scholarly journals Modelling to infer the role of animals in gambiense human African trypanosomiasis transmission and elimination in DRC

2021 ◽  
Author(s):  
Ronald E Crump ◽  
Ching-I Huang ◽  
Simon E F Spencer ◽  
Paul E Brown ◽  
Chansy Shampa ◽  
...  
Keyword(s):  
Human African Trypanosomiasis ◽  
Democratic Republic Of Congo ◽  
Human Case ◽  
Model Parameters ◽  
African Trypanosomiasis ◽  
Treatment Interventions ◽  
Model Variant ◽  
Statistical Support ◽  
Health Zone ◽  
The Impact

Gambiense human African trypanosomiasis (gHAT) has been targeted for elimination of transmission (EoT) to humans by 2030. Whilst this ambitious goal is rapidly approaching, there remain fundamental questions about the presence of non-human animal transmission cycles and their potential role in slowing progress towards, or even preventing, EoT. In this study we focus on the country with the most gHAT disease burden, the Democratic Republic of Congo (DRC), and use mathematical modelling to assess whether animals may contribute to transmission in specific regions, and if so, how their presence could impact the likelihood and timing of EoT. By fitting two model variants – one with, and one without animal transmission – to the human case data from 2000–2016 we estimate model parameters for 158 endemic health zones of DRC. We evaluate the statistical support for each model variant in each health zone and infer the contribution of animals to overall transmission and how this could impact predicted time to EoT. We conclude that there are 24/158 health zones where there is moderate or high statistical support for some animal transmission. However, – even in these regions – we estimate that animals would be extremely unlikely to maintain transmission on their own. Animal transmission could hamper progress towards EoT in some settings, with projections under continuing interventions indicating that the number of health zones expected to achieve EoT by 2030 reduces from 68 to 61 if animals are included in the model. With supplementary vector control (at a modest 60% tsetse reduction) added to medical screening and treatment interventions, the predicted number of health zones meeting the goal increases to 147/158 for the model including animals. This is due to the impact of vector reduction on transmission to and from all hosts.

scholarly journals Quantifying epidemiological drivers of gambiense human African Trypanosomiasis across the Democratic Republic of Congo

2020 ◽  
Author(s):  
Ronald E Crump ◽  
Ching-I Huang ◽  
Ed Knock ◽  
Simon E F Spencer ◽  
Paul Brown ◽  
...  
Keyword(s):  
Human African Trypanosomiasis ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Model Fitting ◽  
Case Finding ◽  
World Health ◽  
Model Parameters ◽  
African Trypanosomiasis ◽  
Republic Of Congo ◽  
Case Data

AbstractGambiense 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 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 1.19, 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.Author summaryGambiense human African trypanosomiasis (gHAT; sleeping sickness) is a deadly disease targeted for elimination by 2030, however there are still several unknowns about what factors influence continued transmission and how this changes with geographic location.In this study we focus on the Democratic Republic of Congo (DRC), which reported 84% of the global cases in 2016 to try and explain why some regions of the country have had more success than others in bringing down case burden. To achieve this we used a state-of-the-art statistical framework to match a mathematical gHAT model to reported case data for 168 regions with some case reporting during 2000–2016.The analysis indicates that two former provinces, Bandundu and Bas Congo had substantial improvements to case detection in fixed health facilities in the time period. Overall, all provinces were estimated to have reductions in (unobservable) transmission including ∼ 96% in former Equateur. This is reassuring as case finding effort has decreased in that region.The model fitting presented here will allow predictions of gHAT under future strategies to be performed in the future.

scholarly journals Quantifying epidemiological drivers of gambiense human African Trypanosomiasis across the Democratic Republic of Congo

2021 ◽  
Vol 17 (1) ◽  
pp. e1008532
Author(s):  
Ronald E. Crump ◽  
Ching-I Huang ◽  
Edward S. Knock ◽  
Simon E. F. Spencer ◽  
Paul E. Brown ◽  
...  
Keyword(s):  
Human African Trypanosomiasis ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Probability Distributions ◽  
Central Africa ◽  
World Health ◽  
Model Parameters ◽  
African Trypanosomiasis ◽  
Republic Of Congo ◽  
Variable Screening

