São Tomé and Príncipe on the Verge of Eliminating Lymphatic Filariasis as a Public Health Problem: Evidence from IDA Impact Assessment Surveys.
5 affiliations
- 1Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN), World Health Organization, Regional Office for Africa, Brazzaville P.O. Box 06, Democratic Republic of the Congo.
- 2National Programme for the Control of Neglected Tropical Diseases, Ministry of Health, Sao Tome P.O. Box 23, Sao Tome and Principe.
- 3Preventive Chemotherapy Neglected Tropical Diseases Programme, Ministry of Public Health, Hygiene, and Social Welfare, Kinshasa P.O. Box 8081, Democratic Republic of the Congo.
- 4São Tomé and Príncipe Country Office, World Health Organization, Sao Tome P.O. Box 287, Sao Tome and Principe.
- 5Department of Malaria and Neglected Tropical Diseases, World Health Organization, CH-1211 Geneva, Switzerland.
Abstract
Accelerated efforts to eliminate lymphatic filariasis (LF) as a public health problem have been supported by the introduction of the triple-drug regimen of ivermectin, diethylcarbamazine and albendazole (IDA) in endemic settings. In São Tomé and Príncipe, nationwide mass drug administration (MDA) with diethylcarbamazine and albendazole was implemented in 2018, followed by IDA in 2019 and 2020. This study assesses progress towards elimination using post-MDA impact assessment surveys conducted after cessation of treatment. Cross-sectional surveys were conducted among adults aged 20 years and older in 2022 and again between December 2024 and January 2025. Circulating filarial antigen (CFA) was detected using the filarial test strip (FTS). Individuals who tested positive were examined for microfilaremia using nocturnal calibrated thick blood smear microscopy. MDA coverage data were obtained from national programme records, and morbidity was assessed by clinical screening during the surveys. Three rounds of nationwide MDA achieved high epidemiological coverage (86.4% in 2018, 74.2% in 2019 and 80.0% in 2020). The impact assessment surveys conducted in 2022 evaluated 14,132 adults, with 21 individuals (0.15%) testing positive for CFA, while the follow-up survey conducted between December 2024 and January 2025 assessed 14,653 adults and detected seven positive cases (0.05%). No microfilariae were detected among the 28 antigen-positive individuals examined using nocturnal calibrated thick blood smears. Clinical screening during the surveys identified 190 cases of lymphoedema and nine cases of hydrocoele. Infection indicators remain well below WHO decision thresholds, suggesting that LF transmission is unlikely to be sustained. São Tomé and Príncipe appears to be close to eliminating LF as a public health problem. However, strengthening morbidity management services will be essential to support the preparation of the national elimination dossier.
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BibTeX
@article{bakajika2026são,
title = {{São Tomé and Príncipe on the Verge of Eliminating Lymphatic Filariasis as a Public Health Problem: Evidence from IDA Impact Assessment Surveys.}},
author = {Didier Bakajika and Alzíra Rosário and Jessica Vicente Fernandes and Lamine Diawara and Jean-Paul Tambwe Mangala and Jean Kale Kalenga and Vilfrido Santana Gil and Dyesse Yumba and Honorat Zouré and Elizabeth Juma and Abdoulaye Diarra and Jonathan King and Jorge Cano},
journal = {Tropical medicine and infectious disease},
year = {2026},
month = sep,
doi = {10.3390/tropicalmed11100262},
url = {https://europepmc.org/article/MED/42931448},
note = {CC BY},
}
RIS
TY - JOUR
TI - São Tomé and Príncipe on the Verge of Eliminating Lymphatic Filariasis as a Public Health Problem: Evidence from IDA Impact Assessment Surveys.
AU - Didier Bakajika
AU - Alzíra Rosário
AU - Jessica Vicente Fernandes
AU - Lamine Diawara
AU - Jean-Paul Tambwe Mangala
AU - Jean Kale Kalenga
AU - Vilfrido Santana Gil
AU - Dyesse Yumba
AU - Honorat Zouré
AU - Elizabeth Juma
AU - Abdoulaye Diarra
AU - Jonathan King
AU - Jorge Cano
PY - 2026
DA - 2026/09/23
JO - Tropical medicine and infectious disease
DO - 10.3390/tropicalmed11100262
UR - https://europepmc.org/article/MED/42931448
AB - Accelerated efforts to eliminate lymphatic filariasis (LF) as a public health problem have been supported by the introduction of the triple-drug regimen of ivermectin, diethylcarbamazine and albendazole (IDA) in endemic settings. In São Tomé and Príncipe, nationwide mass drug administration (MDA) with diethylcarbamazine and albendazole was implemented in 2018, followed by IDA in 2019 and 2020. This study assesses progress towards elimination using post-MDA impact assessment surveys conducted after cessation of treatment. Cross-sectional surveys were conducted among adults aged 20 years and older in 2022 and again between December 2024 and January 2025. Circulating filarial antigen (CFA) was detected using the filarial test strip (FTS). Individuals who tested positive were examined for microfilaremia using nocturnal calibrated thick blood smear microscopy. MDA coverage data were obtained from national programme records, and morbidity was assessed by clinical screening during the surveys. Three rounds of nationwide MDA achieved high epidemiological coverage (86.4% in 2018, 74.2% in 2019 and 80.0% in 2020). The impact assessment surveys conducted in 2022 evaluated 14,132 adults, with 21 individuals (0.15%) testing positive for CFA, while the follow-up survey conducted between December 2024 and January 2025 assessed 14,653 adults and detected seven positive cases (0.05%). No microfilariae were detected among the 28 antigen-positive individuals examined using nocturnal calibrated thick blood smears. Clinical screening during the surveys identified 190 cases of lymphoedema and nine cases of hydrocoele. Infection indicators remain well below WHO decision thresholds, suggesting that LF transmission is unlikely to be sustained. São Tomé and Príncipe appears to be close to eliminating LF as a public health problem. However, strengthening morbidity management services will be essential to support the preparation of the national elimination dossier.
SN - 2414-6366
ER -