环子孢子蛋白基因检测法对1例间日疟病例的溯源

对2014年1例初诊为河南省本地感染的间日疟病例进行实验室检测与流行病学溯源调查,以明确其感染来源。收集该病例的流行病学资料,分别采用厚薄血膜吉氏染色法、疟疾快速诊断试纸(RDT)法和巢式PCR法检查患者外周血液,并对其环子孢子蛋白(CSP)基因序列进行分析。流行病学调查显示,该患者曾于2013年5月至缅甸停留约1周,同年6月发病,确诊为间日疟,经青蒿琥酯治疗后,疟原虫转阴,症状消失。CSP基因序列分析显示,该患者前后两次发病时的血样扩增出的CSP序列的中央重复区完全一致,与缅甸分离株(Gen Bank登录号为ABS95455和ABS95456)的序列一致性分别为95.1%和100%,与2个河南分离株HN3和HN7(登录号为KP888996和KP889000)的序列一致性分别为88.8%和67.1%。推测该病例为输入性间日疟复发病例。     

Humanized mouse models infected with human Plasmodium species for antimalarial drug discovery

Introduction: Efforts on malaria drug discovery are expected to increase in the coming years to achieve malaria eradication. Owing to the increasing number of new potential candidates together with the actual limitations of the primate models, humanized mouse models infected with human Plasmodium spp. (HmHP) now appear as an alternative to the primate model.

Areas covered: The authors review the progress obtained in the HmHP in the last two decades, with a special emphasis of their input on the drug discovery pathway. The authors discuss the methodologies and strategies used in these models to obtain an accurate assessment of the compound activity and a reliable prediction of the human efficacious regimen.

Expert opinion: Research efforts have led us to an era in which HmHP can successfully be infected with P. falciparum, P vivax and P. ovale. Furthermore, it is now a reality that the complete human cycle of P. falciparum can be obtained in HmHP. The HmHP has shown a real input mainly in the preclinical evaluation of new compounds against the erythrocytic stages of P. falciparum. However, further technical improvements are needed before HmHP may replace the primate model.     

江苏省2015—2019年输入性疟疾疫情及病例诊断

目的 分析江苏省2015—2019年输入性疟疾疫情流行特征及诊断情况,为防止疟疾输入再传播,巩固消除疟疾成果提供科学参考。方法 疟疾疫情资料来自国家传染病监测系统和寄生虫病防治信息管理系统,采用流行病学研究方法,描述2015—2019年江苏省疟疾发病、感染来源和病例三间分布情况,对输入性疟疾病例的诊断以及发病到诊断的时间间隔进行分析。结果 2015—2019年,江苏省共报告1 439例疟疾病例,其中1 436例为境外输入病例, 3例为输血感染病例。1 439例疟疾病例中,恶性疟1 075例（占74.7%）、间日疟63例（占4.4%）、卵形疟233例（占16.2%）、三日疟65例（占4.5%）、同一时间发病的混合感染病例3例（占0.2%）。境外输入性疟疾病例中,1 400例来自非洲（占97.5%）,其他来自亚洲28例（占1.9%）,以及南美洲和大洋洲8例（占0.6%）。江苏省13个设区市均有疟疾病例报告;疟疾病例以35~<50岁男性青壮年居多,每年的1、6和10月出现病例报告高峰。82.3%的病例由医疗机构诊断,由疾控机构诊断的病例占比逐年降低（P<0.05）。2019年发病到确诊超过9 d的病人所占比明显低于前四年（P<0.01）。结论 近5年江苏省疟疾疫情稳定,绝大部分为境外输入性病例,存在少数输血感染;病人就诊到确诊间隔时间有所缩短。继续做好风险人群健康宣教,提高医疗机构诊治能力,防止发生境外输入再传播,是今后疟疾防控工作的重点。     

Malaria epidemiology in a rural area of the Mekong Delta: a prospective community-based study

Over the past 10 years, the Mekong Delta region in Vietnam has experienced fast socio-economic development with subsequent changes in malaria vectors ecology. We conducted a 2-year prospective community-based study in a coastal rural area in the southern Mekong Delta to re-assess the malaria epidemiological situation and the dynamics of transmission. The incidence rate of clinical malaria, established on 558 individuals followed for 23 months by active case detection and biannual cross-sectional surveys, was 2.6/100 person-years. Over the 2-year study period, the parasite rate and malaria seroprevalence (Plasmodium falciparum and P. vivax) decreased significantly from 2.4% to almost 0%. Passive case detection (PCD) of clinical cases and serological follow-up of newborns carried out in a larger population confirmed the low and decreasing trend of malaria transmission. The majority of fever cases were seen in the private sector and most were unnecessarily treated with antimalarials. Training and involvement of the private sector in detection of malaria cases would greatly improve the quality of health care and health information system.     

Existing antimalarial agents and malaria-treatment strategies

In the absence of prompt and efficacious treatment, malaria patients may progress within a few hours from having minor symptoms to severe disease and death. These last years have seen the development of several artemisinin-based combinations, new treatments for severe malaria patients, and new strategies such as intermittent preventive treatment or the home-based/near-home management of malaria. The health sector is now confronted with several treatment options and strategies, in contrast with the period when chloroquine monotherapy was the standard treatment. The major challenge remains the large-scale deployment, in the most efficient way, of the tools available today, including artemisinin-based combination treatments, within health systems that remain extremely weak in malaria endemic countries, particularly in sub-Saharan Africa. Health system research, exploring new potential approaches for the large-scale implementation of these interventions, should be promoted in parallel with that on new therapeutic agents to be used in the unlucky event of the emergence and spread of artemisinin resistance. The prospects of substantially decreasing the malaria burden are brighter today than 20 – 30 years ago, but the efforts and resources committed to this purpose should be maintained over a long period.     