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.

scholarly journals Shrinking the gHAT map: identifying target regions for enhanced control of gambiense human African trypanosomiasis in the Democratic Republic of Congo

2020 ◽  
Author(s):  
Ching-I Huang ◽  
Ronald E Crump ◽  
Paul Brown ◽  
Simon E F Spencer ◽  
Erick Mwamba Miaka ◽  
...  
Keyword(s):  
Vector Control ◽  
Large Scale ◽  
Human African Trypanosomiasis ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
African Trypanosomiasis ◽  
Republic Of Congo ◽  
Priority List ◽  
Modelling Studies ◽  
The Impact

AbstractBackgroundGambiense human African trypanosomiasis (gHAT) is a disease targeted for elimination of transmission (EOT) by 2030, however the likelihood of achieving it is unknown. We utilised modelling to study the impact of currently-available intervention methods on transmission across the Democratic Republic of Congo (DRC) – which accounts for ∼ 70% of global burden – and highlight regions requiring intensified interventions.MethodsA model previously fitted to case data in DRC was used to predict cases and new infections under four future strategies in 168 health zones. The strategies comprise of medical interventions – active and passive screening (AS and PS) and some include large-scale vector control (VC). In each health zone, we estimate the median year of EOT and the probability of EOT by 2030 under each and compute the least ambitious strategy predicted to achieve EOT by 2030.FindingsThe model predicts 42 health zones are very likely to achieve EOT (> 90% probability) using medical-only strategies continued at mean coverage levels; this increases to 52 when AS coverage is increased to maximum previous coverage. In all VC strategies, health zones are predicted to meet EOT by 2030, although there are several where increasing low AS coverage could achieve this.InterpretationThis analysis provides a priority list for consideration for supplementary VC implementation (Bagata, Bandundu, Bolobo, Kikongo, Kwamouth and Masi Manimba in former Bandundu province) in conjunction with the recent AS coverage.FundingBill Melinda Gates Foundation [OPP1177824, OPP1184344, OPP1156227, OPP1186851, and OPP1155293] and Belgian Development Agency (ENABEL).Research in contextEvidence before this studyOn 30th April 2020 we searched PubMed and ScienceDirect to identify previous predictive modelling studies of gHAT in DRC using the search terms “model” AND “Democratic Republic of Congo” OR “DRC” AND “try-panosomiasis” OR “sleeping sickness”. There are numerous modelling studies which have looked at estimating the impact of a variety of strategies on transmission and elimination, however many utilise infection prevalence categories for performing simulations rather than location-specific data. For DRC, modelling studies have made projections at a province-level (i.e. Bandundu), and for health zones (i.e all of Equateur and some in Bandundu), concluding that there is high heterogeneity in underlying transmission, consequently whether medical-only strategies will suffice to meet elimination of transmission (EOT) by 2030. They find that supplemental, large-scale vector control would be expected to result in rapid EOT across settings. Two high-endemicity, village-level studies suggest that regular, high-coverage screening is needed to achieve EOT within 15 years without additional interventions.Added value of this studyThis study presents predictions for EOT across the whole DRC for the first time. Since DRC has the highest disease burden it is critical to understand how far current tools might go towards achieving this 2030 target across the country, and how strategies may need to be adapted for specific locations in the endgame. It also provides a priority list for regions requiring intensified interventions.Implications of all the available evidenceOur analysis suggests that, whilst many regions of DRC are expected to meet the EOT goal by 2030 with medical-only strategies, for some regions current strategies may need to be bolstered to achieve EOT within the next decade. Although some regions could consider increasing coverage of active screening, vector control appears a desirable supplemental intervention in several specific high-prevalence locations.

scholarly journals Predicting the impact of COVID-19 interruptions on transmission of gambiense human African trypanosomiasis in two health zones of the Democratic Republic of Congo

