Browsing by Author "Rudra Pratap Singh"

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Comparison of different wavelets for watermarking of colored images
(2011) Achintya Singhal; Rudra Pratap Singh; Monal Tenguria
Digital watermarking is very lucrative field over the years. Researchers have tried various techniques for watermarking images. In recent time, wavelet transforms has emerged as a popular technique for image compression and watermark applications. The wavelet transform has high de-correlation and energy compaction efficiency. This paper presents a comparative study of various wavelet techniques for watermarking and tests the results in terms of watermarked image quality, extracted watermark quality and its substance to JPEG 2000 compression. © 2011 IEEE.
Determinants for progression from asymptomatic infection to symptomatic visceral leishmaniasis: A cohort study
(Public Library of Science, 2018) Jaya Chakravarty; Epco Hasker; Sangeeta Kansal; Om Prakash Singh; Paritosh Malaviya; Abhishek Kumar Singh; Ankita Chourasia; Toolika Singh; Medhavi Sudarshan; Akhil Pratap Singh; Bhawana Singh; Rudra Pratap Singh; Bart Ostyn; Michaela Fakiola; Albert Picado; Joris Menten; Jenefer M. Blackwell; Mary E. Wilson; David Sacks; Marleen Boelaert; Shyam Sundar
Background: Asymptomatic Leishmania donovani infections outnumber clinical presentations, however the predictors for development of active disease are not well known. We aimed to identify serological, immunological and genetic markers for progression from L. donovani infection to clinical Visceral Leishmaniasis (VL). Methods: We enrolled all residents >2 years of age in 27 VL endemic villages in Bihar (India). Blood samples collected on filter paper on two occasions 6–12 months apart, were tested for antibodies against L. donovani with rK39-ELISA and DAT. Sero converters, (negative for both tests in the first round but positive on either of the two during the second round) and controls (negative on both tests on both occasions) were followed for three years. At the start of follow-up venous blood was collected for the following tests: DAT, rK39- ELISA, Quantiferon assay, SNP/HLA genotyping and L.donovani specific quantitative PCR. Results: Among 1,606 subjects enrolled,17 (8/476 seroconverters and 9/1,130 controls) developed VL (OR 3.1; 95% CI 1.1–8.3). High DAT and rK39 ELISA antibody titers as well as positive qPCR were strongly and significantly associated with progression from seroconversion to VL with odds ratios of 19.1, 30.3 and 20.9 respectively. Most VL cases arose early (median 5 months) during follow-up. Conclusion: We confirmed the strong association between high DAT and/or rK39 titers and progression to disease among asymptomatic subjects and identified qPCR as an additional predictor. Low predictive values do not warrant prophylactic treatment but as most progressed to VL early during follow-up, careful oberservation of these subjects for at least 6 months is indicated. © 2018, Public Library of Science. All rights reserved. https://creativecommons.org/publicdomain/zero/1.0/.
Genetic variability and ecosystem services of Neem (Azadirachta indica A. Juss): A two-decadal systematic study for harnessing global sustainable goals
(Elsevier B.V., 2025) Ayushman Malakar; Suman Dutta; Navneet Shukla; Spandan Dasgupta; Rudra Pratap Singh; Shripati Dwivedi; Shivangi Maheshwari; Pankaj Dayal Sharma; Avijit Pattanaik; Subrata Gorain; Animesh Sinha
Neem is native to the Indian subcontinent and recognized globally for its ethno-medicinal and bio-pesticidal properties. The increasing global demand for Neem and its derivatives has intrigued researchers worldwide to concentrate on its medicinal, agrochemical, and industrial applications. Despite its high significance, a thorough understanding of the genetic potential and ecosystem services of this species remains insufficient till date. In this systematic review, we have utilized two decades of literatures from the Web of Science database from 2000 to 2024. We identified 696 articles after applying inclusion-exclusion criteria structured by PRISMA. The primary aim of this systematic review is to provide a comprehensive knowledge base for the current research landscape regarding the genetics and ecology of Neem and how its potential can be used to sustainably mitigate global problems. The analysis of existing literatures identified highest contributions from India with expanding interests