Schistosomiasis japonica is one of the most important parasitic diseases in China despite a documented history of more than 2100 years. The study and use of diagnostic techniques play an important role in targeting chemotherapy, assessing morbidity, and evaluating control strategies that have been continuously applied in the national schistosomiasis control programme for more than 60 years. The current widely used diagnostic approaches include two types, [1, 2] one is the parasitological techniques (detection of parasite eggs or miracidia in feces), and the other one is immunologic methods (detection of specific antibodies or circulating antigens). In addition, two approaches of molecular biotechnology, such as loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR), both of which are based on amplification of DNA fragments have been developed and successfully transferred from the laboratory to the field [3–5].

目的 研究自动注药滴渗灭螺装置技术,为特殊环境钉螺控制提供灭螺新方法.方法 利用滴灌技术,采用输水增压、连续注药方法,研发自动注药滴渗灭螺装置,评估该方法的灭螺效果及成本投入,采用Excel 2016软件进行数据汇总,用SPSS 16.0统计软件对钉螺死亡率、钉螺校正死亡率进行x2检验分析.结果 自动注药滴渗灭螺装置包括增压输水、过滤净化、自动注药和滴渗管网4大系统,其中增压泵的额定功率为4 kW,过滤器耐受压力为800 kPa,滴渗管单孔流量为2L/h.滴渗管间距2、1 m组和喷洒对照组,施药7 d后,钉螺校正死亡率分别为67.08％、75.71％和66.22％,以滴渗管间距1 m组为最高,差异有统计学意义(x2=8.809,P=0.012);施药15 d后,钉螺校正死亡率分别为75.15％、79.27％和78.34％,差异无统计学意义(x2=1.369,P=0.504);施药30 d后,3组环境活螺密度下降率分别为80.78％、83.81％和80.63％.一套滴渗灭螺装置设备总投入为9 805元,其中移动设备和固定管网费用分别占68.33％和31.67％.以滴渗管网使用10年为限,每年灭螺管网设备费用消耗为0.16元/m2.结论 自动注药滴渗灭螺技术是省工、高效、实用的灭螺方法,滴渗管网间距以1 m为宜.

Controlling the snail intermediate hosts of schistosomiasis is an efficient and rapid method for reducing or eliminating the transmission of this disease.The present study aimed to assess the molluscicidal activity of Luowei/TDS 4% against Biomphalaria alexandrina and Bulinus truncatus under semi-field and field conditions in Egypt.Moreover, its effect on Schistosoma mansoni miracidial viability and infectivity to B. alexandrina snails and on cercarial production from infected snails were evaluated.In the present study, miracidia of Schistosoma mansoni and S. haematobium were exposed to sublethal concentrations of Luowi/TDS 4% and miracidial mortality rates in the test and control groups were recorded.The effect of exposure to LC10 and LC25 of Luowei/TDS 4% after 1, 2 and 3 weeks of B. alexandrina infection with miracidia on their cercarial production was determined.The molluscicidal activity of 2LC90 Luowei/TDS 4% against B. alexandrina and B. truncatus was tested under semi-field and field conditions.Luowei/TDS 4% exhibited a promising molluscicidal potency against B. alexandrina and B. truncatus as their LC90 values were considerably low, 2.851 and 1.936 mg/L, respectively, after 24 h of exposure.Moreover, infection rates of B. alexandrina with S. mansoni and cercarial production from snails exposed to LC10 and LC25 of Luowei/TDS 4% post miracidial exposure were reduced.Moreover, Luowei/TDS 4% at semi-field and field trials proved to be a potent molluscicidal agent against schistosomiasis intermediate host snails as mortality rates of free and caged sentinel snails from these trials were considerably high ranging from 87% to 100% after 24 h of treatment with 5.702 mg/L (2LC90 for B. alexandrina snails).Luowei/TDS 4% should be considered as a candidate molluscicide in schistosomiasis control programs.Implementation of this plant molluscicide in operational schistosomiasis control strategies will minimize the ecological side-effects associated with using synesthetic chemicals.