2021 ◽  
Author(s):  
Maryam Aliee ◽  
Soledad Castaño ◽  
Christopher N Davis ◽  
Swati Patel ◽  
Erick Mwamba Miaka ◽  
...  
Keyword(s):  
Human African Trypanosomiasis ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Neglected Tropical Diseases ◽  
Passive Surveillance ◽  
African Trypanosomiasis ◽  
Republic Of Congo ◽  
Active Screening ◽  
Control Programmes ◽  
The Impact

Abstract Many control programmes against neglected tropical diseases have been interrupted due to the coronavirus disease 2019 (COVID-19) pandemic, including those that rely on active case finding. In this study we focus on gambiense human African trypanosomiasis (gHAT), where active screening was suspended in the Democratic Republic of Congo (DRC) due to the pandemic. We use two independent mathematical models to predict the impact of COVID-19 interruptions on transmission and reporting and achievement of the 2030 elimination of transmission (EOT) goal for gHAT in two moderate-risk regions of the DRC. We consider different interruption scenarios, including reduced passive surveillance in fixed health facilities, and whether this suspension lasts until the end of 2020 or 2021. Our models predict an increase in the number of new infections in the interruption period only if both active screening and passive surveillance were suspended, and with a slowed reduction—but no increase—if passive surveillance remains fully functional. In all scenarios, the EOT may be slightly pushed back if no mitigation, such as increased screening coverage, is put in place. However, we emphasise that the biggest challenge will remain in the higher-prevalence regions where EOT is already predicted to be behind schedule without interruptions unless interventions are bolstered.

scholarly journals Predicting the impact of COVID-19 interruptions on transmission of gambiense human African trypanosomiasis in two health zones of the Democratic Republic of Congo

2020 ◽  
Author(s):  
Maryam Aliee ◽  
Soledad Castaño ◽  
Christopher N Davis ◽  
Swati Patel ◽  
Erick Mwamba Miaka ◽  
...  
Keyword(s):  
Human African Trypanosomiasis ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Neglected Tropical Diseases ◽  
Passive Surveillance ◽  
African Trypanosomiasis ◽  
Republic Of Congo ◽  
Active Screening ◽  
Control Programmes ◽  
The Impact

AbstractMany control programmes against neglected tropical diseases have been interrupted due to COVID-19 pandemic, including those that rely on active case finding. In this study we focus on gambiense human African trypanosomiasis (gHAT), where active screening was suspended in the Democratic Republic of Congo (DRC) due to the pandemic. We use two independent mathematical models to predict the impact of COVID-19 interruptions on transmission and reporting, and the achievement of 2030 elimination of transmission (EOT) goal for gHAT in two moderate-risk regions of DRC. We consider different interruption scenarios, including reduced passive surveillance in fixed health facilities, and whether this suspension lasts until the end of 2020 or 2021. Our models predict an increase in the number of new infections in the interruption period only if both active screening and passive surveillance were suspended, and with slowed reduction - but no increase - if passive surveillance remains fully functional. In all scenarios, the EOT may be slightly pushed back if no mitigation such as increased screening coverage is put in place. However, we emphasise that the biggest challenge will remain in the higher prevalence regions where EOT is already predicted to be behind schedule without interruptions unless interventions are bolstered.

scholarly journals Modelling gambiense human African trypanosomiasis infection in villages of the Democratic Republic of Congo using Kolmogorov forward equations

2021 ◽  
Author(s):  
Christopher N Davis ◽  
Matt J Keeling ◽  
Kat S Rock
Keyword(s):  
Human African Trypanosomiasis ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Mechanistic Model ◽  
Stochastic Methods ◽  
African Trypanosomiasis ◽  
Exact Methods ◽  
Republic Of Congo ◽  
Forward Equations ◽  
Kolmogorov Forward Equations

