The impact of four years of semiannual treatments with albendazole alone on lymphatic filariasis and soil-transmitted helminth infections: A community-based study in the Democratic Republic of the Congo

Background The World Health Organization now recommends semiannual mass drug administration (MDA) of albendazole with integrated vector management as an option for eliminating lymphatic filariasis (LF) in areas of loiasis-endemic countries where it may not be safe to use diethylcarbamazine or ivermectin in MDA programs. However, the published evidence base to support this policy is thin, and uptake by national programs has been slow. Methodology/Principal findings We conducted a community trial to assess the impact of semiannual MDA on lymphatic filariasis and soil-transmitted helminth infections (STH) in two villages in the Bandundu province of the Democratic Republic of the Congo with moderately high prevalences for LF and hookworm infections. MDA with albendazole was provided every six months from June 2014 to December 2017 with treatment coverages of the eligible population (all >= 2 year of age) that ranged between 56% and 88%. No adverse effects were reported during the trial. Evaluation at 48 months, (i.e. 6 months after the 8(th)round of MDA), showed thatW.bancroftimicrofilaremia (Mf) prevalence in the study communities had decreased between 2014 to 2018 from 12% to 0.9% (p<0.001). The prevalence ofW.bancroftiantigenemia was also significantly reduced from 31.6% to 8.5% (p<0.001). MDA with albendazole also reduced hookworm,Ascaris lumbricoidesandTrichuris trichiurainfection prevalences in the community from 58.6% to 21.2% (p<0.001), from 14.0% to 1.6% and 4.1% to 2.9%, respectively. Hookworm andAscarisinfection intensities were reduced by 93% (p = 0.02) and 57% (p = 0.03), respectively. In contrast,Trichurisinfection intensity was not significantly reduced by MDA (p = 0.61) over this time period. Conclusion/Significance These results provide strong evidence that semiannual MDA with albendazole alone is a safe and effective strategy for LF elimination in Central Africa. Community MDA also had a major impact on STH infections. Author summary In low-income rural settings of Africa, populations are commonly affected by multiple parasitic diseases. Some of these diseases have been targeted for elimination through dedicated national or international programs. In 2012, the World Health Organization (WHO) defined a specific strategy to eliminate lymphatic filariasis, the disease responsible for elephantiasis, in central Africa. This strategy consists in treating the whole population living in endemic areas every six months with a single donated drug-albendazole. Together with the use of the night bed nets distributed as part of malaria programs, it was expected that this strategy could interrupt the transmission and eliminate lymphatic filariasis locally within period of 4 to 7 years. Here, we evaluated this strategy in two endemic communities near Bandundu in the Democratic Republic of the Congo. We also assessed the impact of the semiannual community treatments on three species of gastrointestinal parasitic worms. Our results suggest that semiannual MDA with albendazole is effective for LF elimination in Central Africa, but they also indicate that drug-based only intervention is not enough to eliminate gastrointestinal worm infections in areas with high transmission.