivariate drug pressure due to cross border migration and transmission. Mizoram is gateway to south east Asia through Myanmar whereas Tripura, Meghalaya share porous border with Bangladesh. Baseline finger pricked blood stained filter paper for confirmed uncomplicated Plasmodium falciparum infected patients (year 2015) were obtained from National Institute of Malaria Research, New Delhi, India. PfMDR1 polymorphism for codon N86Y, Y184F, D1246Y was determined by PCR-RFLP, further confirmed by sequencing. There observed marked predominance of Plasmodium isolates with PfMDR1 wild type alleles for all codons under study i.e. 86, 184, 1246. Spatially, Plasmodium isolates from Mizoram were most diverse with co-existence of PfMDR1 genotype with NYD, YYD, NFD haplotypes, followed by Tripura. Isolates from Meghalaya were of all NYD haplotype. Reports, referring to screening of PfMDR1 SNPs to CQ/SP/AS-SP across India, were archived. Temporal study show distinct rise in proportion of PfMDR1 wild type N86 allele since introduction of Artemether-Lumefantrine as first line antimalarial. Hence spatio-temporal screening of Plasmodium population with PfMDR1 single nucleotide polymorphism accounts for its association with antimalarial susceptibility and validate PfMDR1 SNPs as antimalarial drug resistant marker.

Establishment and application of a novel isothermal amplification assay for rapid detection of chloroquine resistance (K76T) in Plasmodium falciparum

Chloroquine (CQ) resistance in Plasmodium falciparum is determined by the mutations in the chloroquine resistance transporter (Pfcrt) gene. The point mutation at codon 76 (K76T), which has been observed in more than 91% of P. falciparum isolates in India, is the major determinant of CQ resistance. To overcome the limitations and challenges of traditional methods, in this investigation we developed an easy to use loop mediated isothermal amplification (LAMP) protocol for rapid detection of the K76T mutation associated with CQ resistance in P. falciparum with naked eye visualization. In- house designed primers were synthesized and optimized to specifically distinguish the CQ resistant mutants of P. falciparum. The LAMP reaction was optimal at 61 °C for 60 min and calcein dye was added prior to amplification to enable visual detection. We demonstrate the detection limit of <2 ng/μl respectively, supporting the high sensitivity of this calcein based LAMP method. To the best of our knowledge this is the first report on the establishment of an easy, reliable and cost effective LAMP assay for rapid and specific detection of highly CQ resistance in P. falciparum malaria.

Engineering Nucleotide Specificity of Succinyl-CoA Synthetase in Blastocystis: The Emerging Role of Gatekeeper Residues

Charged, solvent-exposed residues at the entrance to the substrate binding site (gatekeeper residues) produce electrostatic dipole interactions with approaching substrates, and control their access by a novel mechanism called “electrostatic gatekeeper effect”. This proof-of-concept study demonstrates that the nucleotide specificity can be engineered by altering the electrostatic properties of the gatekeeper residues outside the binding site. Using Blastocystis succinyl-CoA synthetase (SCS, EC 6.2.1.5), we demonstrated that the gatekeeper mutant (ED) resulted in ATP-specific SCS to show high GTP specificity. Moreover, nucleotide binding site mutant (LF) had no effect on GTP specificity and remained ATP-specific. However, via combination of the gatekeeper mutant with the nucleotide binding site mutant (ED+LF), a complete reversal of nucleotide specificity was obtained with GTP, but no detectable activity was obtained with ATP. This striking result of the combined mutant (ED+LF) was due to two changes; negatively charged gatekeeper residues (ED) favored GTP access, and nucleotide binding site residues (LF) altered ATP binding, which was consistent with the hypothesis of the “electrostatic gatekeeper effect”. These results were further supported by molecular modeling and simulation studies. Hence, it is imperative to extend the strategy of the gatekeeper effect in a different range of crucial enzymes (synthetases, kinases, and transferases) to engineer substrate specificity for various industrial applications and substrate-based drug design.

