The impact of the National Programme to Eliminate Lymphatic Filariasis on filariasis morbidity in Sri Lanka: Comparison of current status with retrospective data following the elimination of lymphatic filariasis as a public health problem

• Published in: PLoS neglected tropical diseases 2024-08, Vol.18 (8), p.e0012343
• Main Authors: Gunaratna, Indeewarie E, Chandrasena, Nilmini T G A, Vallipuranathan, Murali, Premaratna, Ranjan, Ediriweera, Dileepa, de Silva, Nilanthi R
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Albendazole - administration & dosage; Albendazole - therapeutic use; Care and treatment; Child; Comorbidity; Computer and Information Sciences; Diagnosis; Diethylcarbamazine - administration & dosage; Diethylcarbamazine - therapeutic use; Disease Eradication - methods; Drug therapy, Combination; Elephantiasis, Filarial - drug therapy; Elephantiasis, Filarial - epidemiology; Elephantiasis, Filarial - prevention & control; Female; Filariasis; Filaricides - therapeutic use; Humans; Lymphedema - epidemiology; Male; Mass Drug Administration; Medicine and Health Sciences; Middle Aged; Morbidity - trends; National Health Programs; Patient outcomes; People and places; Public Health; Retrospective Studies; Risk factors; Sri Lanka - epidemiology; Testicular Hydrocele - epidemiology; Young Adult
• ISSN: 1935-2727; 1935-2735; 1935-2735
• DOI: 10.1371/journal.pntd.0012343

Sri Lanka implemented the National Programme for Elimination of Lymphatic Filariasis (NPELF) in its endemic regions in 2002. Five annual rounds of mass drug administration using the two-drug combination diethylcarbamazine (DEC) and albendazole led to sustained reductions in infection rates below threshold levels. In 2016, WHO validated that Sri Lanka eliminated lymphatic filariasis as a public health problem. To explore the impact of the NPELF on lymphatic filariasis morbidity in Sri Lanka. Passive Case Detection (PCD) data maintained in filaria clinic registries from 2006-2022 for lymphoedema and hospital admission data for managing hydroceles/spermatoceles from 2007-2022 were analyzed. The morbidity status in 2022 and trends in overall and district-wise PCD rates were assessed. Poisson log-linear models were used to assess the trends in PCD for endemic regions, including district-wise trends and hospital admissions for the management of hydroceles/spermatoceles. In 2022, there were 566 new lymphoedema case visits. The mean (SD) age was 53.9 (16.0) years. The staging was done for 94% of cases, of which 79% were in the early stages (57.3% and 21.4% in stages two and one, respectively). Western Province had the highest caseload (52%), followed by the Southern (32%) and Northwestern (16%) Provinces, respectively. The reported lymphoedema PCD rate in 2022 was 0.61 per 10,000 endemic population. The overall PCD rate showed a decline of 7.6% (95%CI: 4.9% - 10.3%) per year (P < 0.0001) from 2007 to 2022. A steady decline was observed in Colombo, Gampaha and Kurunegala districts, while Kalutara remained static and other districts showed a decline in recent years. Further, admissions for inpatient management of hydroceles/spermatoceles showed a declining trend after 2015. The PCD rates of lymphoedema and hydroceles/spermatoceles showed a declining trend in Sri Lanka after the implementation of the NPELF.