Feasibility of a dried blood spot strategy for serological screening and surveillance to monitor elimination of Human African Trypanosomiasis in the Democratic Republic of the Congo

Luz, Raquel Inocêncio da; Phanzu, Delphin Mavinga; Kiabanzawoko, Oscar N’lemvo; Miaka, Eric Mwamba; Verlé, Paul; Weggheleire, Anja De; Büscher, Philippe; Hasker, Epco; Boelaert, Marleen

doi:10.1371/journal.pntd.0009407

Cited by 11 publications

(7 citation statements)

References 23 publications

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“…As expected, the laboratory tests on DBS showed high specificity. The specificity of the ELISA/ T. b. gambiense was similar to the specificity in Côte d’Ivoire [ 29 ], and in several studies carried out in the Democratic Republic of Congo [ 20 , 22 , 33 ]. The 100% specificity for trypanolysis confirms previous observations in the historical Gaoua HAT focus [ 12 ].…”

Section: Discussionsupporting

confidence: 69%

Monitoring the elimination of gambiense human African trypanosomiasis in the historical focus of Batié, South–West Burkina Faso

et al. 2022

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The World Health Organisation has targeted the elimination of human African trypanosomiasis (HAT) as zero transmission by 2030. Continued surveillance needs to be in place for early detection of re-emergent cases. In this context, the performance of diagnostic tests and testing algorithms for detection of the re-emergence of Trypanosoma brucei gambiense HAT remains to be assessed. We carried out a door-to-door active medical survey for HAT in the historical focus of Batié, South–West Burkina Faso. Screening was done using three rapid diagnostic tests (RDTs). Two laboratory tests (ELISA/T. b. gambiense and immune trypanolysis) and parasitological examination were performed on RDT positives only. In total, 5883 participants were screened, among which 842 (14%) tested positive in at least one RDT. Blood from 519 RDT positives was examined microscopically but no trypanosomes were observed. The HAT Sero-K-Set test showed the lowest specificity of 89%, while the specificities of SD Bioline HAT and rHAT Sero-Strip were 92% and 99%, respectively. The specificity of ELISA/T. b. gambiense and trypanolysis was 99% (98–99%) and 100% (99–100%), respectively. Our results suggest that T. b. gambiense is no longer circulating in the study area and that zero transmission has probably been attained. While a least cost analysis is still required, our study showed that RDT preselection followed by trypanolysis may be a useful strategy for post-elimination surveillance in Burkina Faso.

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Section: Discussionsupporting

confidence: 69%

Monitoring the elimination of gambiense human African trypanosomiasis in the historical focus of Batié, South–West Burkina Faso

et al. 2022

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“…For example, in the Democratic Republic of Congo (DRC) the large geographic spread of endemic gHAT foci coupled with financial and logistical constraints currently limit the capacity to perform country-wide vector control. Some regions additionally have access challenges associate with limited infrastructure or political instability [ 22 ]. Therefore, current efforts in vector control for DRC target the regions of highest incidence [ 20 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

Update of transmission modelling and projections of gambiense human African trypanosomiasis in the Mandoul focus, Chad