In vitro sensitivity pattern of chloroquine and artemisinin in Plasmodium falciparum

Artemisinin (ART) and its derivatives form the mainstay of antimalarial therapy. Emergence of resistance to them poses a potential threat to future malaria control and elimination on a global level. It is important to know the mechanism of action of drug and development of drug resistance. We put forwards probable correlation between the mode of action of chloroquine (CQ) and ART. Modified trophozoite maturation inhibition assay, WHO Mark III assay and molecular marker study for CQ resistance at K76T codon in Plasmodium falciparum CQ-resistant transporter gene were carried out on cultured P. falciparum. On comparing trophozoite and schizont growth for both CQ-sensitive (MRC-2) and CQ-resistant (RKL-9) culture isolates, it was observed that the clearance of trophozoites and schizonts was similar with both drugs. The experiment supports that CQ interferes with heme detoxification pathway in food vacuoles of parasite, and this may be correlated as one of the plausible mechanisms of ART.

Emerging polymorphisms in falciparum Kelch 13 gene in Northeastern region of India

Background

Recent reports of emergence and spread of artemisinin resistance in the Southeast Asia region, including Myanmar, pose a greater threat to malaria control and elimination in India. Whole genome sequencing studies have associated mutations in the K13 propeller gene (k13), PF3D7_1343700 with artemisinin resistance both in vitro and in vivo. The aim of the present study was to find the k13 gene polymorphisms in Plasmodium falciparum parasites from the three sites in the Northeast region of India, bordering Bangladesh and Myanmar.

Methods

A total of 254 samples collected during 2014–2015 from Tripura, Mizoram and Arunachal Pradesh states in the Northeast region of India were used to obtain the full-length k13 gene sequences.

Results

Three non-synonymous (NS) mutations: two in the propeller region, namely at codon 446 and 578, were observed besides one at codon 189 in the non-propeller region. The treatment outcome was not affected by these mutations at any of the sites. In addition, microsatellite variation in the N-terminus of the k13 protein was observed at all the study sites.

Conclusion

This is the first study to document the presence of F446I NS mutation in the k13 propeller region from Changlang district, Arunachal Pradesh, a site adjoining the Indo-Myanmar border region, where this mutation is highly prevalent. In addition, NS mutation A578S has been observed only at Lunglei district, Mizoram, a site bordering Bangladesh and K189T mutation with relatively higher frequency in Mizoram and Tripura states. The presence of F446I mutation in a region close to the Myanmar border is notable. Considering the spread of anti-malarial drug resistance from Southeast Asia to the Northeast region of India in the past, there is an urgent need to undertake systematic mapping studies to ascertain the role and extent of this mutation in artemisinin resistance in this region of country.

Comparison of WHO Mark III and HRP II ELISA for in vitro sensitivity of Plasmodium falciparum

BACKGROUND & OBJECTIVES

Antimalarial drug resistance is a serious challenge to malaria control worldwide. In vitro sensitivity assays provide an early indication of emerging drug resistance. In vitro susceptibility of field and culture adapted Plasmodium falciparum isolates to different antimalarials was compared using two Methods: World Health Organization (WHO) micro-test (MARK III) and histidine rich protein II (HRP II) based enzyme- linked immunosorbent assay (ELISA).

METHODS

In total, 50 P. falciparum isolates were collected from five states, viz. Chhattisgarh, Meghalaya, Mizoram, Tripura and Odisha of India during December 2011-September 2014. The isolates were revived and evaluated for their susceptibility to chloroquine (CQ), monodesethylamodiaquine (AQ), mefloquine (MQ), quinine (QN) and artemisinin (ART) using the WHO micro-test (Mark III) and HRP II ELISA. The data were analyzed using non- linear regression analysis.