目的 分析扬州市新砂滩利用农业生态综合开发消除血吸虫病效果,为血吸虫病传播阻断地区走向血吸虫病消除阶段提供借鉴.方法 采用回顾性调查法,收集2005-2016年新砂滩查灭螺、环境改造、查治病、健康行为调查资料并对结果进行统计分析.结果 新砂滩有螺面积年平均值从农业生态综合开发前(2005-2010年)194.86万m2(1 169.18/6)下降到开发后(2011-2016年)12.13万m2(72.75/6);血检阳性率从开发前9.28％下降到开发后1.05％,粪检阳性率从2.28％下降到0％;2017年4月调查新砂滩无害化卫生公厕经常使用率为88.1％;开发后每年共产生经济效益约为300万元.结论 新砂滩以农业生态综合开发的治理方式,进一步消除血吸虫病危害,巩固了血防成果,提高了人群健康意识,并产生了可观的经济效益.

目的 通过问卷调查了解全国寄生虫病防治研究论文写作讲习班的培训效果及学员论文写作需求.方法 利用全国寄生虫病防治研究论文写作讲习班培训契机,采用《中华预防医学会继续医学教育项目质量评估表》及自行设计的问卷调查表进行调查,了解学员人口学特征、近年来论文发表情况,分析其对科技论文写作培训的需求,并对本次培训效果进行评价.结果 本次共发放问卷80份,回收有效问卷77份,有效问卷回收率为96.25％.77名有效应答者中,男性40名、女性37名,年龄22～55岁,学历以本科为主(63.64％),职称以中、初级为主(79.22％),主要来自县市级疾控中心(70.13％),多从事寄生虫病防治工作(75.32％),工作年限多在20年以内(62.33％).近3年来,41人(53.25％)未发表过论文,仅7人发表论文篇数≥3篇,近半数(46.75％)学员认为讨论部分最难写.学员对此次讲授内容、教学计划、教材满意度均>90％,94.81％的学员认为此次培训收获较大或很大.结论 全国寄生虫病防治研究论文写作讲习班契合了绝大多数学员的需求.为进一步提高办班质量和学员满意度,今后应根据培训目的进一步明确和细分培训对象,并增加科研设计、论文写作实操内容培训.

目的 评价5％杀螺胺乙醇胺盐颗粒剂在不同类型环境的灭螺效果,为实施钉螺控制措施提供应用技术.方法 选择江滩、水网、山丘地区各1处作为试验现场,每种不同类型的环境分成试验Ⅰ、试验Ⅱ和空白对照3个组别,其中试验Ⅰ组用5％杀螺胺乙醇胺盐颗粒剂,剂量为40 g/m2;试验Ⅱ组用4％氯硝柳胺乙醇胺盐粉剂,剂量为50 g/m2;空白对照组不进行现场灭螺处理.比较不同环境类型、不同施药时间钉螺死亡率和密度的差异程度,绘制变化趋势图.结果 5％杀螺胺乙醇胺盐颗粒剂喷撒7d后,江滩、水网、山丘3类现场钉螺死亡率分别为84.97％、87.57％和86.01％,其钉螺校正死亡率分别为84.55％、87.41％和85.80％;4％氯硝柳胺乙醇胺盐粉剂喷撒7d后现场钉螺死亡率分别为83.75％、85.42％和87.68％,其钉螺校正死亡率分别为83.37％、85.27％和87.55％;2种剂型药物在同一环境中灭螺后钉螺死亡率差异均无统计学意义(x2=3.528、2.910、0.015,均P＞0.05).江滩、水网、山丘3类环境中,5％杀螺胺乙醇胺盐颗粒剂喷撒15d后现场钉螺平均密度分别下降了88.42％、91.25％和85.57％,4％氯硝柳胺乙醇胺盐粉剂喷撒15 d后现场钉螺平均密度分别下降了83.91％、85.29％和86.67％.5％杀螺胺乙醇胺盐颗粒剂在江滩、水网和山丘3类环境中,灭螺后3～15d钉螺总死亡率分别为84.12％、87.68％和85.74％,差异有统计学意义(x2=6.440,P=0.040),以水网沟渠灭螺效果最好.结论 5％杀螺胺乙醇胺盐颗粒剂在江滩、水网、山丘均有较好的灭螺效果,可作为不同类型环境现场灭螺备选药物之一.

