Schistosomiasis in a migrating population in the lake region of China and its potential impact on control operation

Coverage of migrating people in schistosomiasis control program is a growing concern in China. Schistosomiasis caused by Schistosoma japonicum is still one of the major infectious diseases of public health importance in China though tremendous efforts have been made to control the transmission over the past decades. Along with the rapid social-economic development, migrant population has been remarkably increasing across the country. The infected migrants may introduce a new souse of infection to endemic areas or the areas where the transmission had been controlled or interrupted but the intermediate host Oncomelania snail is still present. Preliminary studies for surveillance on schistosomiasis prevalence in migrants were reported, but there is little basic information provided. We carried out an investigation on the prevalence in immigrants, emigrants and permanent residents in three villages of Hunan province located in the main endemic area of lake region, and analyzed the potential impact of migration on control practice. In the study villages, the migrant population accounts for 53.6% of the total. Schistosoma infection was detected by modified Kato-Katz method and miracidium hatching test. Questionnaire survey was conducted comprising knowledge of disease and its transmission, water contact, personal protective measures, and whether examined and treated after water contact. The survey indicated that the migrants and permanent residents had similar life style, and the majority of them experienced water contact in agricultural work or routine life activities. However, the infection rate in immigrants was significantly higher than that in permanent residents. It was also found that the migrants had significantly less knowledge about the disease than the permanent residents, and took no personal protective measures. This is due to that the control program could not cover the migrants when they were absent at the time the program being implemented. The present study suggested that the surveillance and intervention for migrants, immigrants in particular, should be included and strengthened in schistosomiasis control program and a feasible scheme be developed.     

Rapid Point-of-Contact Tool for Mapping and Integrated Surveillance of Wuchereria bancrofti and Onchocerca volvulus Infection

Elimination programs for Wuchereria bancrofti and Onchocerca volvulus are in critical need of sensitive, specific, and point-of-contact (POC) tools that can be used for surveillance years beyond cessation of mass drug administration when infection intensities are low. Previously, Wb123 and Ov16 were identified individually as potential filarial antigens for an antibody-based POC test. The present study compares single-antigen Wb123- and Ov16-based POC tests with an integrated configuration to detect antibodies to Wb123 and Ov16 simultaneously. Wb123 and Ov16 isolates were striped onto lateral flow strips containing anti-IgG4. Sera from W. bancrofti-, O. volvulus-, and other helminth-infected or -uninfected individuals were added to the strips with buffer. Strips were read for the appearance of a positive or negative test line for both antigens at 20 min and following drying. Sensitivity, specificity, and predictive values were calculated for the single-antigen and biplex strips. Single and biplex lateral flow strips showed nearly identical results, with >90% sensitivity for Ov16 and >92% sensitivity for Wb123. Overall specificities for the single and biplex tests were 98% and 96% for Ov16 and Wb123, respectively. Biplex tests performed as well as the single-antigen tests regardless of the intensity of patient IgG4 response. The high sensitivity and specificity make these new biplex tests extremely useful for POC long-term surveillance following mass drug administration in Africa that should reduce time and cost in areas where bancroftian filariasis and onchocerciasis are coendemic.     