RESULTS

The geometric mean (GM) IC50 values of different antimalarials for WHO Mark III assay were comparatively lower than HRP II ELISA assay. The GM IC50 value for CQ was 59.5 nM (95% confidence interval [CI]: 49.35-71.73 nM) and 78.34 nM (95% CI: 64.57-95.03 nM) for Mark III and HRP II ELISA, respectively. Similarly, the values of GM IC50 for AQ, MQ, QN and ART by Mark III and HRP II ELISA were 13.31, 7.07, 146.4, 0.43 nM and 22.02, 11.46, 258.7, 1.00 nM, respectively. On analyzing statistically, the results of both assays were comparable (R2 = 0.96, p < 0.001; mean log difference at IC50= 0.037).

INTERPRETATION & CONCLUSION

The HRP II ELISA assay showed a reliable sensitivity in comparison to WHO Mark III micro-test complemented with distinguishing features such as high specificity, ease of performance, and notable consistency.

Syncytial Hepatitis of Tilapia ( Oreochromis niloticus L.) is Associated With Orthomyxovirus-Like Virions in Hepatocytes

Using transmission electron microscopy (TEM), the presented work expands on the ultrastructural findings of an earlier report on "syncytial hepatitis," a novel disease of tilapia (SHT). Briefly, TEM confirmed the presence of an orthomyxovirus-like virus within the diseased hepatocytes but not within the endothelium. This was supported by observing extracellular and intracellular (mostly intraendosomal), 60-100 nm round virions with a trilaminar capsid containing up to 7 electron-dense aggregates. Other patterns noted included enveloped or filamentous virions and virion-containing cytoplasmic membrane folds, suggestive of endocytosis. Patterns atypical for orthymyxovirus included the formation of syncytia and the presence of virions within the perinuclear cisternae (suspected to be the Golgi apparatus). The ultrastructural morphology of SHT-associated virions is similar to that previously reported for tilapia lake virus (TiLV). A genetic homology was investigated using the available reverse transcriptase polymerase chain reaction (RT-PCR) probes for TiLV and comparing clinically sick with clinically normal fish and negative controls. By RT-PCR analysis, viral nucleic acid was detected only in diseased fish. Taken together, these findings strongly suggest that a virus is causally associated with SHT, that this virus shares ultrastructural features with orthomyxoviruses, and it presents with partial genetic homology with TiLV (190 nucleotides).

Cation exchange synthesis of uniform PbSe/PbS core/shell tetra-pods and their use as near-infrared photodetectors

In this work we explore the preparation of complex-shaped semiconductor nanostructures composed of different materials via a cationic exchange process in which the cations of the original semiconductor nanostructure are replaced by cations of different metals with preservation of the shape and the anionic framework of the nanocrystals. Utilizing this cation exchange method, we synthesized two new tetrapods for the first time: Cu2-xSe/Cu2-xS and PbSe/PbS, both prepared from CdSe/CdS tetrapods as 'templates'. We also fabricated near-infrared (NIR) photodetectors with a very simple architecture comprising a PbSe/PbS tetrapod layer between two Au electrodes on a glass substrate. When illuminated by a NIR laser, these devices are capable of achieving a responsivity of 11.9 A W(-1) without the use of ligand-exchange processes, thermal annealing or hybrid device architecture. Transient absorption spectroscopy was carried out on these PbSe/PbS tetrapods, the results of which suggest that the branched morphology contributes in part to device performance. Investigation of the charge dynamics of the PbSe/PbS tetrapods revealed an extremely long-lived exciton recombination lifetime of ∼17 ms, which can result in enhanced photoconductive gain. Overall, these heterostructured tetrapods showcase simultaneously the importance of nanoparticle shape, band structure, and surface chemistry in the attainment of NIR photodetection.

Monitoring the efficacy of antimalarial medicines in India via sentinel sites: Outcomes and risk factors for treatment failure

BACKGROUND & OBJECTIVES

To combat the problem of antimalarial drug resistance, monitoring the changes in drug efficacy over time through periodic surveillance is essential. Since 2009, systematic and continuous monitoring is being done through nationwide sentinel site system. Potential early warning signs like partner drug resistance markers were also monitored in the clinical samples from the study areas.

