Dataset Information

Melarsoprol sensitivity profile of Trypanosoma brucei gambiense isolates from cured and relapsed sleeping sickness patients from the Democratic Republic of the Congo.

ABSTRACT:

Background

Sleeping sickness caused by Trypanosoma brucei (T.b.) gambiense constitutes a serious health problem in sub-Sahara Africa. In some foci, alarmingly high relapse rates were observed in patients treated with melarsoprol, which used to be the first line treatment for patients in the neurological disease stage. Particularly problematic was the situation in Mbuji-Mayi, East Kasai Province in the Democratic Republic of the Congo with a 57% relapse rate compared to a 5% relapse rate in Masi-Manimba, Bandundu Province. The present study aimed at investigating the mechanisms underlying the high relapse rate in Mbuji-Mayi using an extended collection of recently isolated T.b. gambiense strains from Mbuji-Mayi and from Masi-Manimba.

Methodology/principal findings

Forty five T.b. gambiense strains were used. Forty one were isolated from patients that were cured or relapsed after melarsoprol treatment in Mbuji-Mayi. In vivo drug sensitivity tests provide evidence of reduced melarsoprol sensitivity in these strains. This reduced melarsoprol sensitivity was not attributable to mutations in TbAT1. However, in all these strains, irrespective of the patient treatment outcome, the two aquaglyceroporin (AQP) 2 and 3 genes are replaced by chimeric AQP2/3 genes that may be associated with resistance to pentamidine and melarsoprol. The 4 T.b. gambiense strains isolated in Masi-Manimba contain both wild-type AQP2 and a different chimeric AQP2/3. These findings suggest that the reduced in vivo melarsoprol sensitivity of the Mbuji-Mayi strains and the high relapse rates in that sleeping sickness focus are caused by mutations in the AQP2/AQP3 locus and not by mutations in TbAT1.

Conclusions/significance

We conclude that mutations in the TbAQP2/3 locus of the local T.b. gambiense strains may explain the high melarsoprol relapse rates in the Mbuji-Mayi focus but other factors must also be involved in the treatment outcome of individual patients.

SUBMITTER: Pyana Pati P

PROVIDER: S-EPMC4183442 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

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Publications

Melarsoprol sensitivity profile of Trypanosoma brucei gambiense isolates from cured and relapsed sleeping sickness patients from the Democratic Republic of the Congo.

Pyana Pati Patient P Van Reet Nick N Mumba Ngoyi Dieudonné D Ngay Lukusa Ipos I Karhemere Bin Shamamba Stomy S Büscher Philippe P

PLoS neglected tropical diseases 20141002 10

<h4>Background</h4>Sleeping sickness caused by Trypanosoma brucei (T.b.) gambiense constitutes a serious health problem in sub-Sahara Africa. In some foci, alarmingly high relapse rates were observed in patients treated with melarsoprol, which used to be the first line treatment for patients in the neurological disease stage. Particularly problematic was the situation in Mbuji-Mayi, East Kasai Province in the Democratic Republic of the Congo with a 57% relapse rate compared to a 5% relapse rate ...[more]

PMID: 25275572

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Project description:BACKGROUND: Sleeping sickness due to Trypanosoma brucei (T.b.) gambiense is still a major public health problem in some central African countries. Historically, relapse rates around 5% have been observed for treatment with melarsoprol, widely used to treat second stage patients. Later, relapse rates of up to 50% have been recorded in some isolated foci in Angola, Sudan, Uganda and Democratic Republic of the Congo (DRC). Previous investigations are not conclusive on whether decreased sensitivity to melarsoprol is responsible for these high relapse rates. Therefore we aimed to establish a parasite collection isolated from cured as well as from relapsed patients for downstream comparative drug sensitivity profiling. A major constraint for this type of investigation is that T.b. gambiense is particularly difficult to isolate and adapt to classical laboratory rodents. METHODOLOGY/PRINCIPAL FINDINGS: From 360 patients treated in Dipumba hospital, Mbuji-Mayi, D.R. Congo, blood and cerebrospinal fluid (CSF) was collected before treatment. From patients relapsing during the 24 months follow-up, the same specimens were collected. Specimens with confirmed parasite presence were frozen in liquid nitrogen in a mixture of Triladyl, egg yolk and phosphate buffered glucose solution. Isolation was achieved by inoculation of the cryopreserved specimens in Grammomys surdaster, Mastomys natalensis and SCID mice. Thus, 85 strains were isolated from blood and CSF of 55 patients. Isolation success was highest in Grammomys surdaster. Forty strains were adapted to mice. From 12 patients, matched strains were isolated before treatment and after relapse. All strains belong to T.b. gambiense type I. CONCLUSIONS AND SIGNIFICANCE: We established a unique collection of T.b. gambiense from cured and relapsed patients, isolated in the same disease focus and within a limited period. This collection is available for genotypic and phenotypic characterisation to investigate the mechanism behind abnormally high treatment failure rates in Mbuji-Mayi, D.R. Congo.

