Malaria co-infection in children influences antibody response to schistosome antigens and inflammatory markers associated with morbidity

The epidemiological coexistence of schistosomiasis and malaria is frequently observed in developing countries. Co-infection with malaria in children could influence the development of acquired immunity associated with the resistance or the pathology of schistosomiasis. In the present study, performed during May to June 1996 in Senegal, the humoral immune response to Schistosoma haematobium 28 kDa glutathione S-transferase (Sh28GST) vaccinal antigen and to soluble egg antigens (SEA) has been evaluated in individuals infected by S. haematobium. Specific immunoglobulin G3 (IgG3) and IgE responses were significantly higher in co-infected children with Plasmodium falciparum compared with children infected with S. haematobium only. In addition, circulating levels of interferon-gamma (IFN-gamma), interleukin-10 (IL-10), and soluble tumor necrosis factor receptor II (sTNF-RII), 3 parameters associated with schistosomiasis morbidity, were significantly increased in co-infected children. Taken together, this study indicated that malaria co-infection can both influence the acquired specific immune response to schistosome antigens and unbalance the regulation of inflammatory factors closely involved in schistosomiasis pathology.     

Schistosomiasis control in Ghana: case management and means for diagnosis and treatment within the health system

An essential component of integrated schistosomiasis control as promoted by WHO is adequate clinical care for patients presenting at health care facilities. We evaluated the functioning of the Ghanaian health system for diagnosis and treatment of schistosomiasis by interviewing health workers from 70 health care facilities in 4 geographical areas in April and May 2000. Results from presentation of 4 hypothetical cases and a subsequent interview demonstrated that patients presenting with symptoms related to schistosomiasis have a small chance of receiving adequate treatment: often health workers do not recognize the symptoms, especially those of Schistosoma mansoni; patients are frequently referred for a diagnostic test or treatment with a large risk of non-compliance; and praziquantel was not available in 78% of the health care facilities with reported schistosomiasis in their coverage area. The overall cost of treatment is considerable: [symbol: see text] 2.13 for S. haematobium and [symbol: see text] 1.81 for S. mansoni patients, with drug costs contributing approximately 40% of the total cost. To better meet WHO recommendations for passive case detection as part of integrated schistosomiasis control, the Ghanaian health system needs to emphasize training of health workers in schistosomiasis case recognition and case management and increase the availability of praziquantel. Experience from other West African countries indicate that this is feasible.     

On the increase of portal pressure during the acute and chronic phases of murine schistosomiasis mansoni and its reversibility after treatment with oxamniquine

The purpose of the present study was to evaluate the effect of treatment with oxamniquine on the portal pressure of mice infected with Schistosoma mansoni. The animals were infected with 30 cercariae and portal pressure was measured with a polygraph at 70 (acute phase) and 160 (chronic phase) days after infection. On days 70 and 160 two other groups of infected mice were treated with 400 mg/kg of oxamniquine and portal pressure was measured 90 days later (160 and 250 days after infection). A group of uninfected mice was used as control. The measured portal pressures, in mmHg, were: matched uninfected control mice 8.7+/-2.1 and acute phase group, measured at day 70, 13.4+/-3.5. Matched uninfected control 7.5+/-0.6 and chronic phase group, measured at day 160 post-infection, 11.6+/-1.5. Matched uninfected mice 6.9+/-0.9 and chronic phase group, measured at day 250, 10.4+/-1.8. Oxamniquine-treated at day 70 and measured at day 160 7.9+/-0.4; oxamniquine-treated at day 160 and measured at day 250, 7.6+/-1.7. The infection of mice with 30 cercariae of S. mansoni induced portal hypertension, both during the acute and chronic phases and treatment with oxamniquine caused portal pressure to return to normal levels.     

小鼠日本血吸虫病肝纤维化肝脏CTGF的表达及意义

目的研究结缔组织生长因子(connective tissue growth factor,CTGF)在日本血吸虫病肝纤维化小鼠肝脏中的表达状况及意义。方法用昆明小鼠感染尾蚴复制小鼠日本血吸虫病肝纤维化模型;RT-PCR和免疫组化分别检测小鼠肝脏CTGFmRNA和蛋白的表达,免疫组化方法观察各阶段肝脏α-SMA阳性细胞的表达。结果模型组10周时形成典型的肝纤维化,此时模型组小鼠肝脏CTGFmRNA和蛋白表达、α-SMA 细胞数达高峰,10周、14周、18周时与治疗组相比均有明显的统计学差异(P均>0.05);CTGFmRNA和蛋白表达水平与α-SMA 细胞数均呈直线相关性。结论CTGF基因和蛋白表达增高与小鼠日本血吸虫病肝纤维化形成有密切关系;CTGF在小鼠日本血吸虫病肝纤维化形成过程中的作用可能主要通过作用于活化的肝星状细胞来实现的。     