METHODS

A total of 1864 patients with acute uncomplicated malaria were enrolled in therapeutic efficacy studies of artesunate plus sulphadoxine-pyrimethamine (AS+SP) for Plasmodium falciparum; those infected with P. vivax were given chloroquine (CQ). Polymerase chain reaction (PCR) was used to distinguish post-treatment reinfection from treatment failures. Isolates of P. falciparum were also analysed for dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr) gene mutations.

RESULTS

Overall, 1687 (91.7%) patients completed the follow-up. In most of the falciparum patients the parasitaemia was cleared within 24 h of treatment, except 12 patients who remained parasite positive after 72 h. Presence of dhfr and dhps quintuple mutation was observed predominantly in treatment failure samples. A daily dose of artesunate of < 3 mg/kg of body weight, age of <5 yr, and fever at enrolment were associated with an increased risk of treatment failure. The AS+SP in P. falciparum was effective in > 95% cases in all the sentinel sites except in Northeastern region (NE). Chloroquine remained 100% efficacious in case of P. vivax infections.

INTERPRETATION & CONCLUSION

Till 2012, India's national antimalarial drug resistance monitoring system proved highly efficacious and safe towards first-line antimalarials used in the country, except in Northeastern region where a decline in efficacy of AS+SP has been observed. This led to change in first-line treatment for P. falciparum to artemether-lumefantrine in Northeastern region.

Computer-vision-based technology for fast, accurate and cost effective diagnosis of malaria

Background

Microscopy has long been considered to be the gold standard for diagnosis of malaria despite the introduction of newer assays. However, it has many challenges like requirement of trained microscopists and logistic issues. A vision based device that can diagnose malaria, provide speciation and estimate parasitaemia was evaluated.

Methods

The device was evaluated using samples from 431 consented patients, 361 of which were initially screened by RDT and microscopy and later analysed by PCR. It was a prospective, non-randomized, blinded trial. Quantification of parasitaemia was performed by two experienced technicians. Samples were subjected to diagnosis by Sight Dx digital imaging scanning.

Results

The sensitivity and specificity of the SightDx P1 device for analysed samples were found to be 97.05 and 96.33 %, respectively, when compared to PCR. When compared to microscopy, sensitivity and specificity were found to be 94.4 and 95.6 %, respectively. The device was able to speciate 73.3 % of the PCR Plasmodium falciparum positive samples and 91.4 % of PCR Plasmodium vivax positive samples.

Conclusion

The ability of the device to detect parasitaemia as compared with microscopy, was within 50 % in 71.3 % of cases and demonstrated a correlation coefficient of 0.89.

Comparative assessment of genomic DNA extraction processes for Plasmodium: Identifying the appropriate method

Plasmodium DNA, in addition to being used for molecular diagnosis of malaria, find utility in monitoring patient responses to antimalarial drugs, drug resistance studies, genotyping and sequencing purposes. Over the years, numerous protocols have been proposed for extracting Plasmodium DNA from a variety of sources. Given that DNA isolation is fundamental to successful molecular studies, here we review the most commonly used methods for Plasmodium genomic DNA isolation, emphasizing their pros and cons. A comparison of these existing methods has been made, to evaluate their appropriateness for use in different applications and identify the method suitable for a particular laboratory based study. Selection of a suitable and accessible DNA extraction method for Plasmodium requires consideration of many factors, the most important being sensitivity, cost-effectiveness and, purity and stability of isolated DNA. Need of the hour is to accentuate on the development of a method that upholds well on all these parameters.

