Genetic variation in histidine rich proteins among Indian Plasmodium falciparum population: possible cause of variable sensitivity of malaria rapid diagnostic tests

BACKGROUND: Rapid diagnostic tests (RDTs) have revolutionized the diagnosis of malaria. Among the various factors affecting RDTs sensitivity is genetic variation of the antigen used. The genetic variation in PfHRP2 and PfHRP3 proteins was studied among the Indian Plasmodium falciparum isolates. METHODS: One hundred and forty isolates of P. falciparum were collected from six geographical regions of India. Target genes encoding PfHRP2 and PfHRP3 antigens were sequenced to study genetic polymorphism. Minimum detection limit giving a positive rapid diagnostic test was also determined. RESULTS: Extensive variations were observed in amino acid repeat types of PfHRP2 and PfHRP3. PfHRP2 exhibited more polymorphism than PfHRP3. Significant relation was observed between type 2 and type 7 repeats and RDT detection rate as higher number of these repeats showed better sensitivity with RDTs. CONCLUSION: The results provide insights into the genetic diversity of Pfhrp2 and Pfhrp3 genes among Indian P. falciparum population and its relation to RDT sensitivity

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 registration CTRI 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

Nonrandomized Controlled Trial of Artesunate plus Sulfadoxine-Pyrimethamine with or without Primaquine for Preventing Posttreatment Circulation of Plasmodium falciparum Gametocytes

ABSTRACT Artemisinin combination therapies eliminate immature Plasmodium falciparum gametocytes but not mature gametocytes, which may persist for up to 1 month posttreatment. A single dose of primaquine, which is inexpensive and effective against mature gametocytes, could be added to further reduce the potential for posttreatment parasite transmission. Currently, we have few data regarding the effectiveness or safety of doing so. We collected data from 21 therapeutic efficacy trials of the National Antimalarial Drug Resistance Monitoring System of India conducted during 2009 to 2010, wherein 9 sites used single-dose primaquine (0.75 mg/kg of body weight) administered on day 2 along with artesunate plus sulfadoxine-pyrimethamine (AS+SP) while 12 did not. We estimated the effect of primaquine on posttreatment gametocyte clearance and the total number of gametocyte-weeks as determined by microscopy. We compared the median area under the curve for gametocyte density and reported adverse events. One thousand three hundred thirty-five patients completed the antimalarial drug treatment. Adjusting for region, primaquine increased the rate of gametocyte clearance (hazard ratio, 1.9; 95% confidence interval [CI], 1.1 to 3.3), prevented 45% (95% CI, 19 to 62) of posttreatment gametocyte-weeks, and decreased the area under the gametocyte density curve over the 28-day follow-up compared to AS+SP alone ( P value = 0.01). The results were robust to other adjustment sets, and the estimated effect of primaquine increased during sensitivity analysis on the measurement of exposure time. No serious adverse events were detected. In conclusion, the addition of primaquine to AS+SP was effective in reducing the posttreatment presence of P. falciparum gametocytes. Primaquine was well tolerated and could be administered along with an artemisinin combination therapy as the first-line therapy

Three Indian siblings affected with progressive myoclonic epilepsy due to unverricht–Lundborg disease

Background: Progressive myoclonus epilepsy (PME) is a group of heterogeneous genetic disorders characterized by action myoclonus, epileptic seizures, and progressive neurologic deterioration with onset of symptoms in adolescence and adulthood. Unverricht–Lundborg disease (ULD) is the most common type of PME in high-income countries; however, it is under-reported from India due to challenges in clinical recognition and establishment of diagnosis due to lack of availability of genetic studies. Clinical Description: We herewith report three siblings (two girls and a boy) born out of a third-degree consanguineous marriage, with onset of “difficult-to-treat” seizures since early adolescence, with concurrent action myoclonus and ataxia. All three had a waxing and waning course. Electroencephalography exhibited generalized spike-wave and polyspike-wave discharges with photosensitivity while neuroimaging was normal. Management and Outcome: The possibility of PME was considered in view of the clinical phenotype and strong family history. Following detailed elicitation of history, focused physical examination, and rational investigative work-up specific molecular genetic testing were planned for ULD. This showed homozygous expansion of dodecamer (set of 12 nucleotides) repeat in the cystatin B gene in all the three affected siblings. The parents were heterozygous carriers. Genetic counseling was undertaken and anticonvulsant drugs (ACDs) modified accordingly. The definitive diagnosis helped in accurate prognostication and management to improve the quality of life of all three siblings. Conclusion: Clinicians should consider a specific epilepsy syndrome in patients with onset of symptoms in adolescence. ULD is a type of PME with a relatively better course of illness. Establishing the diagnosis has implications on the extent of investigative workup, choice of ACD, and prognosis