Stochastic methods for modelling disease dynamics enables the direct computation of the probability of elimination of transmission (EOT). For the low-prevalence disease of human African trypanosomiasis (gHAT), we develop a new mechanistic model for gHAT infection that determines the full probability distribution of the gHAT infection using Kolmogorov forward equations. The methodology allows the analytical investigation of the probabilities of gHAT elimination in the spatially-connected villages of the Kwamouth and Mosango health zones of the Democratic Republic of Congo, and captures the uncertainty using exact methods. We predict that, if current active and passive screening continue at current levels, local elimination of infection will occur in 2029 for Mosango and after 2040 in Kwamouth, respectively. Our method provides a more realistic approach to scaling the probability of elimination of infection between single villages and much larger regions, and provides results comparable to established models without the requirement of detailed infection structure. The novel flexibility allows the interventions in the model to be implemented specific to each village, and this introduces the framework to consider the possible future strategies of test-and-treat or direct treatment of individuals living in villages where cases have been found, using a new drug.

Characteristics, behaviors and association between Human African Trypanosomiasis and HIV seropositivity among volunteer blood donors in a semi-rural area: A survey from Kikwit, the Democratic Republic of Congo

2016 ◽  
Vol 61 (4) ◽  
Author(s):  
Lefils Kasiama Ndilu ◽  
Mathilde Bothale Ekila ◽  
Donald Fundji Mayuma ◽  
Alain Musaka ◽  
Roger Wumba ◽  
...  
Keyword(s):  
Alcohol Intake ◽  
Blood Donors ◽  
Human African Trypanosomiasis ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Casual Sex ◽  
Unprotected Sex ◽  
African Trypanosomiasis ◽  
Republic Of Congo ◽  
Hiv Test

AbstractBlood safety is a major element in the strategy to control the HIV epidemic. The aim of this study was to determine the prevalence and the associated factors of a positive HIV test among blood donors and its association between Human African Trypanosomiasis in Kikwit, the Democratic Republic of Congo. A cross-sectional study was conducted between November 2012 and May 2013. An anonymous questionnaire was designed to extract relevant data. The average mean age of participants was 30 years. The majority were man (67.8%). The overall prevalence of HIV, syphilis, hepatitis B, hepatitis C and human African trypanosomiasis was respectively 3.2%, 1.9%, 1.6%, 1.3% and 1.3%. Alcohol intake, casual unprotected sex, not using condoms during casual sex, sex after alcohol intake and seroprevalence of human African trypanosomiasis were significantly associated with a positive HIV test result ( p<0.05). In this study, sexual risk behaviors were the major risk factors associated with positive HIV tests in blood donors living in Kikwit. It is important to raise awareness about HIV and voluntary blood donation in response to some observations noted in this study such as the low educational level of the blood donors, the low level of knowledge of HIV prevention methods.

scholarly journals The Flipside of Eradicating a Disease; Human African Trypanosomiasis in a Woman in Rural Democratic Republic of Congo: A Case Report

2019 ◽  
Vol 4 (4) ◽  
pp. 142 ◽  
Author(s):  
Junior Mudji ◽  
Jonathan Benhamou ◽  
Erick Mwamba-Miaka ◽  
Christian Burri ◽  
Johannes Blum
Keyword(s):  
Case Report ◽  
Sleep Disorder ◽  
Human African Trypanosomiasis ◽  
Democratic Republic Of Congo ◽  
Disease Diagnosis ◽  
Tsetse Flies ◽  
Test Results ◽  
African Trypanosomiasis ◽  
Laboratory Test Results ◽  
Two Phases

Human African Trypanosomiasis (HAT) is a neglected disease caused by the protozoan parasites Trypanosoma brucei and transmitted by tsetse flies that progresses in two phases. Symptoms in the first phase include fever, headaches, pruritus, lymphadenopathy, and in certain cases, hepato- and splenomegaly. Neurological disorders such as sleep disorder, aggressive behavior, logorrhea, psychotic reactions, and mood changes are signs of the second stage of the disease. Diagnosis follows complex algorithms, including serological testing and microscopy. Our case report illustrates the course of events of a 41-year old woman with sleep disorder, among other neurological symptoms, whose diagnosis was made seven months after the onset of symptoms. The patient had consulted two different hospitals in Kinshasa and was on the verge of being discharged from a third due to negative laboratory test results. This case report highlights the challenges that may arise when a disease is on the verge of eradication.

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