Molecular mechanism of in vitro transformation of mammalian cells by chemical carcinogens

BHK21 clone 13 cells transformed by dimethylnitrosamine (DMN) or nitrosomethylurea (NMU) ("alkylating" chemical carcinogens) appear to be restricted by temperature in the expression of their transformed phenotype. When grown at 38.5 degrees C, they exhibit a transformed phenotype (clonal morphology and ability to plate in agar), when grown at 32 degrees C, their phenotype is normal. Conversion from the normal to the transformed phenotype and the reverse is possible by temperature shifts. Conversely of the BHK21 clone 13 cells, of the rat fibroblasts (R111) transformed by 4-nitroquinoline-N-oxide (NQN), some exhibit a transformed phenotype restricted by temperature while others are not restricted by temperature in the expression of transformation. A working hypothesis is proposed suggesting that the phenotype of cells transformed by chemical carcinogens may be determined by the nature of the chemical reaction with the cell DNA. "Alkylating" carcinogens cause prevalently point mutation in bacteria (of the base substitution kind); in the case of transformation of mammalian cells temperature-sensitive phenotypes will be obtained. "Frameshift" carcinogens cause frameshift mutation in bacteria and cells transformed by this class of carcinogens will exhibit a transformed phenotype unrestricted by temperature.

Microwave assisted synthesis, characterization and biocidal activities of some new chelates of carbazole derived Schiff bases of cadmium and tin metals

This study is planned to report the advancement of green microwave approach in the fabrication of a new series of biologically potent (N^X, where X=O/S) donor Schiff bases and their cadmium(II) and tin(II) complexes. The ligands and their metal complexes have been characterized in terms of elemental analysis, molar ionic conductance, magnetic moment and spectral (IR, UV-Vis, NMR ((1)H, (119)Sn), FAB-mass, thermal and XRD) data. The data revealed that the ligands coordinated to the metal center via nitrogen and oxygen/sulfur atoms and form an octahedral arrangement of the ligands around central metal atom. All compounds were evaluated for their in vitro antimicrobial activities against two pathogenic bacteria Bacillus subtilis and Escherichia coli and two fungi Aspergillus niger and Aspergillus flavus by standard disc diffusion method. The discs were stored in an incubator at 37°C. The compounds were dissolved in DMF at 500 and 1000 ppm concentrations for screening biocidal activity. The compounds were dissolved in DMF to get the 100 and 200 ppm concentration of test solutions for screening fungicidal activity. The inhibition zone around each disc was measured (in mm) after 24 h and 96 h for biocidal and fungicidal activities respectively.

Spread of artemisinin resistance in Plasmodium falciparum malaria

BACKGROUND

Artemisinin resistance in Plasmodium falciparum has emerged in Southeast Asia and now poses a threat to the control and elimination of malaria. Mapping the geographic extent of resistance is essential for planning containment and elimination strategies.

METHODS

Between May 2011 and April 2013, we enrolled 1241 adults and children with acute, uncomplicated falciparum malaria in an open-label trial at 15 sites in 10 countries (7 in Asia and 3 in Africa). Patients received artesunate, administered orally at a daily dose of either 2 mg per kilogram of body weight per day or 4 mg per kilogram, for 3 days, followed by a standard 3-day course of artemisinin-based combination therapy. Parasite counts in peripheral-blood samples were measured every 6 hours, and the parasite clearance half-lives were determined.

RESULTS

The median parasite clearance half-lives ranged from 1.9 hours in the Democratic Republic of Congo to 7.0 hours at the Thailand-Cambodia border. Slowly clearing infections (parasite clearance half-life >5 hours), strongly associated with single point mutations in the "propeller" region of the P. falciparum kelch protein gene on chromosome 13 (kelch13), were detected throughout mainland Southeast Asia from southern Vietnam to central Myanmar. The incidence of pretreatment and post-treatment gametocytemia was higher among patients with slow parasite clearance, suggesting greater potential for transmission. In western Cambodia, where artemisinin-based combination therapies are failing, the 6-day course of antimalarial therapy was associated with a cure rate of 97.7% (95% confidence interval, 90.9 to 99.4) at 42 days.

CONCLUSIONS

Artemisinin resistance to P. falciparum, which is now prevalent across mainland Southeast Asia, is associated with mutations in kelch13. Prolonged courses of artemisinin-based combination therapies are currently efficacious in areas where standard 3-day treatments are failing. (Funded by the U.K. Department of International Development and others; ClinicalTrials.gov number, NCT01350856.).