Efficacy and safety of Artemisinin Combination Therapy for the treatment of uncomplicated Plasmodium falciparum malaria across international borders of India

Background & objectives: Malaria due to Plasmodium falciparum (Pf) remains a major public threat in India. Artemisinin-based combination therapy (ACT) has been the country’s first-line drug for uncomplicated Pf malaria. In 2013-2014, Artesunate plus sulfadoxine (AS+SP) was replaced by Artemether Lumefantrine (AL) as the first- line antimalarial in North East (NE) states of the country which are endemic for Pf malaria. Regular monitoring of antimalarial drugs is of utmost importance to achieve the goal of elimination. This study aimed to assess the efficacy and safety of ACT for treating uncomplicated Pf malaria in the NE states of India. Methods: A prospective study of 28-day follow-up was conducted to monitor the efficacy and safety of AL from 2018-2019 in four districts, Udalgiri, Meghalaya, Lawngtlai, and Dhalai of NE, India. The clinical and parasitological response and the polymorphism analysis of the Pfdhps, P/dhfr, and Pfkelch 13 gene were evaluated. Results: A total of 234 patients were enrolled in the study out of 216 patients who completed the follow-up to 28 days. One-hundred percent adequate clinical and parasitological responses (ACPR) were observed with polymerase chain reaction (PCR) correction. The genotype results suggest no recrudescence in the treatment-failure patients. The classical single nucleotide polymorphisms (SNP) in the Pfdhfr gene was S108N (94.9%), followed by C59R (91.5%), whereas, in the Pfdhps gene, the common SNP was A437G (79.6%), followed by S3436A. No associated or validated mutations were found in the propeller region of the PfKelch13 gene. Interpretation & conclusion: AL was efficacious and safe in uncomplicated P. falciparum malaria in North East India. In contrast, mutations in the genes responsible for sulfadoxine and pyrimethamine resistance have been fixed in northeast India’s population

Genetic variation in histidine rich proteins among Indian <it>Plasmodium falciparum</it> population: possible cause of variable sensitivity of malaria rapid diagnostic tests

Abstract Background Rapid diagnostic tests (RDTs) have revolutionized the diagnosis of malaria. Among the various factors affecting RDTs sensitivity is genetic variation of the antigen used. The genetic variation in PfHRP2 and PfHRP3 proteins was studied among the Indian Plasmodium falciparum isolates. Methods One hundred and forty isolates of P. falciparum were collected from six geographical regions of India. Target genes encoding PfHRP2 and PfHRP3 antigens were sequenced to study genetic polymorphism. Minimum detection limit giving a positive rapid diagnostic test was also determined. Results Extensive variations were observed in amino acid repeat types of PfHRP2 and PfHRP3. PfHRP2 exhibited more polymorphism than PfHRP3. Significant relation was observed between type 2 and type 7 repeats and RDT detection rate as higher number of these repeats showed better sensitivity with RDTs. Conclusion The results provide insights into the genetic diversity of Pfhrp2 and Pfhrp3 genes among Indian P. falciparum population and its relation to RDT sensitivity.</p

An epidemiological study of dengue and its coinfections in Delhi

Objectives: To study the epidemiology of dengue with reference to serological, demographic profile, spatio-temporal distribution, vectors, circulating serotypes and coinfections. Methods: Demographic data and presenting symptoms of fever cases reporting to the clinic were recorded. Suspected patients were tested for dengue, chikungunya and malaria. Dengue specific RT-PCR was performed to detect circulating DENV serotypes. Vector surveys were carried out to detect Aedes breeding. Results: Of the 5536 fever patients tested during 2012 to 2015, 1536 (27.7%) had confirmed dengue. The peak in dengue positivity was observed during September and October. Of the 60 samples analysed, 10 (16.7%) had concurrent infection with multiple dengue serotypes; one of them had all the four serotypes. Coinfection of dengue with malaria and chikungunya was also observed. The occurrence of dengue and malaria was inversely related. Seven percent of the dengue patients required hospitalization. Vector surveys in the draining area revealed Aedes breeding with a high house index. Conclusion: Delhi being hyperendemic, the occurrence of concurrent infections with multiple DENV serotypes has become a frequent finding. The study emphasizes the need of epidemiological and entomological surveillance to monitor trends in dengue distribution, seasonal patterns and circulating serotypes to guide dengue control activities. Keywords: Dengue, Epidemiology, India, Serotype