OBJECTIVE:To compare the approaches used for the assessment of disability adjust life years (DALYs) for advanced schistosomiasis japonica, so as to provide scientific evidence for accurate assessment of the burden of advanced schistosomiasis japonica.METHODS:The patients with advanced schistosomiasis japonica receiving treatment and assistance programs in Hunan Province in 2017 were enrolled, and the years lived with disability (YLD) for the patients with advanced schistosomiasis japonica was calculated using the common global burden of disease (GBD) estimation method, the modified GBD method with addition of common syndromes of advanced schistosomiasis japonica, and the quality of life assessment method.RESULTS:The YLDs of patients with advanced schistosomiasis japonica, the mean YLDs per capita, and the percentages of YLD were 673.94, 728.77 person-years and 1 761.99 person-years; 0.181, 0.196 person-years and 0.474 person-years; and 10.61, 11.48 person-years per 100 thousand persons and 27.75 person-years per 100 thousand persons with the common GBD method, modified GBD method and the quality of life method, respectively. The YLDs of the patients with advanced schistosomiasis japonica in Hunan Province estimated with the modified GBD method and the quality of life method were 8.14% and 2.61 times higher than that with the common GBD method. Of the major symptoms included in the calculation, the 5 symptoms with the greatest contribution to the burden of advanced schistosomiasis japonica included ascites, moderate anemia, severe anemia, diarrhea and hematochezia.CONCLUSIONS:The quality of life method may more comprehensively assess the YLDs in patients with advanced schistosomiasis japonica than the common and modified GBD methods.

目的 分析扬州市广陵区沿江村国家血吸虫病监测点血吸虫病疫情现状,为制定血吸虫病防治措施提供依据.方法 收集2012～2017年沿江村螺情、人群疫情、家畜疫情、相关因素调查等资料并进行分析.结果 该监测点从2012年捕起因地制宜,采用多种方式对沿江村新砂滩滩进行综合治理,永久性改变钉螺孳生环境,2012年获930只活螺,有螺面积32.349 hm2,自2013年后以来沿江村新砂滩已经连续5年未查到活螺.常住居民人群查病胶体染料试纸条法阳性率为1.01％～33.85％;间接血凝试验检测,阳性率0.33％～26.94％,未发现粪检阳性病例,流动人群监测中均未发现血清学检测阳性人员,居民受血防教育人次2.5万人次以上,扎实开展渔船民粪便管理.结论 该形式多样的综合治理模式对压缩江滩钉螺面积效果明显,该监测点住居民血清阳性率10％左右需重点关注.流动人员查病多年未发现血清阳性者,需要在查病方法和方式上多做思考.

Dipstick Dye Immunoassay (DDIA) and Indirect Haemagglutination Assay (IHA), are two commercially available kits which have been widely used for screening Schistosoma japonicum in P.R. China. Whether they can be used for screening of Schistosoma haematobium are not clear. In order to evaluate the diagnostic efficiency of DDIA and IHA for screening Schistosoma haematobium, serum samples were collected from pupils in endemic areas in Zambia, Southern Africa, and tested by DDIA and IHA by single-blind manner. Meanwhile, the pupils were microscopically examined by infection with Schistosoma and soil-transmitted helminths, visually observed for parasite eggs. Of the enrolled 148 pupils, 61% tested positive for S. haematobium infection, while 31% and 36% of pupils were infected with hookworm and Ascaris respectively. Regarding the parasitological tests as reference standard, for the diagnosis of S. haematobium infection, IHA performed higher sensitivity (74%, 95% CI: 65%-83%) than that of DDIA (60%, 95%CI: 49%-70%). The sensitivities of IHA and DDIA are significant higher in 10-14 years old students than those of 7-9 years old group. The specificity of DDIA and IHA were 61% (95%CI: 49%-74%) and 72% (95%CI: 60%-84%), respectively. The co-infection with STHs decreased the specificity of DDIA but had no impact on that of IHA. Our study indicated that IHA has more potential as an alternative diagnostic tool for identifying schistosomiasis haematobium but need further improvement.