人群TLR基因多态性与间日疟原虫感染的相关性

目的　比较间日疟原虫感染人群的Toll样受体（Toll-like receptor, TLR）5、TLR9基因3个单核苷酸多态性（single nucleotide polymorphism, SNP）位点差异,探讨其与间日疟原虫不同感染类型的相关性。方法　收集中缅边境地区（云南省盈江县和缅甸拉咱市）2017—2019年间日疟原虫感染者202例及健康对照者104例,将上述研究对象分为无症状感染组、有症状感染组及健康对照组,其中无症状感染组与有症状感染组统称为感染组;采用飞行时间质谱分型技术检测以上研究对象TLR5、TLR9基因3个SNP位点,分析不同组之间TLR5、TLR9基因SNP位点等位基因和基因型的分布差异。结果　3组研究对象之间性别与年龄分布差异均无统计学意义（P均＞0.05）;3组之间TLR9 1486C/T位点、TLR9 G1174A位点和TLR5 R392Stop位点的等位基因分布差异均无统计学意义（P均＞0.05）;健康对照组与感染组间及健康对照组与无症状感染组间TLR9 1486C/T位点的AG基因型分布差异均有显著性统计学意义（P均＜0.05）;3组之间TLR9 G1174A位点、TLR5 R392Stop位点的基因型分布差异均无统计学意义（P均＞0.05）。结论　TLR9 1486C/T位点的基因型多态性与间日疟原虫感染相关,但尚未发现TLR9 G1174A位点、TLR5 R392Stop位点与间日疟原虫感染的相关性,本研究结果可为揭示宿主基因多态性对间日疟原虫感染的影响提供重要线索。     

疫苗候选抗原Pvs48/45在中缅边境的遗传多样性特点

目的 了解间日疟原虫传播阻断疫苗候选抗原Pvs48/45在中缅边境地区的基因多态性和自然选择特点。方法 提取39例来自中缅边境主要流行区(Laiza)的间日疟原虫基因组DNA,采用巢式PCR(nest-PCR)扩增Pvs48/45基因开放阅读区(Open reading frame, ORF);通过MEGA 4.0、DnaSP v5.10和NETWORK 4.6对Pvs48/45基因多态性和自然选择特点进行分析。结果 研究发现了6个突变位点,均为非同义突变(E35K ,H211N ,K250N ,D335Y,A376T,K418R),导致了5种单倍型;Pvs48/45基因的核苷酸多态性水平极低(π=0.00064),CRDⅢ区最高(π=0.00163);多种中性检验均表明Pvs48/45基因处于平衡选择;种群进化分析和单倍型网络图显示Pvs48/45具有较强的地理分化,且H2型为中缅边境地区频率最高的单倍型。结论 Pvs48/45在中缅边境地区遗传多样性很低,且在进化过程中经历平衡选择,提示其可作为传播阻断疫苗候选靶点;Pvs48/45在全球具有较强的地理分化,应根据地区遗传特点开发更加有效的传播阻断疫苗。     

萘酚喹治疗间日疟的疗效观察

在海南省疟疾流行区，用萘酚喹６００ｍｇ顿服和氯喹１．５ｇ标准疗法各治疗间日疟病人３５例，服药后两组病例均获即时治愈。萘酚喹组平均退热和原虫转阴时间分别为（２２．７±７．４）ｈ和（４６．４±９．７）ｈ；氯喹组平均退热和原虫转阴时间分别为（１９．１±８．３）ｈ和（４１．６±８．２）ｈ。随访６ｗｋ，萘酚喹组的治愈率为１００％，氯喹组为７４．３％。结果表明，萘酚喹治疗间日疟的远期效果明显优于氯喹（Ｐ＜０．０１）。     

单克隆抗体－ELISA技术检测间日疟感染的现场研究

对１１２例发热病人血样同时进行镜检和用ＭｃＡｂ－ＭｃＡｂＥＬＩＳＡ夹心法检测间日疟抗原，发热病人血片分别由基层镜检员和省级专业人员镜检，检出间日疟阳性率分别为３０．３６％和４３．７５％，ＥＬＩＳＡ法检测阳性率为４２．８６％，其敏感性、特异性均在９５％以上。具有采样方便、样本可成批操作、结果客观等特点，适用于基层开展灭疟后期疟疾传染源监测。     

间日疟原虫特异性DNA片段的克隆和鉴定

本文从间日疟患者血液中分离出间日疟原虫,将其基因组 DNA 片段克隆到载体 pUC12质粒中,构建了间日疟原虫 DNA 文库。利用质粒的遗传标志初步筛选重组克隆;用~(32)P 标记的间日疟原虫DNA,人白细胞 DNA 和恶性疟原虫 DNA 为探针分别作菌落杂交,差异筛选出4株间日疟原虫特异的重组克隆,命名为 pVA1—4。然后酶切鉴定其插入片段,并用 Southern blot 分析,表明重组质粒 pVAl 含有间日疟原虫特异性 DNA 片段。