The prevalence of lymphatic filariasis infection and disease following six rounds of mass drug administration in Mandalay Region, Myanmar

Lymphatic filariasis is widely endemic in Myanmar. Despite the establishment of an elimination program in 2000, knowledge of the remaining burden of disease relies predominantly on programmatic information. To assist the program, we conducted an independent cross-sectional household cluster survey to determine the prevalence of filariasis infection, morbidity and mass-drug administration coverage in four townships of the Mandalay Region: Amarapura, Patheingyi, Tada-U and Wundwin. The survey included 1014 individuals from 430 randomly selected households in 24 villages. Household members one year and older were assessed for antigenaemia using immunochromatographic test cards and if positive, microfilaraemia by night-time thick blood smear. Participants 15 years and older were assessed for filariasis morbidity by ultrasound-assisted clinical examination. The overall prevalence of infection was 2.63% by antigenaemia (95% confidence interval (CI) 1.71–4.04%) and 1.03% by microfilaraemia (95%CI 0.59–1.47%). The prevalence of hydrocoele in adult males was 2.78% (95%CI 1.23–6.15%) and of lymphoedema in both genders was 0% (95%CI 0–0.45%). These results indicate the persistence of filarial infection and transmission despite six rounds of annual mass drug administration and highlight the need for further rounds as well as the implementation of morbidity management programs in the country.

淋巴丝虫病（Lymphatic filariasis）在缅甸广泛流行。尽管该国已于2000年启动消除项目，但目前对疾病剩余负担的认知主要依赖项目官方统计数据。为助力该项目推进，我们开展了一项独立的横断面整群入户调查，以评估曼德勒地区（Mandalay Region）四个镇区——阿马拉布拉（Amarapura）、巴丹吉（Patheingyi）、达达乌（Tada-U）和温登（Wundwin）的丝虫病感染率、发病情况以及大规模药物给药（mass-drug administration）覆盖率。本次调查共纳入24个村庄中随机抽取的430户家庭的1014名受试者。针对1岁及以上的家庭成员，我们采用免疫层析试验试纸（immunochromatographic test cards）检测其抗原血症（antigenaemia）；若结果呈阳性，则进一步通过夜间厚血涂片检测微丝蚴血症（microfilaraemia）。对15岁及以上的受试者，我们采用超声辅助临床检查评估其丝虫病发病情况。整体感染率方面，抗原血症检测阳性率为2.63%（95%置信区间（CI）：1.71%~4.04%），微丝蚴血症阳性率为1.03%（95%CI：0.59%~1.47%）。成年男性鞘膜积液（hydrocoele）患病率为2.78%（95%CI：1.23%~6.15%）；两性淋巴水肿（lymphoedema）患病率均为0%（95%CI：0~0.45%）。上述结果表明，尽管已完成6轮年度大规模药物给药，丝虫病感染与传播仍在当地持续存在；同时凸显出该国需继续开展大规模药物给药，并推进发病管理项目的实施。