Strengthening Cutaneous Leishmaniasis Diagnosis in Guyana: Surveillance, Molecular Analysis, and Performance Evaluation to Improve Access to Care
1
College of Medical Sciences, University of Guyana, Georgetown, Guyana
Popul. Med. 2026;8(Supplement Supplement 1):
ABSTRACT
BACKGROUND:
Cutaneous leishmaniasis remains a significant public health challenge in Guyana, particularly in remote interior regions where access to reliable diagnostic services is limited. This study aimed to strengthen national diagnostic capacity by implementing comprehensive surveillance, validating microscopy through molecular methods, and evaluating the performance of existing diagnostic approaches.
METHODS:
A retrospective analysis (2017–2021) was conducted to assess the epidemiological distribution of cutaneous leishmaniasis using choropleth and heat maps. Case data were obtained from key diagnostic sites, including Vector Control Services (Georgetown), Lethem Hospital, and Bartica Hospital. Preserved microscopy-positive slides from this period were subjected to molecular species identification at the Fiocruz Laboratory, Brazil. A prospective evaluation (2022–2024) compared the diagnostic performance of field microscopy with molecular testing, including genotyping and conventional PCR (cPCR). Diagnostic agreement was assessed using Kappa statistics. Quality assurance was supported through participation in the Direct External Evaluation Program of Performance (PEED), coordinated by Colombia’s National Health Institute and supported by the Pan American Health Organization, in accordance with ISO/IEC 17043:2010 and ISO 13528:2015 standards.
RESULTS:
Disease hotspots persisted in interior regions, particularly Regions 7 and 9. PEED assessments demonstrated good diagnostic agreement, with a Kappa index of 0.8 across 2023 and 2024. Positive agreement remained high (~90%), while negative agreement declined from 88.9% in 2023 to 80.0% in 2024, suggesting a risk of false-negative results with microscopy. Molecular testing, particularly PCR, demonstrated superior diagnostic accuracy.
CONCLUSIONS:
Integrating epidemiological mapping, molecular validation, and external quality assessment enhanced understanding of disease distribution and diagnostic performance in Guyana. Strengthening microscopy quality and expanding molecular diagnostic capacity are critical for improving case detection and patient outcomes in endemic regions.
Cutaneous leishmaniasis remains a significant public health challenge in Guyana, particularly in remote interior regions where access to reliable diagnostic services is limited. This study aimed to strengthen national diagnostic capacity by implementing comprehensive surveillance, validating microscopy through molecular methods, and evaluating the performance of existing diagnostic approaches.
METHODS:
A retrospective analysis (2017–2021) was conducted to assess the epidemiological distribution of cutaneous leishmaniasis using choropleth and heat maps. Case data were obtained from key diagnostic sites, including Vector Control Services (Georgetown), Lethem Hospital, and Bartica Hospital. Preserved microscopy-positive slides from this period were subjected to molecular species identification at the Fiocruz Laboratory, Brazil. A prospective evaluation (2022–2024) compared the diagnostic performance of field microscopy with molecular testing, including genotyping and conventional PCR (cPCR). Diagnostic agreement was assessed using Kappa statistics. Quality assurance was supported through participation in the Direct External Evaluation Program of Performance (PEED), coordinated by Colombia’s National Health Institute and supported by the Pan American Health Organization, in accordance with ISO/IEC 17043:2010 and ISO 13528:2015 standards.
RESULTS:
Disease hotspots persisted in interior regions, particularly Regions 7 and 9. PEED assessments demonstrated good diagnostic agreement, with a Kappa index of 0.8 across 2023 and 2024. Positive agreement remained high (~90%), while negative agreement declined from 88.9% in 2023 to 80.0% in 2024, suggesting a risk of false-negative results with microscopy. Molecular testing, particularly PCR, demonstrated superior diagnostic accuracy.
CONCLUSIONS:
Integrating epidemiological mapping, molecular validation, and external quality assessment enhanced understanding of disease distribution and diagnostic performance in Guyana. Strengthening microscopy quality and expanding molecular diagnostic capacity are critical for improving case detection and patient outcomes in endemic regions.
| eISSN: | 2654-1459 |
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