scholarly journals Insights from quantitative and mathematical modelling on the proposed 2030 goal for gambiense human African trypanosomiasis (gHAT)

2020 ◽  
Vol 3 ◽  
pp. 1553 ◽  
Author(s):  
Keyword(s):  
Mathematical Modelling ◽  
Human African Trypanosomiasis ◽  
Stochastic Dynamics ◽  
Spatial Scales ◽  
Central Africa ◽  
Cost Effective ◽  
Predictive Modelling ◽  
World Health ◽  
African Trypanosomiasis ◽  
Health Organization

Gambiense human African trypanosomiasis (gHAT) is a parasitic, vector-borne neglected tropical disease that has historically affected populations across West and Central Africa and can result in death if untreated. Following from the success of recent intervention programmes against gHAT, the World Health Organization (WHO) has defined a 2030 goal of global elimination of transmission (EOT). The key proposed indicator to measure achievement of the goal is zero reported cases. Results of previous mathematical modelling and quantitative analyses are brought together to explore both the implications of the proposed indicator and the feasibility of achieving the WHO goal. Whilst the indicator of zero case reporting is clear and measurable, it is an imperfect proxy for EOT and could arise either before or after EOT is achieved. Lagging reporting of infection and imperfect diagnostic specificity could result in case reporting after EOT, whereas the converse could be true due to underreporting, lack of coverage, and cryptic human and animal reservoirs. At the village-scale, the WHO recommendation of continuing active screening until there are three years of zero cases yields a high probability of local EOT, but extrapolating this result to larger spatial scales is complex. Predictive modelling of gHAT has consistently found that EOT by 2030 is unlikely across key endemic regions if current medical-only strategies are not bolstered by improved coverage, reduced time to detection and/or complementary vector control.  Unfortunately, projected costs for strategies expected to meet EOT are high in the short term and strategies that are cost-effective in reducing burden are unlikely to result in EOT by 2030. Future modelling work should aim to provide predictions while taking into account uncertainties in stochastic dynamics and infection reservoirs, as well as assessment of multiple spatial scales, reactive strategies, and measurable proxies of EOT.

scholarly journals Insights from quantitative and mathematical modelling on the proposed 2030 goal for gambiense human African trypanosomiasis (gHAT)

2019 ◽  
Vol 3 ◽  
pp. 1553
Author(s):  
Keyword(s):  
Mathematical Modelling ◽  
Human African Trypanosomiasis ◽  
Stochastic Dynamics ◽  
Spatial Scales ◽  
Central Africa ◽  
Cost Effective ◽  
Predictive Modelling ◽  
World Health ◽  
African Trypanosomiasis ◽  
Health Organization

Gambiense human African trypanosomiasis (gHAT) is a parasitic, vector-borne neglected tropical disease that has historically affected populations across West and Central Africa and can result in death if untreated. Following from the success of recent intervention programmes against gHAT, the World Health Organization (WHO) has defined a 2030 goal of global elimination of transmission (EOT). The key proposed indicator to measure achievement of the goal is to have zero reported cases. Results of previous mathematical modelling and quantitative analyses are brought together to explore both the implications of the proposed indicator and the feasibility of achieving the WHO goal. Whilst the indicator of zero case reporting is clear and measurable, it is an imperfect proxy for EOT and could arise either before or after EOT is achieved. Lagging reporting of infection and imperfect diagnostic specificity could result in case reporting after EOT, whereas the converse could be true due to underreporting, lack of coverage, and cryptic human and animal reservoirs. At the village-scale, the WHO recommendation of continuing active screening until there are three years of zero cases yields a high probability of local EOT, but extrapolating this result to larger spatial scales is complex. Predictive modelling of gHAT has consistently found that EOT by 2030 is unlikely across key endemic regions if current medical-only strategies are not bolstered by improved coverage, reduced time to detection and/or complementary vector control.  Unfortunately, projected costs for strategies expected to meet EOT are high in the short term and strategies that are cost-effective in reducing burden are unlikely to result in EOT by 2030. Future modelling work should aim to provide predictions while taking into account uncertainties in stochastic dynamics and infection reservoirs, as well as assessment of multiple spatial scales, reactive strategies, and measurable proxies of EOT.

