ABSTRACT
BACKGROUND: Lymphatic filariasis is a mosquito transmitted parasitic infection in tropical regions. Annual mass treatment with ivermectin and albendazole is used for transmission control of Wuchereria bancrofti, the infective agent of lymphatic filariasis in many African countries, including Tanzania. METHODOLOGY: In a general population study in Southwest Tanzania, individuals were tested for circulating filarial antigen, an indicator of W. bancrofti adult worm burden in 2009 before mass drug administration commenced in that area. Seven annual rounds with ivermectin and albendazole were given between 2009 and 2015 with a population coverage of over 70%. Participants of the previous study took part in a follow-up activity in 2019 to measure the effect of this governmental activity. FINDINGS: One thousand two hundred and ninety nine inhabitants of Kyela district in Southwest Tanzania aged 14 to 65 years who had participated in the study activities in 2009 were revisited in 2010/11 and 2019. Among this group, the prevalence of lymphatic filariasis of the 14-65 years olds in 2009 was 35.1%. A follow-up evaluation in 2010/11 had shown a reduction to 27.7%. In 2019, after 7 years of annual treatment and an additional three years of surveillance, the prevalence had dropped to 1.7%, demonstrating successful treatment by the national control programme. Risk factors for W. bancrofti-infection were the occupation as farmer, male sex, and older age. Most infected individuals in the 2019 follow-up study already had a positive test for filarial antigen in 2009 and/or 2010/11. CONCLUSIONS: This data supports the findings of the Tanzanian Neglected Tropical Disease Control Programme (NTDCP), who conducted Transmission Assessment Surveys and found an impressive reduction in the prevalence of LF in children. Our results complement this data by showing a similar decrease in prevalence of LF in the adult population in the same area. The elimination of LF seems achievable in the near future.
Subject(s)
Elephantiasis, Filarial , Filaricides , Albendazole/adverse effects , Animals , Antigens, Helminth/therapeutic use , Elephantiasis, Filarial/drug therapy , Elephantiasis, Filarial/epidemiology , Elephantiasis, Filarial/prevention & control , Filaricides/therapeutic use , Follow-Up Studies , Humans , Ivermectin/adverse effects , Male , Mass Drug Administration , Tanzania/epidemiology , Wuchereria bancroftiABSTRACT
OBJECTIVE: Early identification of confirmed virological failure is paramount to avoid accumulation of drug resistance in patients on antiretroviral therapy (ART). Scale-up of HIV-RNA monitoring in Africa and timely switch to second-line regimens are challenged. METHODS: A WHO adapted confirmed virological treatment screening algorithm (HIV-RNA screening, enhanced adherence counselling, confirmatory HIV-RNA testing) was evaluated in HIV-infected patients on first-line ART from Tanzania. The main endpoints included viral resuppression and virological failure rates, retention and turnaround time of the screening algorithm until second-line ART initiation. Secondary endpoints included risk factors for virological treatment failure and patterns of genotypic drug resistance. RESULTS: HIV-RNA >1000 copies/ml at first screening was detected in 58/356 (16.3%) patients (median time-on-treatment 6.3 years, 25% immunological treatment failure). Adjusted risk factors for virological failure were age <30 years (RR 5.2 [95% CI: 2.5-10.8]), years on ART ≥3 years (RR 3.0 [1.0-8.9]), CD4-counts <200 cells/µl (RR 9.3 [4.0-21.8]) and poor self-reported treatment adherence (RR 2.0 [1.2-3.4]). Resuppression of HIV-RNA <1000 copies/ml was observed in 5/50 (10%) cases after enhanced adherence counselling. Confirmatory testing within 3 months was performed in only 46.6% and switch to second-line ART within 6 months in 60.4% of patients. Major NNRTI-mutation were detected in all of 30 patients, NRTI mutations in 96.7% and ≥3 thymidine-analogue mutations in 40%. No remaining NRTI options were predicted in 57% and limited susceptibility in 23% of patients. CONCLUSION: We observed low levels of viral resuppression following adherence counselling, associated with high levels of accumulated drug resistance. High visit burden and turnaround times for confirmed virological failure diagnosis further delayed switching to second-line treatment which could be improved using novel point-of-care viral load monitoring systems.
OBJECTIF: L'identification précoce de l'échec virologique confirmé est primordiale pour éviter l'accumulation de résistance aux médicaments chez les patients sous traitement antirétroviral (ART). L'intensification du suivi de l'ARN du VIH en Afrique et le passage en temps opportun aux schémas thérapeutiques de deuxième intention sont adressés. MÉTHODES: Nous avons évalué un algorithme adapté de l'OMS confirmé pour le dépistage du traitement virologique (dépistage de l'ARN du VIH, adhésion renforcée du conseil, test de confirmation de l'ARN du VIH) chez des patients infectés par le VIH sous ART de première intention en Tanzanie. Les critères principaux comprenaient la répression virale et les taux d'échec virologique, la rétention et et la durée de rotation de l'algorithme de dépistage jusqu'à l'initiation de l'ART de deuxième ligne. Les critères d'évaluation secondaires comprenaient les facteurs de risque d'échec du traitement virologique et les profils de résistance génotypique aux médicaments. RÉSULTATS: Un ARN-VIH >1000 copies/ml au premier dépistage a été détecté chez 58/356 (16,3%) patients (durée médiane de traitement de 6,3 ans, 25% d'échec immunologique du traitement). Les facteurs de risque ajustés pour l'échec virologique étaient l'âge <30 ans (RR: 5,2 [IC95%: 2,5-10,8]), les années sous ART ≥3 ans (RR: 3,0 [1,0-8,9]), la numération des CD4 <200 cellules/µL (RR: 9,3 [4,0-21,8]) et une mauvaise compliance au traitement autodéclarée (RR: 2,0 [1,2-3,4]). Une re-suppression du VIH-ARN <1000 copies/mL a été observée chez 5/50 (10%) des cas après renforcement du conseil pour la compliance. Un test de confirmation dans les 3 mois n'a été réalisé que dans 46,6% des cas et le passage à l'ART de deuxième ligne dans les 6 mois chez 60,4% des patients. Des mutations NNRTI majeures ont été détectées chez tous les 30 patients, des mutations NRTI chez 96,7% et ≥3 mutations analogues à la thymidine chez 40%. Aucune option NRTI restante n'a été prévue chez 57% des cas et une sensibilité limitée chez 23% des patients. CONCLUSION: Nous avons observé de faibles taux de re-suppression virale après des conseils d'adhésion, associés à des taux élevés de résistance accumulée aux médicaments. La charge élevée des visites et les délais de rotation pour le diagnostic confirmé d'échec virologique ont retardé le passage au traitement de deuxième intention, ce qui pourrait être amélioré à l'aide de nouveaux systèmes de surveillance de la charge virale au point des soins.