疟原虫毒力进化

在毒力稳定进化水平上,寄生虫增加利用宿主资源的程度(即增加传播)带来优势的同时也要付出代价,即能够传播毒力的感染阶段相应缩短。在这种优势与代价之间存在着一种平衡(trade-off)。该文综述了疟原虫毒力进化的假说及其相关的分子机制。     

浅析儿童肠道寄生虫的危害与防治

人体寄生虫病是严重危害少年儿童健康的常见病,特别是以蛔虫、钩虫、鞭虫、蛲虫病等为代表的土源性肠道线虫病,一般儿童于每年春、秋季驱虫治疗1～2次为宜,同时要加强健康及卫生教育,养成良好的个人卫生习惯,每日按要求洗手,保持手部清洁卫生,可以有效减少或避免肠道线虫感染。     

XS-1000i血液分析仪异常嗜酸性粒细胞散点图对疟原虫感染的提示作用

目的利用血液分析仪提示的嗜酸性粒细胞(eosinophil,EO)增高及异常散点图信息,结合显微镜镜检检出疟原虫。方法用XS-1000i血液分析仪进行血常规检测,对仪器报警提示嗜酸粒性细胞比值增高(EO )的标本用显微镜进行涂片检查,当发现E0无异常时,则镜检红细胞,查找疟原虫。结果在289例仪器报警提示EO 增高的标本中,显微镜镜检发现有3例EO结果正常与仪器报警不符,这3例标本均在红细胞中检出疟原虫的滋养体、裂殖体或配殖体。结论在用Sysmex XS-1000i血液分析仪进行血常规检测时,若仪器提示"EO "而未得到显微镜镜检证实,则高度提示有疟原虫存在的可能性。     

Diagnosis and treatment of Q fever: attempts to clarify current problems in Japan

“Q fever” is a generic term for infection caused, mostly in the form of pneumonia or bronchitis, by Coxiella burnetii (Q-fever Coxiella), a pathogen closely related to Rickettsia and Legionella. Q fever is an influenza-like, transient febrile infectious disease that is common to humans and animals; it develops after the transmission of the infectious agent from livestock or pet animals, but person-toperson transmission is rare. In Europe and the United States, it is ranked fourth or fifth as an underlying cause of community-acquired pneumonia. Many patients with Q fever have a good prognosis, and their mortality is about 1%–2% when left untreated. However, because some patients may take a long time to be cured or may have a chronic condition with poor prognosis, patients with definitely diagnosed Q fever or those strongly suspected of having Q fever are strongly recommended to receive treatment. The definite diagnosis of Q fever is made based on a significant increase in serum antibody titers, the determination of which often requires considerable time, and therefore patients must be monitored for a certain period. Q-fever Coxiella, an obligate intracellular parasite, is basically not susceptible to β-lactam antibiotics, which barely permeate into the cells, but the parasite is susceptible to tetracyclines, macrolides, and quinolones, with these agents being sufficiently permeable into the cells. However, there are many cases of spontaneous cure, and it is likely that β-lactam treatment may have been involved in these cases. Vaccination against Q fever is not common in Japan.     

Concentrations of selected heavy metals in Ligula intestinalis L., 1758 plerocercoids (Cestoda) compared to it host’s (Tinca tinca L., 1758) organs from Beyşehir Lake (Turkey)

Summary  The accumulation of heavy metals (Cu, Fe, Zn and Mn) was measured by atomic absorption spectrophotometry in some organs of tench (Tinca tinca L., 1758) and tissues of its parasite collected from Beyşehir Lake, and compared with the data from sediments and water. The Cu levels in L. intestinalis L., 1758 plerocercoids were 1.69 times, respectively, higher than those in fish gill. Zn level in L. intestinalis plerocercoids was 2.13 times higher than those in fish liver, was 5.53 times higher than that of the muscle and 3.33 times higher than that in the gill. Significant negative (for Mn) correlation was found between the quantity of heavy metals in water and tissues of L. intestinalis plerocercoids while there was significant negative (for Cu) correlation between the quantity the heavy metals in bottom sediment and tissues of L. intestinalis plerocercoids. This study supports the idea that cestodes aren’t very useful to determine the heavy metal pollution in aquatic system when they are located in their intermediate host’s body cavity.     