in international collaborations among the researchers. This study highlighted existence of ample genetic variability in natural Neem population across the globe and explored various ecosystem services provided by Neem, facilitating the achievement of multiple sustainable development goals. The co-occurrence analysis and thematic mapping of keywords showcased Neem's efficacy in agroforestry and integrated pest management practices. The uniqueness of this study is integration of qualitative synthesis and in-depth systematic review, which guarantees a comprehensive understanding of global research trends in Neem and its future prospects. Further, this study identified several remaining gaps in tree-breeding, improvement and population ecology of Neem that warrant further investigation as future research prospects. © 2025 The Authors
Health & demographic surveillance system profile: The muzaffarpur-tmrc health and demographic surveillance system
(Oxford University Press, 2014) Paritosh Malaviya; Albert Picado; Epco Hasker; Bart Ostyn; Sangeeta Kansal; Rudra Pratap Singh; Ravi Shankar; Marleen Boelaert; Shyam Sundar
The Muzaffarpur-TMRC Health and Demographic Surveillance System (HDSS), established in 2007, was developed as an enlargement of the scope of a research collaboration on the project Visceral Leishmaniasis in Bihar, which had been ongoing since 2005. The HDSS is located in a visceral leishmaniasis (VL)-endemic area in the Muzaffarpur district of Bihar state in India. It is the only HDSS conducting research on VL, which is a vectorborne infectious disease transmitted by female phlebotomine sandflies and is fatal if left untreated. Currently the HDSS serves a population of over 105 000 in 66 villages. The HDSS collects data on vital events including pregnancies, births, deaths, migration and marriages, as well as other socio-economic indicators, at regular intervals. Incident VL cases are identified. The HDSS team is experienced in conducting both qualitative and quantitative studies, sample collection and rapid diagnostic tests in the field. In each village, volunteers connect the HDSS team with the community members. The Muzaffarpur-TMRC HDSS provides opportunities for studies on VL and other neglected tropical diseases (NTDs) and their interaction with demographic events such as migration. © The Author 2014; all rights reserved.
Latent Infection with Leishmania donovani in Highly Endemic Villages in Bihar, India
(Public Library of Science, 2013) Epco Hasker; Sangeeta Kansal; Paritosh Malaviya; Kamlesh Gidwani; Albert Picado; Rudra Pratap Singh; Ankita Chourasia; Abhishek Kumar Singh; Ravi Shankar; Joris Menten; Mary Elizabeth Wilson; Marleen Boelaert; Shyam Sundar
Introduction: Asymptomatic persons infected with the parasites causing visceral leishmaniasis (VL) usually outnumber clinically apparent cases by a ratio of 4-10 to 1. We describe patterns of markers of Leishmania donovani infection and clinical VL in relation to age in Bihar, India. Methods: We selected eleven villages highly endemic for Leishmania donovani. During a 1-year interval we conducted two house to house surveys during which we collected blood samples on filter paper from all consenting individuals aged 2 years and above. Samples were tested for anti-leishmania serology by Direct Agglutination Test (DAT) and rK39 ELISA. Data collected during the surveys included information on episodes of clinical VL among study participants. Results: We enrolled 13,163 persons; 6.2% were reactive to DAT and 5.9% to rK39. Agreement between the tests was weak (kappa = 0.30). Among those who were negative on both tests at baseline, 3.6% had converted to sero-positive on either of the two tests one year later. Proportions of sero-positives and sero-converters increased steadily with age. Clinical VL occurred mainly among children and young adults (median age 19 years). Discussion: Although infection with L. donovani is assumed to be permanent, serological markers revert to negative. Most VL cases occur at younger ages, yet we observed a steady increase with age in the frequency of sero-positivity and sero-conversion. Our findings can be explained by a boosting effect upon repeated exposure to the parasite or by intermittent release of parasites in infected subjects from safe target cells. A certain proportion of sero-negative subjects could have been infected but below the threshold of antibody abundance for our serologic testing.
