Publications by authors named "Ostyn B"

Article Synopsis
  • Nepal's visceral leishmaniasis elimination initiative, launched in 2005, aimed to determine if the transmission of Leishmania donovani had decreased over the years, specifically comparing seroprevalence data from 2006 to 2016.
  • A repeat survey involving 6,609 individuals showed a significant reduction in seroprevalence across all age groups, particularly in children under 10, with a drop from 4.1% in 2006 to 0.5% in 2016, indicating a successful decrease in transmission.
  • The study concludes that the decline in transmission correlates with the elimination program's efforts, and the direct agglutination test (DAT) is a
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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).

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Objective: To assess the rate of default from treatment in the visceral leishmaniasis (VL) elimination programme and to identify risk factors and its underlying causes.

Methods: Case-control study conducted between December 2009 and June 2012 in three primary health centres (PHCs) of Muzaffarpur district, India. Patients who defaulted from treatment from the PHCs were considered as 'cases' and those who completed their treatment as 'controls'.

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Leishmania donovani causes visceral leishmaniasis (VL), the second most deadly vector-borne parasitic disease. A recent epidemic in the Indian subcontinent (ISC) caused up to 80% of global VL and over 30,000 deaths per year. Resistance against antimonial drugs has probably been a contributing factor in the persistence of this epidemic.

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Background: In the Indian subcontinent, Visceral leishmaniasis is endemic in a geographical area coinciding with the Lower Gangetic Plain, at low altitude. VL occurring in residents of hill districts is therefore often considered the result of Leishmania donovani infection during travel. Early 2014 we conducted an outbreak investigation in Okhaldhunga and Bhojpur districts in the Nepal hills where increasing number of VL cases have been reported.

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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 vector-borne infectious disease transmitted by female phlebotomine sandflies and is fatal if left untreated.

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Background: High frequency of relapse in miltefosine-treated visceral leishmaniasis (VL) patients in India and Nepal followed up for twelve months.

Objective: To identify epidemiological and clinical risk factors for relapse of VL in patients recently treated with standard dosing of miltefosine in India and Nepal.

Design: Prospective observational study in three Primary Health Centers and one reference center in Muzaffarpur district, Bihar, India; and two zonal hospitals and a university hospital in South-east Nepal; records of all consenting patients diagnosed with VL and treated with miltefosine according to the current treatment guidelines of the Kala azar elimination program between 2009 and 2011.

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The elimination of infectious diseases requires reducing transmission below a certain threshold. The Visceral Leishmaniasis (VL) Elimination Initiative in Southeast Asia aims to reduce the annual VL incidence rate below 1 case per 10,000 inhabitants in endemic areas by 2015 via a combination of case management and vector control. Using a previously developed VL transmission model, we investigated transmission thresholds dependent on measures reducing the sand fly density either by killing sand flies (e.

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There is increasing interest in the role of asymptomatic infection in transmission of Visceral Leishmaniasis (VL). We studied the individual, household and environmental factors associated with asymptomatic Leishmania donovani infected individuals and VL. 7,538 individuals living in VL endemic villages in India and Nepal were divided into three mutually exclusive groups based on their VL history and Direct Agglutination Test (DAT) results in yearly serosurveys over a two-year period.

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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.

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Background: Recent reports indicated high miltefosine treatment failure rates for visceral leishmaniasis (VL) on the Indian subcontinent. To further explore the pharmacological factors associated with these treatment failures, a population pharmacokinetic-pharmacodynamic study was performed to examine the relationship between miltefosine drug exposure and treatment failure in a cohort of Nepalese patients with VL.

Methods: Miltefosine steady-state blood concentrations at the end of treatment were analyzed using liquid chromatography tandem mass spectrometry.

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Unlabelled: Leishmania donovani is an intracellular protozoan parasite that causes leishmaniasis, which can range from a self-healing cutaneous disease to a fatal visceral disease depending on the infecting species. Miltefosine is currently the latest and only oral antileishmanial that came out of drug discovery pipelines in the past few decades, but recent reports indicate a significant decline in its efficacy against visceral leishmaniasis (also known as kala-azar) in the Indian subcontinent. This relapse rate of up to 20% within 12 months after treatment was shown not to be related to reinfection, drug quality, drug exposure, or drug-resistant parasites.

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Promastigote miltefosine (MIL) susceptibility was performed on Leishmania donovani isolates from Indian patients with visceral leishmaniasis treated with MIL. Isolates that were obtained before the onset of MIL treatment, after completion of treatment (29th day), or at the time of treatment failure, were screened using in vitro promastigote assay. The MIL susceptibility of the pre-treatment isolates (N = 24, mean IC50 ± SEM = 3.

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Objective: To evaluate a new tool for the monitoring of Visceral Leishmaniasis (VL) treatment outcomes in primary healthcare (PHC) settings, adapted from the standardised Retrospective Quarterly Cohort Monitoring done in tuberculosis control.

Methods: We developed standard case definitions for early and late VL treatment outcomes, a single register allowing for one-line entry per patient as registration tool, and quarterly reporting formats for the clinical outcomes. We pilot-tested these tools in three Indian Primary Health Centres and two Nepalese district hospitals, as well as in a charity VL treatment centre and a university hospital.

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Objectives: Recent epidemiological reports indicate that asymptomatic human infections with Leishmania donovani, the causative agent of visceral leishmaniasis or Kala-azar (KA), occur frequently in India. We explored markers of infection.

Methods: Blood samples were collected from 286 healthy subjects from 16 villages in the Muzaffarpur district of Bihar.

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Background: Miltefosine (MIL), the only oral drug for visceral leishmaniasis (VL), is currently the first-line therapy in the VL elimination program of the Indian subcontinent. Given the paucity of anti-VL drugs and the looming threat of resistance, there is an obvious need for close monitoring of clinical efficacy of MIL.

Methods: In a cohort study of 120 VL patients treated with MIL in Nepal, we monitored the clinical outcomes up to 12 months after completion of therapy and explored the potential role of drug compliance, parasite drug resistance, and reinfection.

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OBJECTIVE: To assess the prevalence of Post-kala-azar dermal leishmaniasis (PKDL) in 16 visceral leishmaniasis-endemic communities in Bihar, India. METHODS: Three-stage house-to-house survey of 2020 households to identify and confirm PKDL cases. RESULTS: The prevalence of confirmed PKDL cases was 4.

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Objective: To assess patient adherence to unsupervised single-drug miltefosine treatment for visceral leishmaniasis and to identify the factors influencing adherence.

Methods: This is a prospective cohort study of 171 patients with Visceral leishmaniasis (VL) in three healthcare settings in Nepal. Adherence was assessed through pill count, checking of treatment cards and adherence questionnaires, as well as miltefosine concentration measurements at the end of treatment.

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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 10 000 individuals and 7.

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The current standard to assess pentavalent antimonial (SSG) susceptibility of Leishmania is a laborious in vitro assay of which the result has little clinical value because SSG-resistant parasites are also found in SSG-cured patients. Candidate genetic markers for clinically relevant SSG-resistant parasites identified by full genome sequencing were here validated on a larger set of clinical strains. We show that 3 genomic locations suffice to specifically detect the SSG-resistant parasites found only in patients experiencing SSG treatment failure.

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Background: Miltefosine is the only oral drug available for treatment of Indian visceral leishmaniasis (VL), which was shown to have an efficacy of 94% in a phase III trial in the Indian subcontinent. Its unrestricted use has raised concern about its continued effectiveness. This study evaluates the efficacy and safety of miltefosine for the treatment of VL after a decade of use in India.

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