scholarly journals Human African trypanosomiasis in two historical foci of the estuaire province, gabon: A case report

2020 ◽  
Vol 8 ◽  
pp. 2050313X2095989
Author(s):  
Berthe Amélie Iroungou ◽  
Larson Boundenga ◽  
Laurette Guignali Mangouka ◽  
Berthold Bivigou-Mboumba ◽  
Jean Raymond Nzenze ◽  
...  
Keyword(s):  
Human African Trypanosomiasis ◽  
Central Africa ◽  
World Health ◽  
African Trypanosomiasis ◽  
Second Stage ◽  
West And Central Africa ◽  
Altered State Of Consciousness ◽  
Polymerase Chain ◽  
Health Organization ◽  
Stage Infection

Human African Trypanosomiasis (HAT) is an infectious disease due to a protozoa parasite of the Trypanosoma genus. In West and Central Africa, this disease is caused by the subspecies Trypanosoma brucei gambiense. Several foci of this disease are currently active and causing the death of hundreds of people in endemic areas. In this article, we report two cases of gambiense HAT in one Indonesian and one Gabonese men in two historical foci of Gabon in 2019. Both patients had fever with temperatures above 38°C, an altered state of consciousness, cachexia, and multiple dermabrasions on the abdomen related to scratching lesions. The diagnostic revealed second-stage infection of both patients with T. b. gambiense; this result was confirmed by a polymerase chain reaction assay. Despite treatment with a combination of eflornithine and nifurtimox, as recommended by the World Health Organization for late-stage T. b. gambiense HAT, one of the two patients died. Thus, these cases highlight the importance of early HAT diagnosis and prompt patient care to fight effectively against this disease.

scholarly journals New Drugs for Human African Trypanosomiasis: A Twenty First Century Success Story

2020 ◽  
Vol 5 (1) ◽  
pp. 29 ◽  
Author(s):  
Emily A. Dickie ◽  
Federica Giordani ◽  
Matthew K. Gould ◽  
Pascal Mäser ◽  
Christian Burri ◽  
...  
Keyword(s):  
Oral Therapy ◽  
Human African Trypanosomiasis ◽  
First Century ◽  
New Drugs ◽  
World Health ◽  
African Trypanosomiasis ◽  
Twenty First Century ◽  
Health Organization ◽  
Stage 1 ◽  
Competing Priorities

The twentieth century ended with human African trypanosomiasis (HAT) epidemics raging across many parts of Africa. Resistance to existing drugs was emerging, and many programs aiming to contain the disease had ground to a halt, given previous success against HAT and the competing priorities associated with other medical crises ravaging the continent. A series of dedicated interventions and the introduction of innovative routes to develop drugs, involving Product Development Partnerships, has led to a dramatic turnaround in the fight against HAT caused by Trypanosoma brucei gambiense. The World Health Organization have been able to optimize the use of existing tools to monitor and intervene in the disease. A promising new oral medication for stage 1 HAT, pafuramidine maleate, ultimately failed due to unforeseen toxicity issues. However, the clinical trials for this compound demonstrated the possibility of conducting such trials in the resource-poor settings of rural Africa. The Drugs for Neglected Disease initiative (DNDi), founded in 2003, has developed the first all oral therapy for both stage 1 and stage 2 HAT in fexinidazole. DNDi has also brought forward another oral therapy, acoziborole, potentially capable of curing both stage 1 and stage 2 disease in a single dosing. In this review article, we describe the remarkable successes in combating HAT through the twenty first century, bringing the prospect of the elimination of this disease into sight.

scholarly journals Update on field use of the available drugs for the chemotherapy of human African trypanosomiasis