Plant Secondary Metabolites as Defense Tools against Herbivores for Sustainable Crop Protection
(MDPI, 2022) Pratap Adinath Divekar; Srinivasa Narayana; Bhupendra Adinath Divekar; Rajeev Kumar; Basana Gowda Gadratagi; Aishwarya Ray; Achuit Kumar Singh; Vijaya Rani; Vikas Singh; Akhilesh Kumar Singh; Amit Kumar; Rudra Pratap Singh; Radhe Shyam Meena; Tusar Kanti Behera
Plants have evolved several adaptive strategies through physiological changes in response to herbivore attacks. Plant secondary metabolites (PSMs) are synthesized to provide defensive functions and regulate defense signaling pathways to safeguard plants against herbivores. Herbivore injury initiates complex reactions which ultimately lead to synthesis and accumulation of PSMs. The biosynthesis of these metabolites is regulated by the interplay of signaling molecules comprising phytohormones. Plant volatile metabolites are released upon herbivore attack and are capable of directly inducing or priming hormonal defense signaling pathways. Secondary metabolites enable plants to quickly detect herbivore attacks and respond in a timely way in a rapidly changing scenario of pest and environment. Several studies have suggested that the potential for adaptation and/or resistance by insect herbivores to secondary metabolites is limited. These metabolites cause direct toxicity to insect pests, stimulate antixenosis mechanisms in plants to insect herbivores, and, by recruiting herbivore natural enemies, indirectly protect the plants. Herbivores adapt to secondary metabolites by the up/down regulation of sensory genes, and sequestration or detoxification of toxic metabolites. PSMs modulate multi-trophic interactions involving host plants, herbivores, natural enemies and pollinators. Although the role of secondary metabolites in plant-pollinator interplay has been little explored, several reports suggest that both plants and pollinators are mutually benefited. Molecular insights into the regulatory proteins and genes involved in the biosynthesis of secondary metabolites will pave the way for the metabolic engineering of biosynthetic pathway intermediates for improving plant tolerance to herbivores. This review throws light on the role of PSMs in modulating multi-trophic interactions, contributing to the knowledge of plant-herbivore interactions to enable their management in an eco-friendly and sustainable manner. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
Post-kala-azar dermal leishmaniasis in visceral leishmaniasis-endemic communities in Bihar, India
(2012) Rudra Pratap Singh; Albert Picado; Shahnawaz Alam; Epco Hasker; Shri Prakash Singh; Bart Ostyn; François Chappuis; Shyam Sundar; Marleen Boelaert
We assessed the prevalence of post-kala-azar dermal leishmaniasis (PKDL), a late cutaneous manifestation of visceral leishmaniasis (VL), in 16 VL-endemic communities in Bihar, India. The prevalence of confirmed PKDL cases was 4.4 per 10000 individuals and 7.8 if probable cases were also considered. The clinical history and treatment of the post-kala-azar dermal leishmaniasis cases are discussed. © 2012 Blackwell Publishing Ltd.
Prevalence of sand flies and Leishmania donovani infection in a natural population of female Phlebotomus argentipes in Bihar state, India
(2012) Puja Tiwary; Dinesh Kumar; Rudra Pratap Singh; Madhukar Rai; Shyam Sundar
Leishmaniasis is a vector-borne disease, and in the Indian subcontinent the female Phlebotomus argentipes is the vector for Leishmania donovani. However, data on the extent of sand fly infection rates in natural settings using molecular methods have not been extensively reported in India. In this study a PCR technique was applied targeting the 18S rRNA encoding region to determine the prevalence of Leishmania infection in female P. argentipes captured in the field. For this study, sand flies were collected from 897 houses selected from 50 villages endemic for visceral leishmaniasis (VL) in Muzaffarpur district, Bihar state, using CDC miniature light traps and mouth aspirators. A total of 14,585 sand flies were collected of which 449 were female P. argentipes divided into 132 pools. Molecular detection using PCR targeting the 18S rRNA gene was carried out for the identification of P. argentipes and Leishmania. The overall prevalence of infection was 4.90-17.37% for L. donovani in female P. argentipes in endemic regions of Bihar state. In this study no correlation was found between the presence of infected sand flies and the occurrence of clinical VL. This study provides the first report evaluating the prevalence of Leishmania infection in sand flies in a region endemic for VL in India. Sergentomyia species are the most common species of sand fly. Knowledge of the infection rate in female P. argentipes may help in predicting severity of disease and in vector elimination programs. © Copyright 2012, Mary Ann Liebert, Inc.
Seasonal Variation in the Prevalence of Sand Flies Infected with Leishmania donovani
(2013) Puja Tiwary; Dinesh Kumar; Mukesh Mishra; Rudra Pratap Singh; Madhukar Rai; Shyam Sundar
Background: Visceral Leishmaniasis (VL) is a life threatening neglected infectious disease in the Indian subcontinent, transmitted by the bite of female sand flies. Estimation of the infectivity in the vector population, collected in different seasons, may be useful to better understanding the transmission dynamics of VL as well as to plan vector control measures. Methodology: We collected sand flies from highly endemic regions of Bihar state, India for one year over three seasons. The species of the sand flies were confirmed by species-specific PCR-RFLP. Leishmania donovani infection was investigated in 1397 female Phlebotomus argentipes using PCR, targeting the Leishmania specific minicircle of the kDNA region. Further, the parasitic load in the infected sand flies was measured using quantitative PCR. Conclusion: Though sand flies were most abundant in the rainy season, the highest rate of infection was detected in the winter season with 2.84% sand flies infected followed by the summer and rainy seasons respectively. This study can help in vector elimination programmes and to reduce disease transmission. © 2013 Tiwary et al.