BackgroundControl of snail intermediate hosts has been proved to be a fast and efficient approach for interrupting the transmission of schistosomiasis. Some plant extracts have shown obvious molluscicidal activity, and a new compound Luo-Wei, also named tea-seed distilled saponin (TDS), was developed based on the saponins extracted from Camellia oleifera seeds. We aimed to test the molluscicidal activity of 4% TDS against the intermediate host snails in China and Egypt, and evaluate its environmental safety to non-target organisms.MethodsIn the laboratory, Oncomelania hupensis, Biomphalaria alexandrina and Bulinus truncatus were exposed to 4% TDS, and the median lethal concentration (LC50) was estimated at 24, 48 and 72h. In the field, snail mortalities were assessed 1, 2, 3 and 7 d post-immersion with 2.5g/m(3) 4% TDS and 1, 3, 7 and 15 d post-spraying with 5g/m(2) 4% TDS. In addition, the acute toxicity of 4% TDS to Japanese quail (Coturnix japonica), zebrafish (Brachydanio rerio) and freshwater shrimp (Macrobrachium nipponense) was assessed by estimations of LC50 or median lethal dose (LD50).ResultsIn the laboratory, the LC50 values of 4% TDS for O. hupensis were 0.701, 0.371 and 0.33mg/L at 24, 48 and 72h, respectively, and 4% TDS showed a 0.33mg/L 24h LC50 against B. alexandrina, and a 1.396mg/L 24h LC50 against B. truncatus. Across all study regions, the pooled mortalities of O. hupensis were 72, 86, 94 and 98% at 1, 2, 3 and 7 d, following field immersion of 4% TDS at a dose of 2.5g/m(3), and were 69, 77, 85 and 88% at 1, 3, 7 and 15 d, following field spraying at 5g/m(2), respectively. 4% TDS had moderate toxicity to Japanese quail (7 d LD50>60mg/kg) and to shrimp (96h LC50=6.28mg/L; 95% CI: 3.53-11.2mg/L), whereas its toxicity to zebrafish was high (96h LC50=0.15mg/L; 95% CI: 0.14-0.17mg/L).Conclusions4% TDS is active against O. hupensis, B. alexandrina and B. truncatus under laboratory and field conditions, and it may be a candidate molluscicide of plant origin.

Parasitic diseases are common infectious diseases closely related to poverty, which are mainly endemic in the tropical and subtropical regions. Africa is the major epidemic area of parasitic diseases, and the global burden of malaria and schistosomiasis is over 85% in Africa. This paper reviews the disease burden, regional distribution and control strategies of the main parasitic diseases in Africa, in order to promote the prevention and control of parasitic diseases in this area.

目的 对2004-2015年中文期刊刊载的血吸虫病相关论文及高被引论文进行分析,为相关期刊制定选题及组稿计划提供参考.方法 以中国知网和万方数据知识服务平台为检索对象,检索发表于2004-2015年的血吸虫病相关论文,对各年发文量及论文类型进行分析;同时确定高被引论文,对其被引频次、分布期刊及类型进行分析.结果 2004-2015年中文期刊共发表血吸虫病相关论文6 756篇,其中防治类论文数最多3 411篇(50.48％).2008年以前,总发文量及防治类论文数量总体呈上升趋势,2008年后均呈下降趋势.57.84％的(3 908篇)论文分布于10本国内寄生虫学期刊,其余散在分布于其他775种期刊.被引频次≥15次的高被引论文共209篇,分布于49种期刊,总被引频次为6 486次;其中防治类论文篇数最多110篇(53.63％),被引频次亦最高4 274次(65.90％).前20篇高被引论文均为防治类,多为各年疫情通报或涉及防治策略的述评类文章.结论 2004-2015年中文期刊刊载血吸虫病相关论文(尤其是防治类论文)及高被引论文数量及类型在一定程度上反映了我国血防工作的历程及关注热点,相关期刊可在不同防治阶段的关键节点就相关热点问题进行选题及组稿.

