Vector Control Research Centre, Indian Council of Medical Research, Medical Complex, Indira Nagar, Pondicherry 605006, India.
Trans R Soc Trop Med Hyg. 2013 May;107(5):293-300. doi: 10.1093/trstmh/trt011. Epub 2013 Feb 26.
While various studies provided insight into the impact of mass drug administration (MDA), information on the dynamics of the post-MDA threshold level lymphatic filariasis (LF) infection facilitates understanding its disappearance pattern and determining the duration of post-MDA monitoring and evaluation.
The changes in microfilaraemia (Mf) prevalence and vector infection rates were monitored for four (2005-2008) and six years (2005-2010) respectively after stopping ten rounds of annual mass diethylcarbamazine (DEC) administration in a group of five villages located in South India. Four years after stopping MDA, circulating filarial antigenaemia (Ag) status among children and adults was also assessed in two villages.
Overall Mf prevalence (n = 700) and vector infection rates (n=803-3520) showed a declining trend. Two villages maintained zero Mf status in each of the four years, vector infection rate was zero from the third year onwards and Ag prevalence in adults was 0.4% (n = 226). In two other villages despite persistence of Mf and vector infection there was zero vector infectivity rate during the third to sixth year and Ag prevalence among children (n = 50) was nil. In the fifth village Mf prevailed at <1.0% and Ag prevalence among 1-7 year old children was 4.6% (n = 44) and vector infectivity rate during the sixth year was 0.1% (n = 852).
The incidence of sporadic new infections is evident in highly endemic communities such as the fifth village. However, there is uncertainty on the potential of the Ag positive children to reestablish infection. Six years of post-MDA monitoring and evaluation appears to be adequate to discern the status of transmission interruption and appropriate decision making.
虽然多项研究提供了关于大规模药物治疗（MDA）影响的信息，但了解 MDA 后阈值水平淋巴丝虫病（LF）感染的动态有助于理解其消失模式，并确定 MDA 后监测和评估的持续时间。
在印度南部的五个村庄停止十轮年度乙胺嗪（DEC）大规模给药后，分别监测了四年（2005-2008 年）和六年（2005-2010 年）的微丝蚴血症（Mf）患病率和媒介感染率变化。在停止 MDA 四年后，还评估了两个村庄儿童和成人的循环丝状抗原血症（Ag）状况。
总体 Mf 患病率（n = 700）和媒介感染率（n = 803-3520）呈下降趋势。两个村庄在每四年的时间里都保持零 Mf 状态，从第三年开始，媒介感染率为零，成人的 Ag 患病率为 0.4%（n = 226）。在另外两个村庄，尽管存在 Mf 和媒介感染，但在第三至第六年期间，媒介感染率为零，儿童的 Ag 患病率（n = 50）为零。在第五个村庄，Mf 患病率低于 1.0%，1-7 岁儿童的 Ag 患病率为 4.6%（n = 44），第六年的媒介感染率为 0.1%（n = 852）。
在像第五个村庄这样高度流行的社区中，显然存在散发性新感染的发生。然而，对于 Ag 阳性儿童重新建立感染的潜力存在不确定性。六年的 MDA 后监测和评估似乎足以确定传播中断的状态并做出适当的决策。