巴西日圆线虫虫体蛋白体外诱导THP-1来源巨噬细胞极化的研究

目的　分析巴西日圆线虫虫体蛋白体外诱导人单核细胞白血病THP?1细胞来源巨噬细胞的极化方向,探索机体对巴西日圆线虫感染的免疫应答机制。方法　建立并维持巴西日圆线虫培养的实验室循环,无菌条件下收集L3和L5虫体,分别制备虫体蛋白;建立THP?1细胞体外培养体系,经500 ng/mL佛波酯（PMA）刺激培养后呈贴壁状态的M0型细胞分别采用500 ng/mL脂多糖（LPS）+ 100 ng/mL γ?干扰素（IFN?γ）、白细胞介素4（IL?4）+ IL?13（浓度均为100 ng/mL）、L3及L5虫体蛋白（浓度均为5 mg/mL）进行刺激,同时设不加任何刺激的阴性对照组。通过显微镜镜检观察刺激后细胞形态、实时荧光定量PCR（qPCR）检测M1/M2型巨噬细胞特异性基因mRNA表达水平、流式细胞术检测巨噬细胞表面标志物及酶联免疫吸附试验（ELISA）检测M1/M2型巨噬细胞分泌的细胞因子含量,观察巴西日圆线虫虫体蛋白体外诱导THP?1来源巨噬细胞的极化方向。结果　THP?1细胞经PMA刺激培养呈贴壁的M0型细胞后,经LPS + IFN?γ刺激培养后呈特征性M1型极化;经IL?4 + IL?13刺激培养后呈特征性M2型极化;经L3和L5蛋白刺激培养后均呈特征性M2型极化。阴性对照组、LPS + IFN?γ刺激组、IL?4 + IL?13刺激组、L3蛋白刺激组、L5蛋白刺激组间M1型巨噬细胞比例差异有统计学意义（[χ2] = 3 721.00,P < 0.001）,其中LPS + IFN?γ刺激组M1型巨噬细胞比例最高;各组间M2型巨噬细胞比例差异有统计学意义（[χ2] = 105.43,P < 0.001）。各组间C?C基序趋化因子配体2（CCL2）、肿瘤坏死因子α（TNF?α）、IL?12b、过氧化物酶体增殖物激活受体γ（PPARγ）、IL?10、甘露糖受体C型1（Mrc1）基因mRNA表达水平差异均有统计学意义（F = 191.95、129.95、82.89、11.30、9.51、12.35,P均< 0.001）,各组间CD86、CD206阳性率差异均有统计学意义（[χ2] = 24 004.33、832.50,P均< 0.001）。LPS + IFN?γ刺激组IL?1β、TNF?α表达水平均显著高于IL?4 + IL?13刺激组、L3蛋白刺激组及L5蛋白刺激组（P均< 0.001）;IL?4 + IL?13刺激组、L3蛋白刺激组和L5蛋白刺激组TGF?β1、IL?10表达水平均显著高于阴性对照组和LPS + IFN?γ刺激组（P均< 0.05）。结论　巴西日圆线虫L3和L5虫体蛋白体外均可诱导THP?1来源巨噬细胞向M2型极化。     

重组酶介导的蓝氏贾第鞭毛虫特异性等温核酸扩增方法的建立及评价

目的　建立基于重组酶介导的等温扩增技术（RAA）的蓝氏贾第鞭毛虫核酸检测方法,并评价其检测敏感性和特异性。方法　选择蓝氏贾第鞭毛虫β?贾第素（β?giardin）基因作为检测靶基因,设计、合成特异性检测引物及荧光探针,建立荧光RAA检测体系。分别以不同拷贝数的重组质粒（含β?giardin基因靶序列）和不同浓度蓝氏贾第鞭毛虫基因组DNA为模板进行荧光RAA扩增,评价其检测敏感性;分别以蓝氏贾第鞭毛虫、日本血吸虫、华支睾吸虫、微小隐孢子虫、似蚓蛔线虫、沙门氏菌及志贺氏菌基因组DNA为模板进行扩增,评价其检测特异性。结果　成功建立了蓝氏贾第鞭毛虫荧光RAA检测方法,其可在等温（39 ℃）条件下实现对靶基因片段的快速、特异性扩增（20 min内）。分别以重组质粒和蓝氏贾第鞭毛虫基因组DNA为模板,该方法的检测敏感性可达102拷贝/μL和1 pg/μL;以日本血吸虫、华支睾吸虫、微小隐孢子虫、似蚓蛔线虫、沙门氏菌及志贺氏菌基因组DNA为模板的RAA检测结果均为阴性,具备较好特异性。结论　建立了一种操作简便、敏感、特异的可用于蓝氏贾第鞭毛虫核酸检测的荧光RAA方法。     