Parasitology ◽  
2012 ◽  
Vol 139 (7) ◽  
pp. 842-846 ◽  
Author(s):  
P. P. SIMARRO ◽  
J. FRANCO ◽  
A. DIARRA ◽  
J. A. RUIZ POSTIGO ◽  
J. JANNIN
Keyword(s):  
Human African Trypanosomiasis ◽  
Treatment Time ◽  
Financial Burden ◽  
World Health ◽  
African Trypanosomiasis ◽  
Patient Cost ◽  
Drug Of Choice ◽  
Control Programmes ◽  
Health Organization ◽  
The Cost

SUMMARYDespite the fact that eflornithine was considered as the safer drug to treat human African trypanosomiasis (HAT) and has been freely available since 2001, the difficulties in logistics and cost burden associated with this drug meant that the toxic melarsoprol remained the drug of choice. The World Health Organization responded to the situation by designing a medical kit containing all the materials needed to use eflornithine, and by implementing a training and drugs distribution programme which has allowed a transition to this much safer treatment. The introduction of the combination of nifurtimox and eflornithine (NECT) has accelerated the shift from melarsoprol to the best treatment available, due to reduced dosage and treatment time for eflornithine that has significantly lessened the cost and improved the burden of logistics encountered during treatment and distribution. The decrease in the use of more dangerous but cheaper melarsoprol has meant a rise in the per patient cost of treating HAT. Although NECT is cheaper than eflornithine monotherapy, an unexpected consequence has been a continuing rise in the per patient cost of treating HAT. The ethical decision of shifting to the best available treatment imposes a financial burden on HAT control programmes that might render long-term application unsustainable. These factors call for continuing research to provide new safer and more effective drugs that are simple to administer and cheaper when compared to current drugs.

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 The journey towards elimination of gambiense human African trypanosomiasis: not far, nor easy

Parasitology ◽  
2014 ◽  
Vol 141 (6) ◽  
pp. 748-760 ◽  
Author(s):  
J. R. FRANCO ◽  
P. P. SIMARRO ◽  
A. DIARRA ◽  
J. A. RUIZ-POSTIGO ◽  
J. G. JANNIN
Keyword(s):  
Human African Trypanosomiasis ◽  
Public Health Problem ◽  
World Health ◽  
African Trypanosomiasis ◽  
Adequate Funding ◽  
Current State ◽  
Control Programmes ◽  
Achievable Goal ◽  
Health Organization ◽  
User Friendly

SUMMARYConsidering the epidemic situation of gambiense human African trypanosomiasis (HAT) at the end of the twentieth century, the World Health Organization (WHO) and partners strengthened disease control and surveillance. Over the last 15 years, the activities implemented through the National Control Programmes have brought gambiense HAT under control and now its elimination is deemed as an achievable goal. In 2012, WHO targeted gambiense HAT for elimination as a public health problem by 2020. The final goal will be the sustainable disease elimination by 2030, defined as the interruption of the transmission of gambiense HAT. The elimination is considered feasible, because of the epidemiological vulnerability of the disease, the current state of control, the availability of strategies and tools and international commitment and political will. Integration of activities in the health system is needed to ensure the sustainability of the elimination. The development of user-friendly diagnostic and treatment tools will facilitate the integration process. Adequate funding is needed to implement activities, but also to support research that will make the elimination sustainable. A long-term commitment by donors is needed and ownership of the process by endemic countries is critical.

scholarly journals Economic evaluation of disease elimination: An extension to the net-benefit framework and application to human African trypanosomiasis

2021 ◽  
Vol 118 (50) ◽  
pp. e2026797118
Author(s):  
Marina Antillon ◽  
Ching-I Huang ◽  
Kat S. Rock ◽  
Fabrizio Tediosi
Keyword(s):  
Human African Trypanosomiasis ◽  
Central Africa ◽  
Cost Savings ◽  
Cost Effective ◽  
African Trypanosomiasis ◽  
Net Benefit ◽  
Long Run ◽  
Health Community ◽  
Effective Use ◽  
The Cost

