Zootechnical wastewater reuse: constructed wetland as a challenge for protozoan parasite removal

Samples of soil, well water, and wastewater from a zootechnical farm, water after phytodepuration and maize plants (Zea mays) grown on soils irrigated with these different kinds of water were analysed for indicator bacteria and the protozoa Giardia and Cryptosporidium. Protozoa and bacterial indicators, except coliforms, were not recovered from well water samples. In the effluent from the zootechnical farm, high parasitological concentrations were observed, whilst water after the phytodepuration process showed a concentration reduction of two orders of magnitude. The high numbers of Giardia and Cryptosporidium in the zootechnical effluent could represent a potential risk for the spread of the pathogens. Nevertheless the environmental spread is minimized when data on soils and plants are observed. From the study, it emerges that this water treatment system could represent an alternative option to other conventional wastewater treatments and an economic and environmental advantage.     

Molecular Epidemiology of Cryptosporidiosis in Iranian Children,Tehran, Iran

Background

Cryptosporidium is a worldwide protozoan parasite and one of the most common causes of infection and diarrhea in humans and cattle. The aim of the present study was determination of subtypes of Cryptosporidium among children with diarrhea in Tehran by sequence analysis of the highly polymorphic 60-kDa glycoprotein (GP60) gene.

Methods

Fecal samples were collected from 794 diarrheic children. Initial identification of Cryptosporidium was carried out on stool samples by Ziehl-Neelsen acid-fast staining method. DNA was extracted from positive microscopically samples and Cryptosporidium genotypes and subtypes were determined, accordingly.

Results

Out of 794 collected samples, 19 (2.40%) were positive for Cryptosporidium oocysts. Sequences analysis of GP60 gene showed that 17 (89.47%) of the positive isolates were Cryptosporidium parvum and 2 (10.52%) were C. hominis. All subtypes of C. parvum isolates belonged to allele families IIa (6/17) and IId (11/17). The most common allele in all 17 isolates belonged to IId A20G1a (41.18%). A22G1 (IF) subtype was detected in two C. hominis isolates of the children.

Conclusion

The predominancy of C. parvum species (specially, IId A20G1a subtype) in current study underlines the importance of zoonotic Cryptosporidium transmission in Iran.     

艾滋病相关性慢性腹泻隐孢子虫感染患者的临床特征

目的 探讨艾滋病相关性慢性腹泻患者隐孢子虫感染的临床特征.方法 收集2009年11月至2010年12月253例艾滋病相关性慢性腹泻患者的标本,采用甲醛-乙酸乙酰沉淀法,对标本进行集卵,用改良抗酸染色法进行染色,检测隐孢子虫卵囊.根据患者血液中CD4+细胞水平和年龄分别分为＜ 200、≥200～＜500、≥500个/μl3组和20～35、36～55、56～69岁3组,进行组间对比分析.结果 253例粪便标本中,隐孢子虫阳性32例(12.6％),3种CD4+细胞水平组隐孢子虫感染率分别为20.4％ (20/98)、9.2％ (12/130)、0(0/25),差异有统计学意义(x2＝10.33,P＜0.01).在32例隐孢子阳性患者中腹泻5次/d以上22例(68.8％),3种CD4+细胞水平组各有15例(15/20)、7例(7/12)、0例,各组间差异无统计学意义(P＞0.05).艾滋病慢性腹泻患者处于HIV无症状期、AIDS前期、AIDS期,隐孢子虫感染率分别为0(0/7)、21.3％ (19/89)、8.3％( 13/157),差异有统计学意义(x2＝9.822,P＜0.01).32例隐孢子阳性患者中引发肠炎者22例.城市与农村患者阳性率分别为6.7％ (7/104),16.8％ (25/149),差异有统计学意义(x2＝5.596,P＜0.05).253例艾滋病患者3个年龄组的感染率分别为7.3％(4/55),13.4％ (22/164),17.6％ (6/34),差异无统计学意义(x2＝2.29,P＞0.05).结论 隐孢子虫感染率及临床症状的严重程度与CD4+水平、艾滋病分期及疾病发展到直肠炎相关.     