Objectives To implement schistosomiasis surveillance and alerts,prompt responses to outbreaks,and integrated interventions in key aquatic regions in the City of Zhenjiang's Dantu district (the transmission of schistosomiasis was previously controlled in the Dantu district) along the lower reaches of the Yangtze River during seasons of high prevalence in order to provide scientific evidence for creation of a system for surveillance of schistosomiasis and responses to that disease.Methods Based on a baseline epidemiological database and identification of risk factors for schistosomiasis transmission,a total of 7 surveillance and sentinel sites were selected along 68.9 km of marshlands in the Dantu district along the Yangtze River.A snail survey and a study of schistosomiasis among humans and livestock were performed between March and May from 2009 to 2016.Infectivity of water-borne schistosomes was determined using sentinel mice between May and September.In addition,human and livestock contact with the river was observed,and the contamination of water with miracidia was detected using sentinel snails from 2009 to 2011.If infected snails,acute cases of schistosomiasis,patients with Schistosoma eggs in their feces,infected sentinel mice,or infected sentinel snails were detected,alerts were immediately issued and a prompt response was initiated.Results During the period from 2009 through 2016,no infected snails were detected at the 7 surveillance and sentinel sites.A total of 3 643 sentinel mice were tested at the 7 sites,and 30 mice tested positive at a rate of 0.82％.In addition,a bioassay of sentinel mice revealed 6 instances of Schistosoma japonicum infection in the aquatic regions at 3 surveillance and sentinel sites.A total of 9 000 sentinel snails were released from 2009 to 2011,32,490 snails shed cercariae,and 5 191 snails were dissected,with no miracidia detected.To respond to the detection of S.japonicum infection in sentinel mice at the 3 surveillance and sentinel sites,alerts regarding the infectivity of water-borne parasites were issued 6 times.A total of 2 262 high-risk patients were examined at surveillance and sentinel sites where S.japonicum was detected,and 128 patients tested positive according to a DDIA at a rate of 5.66％.Ten patients had Schistosoma eggs in their feces,for a rate of infection of 0.44％.The sero-positive rate was 6.8％ for men and 3.71％ for women,and the rate of infection was 0.56％ for men and 0.24％ for women.The sero-positive rate (x2 =9.42,P ＜ 0.01) and the rate of infection (x2 =6.21,P ＜ 0.01) differed significantly between men and women.No acute cases of schistosomiasis were detected.A total of 228 sheep were examined,and 12 sheep had Schistosoma eggs in their feces,for a rate of infection of ().26％.The 128 patients who tested positive according to a DDIA,10 patients with Schistosoma eggs in their feces,and 12 sheep with Schistosoma eggs in their feces were treated with praziquantel.Plots of 10 hm2 were treated chemically and cercariae were promptly controlled in aquatic sections of 19 hm2.Integrated interventions were implemented,including health education,individual protection,water sanitation,and disposal of feces.Conclusion In marshlands where the transmission of schistosomiasis was previously controlled,schistosomiasis surveillance and alerts in key aquatic regions and initiation of effective responses and interventions effectively inhibited the development and spread of schistosomiasis outbreaks.A bioassay of sentinel mice is a sensitive and feasible tool with which to detect the infectivity of water-borne parasites.

Objective To explore the feasibility of interrupting schistosomiasis transmission with an integrated control strategy based on the elimination of Schistosomajaponicum-infected goats in schistosomiasis-endemic regions with the infected goats as a major source of infection.Methods A field study was conducted in Wudun Village,Jiangxin Township,Dantu District of Zhenjiang City,Jiangsu Province.From 2004 to 2010,the control measures were carried out,including the Oncomelania hupensissnail survey and control,schistosomiasis examination and treatment,health education and elimination of water infectivity.Since 2011,all the goats were eliminated in addition to the conventional interventions.The changes of endemic situation of schistosomiasis were compared from 2004 to 2016,so as to evaluate the effect of eliminating the infected goats on the interruption of schistosomiasis transmission.Results From 2004 to 2011,the positive rate of stool examinations was 0.4％ to 1.4％ in humans,the area with schistosome-infected snails was 180 000 m2 to 250 000 m2,and the infection rate of sentinel mice was 3.3％ to 18.0％ in key water regions.From 2004 to 2008,the schistosome-infection rate of goats was 0 to 7.3％,and the rate increased to 32.0％ to 54.3％ between 2009 and 2011.A total of 239 wild feces were examined,in which the goat feces consisted of 96.3％ (230/239),with 15.5％ to 22.9％ of positive rate.Since 2012,the infection rate was reduced to 0 in both human and domestic animals,and no infected humans,domestic animals,sentinel mice or snails were detected for 5 successive years (2012 to 2016),achieving the criteria of schistosomiasis transmission interruption.Conclusion In transmission-controlled marshland endemic regions,the understanding of the predominant sources of infection and the implementation of eliminating the major source of infection in combination with conventional integrated interventions is an important strategy to achieve the goals of schistosomiasis transmission interruption and elimination on schedule.