Project description:BACKGROUND:Nifurtimox eflornithine combination therapy (NECT) to treat human African trypanosomiasis (HAT), commonly called sleeping sickness, was added to the World Health Organisation's (WHO) Essential Medicines List in 2009 and to the Paediatric List in 2012. NECT was further tested and documented in a phase IIIb clinical trial in the Democratic Republic of Congo (DRC) assessing the safety, effectiveness, and feasibility of implementation under field conditions (NECT-FIELD study). This trial brought a unique possibility to examine concomitant drug management. METHODOLOGY/PRINCIPAL FINDINGS:This is a secondary analysis of the NECT-FIELD study where 629 second stage gambiense HAT patients were treated with NECT, including children and pregnant and breastfeeding women in six general reference hospitals located in two provinces. Concomitant drugs were prescribed by the local investigators as needed. Patients underwent daily evaluations, including vital signs, physical examination, and adverse event monitoring. Concomitant medication was documented from admission to discharge. Patients' clinical profiles on admission and safety profile during specific HAT treatment were similar to previously published reports. Prescribed concomitant medications administered during the hospitalization period, before, during, and immediately after NECT treatment, were mainly analgesics/antipyretics, anthelmintics, antimalarials, antiemetics, and sedatives. Use of antibiotics was reasonable and antibiotics were often prescribed to treat cellulitis and respiratory tract infections. Prevention and treatment of neurological conditions such as convulsions, loss of consciousness, and coma was used in approximately 5% of patients. CONCLUSIONS/SIGNIFICANCE:The prescription of concomitant treatments was coherent with the clinical and safety profile of the patients. However, some prescription habits would need to be adapted in the future to the evolving available pharmacopoeia. A list of minimal essential medication that should be available at no cost to patients in treatment wards is proposed to help the different actors to plan, manage, and adequately fund drug supplies for advanced HAT infected patients. TRIAL REGISTRATION NUMBER:The initial study was registered at ClinicalTrials.gov, number NCT00906880.

Project description:BackgroundNifurtimox-eflornithine combination therapy (NECT) for the treatment of second stage gambiense human African trypanosomiasis (HAT) was added to the World Health Organization's Essential Medicines List in 2009 after demonstration of its non-inferior efficacy compared to eflornithine therapy. A study of NECT use in the field showed acceptable safety and high efficacy until hospital discharge in a wide population, including children, pregnant and breastfeeding women, and patients with a HAT treatment history. We present here the effectiveness results after the 24-month follow-up visit.Methodology/principal findingsIn a multicenter, open label, single arm phase IIIb study, second stage gambiense HAT patients were treated with NECT in the Democratic Republic of Congo. Clinical cure was defined 24 months after treatment as survival without clinical and/or parasitological signs of HAT. Of the 629 included patients, 619 (98.4%) were discharged alive after treatment and were examined for the presence of trypanosomes, white blood cell count in cerebro-spinal fluid, and disease symptoms. The clinical cure rate of 94.1% was comparable for all subpopulations analyzed at the 24-month follow-up visit. Self-reported adverse events during follow-up were few and concerned mainly nervous system disorders, infections, and gastro-intestinal disorders. Overall, 28 patients (4.3%) died during the course of the trial. The death of 16 of the 18 patients who died during the follow-up period was assessed as unlikely or not related to NECT. Within 24 months, eight patients (1.3%) relapsed and received rescue treatment. Sixteen patients were completely lost to follow-up.Conclusions/significanceNECT treatment administered under field conditions was effective and sufficiently well tolerated, no major concern arose for children or pregnant or breastfeeding women. Patients with a previous HAT treatment history had the same response as those who were naïve. In conclusion, NECT was confirmed as effective and appropriate for use in a broad population, including vulnerable subpopulations.Trial registrationThe trial is registered at ClinicalTrials.gov, number NCT00906880.

Project description:Gambiense human African trypanosomiasis (gHAT) is a virulent disease declining in burden but still endemic in West and Central Africa. Although it is targeted for elimination of transmission by 2030, there remain numerous questions about the drivers of infection and how these vary geographically. In this study we focus on the Democratic Republic of Congo (DRC), which accounted for 84% of the global case burden in 2016, to explore changes in transmission across the country and elucidate factors which may have contributed to the persistence of disease or success of interventions in different regions. We present a Bayesian fitting methodology, applied to 168 endemic health zones (∼100,000 population size), which allows for calibration of a mechanistic gHAT model to case data (from the World Health Organization HAT Atlas) in an adaptive and automated framework. It was found that the model needed to capture improvements in passive detection to match observed trends in the data within former Bandundu and Bas Congo provinces indicating these regions have substantially reduced time to detection. Health zones in these provinces generally had longer burn-in periods during fitting due to additional model parameters. Posterior probability distributions were found for a range of fitted parameters in each health zone; these included the basic reproduction number estimates for pre-1998 (R0) which was inferred to be between 1 and 1.14, in line with previous gHAT estimates, with higher median values typically in health zones with more case reporting in the 2000s. Previously, it was not clear whether a fall in active case finding in the period contributed to the declining case numbers. The modelling here accounts for variable screening and suggests that underlying transmission has also reduced greatly-on average 96% in former Equateur, 93% in former Bas Congo and 89% in former Bandundu-Equateur and Bandundu having had the highest case burdens in 2000. This analysis also sets out a framework to enable future predictions for the country.

Dataset Information

Melarsoprol sensitivity profile of Trypanosoma brucei gambiense isolates from cured and relapsed sleeping sickness patients from the Democratic Republic of the Congo.

Background

Methodology/principal findings

Conclusions/significance

Publications

Melarsoprol sensitivity profile of Trypanosoma brucei gambiense isolates from cured and relapsed sleeping sickness patients from the Democratic Republic of the Congo.

Similar Datasets

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