The global health community has earmarked a number of diseases for elimination or eradication, and these goals have often been praised on the premise of long-run cost savings. However, decision makers must contend with a multitude of demands on health budgets in the short or medium term, and costs per case often rise as the burden of a disease falls, rendering such efforts beyond the cost-effective use of scarce resources. In addition, these decisions must be made in the presence of substantial uncertainty regarding the feasibility and costs of elimination or eradication efforts. Therefore, analytical frameworks are necessary to consider the additional effort for reaching global goals, like elimination or eradication, that are beyond the cost-effective use of country resources. We propose a modification to the net-benefit framework to consider the implications of switching from an optimal strategy, in terms of cost-per-burden averted, to a strategy with a higher likelihood of meeting the global target of elimination or eradication. We illustrate the properties of our framework by considering the economic case of efforts to eliminate the transmission of gambiense human African trypanosomiasis (gHAT), a vector-borne, parasitic disease in West and Central Africa, by 2030.

scholarly journals Immune trypanolysis test as a promising bioassay to monitor the elimination of gambiense human African trypanosomiasis

Parasite ◽  
2019 ◽  
Vol 26 ◽  
pp. 68 ◽  
Author(s):  
Emilie Dama ◽  
Oumou Camara ◽  
Dramane Kaba ◽  
Mathurin Koffi ◽  
Mamadou Camara ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Human African Trypanosomiasis ◽  
Public Health Problem ◽  
Population Based ◽  
World Health ◽  
African Trypanosomiasis ◽  
Individual Level ◽  
Trypanosoma Brucei Gambiense ◽  
The World ◽  
Health Organization

The World Health Organization (WHO) has set the goal of gambiense-Human African trypanosomiasis (HAT) elimination as a public health problem for 2020 and interruption of transmission in humans for 2030. In this context, it is crucial to monitor progress towards these targets using accurate tools to assess the level of transmission in a given area. The aim of this study was to investigate the relevance of the immune trypanolysis test (TL) as a population-based bioassay to evaluate Trypanosoma brucei gambiense transmission in various epidemiological contexts. Significant correlations were observed between HAT endemicity levels and the percentage of TL-positive individuals in the population. TL therefore appears to be a suitable population-based biomarker of the intensity of transmission. In addition to being used as a tool to assess the HAT status at an individual level, assessing the proportion of TL positive individuals in the population appears as a promising and easy alternative to monitor the elimination of gambiense HAT in a given area.

scholarly journals Human African Trypanosomiasis: Ethnomedical and Biomedical Relationships

2000 ◽  
Vol 14 (1) ◽  
Author(s):  
Justin Brown
Keyword(s):  
Human African Trypanosomiasis ◽  
Explanatory Models ◽  
Sub Saharan Africa ◽  
World Health ◽  
African Trypanosomiasis ◽  
Sub Saharan ◽  
Biomedical Practitioners ◽  
Models Of Disease ◽  
Health Organization ◽  
The Relationship

Human African Trypanosomiasis (HAT) threatens more than 55 million people in sub-Saharan Africa. The focus of this paper is the relationship that exists between ethnomedical and biomedical practitioners regarding treatment of HAT. The relationship has been one of conflict. Biomedical practitioners have attempted to remove ethnomedicine from African society. This practice has been unsuccessful, especially in rural regions. Ethnomedical practitioners have adopted some aspects of biomedicine, but inadequate application and resources limit their efficacy. The biomedical community, including the World Health Organization, has not recognized the resource potential within ethnomedicine. An examination of the areas of conflict reveals differences in the explanatory models of disease causation and treatment methods. There has been some progress toward a cooperative model of healthcare, but most biomedical practitioners disregard ethnomedical techniques as primitive and ineffective. The conclusion of this paper presents a bleak future for the prevention and treatment of HAT in Africa. This future may be avoided with an increased level of cooperation and understanding between the two systems.

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