Schistosomiasis japonica, caused by the human blood fluke Schistosoma japonicum, remains a major public health problem in China, although great success has been achieved. The control efforts during the past half-decade, notably the wide implementation of the new integrated strategy with emphasis on control of the source of S. japonicum infection across the country since 2004, has greatly reduced S. japonicum in humans, livestock, and intermediate host Oncomelania hupensis snails, and transmission control of schistosomiasis was achieved in China in 2015. A two-stage roadmap was therefore proposed for schistosomiasis elimination in 2015, with aims to achieve transmission interruption by 2020 and achieve disease elimination by 2025 in the country. During the last two decades, a variety of approaches, which target the epidemiological factors of schistosomiasis japonica have been developed, in order to block the transmission cycle of the parasite. These approaches have been employed in the national or local schistosomiasis control activities, and facilitated, at least in part, the progress of the schistosomiasis elimination programs. Here, we present an approach to control the source of S. japonicum infection, three new tools for snail control, three approaches for detecting and monitoring S. japonicum infection, and a novel model for health education. These approaches are considered to play a great role in the stage moving towards transmission interruption and elimination of schistosomiasis in China.

China's prevention and control of parasitic diseases has made remarkable achievements. However, the prevalence and transmission of parasitic diseases is impacted by the complicated natural and social factors of environment, natural disasters, population movements, and so on. Therefore, there are still the risks of the outbreak of emergency parasitic diseases affairs, which may affect the control effectiveness of parasitic diseases and endanger the social stability seriously. In this article, we aim at the analysis of typical cases of emergency parasitic disease affairs and their impacts on public health security in China in recently years, and we also elaborate the disposal characteristics of emergency parasitic disease affairs, and propose the establishment of response system to emergency parasitic disease affairs in China, including the organizational structure and response flow path, and in addition, point out that, in the future, we should strengthen the system construction and measures of the response system to emergency parasitic disease affairs, so as to control the risk and harm of parasitic disease spread as much as possible and to realize the early intervention and proper disposal of emergency parasitic disease affairs.

Background: Although great success has been achieved, schistosomiasis remains a major public health concern in China, and the remaining core endemic regions are concentrated along the middle and lower reaches of the Yangtze River. In this longitudinal study, we evaluated the effectiveness of a multidisciplinary, integrated approach for schistosomiasis elimination in a historically hyper-endemic region in the lower reaches of the Yangtze River, China over the 10-year period from 2005 through 2014.Methods: A three-step roadmap for schistosomiasis elimination was designed in the study site, and multidisciplinary, integrated interventions were implemented by the health, agriculture, water resources development, land and resources, and forestry sectors from 2005 to 2014, including chemotherapy for infected individuals, health education, management of the source of Schistosoma japonicum infection, and intermediate host snail control. The annual number of schistosomiasis patients, S. japonicum infection in humans, bovines and Oncomelania hupensis snails, and water infectivity were observed to assess the effectiveness of the multidisciplinary, integrated approach for the elimination of schistosomiasis.Results: There was a tendency towards a gradual decline in both the number of schistosomiasis cases and the prevalence of S. japonicum human infection across the study period from 2005 through 2014. No S. japonicum human infection was detected since 2012, and no acute infection was seen since 2006. During the study period, no infection was found in bovines, and a 0.03% overall infection rate was observed in O. hupensis snails. Since 2009, no infected snails were identified, and the area of both snail habitats and infected snail habitats appeared a reduction over the study period. Following the 3-year multidisciplinary, integrated control, infection control was achieved, and transmission control was achieved after 6-year implementation, with all infected snails and water infectivity eliminated; in addition, the 10-year implementation resulted in interruption of schistosomiasis transmission in the study site in 2014.Conclusions: The results of the present 10-year longitudinal study demonstrate that the multidisciplinary, integrated approach is effective for the elimination of schistosomiasis as a public health problem in the lower reaches of the Yangtze River, China.