伯氏鼠疟原虫(Plasmodium berghei)对咯萘啶抗药性的研究

用本所传代已二十余年、对药物敏感的伯氏鼠疟原虫作种源,每转种一代给小白鼠口服单次量咯萘啶。第1代剂量为8 mg/kg,其后剂量每代增加2 mg/kg。转种至第23代,剂量达2,400mg/kg时,虽部分小鼠死亡,存活小鼠的原虫血症仍不转阴,此时原虫的抗药性为亲代原虫的300倍以上。抗咯萘啶鼠疟原虫(RPB₂)对氯喹、喹哌、吡咯喹、M-6407、阿的平与青蒿素等有一定程度的交叉抗药性。用对亲代原虫有效量的3～10倍治疗RPB₂原虫时,不能使原虫血症转阴。如不再用药,连续转种5代,RPB₂可恢复对咯萘啶的敏感性。     

兴宁市人体肠道寄生虫感染现状调查

目的了解和分析兴宁市人体肠道寄生虫感染现状与防治效果。方法采用改良加藤涂片法检查肠道寄生虫卵;采用试管滤纸培养法检查钩虫;用肛门透明胶纸拭擦法检查蛲虫卵。结果共调查1663人,查出肠道寄生虫4种,有200人感染,总感染率为12.03％,其中感染钩虫、蛔虫、鞭虫和蛲虫者分别为38人、117人、45人和87人;感染率分别为2.28％、7.03％、2.70％和23.84％。男女感染率为11.74％和12.29％,差异无统计学意义(x2:0.12,P>0.05);小于7岁儿童总感染率为11.76％,7～14岁学生总感染率为15.82％,大于14岁的人群总感染率为10.17％,差异有统计学意义(X2=9.91,P<0.01);不同镇的感染率,差异有统计学意义(X2=23.81,P<0.01);结论肠道寄生虫感染与生活居住环境、卫生条件、生活习惯等因素有关。广泛宣传教育,增强人们的卫生意识,提高自我保健能力是控制或消除人体肠道寄生虫感染的有效措施。     

Periodate treatment of Anisakis simplex allergens

Moneo I, Audicana MT, Alday E, Curiel G, del Pozo MD, García M. Periodate treatment of Anisakis simplex allergens.
Anaphylactic reactions after parasitized fish consumption are mediated by an IgE response. However, positive skin tests and specific IgE can also be found in many asymptomatic subjects who recognize a single medium mol.-wt. antigen by IgE immunoblot. The study aimed to find out whether this unspecificity was due to the carbohydrate moieties of parasite antigens. Sixty-two patients with suspected parasite allergy, 51 blood donors, 18 bakers, and 38 atopic patients were studied by blotting. Parasite proteins were treated with periodate. Several selected sera were inhibited with a crude wheat extract and fungal amylase. Twelve patients '19%', eight donors '16%', six bakers '33%', and one atopic patient '3%' recognized a single mediummol.-wt. band in blotting and should be considered false-positive. This band was periodate-sensitive, but specific IgE to this allergen could not be inhibited by a wheat extract nor by fungal amylase and was clinically irrelevant. Diagnosis of Anisakis simplex hypersensitivity by skin tests and/ or specific IgE values should always be confirmed by specific IgE immunoblotting in order to detect the presence of clinically unrelated antibodies directed to periodate-sensitive allergens. These allergens are probably not a carbohydrate moiety of a parasite glycoprotein.     

The role of low level Plasmodium falciparum parasitaemia in anaemia among infants living in an area of intense and perennial transmission

Summary Children under one year of age in an area of intense and perennial Plasmodium falciparum transmission were followed up for one year to establish to what extent chronic, low parasitaemia was associated with severe anaemia. There was a significant increase in the prevalence of anaemia (PCV ≥ 25%) with increase in parasite density. PCV levels were related not only to concurrent parasite density but also decreased with densities measured one month previously. At any point in time, the mean PCV level in infants with low parasitaemia (<1000 parasites/μ1) was higher than that of infants with intermediate (1000–9999/μ1) and high parasite densities (≥10 000/μl). After the age of 7 months, infants with low parasite densities tend to recover, probably as a result of developing immunity. At the age of 12 months, they have similar PCV levels to infants with no detectable parasitaemia by microscopy. The maintenance of low parasite density appears crucial to the survival of infants in malaria endemic areas. The findings suggest that interventions which lower parasite densities in areas of intense transmission reduce the development of severe malarial anaemia and thus malaria-related mortality and morbidity in infants.