基于重组酶介导核酸等温扩增反应的曼氏血吸虫 基因检测方法的建立

目的　建立一种可用于曼氏血吸虫特异性基因片段检测的重组酶介导的核酸等温扩增方法（Recombinase?aided amplification, RAA）。方法　以曼氏血吸虫121 bp高重复基因片段作为靶序列,根据RAA反应原理设计、合成引物及荧光探针,建立并优化荧光RAA法反应体系。分别以不同拷贝数的含121 bp基因片段的重组质粒及不同浓度曼氏血吸虫基因组DNA为模板进行荧光RAA法扩增,评价该方法的敏感性;分别以日本和埃及血吸虫虫卵、十二指肠钩虫虫卵、华支睾吸虫囊蚴基因组DNA为模板进行荧光RAA法检测,评价其特异性。结果　建立的荧光RAA法可在39 ℃、20 min内特异性扩增曼氏血吸虫基因组DNA。以重组质粒为模板,荧光RAA法最低可检出的质粒拷贝数为10拷贝/μL;以基因组DNA为模板,荧光RAA法最低可检测浓度为0.1 fg/μL。以日本血吸虫虫卵、埃及血吸虫虫卵、十二指肠钩虫虫卵、华支睾吸虫囊蚴基因组DNA为模板进行荧光RAA法检测,结果均为阴性。结论　成功建立了一种可用于曼氏血吸虫DNA检测的荧光RAA法,该方法反应快捷、操作简便,敏感性和特异性均较好。     

新型冠状病毒肺炎疫情对我国消除疟疾工作的挑战及应对策略

2019年底以来,一种新型冠状病毒病肺炎（COVID-19）在我国大范围流行,不仅严重威胁人民群众的生命安全和身体健康,同时也给其他传染病防控带来了严峻挑战。目前,我国每年仍有近3 000例境外输入性疟疾病例,如不能及时开展病例诊治和疫点调查处置,不仅有可能危及患者生命,还可能引起继发传播而威胁我国消除疟疾成果。新型冠状病毒肺炎流行范围广、传播能力强,不仅疟疾患者在就医过程中有可能被感染,而且医务人员在开展临床诊治、样本检测和流行学调查时也面临感染风险。本文分析新型冠状病毒肺炎流行对我国消除疟疾工作的挑战,并探讨相应的应对策略和措施,从而为医务工作者提供参考。     

京杭大运河丹阳段及丹金溧漕河沿线钉螺时空分布特征研究

目的　分析京杭大运河江苏丹阳段及丹金溧漕河沿线钉螺时空分布特征,为动态评估该区域钉螺扩散风险提供科学依据。方法　收集2012－2017年研究区域内水网型血吸虫病流行区螺情数据,采用缓冲区分析、空间自相关分析、热点分析及标准差椭圆分析法,探索京杭大运河丹阳段及丹金溧漕河沿线钉螺时空变化趋势。结果　2012－2017年,研究区域内有螺环境数呈上升趋势;有螺环境主要分布于丹金溧漕河1 000 m缓冲区内,特别是京杭大运河与丹金溧漕河交汇处的老九曲河沿线。2014、2016、2017年,研究区域内钉螺分布存在空间自相关,热点区域主要为丹金溧漕河与京杭大运河交汇处;钉螺分布整体呈东北-西南方向,随着时间变化逐渐向南北方向转变。结论　京杭大运河丹阳段及丹金溧漕河沿线钉螺空间分布复杂,存在从上游向下游扩散的风险,需加强该区域的灭螺工作。     

2016–2018年全国3～9岁儿童蛲虫感染监测

目的　了解我国3～9岁儿童蛲虫感染现状,为制定全国蛲虫病防控策略提供科学依据。方法　2016–2018年在全国30个省（直辖市、自治区）736个国家监测点开展蛲虫病监测。各监测点按地理方位划分为东、西、南、北、中5个片区,每片区抽取1个乡（镇）的1个行政村,每个行政村整群抽取3周岁以上常住居民200人,每个监测点共调查1 000人,对其中3～9岁儿童采用改良加藤厚涂片法和透明胶纸肛拭法进行蛲虫感染检测,计算蛲虫感染率等指标并进行比较分析。结果　2016–2018年,全国30个省（直辖市、自治区）736个监测点3～9岁儿童蛲虫感染率分别为2.50%、2.84%和2.46%,男、女童蛲虫感染率间差异无统计学意义（P ＞ 0.05）;南部和西南部地区（江西、广西、广东、四川、福建、重庆和海南）为蛲虫病主要流行区（感染率 ≥ 5.00%）,江西和广西儿童蛲虫感染率连续3年均位居前两位;汉族儿童蛲虫感染率高于少数民族儿童;4～7岁组儿童感染率较高,3、8岁和9岁组感染率均相对较低。结论　2016–2018年全国3～9岁儿童蛲虫感染率变化幅度不大,南部及西南部地区感染率较高,需重点关注。