Strong Association between Serological Status and Probability of Progression to Clinical Visceral Leishmaniasis in Prospective Cohort Studies in India and Nepal
(Public Library of Science, 2014) Epco Hasker; Paritosh Malaviya; Kamlesh Gidwani; Albert Picado; Bart Ostyn; Sangeeta Kansal; Rudra Pratap Singh; Om Prakash Singh; Ankita Chourasia; Abhishek Kumar Singh; Ravi Shankar; Mary E. Wilson; Basudha Khanal; Suman Rijal; Marleen Boelaert; Shyam Sundar
Introduction:Asymptomatic persons infected with the parasites causing visceral leishmaniasis (VL) usually outnumber clinically apparent cases by a ratio of 4-10 to 1. We assessed the risk of progression from infection to disease as a function of DAT and rK39 serological titers.Methods:We used available data on four cohorts from villages in India and Nepal that are highly endemic for Leishmania donovani. In each cohort two serosurveys had been conducted. Based on results of initial surveys, subjects were classified as seronegative, moderately seropositive or strongly seropositive using both DAT and rK39. Based on the combination of first and second survey results we identified seroconvertors for both markers. Seroconvertors were subdivided in high and low titer convertors. Subjects were followed up for at least one year following the second survey. Incident VL cases were recorded and verified.Results:We assessed a total of 32,529 enrolled subjects, for a total follow-up time of 72,169 person years. Altogether 235 incident VL cases were documented. The probability of progression to disease was strongly associated with initial serostatus and with seroconversion; this was particularly the case for those with high titers and most prominently among seroconvertors. For high titer DAT convertors the hazard ratio reached as high as 97.4 when compared to non-convertors. The strengths of the associations varied between cohorts and between markers but similar trends were observed between the four cohorts and the two markers.Discussion:There is a strongly increased risk of progressing to disease among DAT and/or rK39 seropositives with high titers. The options for prophylactic treatment for this group merit further investigation, as it could be of clinical benefit if it prevents progression to disease. Prophylactic treatment might also have a public health benefit if it can be corroborated that these asymptomatically infected individuals are infectious for sand flies.
Visceral Leishmaniasis in Muzaffarpur district, Bihar, India from 1990 to 2008
(2011) Paritosh Malaviya; Albert Picado; Shri Prakash Singh; Epco Hasker; Rudra Pratap Singh; Marleen Boelaert; Shyam Sundar
Background:Visceral Leishmaniasis (VL) is a vector-borne disease transmitted by Phlebotomus argentipes. To understand the VL seasonality, annual and monthly variations of VL incidence and its relationship to meteorological variables, the numbers of VL cases reported in Muzaffarpur district, Bihar, India from 1990 to 2008 were studied.Methods:Annual VL incidence per 10,000 and the total number of annual VL cases reported at block Community Health Centres (CHC), Public Hospitals or Non-Governmental Organisations (NGO) and the number of VL cases per month from 2000 to 2008 as well as the monthly average of cases for 2000-08, 2000-04 and 2005-08 periods along with the monthly averages of temperature, rainfall and relative humidity were plotted. VL Standardised Incidence Ratios per block were computed for the periods of 1990-1993, 1994-1998, 1999-2004 and 2005-2008 and month wise from 2002 to 2008. A negative binomial regression model was used to evaluate the association between meteorological variables and the number of VL cases per month from 2000 to 2008.Results:A total of 68,358 VL cases were reported in Muzaffarpur district from 1990 to 2008, ranging from 1,2481 in 1992 to 1,161 in 2001. The blocks with the highest number of cases shifted from East (1990-98) to West (1999-2008). Monthly averages of cases ranged from 149 to 309, highest peak in March-April and another one in July. Monthly VL incidence was associated positively to rainfall and negatively to relative humidity and the numbers of VL cases in the previous month.Interpretation:The number of cases reported to the public health sector allowed the describing of the spatial distribution and temporal variations in the Muzaffarpur from 1990 to 2008. However, to assess the actual VL burden, as well as the efficacy of the control measures applied in the district, reporting from private practices and NGOs should be encouraged. © 2011 Malaviya et al.