Journal Article

Changes in circulating filarial antigen status in previously positive individuals: Lessons for treatment monitoring and pre-transmission assessment surveys

Gyasi, Charles, Ahiadorme, Monica, Atisu, Prince Dennis, Opoku, Vera Serwaa, Opoku, John, Osei-Mensah, Jubin, Boateng, John, Debrah, Linda Batsa, Debrah, Alexander Yaw, Obeng, Prince, Mensah, Derrick Adu, Klarmann-Schulz, Ute, Hoerauf, Achim, Kroidl, Inge, Kutu, Emmanuel Donawobuge

2025

Overview

The Global Programme to Eliminate Lymphatic Filariasis has made significant gains through mass drug administration (MDA) of Ivermectin/Albendazole. Periodic evaluation of the MDA programme in lymphatic filariasis elimination is particularly useful in determining end points for stopping the programme. This is a follow-up study that sought to examine the effects of additional time and MDA intake on antigenemia seroreversion in persons who had previously tested positive for LF using the Filarial Test Strip (FTS) and the TropBio ELISA over a period of 1-5 years. A total of 542 individuals, from the Kassena Nankana East Municipal (N = 340) and Nabdam districts (N = 202) in the Upper East Region of Ghana, who had previously tested either positive (N = 446) or negative (N = 96) for FTS-CFA, participated in the study. Two follow-up visits were conducted; 1-4 years (follow-up-1) and 2-5 years (follow-up-2) after the baseline visit. Of the 446 FTS-CFA positives, 175 (39.2%) did not receive additional MDA (ivermectin/Albendazole) after the baseline visit. Overall, from the two follow-up visits, 159/175 (90.9%) FTS-CFA+ participants who did not receive any additional Ivermectin/Albendazole and 226 out of the 271 (83.4%) with additional MDA treatment became CFA negative. A total of 120 randomly selected baseline FTS-CFA+ samples were tested with Og4C3 TropBio ELISA and only 44/120 (36.7%) were found positive. Of these 44 participants, 12 (27.3%) completely became CFA negative and an additional 18 (40.9%) had reduced antigen levels during the follow-up. Likewise, all three previously/baseline microfilariae positive persons had become amicrofilaremic. In the present work, it has been shown that >90% of the previous CFA positive individuals seroreverted in 1 to 5 years post-baseline without additional MDA. The FTS is a more sensitive diagnostic tool that plausibly detects residual CFA in blood. The impact and influence of time as compared to additional ivermectin/Albendazole intake, on CFA seroreversion in this study was significant (p < 0.001).

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adolescent / Adult / Aged / Albendazole / Albendazole - administration & dosage / Albendazole - therapeutic use / Analysis / Animals / Antigenemia / Antigens / Antigens, Helminth - blood / Antiparasitic agents / Biology and Life Sciences / Care and treatment / Child / Diagnosis / Elephantiasis, Filarial - diagnosis / Elephantiasis, Filarial - drug therapy / Elephantiasis, Filarial - epidemiology / Elephantiasis, Filarial - parasitology / Elephantiasis, Filarial - prevention & control / Enzyme-Linked Immunosorbent Assay / Female / Filariasis / Filaricides - administration & dosage / Filaricides - therapeutic use / Follow-Up Studies / Ghana - epidemiology / Humans / Institutional repositories / Ivermectin / Ivermectin - administration & dosage / Ivermectin - therapeutic use / Male / Mass Drug Administration / Medicine and Health Sciences / Microscopy / Middle Aged / People and Places / Testing / Tropical diseases / Vector-borne diseases / Wuchereria bancrofti - immunology / Young Adult