螺旋CT延迟重复扫描对脑血吸虫性肉芽肿的诊断价值(附49例分析)

目的　探讨螺旋CT延迟重复扫描对脑血吸虫性肉芽肿的诊断价值及特征性表现。方法　作者回顾性分析了经手术病理和临床证实的 49例脑血吸虫性肉芽肿的螺旋CT扫描资料。结果　 90s内病灶无强化 ;第 2～ 5min内病灶开始强化 ;第 5～ 15min内病灶出现高度强化 ,并融合成团 ;第 15～ 2 0min内病灶强化逐渐消退 ;第 2 5min以后病灶无强化。结论　螺旋CT延迟重复扫描诊断脑血吸虫性肉芽肿具有特征性表现 ,正确诊断率为 10 0 %。     

血吸虫病肝纤维化兔血浆肿瘤坏死因子水平的动态变化

【目的】研究兔血吸虫病肝纤维化时血浆肿瘤坏死因子（ Ｔ Ｎ Ｆα） 的动态变化。【方法】将３６只家兔随机分为正常组、感染组。于感染尾蚴后第７０ ，１ ００ ，１３０ ｄ ，每组随机选６ 只取血和肝，进行免疫、生化、病理观察。【结果】感染组血浆 Ｔ Ｎ Ｆα、透 明 质 酸（ Ｈ Ａ） 、肝 组 织 羟 脯 氨 酸（ Ｈ Ｙ Ｐ） 、肝胶原纤维含量、肝胶原纤维分布面积百分比均 显著高 于正 常组（ Ｐ ＜ ０ ．０ １） ， 血浆 Ｔ Ｎ Ｆα与血浆 Ｈ Ａ 、肝组织 Ｈ Ｙ Ｐ、肝胶原纤维含量、肝胶原纤维分布面积百分比均呈正相关关系。【结论】 Ｔ Ｎ Ｆα参与了血吸虫病肝纤维化的形成过程。     

洲滩地区两种防治对策控制血吸虫病的效果

为探讨洲滩地区控制血吸虫病的防治对策，1992～1995年选择两个相似的外滩以不同防治对策进行了现场观察，结果在实施人畜扩大化疗＋健康教育＋滩地治理防治的洲滩，人、畜感染率，感染螺密度及钉螺感染率分别下降93．1％、72．6％、66．7％和77．3％，而实施人畜化疗＋易感地带灭螺防治的洲滩人畜感染率分别下降25．0％、18．6％，感染螺密度及钉螺感染率上升12．5％和19．4％；人群感染率每下降1％所需的实际费用，前者高于后者，但相对效果前者为0．64元优于后者0元．     

Community perception of school-based delivery of anthelmintics in Ghana and Tanzania.

This paper presents the results of an evaluation of community perception of two large-scale, government-run, school-based health programmes delivering anthelmintic drugs to primary school children, in Ghana (80 442 children in 577 schools) and Tanzania (110 000 children in 352 schools). Most teachers (96% in Ghana and 98% in Tanzania) were positive about their role in the programme, including administration of anthelmintic drugs, and parents and children fully accepted their taking on this role. The benefits of the programme were apparent to teachers, parents and children in terms of improved health and well-being of the children. Over 90% of parents in both Ghana and Tanzania indicated a willingness to pay for the continuation of drug treatment. The evaluation also highlighted areas that are critical to programme effectiveness, such as communication between schools and parents, the issue of collaboration between the health and education sectors, parents' perception of the importance of helminth infection as a serious and chronic health problem (compared with more acute and life threatening illnesses such as malaria), and who should pay for treatment of side-effects.     

A multi-group model of Schistosoma japonicum transmission dynamics and control: model calibration and control prediction

Previously we formulated a quantitative model to characterize site-specific schistosomiasis transmission. In this paper, we present a procedure to calibrate the model to data collected in endemic villages of south-western Sichuan, China, with the objective of reducing parametric uncertainty to allow the model to describe local transmission with relative confidence. A Bayesian approach using local epidemiological data and expert opinion is employed to calibrate the model. Results indicate that, after calibration, the output uncertainty is reduced substantially. The calibrated model is then used for prediction of the effects of different intervention options. Simulations reflect a bimodal transmission in both human (early summer and early fall) and snail (late summer and late fall) infections in this area, for which there is some field evidence. Also shown in the simulations are relatively high reinfection rates following chemotherapy in these endemic villages. These results suggest that a sustainable control strategy is essential in reducing transmission, and that transmission can be reduced by chemotherapy, focal snail (e.g. snail clusters) control, and egg control. Our work demonstrates the feasibility of characterizing site-specific schistosomiasis transmission using a mathematical model and a calibration approach that integrates diverse field data, and the use of the calibrated model to design control strategies.