Mali International Center for Excellence in Research: Filariasis

全球消除淋巴丝虫病规划（GPELF）于2000年启动，其目标是通过每年大规模给药（MDA）阻止淋巴丝虫病的传播。对马里人口的初步调查表明，班克罗夫特乌切里氏菌感染在西卡索地区高度流行。2001年（在阿苯达唑和伊维菌素开展年度大规模预防活动之前）在6个村庄进行的基线人类和昆虫学研究证实了该地区班氏瓦氏菌的流行和传播，并在2002年至2007年进行年度大规模预防活动期间进行监测。成人志愿者采用校正后的夜间血厚涂片检测微丝虫病，5岁以下儿童采用免疫层析卡试验检测循环丝虫病抗原。在7月至12月期间，采用人落捕法采集蚊子。686名受试者在第6轮MDA治疗12个月后没有出现微丝血症。更重要的是，在120名接受检测的儿童中，没有一名检测到循环抗原，而在MDA实施前，这一比例为53%（103/194）。感染叮咬数/人/年由2002年的4.8次下降至2007年的0.04次，在最后一轮MDA实施12个月后仅发现1只携带1只感染幼虫的蚊子。在停止使用丙二醛后，这种传播的急剧减少是否会持续，仍有待观察。

The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was launched in 2000 with the goal of stopping transmission of lymphatic filariasis (LF) through yearly mass drug administration (MDA). Preliminary surveys of the human population in Mali suggested that Wuchereria bancrofti (W. bancrofti) infection was highly endemic in the Sikasso district. W. bancrofti prevalence and transmission in this region were confirmed in baseline human and entomologic studies in 6 villages in 2001 (prior to the start of yearly MDA with albendazole and ivermectin) and monitored yearly from 2002 to 2007 during MDA. Microfilaremia was determined by calibrated thick smear of night blood in adult volunteers and circulating filarial antigen was measured using immunochromatographic card test in children < 5 years of age. Mosquitoes were collected by human landing catch from July to December. None of the 686 subjects tested were microfilaremic 12 months after the sixth MDA round. More importantly, circulating antigen was not detected in any of the 120 children tested, as compared with 53% (103/194) before the institution of MDA. The number of infective bites/human/year decreased from 4.8 in 2002 to 0.04 in 2007, and only one mosquito containing a single infective larva was observed 12 months after the final MDA round. Whether this dramatic reduction in transmission will be sustained following cessation of MDA remains to be seen. After 7 annual rounds of mass drug administration (MDA) in 6 Malian villages highly endemic for Wuchereria bancrofti, the WHO criteria for stopping MDA were met and treatment ceased in 2008. Surveillance was initiated to detect recrudescence. Surveillance over the subsequent 5 years relied on a variety of methods including circulating filarial antigen (CFA) and antibody tests (Wb123) in 6-7 year olds. Entomological surveillance was performed through dissection of Anopheles gambiae complex specimens collected monthly using human landing catch (HLC) and pyrethrum spray catch (PSC) methods. Infection with Wuchereria bancrofti of Anopheles gambiae complex also used reverse-transcriptase polymerase chain reaction (RT-PCR) of pools of mosquitoes.here were increases in annual CFA prevalence rates using immunochromatographic tests (ICT) in children as surveillance progressed from 0% (0/289) in 2009, 2.7% (8/301) in 2011, 3.9% (11/285) in 2012 to 4.5% (14/309) in 2013 (Trend Chi2= 11.85, p= 0.0006). In 2012, when Wb123 antibody was assessed concurrently, there was antibody positivity in 5/285 (1.8%) that was similar to that of the CFA prevalence using an ELISA for CFA (5/285). By using HLC for entomologic assessments, only two Wb-infected Anopheles were observed from the 12,951 mosquitoes dissected, but none of these pools had infective L3 larvae. Using the PSC method and RT-PCR, no positive pools were observed. Although CFA positivity in children was used as the major surveillance tool, adults (8-65 years old) were also assessed. Unlike the children, the adults showed a decrease in the CFA prevalence from 4.9% (39/800) to 3.5% (28/795) and 2.8% (50/1,812) respectively in 2009, 2011 and 2012 (Trend Chi2= 7.361, p=0.0067). Some of the ICT positive individuals were found to be microfilaremic in 2009 (2.6% (1/39)) and 2011 (8.3% (3/36). Separate from these studies are others in which filarial-infected patients from leishmania co-endemic regions were assessed for innate responses to sandfly salivary products. To date, these products appear to be immunologically inert and follow-up studies to understand the basis of these are being performed.