et al. 2022

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Background In recent years, a programme of vector control, screening and treatment of gambiense human African trypanosomiasis (gHAT) infections led to a rapid decline in cases in the Mandoul focus of Chad. To represent the biology of transmission between humans and tsetse, we previously developed a mechanistic transmission model, fitted to data between 2000 and 2013 which suggested that transmission was interrupted by 2015. The present study outlines refinements to the model to: (1) Assess whether elimination of transmission has already been achieved despite low-level case reporting; (2) quantify the role of intensified interventions in transmission reduction; and (3) predict the trajectory of gHAT in Mandoul for the next decade under different strategies. Method Our previous gHAT transmission model for Mandoul was updated using human case data (2000–2019) and a series of model refinements. These include how diagnostic specificity is incorporated into the model and improvements to the fitting method (increased variance in observed case reporting and how underreporting and improvements to passive screening are captured). A side-by-side comparison of fitting to case data was performed between the models. Results We estimated that passive detection rates have increased due to improvements in diagnostic availability in fixed health facilities since 2015, by 2.1-fold for stage 1 detection, and 1.5-fold for stage 2. We find that whilst the diagnostic algorithm for active screening is estimated to be highly specific (95% credible interval (CI) 99.9–100%, Specificity = 99.9%), the high screening and low infection levels mean that some recently reported cases with no parasitological confirmation might be false positives. We also find that the focus-wide tsetse reduction estimated through model fitting (95% CI 96.1–99.6%, Reduction = 99.1%) is comparable to the reduction previously measured by the decline in tsetse catches from monitoring traps. In line with previous results, the model suggests that transmission was interrupted in 2015 due to intensified interventions. Conclusions We recommend that additional confirmatory testing is performed in Mandoul to ensure the endgame can be carefully monitored. More specific measurement of cases, would better inform when it is safe to stop active screening and vector control, provided there is a strong passive surveillance system in place. Graphical Abstract

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“…27 Individual reticence to participation in a trial in The Gambia involving blood collection via finger stick for malaria screening was linked to fear of blood-taking due to depletion of life force and fear of exploitation. 28 In contrast, a study on the feasibility of bloodspot collection for the surveillance of human African trypanosomiasis in the Democratic Republic of the Congo found that refusal to participate in bloodspot collection was rare, although reasons for non-participation were not analysed. 29 Finger-prick blood samples are routinely taken for malaria testing, 30 which is commonplace in most places that are also trachoma-endemic.…”

Section: Discussionmentioning

confidence: 99%

Acceptability and feasibility of tests for infection, serological testing and photography to define need for interventions against trachoma

Renneker,

Mtuy,

Kabona

et al. 2024

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Background Trachoma causes blindness due to repeated conjunctival infection by Chlamydia trachomatis (Ct). Transmission intensity is estimated, for programmatic decision-making, by prevalence of the clinical sign trachomatous inflammation—follicular (TF) in children aged 1–9 years. Research into complementary indicators to field-graded TF includes work on conjunctival photography, tests for ocular Ct infection, and serology. The perceived acceptability and feasibility of these indicators among a variety of stakeholders is unknown. Methodology Focus group discussions (FGDs) with community members and in-depth interviews (IDIs) with public health practitioners in Tanzania were conducted. FGDs explored themes including participants' experience with, and thoughts about, different diagnostic approaches. The framework method for content analysis was used. IDIs yielded lists of perceived strengths of, and barriers to, implementation for programmatic use of each indicator. These were used to form an online quantitative survey on complementary indicators distributed to global stakeholders via meetings, mailing lists, and social media posts. Results Sixteen FGDs and 11 IDIs were conducted in October–November 2022. In general, all proposed sample methods were deemed acceptable by community members. Common themes included not wanting undue discomfort and a preference for tests perceived as accurate. Health workers noted the importance of community education for some sample types. The online survey was conducted in April–May 2023 with 98 starting the questionnaire and 81 completing it. Regarding barriers to implementing diagnostics, the highest agreement items related to feasibility, rather than acceptability. No evidence of significant differences was found in responses pertaining to community acceptability based on participant characteristics. Conclusions All of the indicators included were generally deemed acceptable by all stakeholders in Tanzania, although community education around the benefits and risks of different sample types, as well as addressing issues around feasibility, will be key to successful, sustainable integration of these indicators into trachoma programs.

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Feasibility of a dried blood spot strategy for serological screening and surveillance to monitor elimination of Human African Trypanosomiasis in the Democratic Republic of the Congo

Cited by 11 publications

References 23 publications

Monitoring the elimination of gambiense human African trypanosomiasis in the historical focus of Batié, South–West Burkina Faso

Monitoring the elimination of gambiense human African trypanosomiasis in the historical focus of Batié, South–West Burkina Faso

Update of transmission modelling and projections of gambiense human African trypanosomiasis in the Mandoul focus, Chad

Acceptability and feasibility of tests for infection, serological testing and photography to define need for interventions against trachoma

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