Background: Schistosomiasis is a global snail-transmitted infectious disease of poverty. Transmission control had been achieved in China in 2015 after the control efforts for over 60 years. Currently, the remaining core regions endemic for Schistosoma japonicum are mainly located in the marshland and lake regions along the Yangtze River basin.Methods: During the period from 2001 through 2015, an integrated environmental improvement of the marshlands was carried out through the implementation of industrial, agricultural and resources development projects in Yizheng County along the Yangtze River. S. japonicum infection in humans, livestock and snails was estimated by serology, stool examination, hatching technique and microscopy during the 15-year study period to evaluate the effect of the integrated environmental improvement on control and elimination of schistosomiasis.Results: A 0.05% overall rate of S. japonicum infection was observed in snails during the 15-year study period, and no infected snails were detected since 2012. The overall prevalence of S. japonicum infection was 0.09% in humans during the study period, and no human infection was found since 2012. In addition, only 13 bovines were identified with S. japonicum infection in 2003 during the 15-year study period, and since 2004, no infection was found in livestock.Conclusion: The results of the present study demonstrate that the implementation of industrial, agricultural and water resources development projects, not only alters snail habitats in marshland regions, and promotes local economic development, which appears a win-to-win strategy to block the transmission of S. japonicum and accelerate socio-economic development along the Yangtze River.

OBJECTIVE:To describe the growth and development of Schistosoma japonicum in goat and the intensity and temporal distribution of eggs excreted by goat feces, so as to provide baseline data for the control and elimination of the role of goat in the transmission of schistosomiasis.METHODS:The goat animal models of schistosomiasis were established, and stool samples were collected for parasitological examinations. The number of adult worms recovered, variation of schistosomes in goat at different time points post-infection, number of eggs in schistosomes, variation in number and temporal profiles of eggs excreted from goat feces were observed.RESULTS:Of the 6 schistosome-infected goat, 415 adult worms were recovered, with a mean adult worm recovery of 34.58% (range, 23.00% to 45.50%). Among the 5 goat infected with 200 cercariae each, 47, 93, 77, 74 and 73 adult worms were recovered 2, 5, 8, 11 and 14 months post-infection, respectively. There were (200.00±42.33), (226.20±45.88), (168.20±25.85), (183.80±55.13) and (190.80±53.53) eggs detected in female schistosomes. The mean prepatent period of eggs excreted by 10 infected goat was (37.7±3.02) d. From 2 to 14 months post-infection, 7 batches of goat feces were hatched, and there were 30, 23, 14, 1 and 2 times for miracidium intensity of "++++", "+++", "++", "+" and "-", respectively, with 42.86%, 32.86%, 20.00%, 1.43% and 2.86% constituent ratios of miracidium intensity.CONCLUSIONS:Approximately 1/3 S. japonicum cercariae may develop to adults in goats post-infection, and the prepatent period of eggs is (37.7±3.02) d. There is no remarkable decrease seen in the number of adult worms, eggs in female schistosomes and eggs in goat feces within 14 months post-infection. Our findings suggest a long duration for infected goat in the transmission of schistosomiasis, and there is no evidence to prove the "self-cure" phenomenon in goat, indicating that goat is an important source of infection for schistosomiasis japonica.

This paper is concerned with the backward differential formula or BDF methods for a class of nonlinear 2-delay differential algebraic equations. We obtain two sufficient conditions under which the methods are stable and asymptotically stable. At last, examples show that our methods are true.