Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
Department of Environmental Biology and Health, Council for Scientific and Industrial Research Water Research Institute, Accra, Ghana.
PLoS Negl Trop Dis. 2019 Jan 4;13(1):e0006994. doi: 10.1371/journal.pntd.0006994. eCollection 2019 Jan.
Despite the progress achieved in scaling-up mass drug administration (MDA) for lymphatic filariasis (LF) in Ghana, communities with persistent LF still exist even after 10 years of community treatment. To understand the reasons for persistence, we conducted a study to assess the status of disease elimination and understand the adherence to interventions including MDA and insecticide treated nets.
We conducted a parasitological and epidemiological cross-sectional study in adults from eight villages still under MDA in the Northern Region savannah and the coastal Western Region of the country. Prevalence of filarial antigen ranged 0 to 32.4% and in five villages the prevalence of night blood microfilaria (mf) was above 1%, ranging from 0 to 5.7%. Median mf density was 67 mf/ml (range: 10-3,560). LF antigen positivity was positively associated with male sex but negatively associated with participating in MDA the previous year. Male sex was also associated with a decreased probability of participating in MDA. A stochastic model (TRANSFIL) was used to assess the expected microfilaria prevalence under different MDA coverage scenarios using historical data on one community in the Western Region. In this example, the model simulations suggested that the slow decline in mf prevalence is what we would expect given high baseline prevalence and a high correlation between MDA adherence from year to year, despite high MDA coverage.
There is a need for an integrated quantitative and qualitative research approach to identify the variations in prevalence, associated risk factors and intervention coverage and use levels between and within regions and districts. Such knowledge will help target resources and enhance surveillance to the communities most at risk and to reach the 2020 LF elimination goals in Ghana.
尽管加纳在扩大淋巴丝虫病（LF）大规模药物治疗（MDA）方面取得了进展，但在社区治疗 10 年后，仍存在持续存在 LF 的社区。为了了解持续存在的原因，我们进行了一项研究，评估消除疾病的现状，并了解包括 MDA 和经杀虫剂处理的蚊帐在内的干预措施的依从性。
我们在该国北部萨凡纳地区和沿海西部地区仍在进行 MDA 的八个村庄的成年人中进行了寄生虫学和流行病学横断面研究。丝虫抗原的流行率为 0 至 32.4%，在五个村庄中，夜间血液微丝蚴（mf）的流行率高于 1%，范围为 0 至 5.7%。中位 mf 密度为 67 mf/ml（范围：10-3560）。LF 抗原阳性与男性性别呈正相关，但与去年参加 MDA 呈负相关。男性性别也与参与 MDA 的可能性降低有关。使用历史数据，我们使用 TRANSFIL 随机模型来评估不同 MDA 覆盖情景下预期的微丝蚴流行率。在这种情况下，模型模拟表明，考虑到高基线流行率和 MDA 依从性的高度相关性，尽管 MDA 覆盖率很高，但 mf 流行率的缓慢下降是我们预期的结果。
需要采用综合的定量和定性研究方法，以确定不同地区和地区之间的流行率、相关风险因素以及干预措施的覆盖率和使用水平的差异。这些知识将有助于针对最有风险的社区分配资源并加强监测，以实现加纳到 2020 年消除 LF 的目标。