基于PNO基因序列分析隐孢子虫种系发育关系

本文以核基因组的功能蛋白丙酮酸∶NADP^＋氧化还原酶（pyruvate∶NADP^＋ oxidoreductase,PNO）编码基因作为研究对象,对本实验室分离保存的隐孢子虫虫株进行扩增测序,用ClustalX 1.81对扩增序列与GenBank相关参考序列进行比对,用Paup4.0程序中邻接法（Neighbor-joining method,NJ）、最大简约法（Parsimony,MP）和最大似然法（Maximum Likelihood,ML）进行聚类分析,以确定不同隐孢子虫分离株之间的遗传进化关系,并以18S rRNA和HSP70基因构僵的基因树作参照,进而评价PNO这一基因座是否适合作为隐孢子虫基因分型和进化关系分析的基因座。结果表明通过PNO构建的进化树将隐孢子虫分为2大类：Cryptosporidium bailey和C.meleagridis处于一个分枝,C.hominis、C.parvum牛基因型和C.parvum鼠基因型处于另一个分枝上。不同隐孢子虫之间的同源性介于95.0%-100%,能有效区分隐孢子虫不同基因型。因此,PNO基因序列也适合作为隐孢子虫分离株种系发育的遗传标记。     

抗隐孢子虫ScFv-PE重组毒素原核表达载体的构建及其对虫体的杀灭作用

目的构建抗隐孢子虫ScFv-PE重组毒素原核表达载体并测定表达产物对隐孢子虫的杀灭作用。方法利用基因工程原理,以含抗隐孢子虫ScFv-PE重组毒素的菌株为模板,利用设计合成的一对引物扩增出ScFv-PE,利用pMAL-p2X载体构建重组毒素pMAL-ScFv-PE,并将其导入大肠杆菌中进行表达,产物进行SDS-PAGE和Western-blot,纯化后治疗感染隐孢子虫的小鼠。结果重组质粒经酶切鉴定正确,IPTG诱导后可看到明显的条带。凝胶薄层扫描分析目的蛋白表达量占菌体蛋白总量的21%。纯化后的表达产物治疗感染隐孢子虫的小鼠治疗组比对照组肠滞留物中卵囊计数（P〈0.05）与肠道平均累计感染积分明显减少（P〈0.01）。结论利用原核表达载体成功构建了可溶性形式表达的pMAL-ScFv-PE重组质粒,重组毒素对隐孢子虫具有明显的杀灭作用。     

Role of Cryptosporidium spp in Development of Colorectal Cancer

Background: Colorectal cancer is one of the most common malignancies in humans. About 20% of the cancer incidence was attributed to infectious agents highlighting the association between infectious agents and the development of cancers. It has been suspected that Cryptosporidium spp. infection may be correlated with colon adenocarcinoma.  Aim: investigate the percentage of cryptosporidiosis among colorectal cancer patients. Subjects: 100 patients were recruited from Medical Research Institute, Alexandria University. Methods: Fresh stool specimens were collected, homogenized and examined using direct wet mount and by permanent staining of faecal smears using Modified ZN staining. Molecular detection by PCR amplification of Cryptosporidium COWP gene. Results: Significantly higher proportion of colorectal cancer patients (32.5%, 42.5%) tested positive by MZN and ELISA respectively compared to only 3.3% and 5% of positive MZN and ELISA among control group. Also, positive PCR was detected among higher proportion of colorectal cancer patients (47.5%) and only 5% of control group. Odds of colorectal cancer is 19 times among positive cases of Cryptosporidium by PCR than those without proven infection by PCR (OR 19.12; 95% CI 4.82-75.99). Comparison of the assessment of Cryptosporidium infection made by two techniques produces a kappa value of 0.770, and .759 respectively between NZN, ELISA and PCR as a gold standard, suggesting a good agreement between the two techniques and PCR. This value of kappa is significantly different from zero, K.770, p<0.001 for MZN and K.759, p<.001 for ELISA. Specificity of MZN (100%) is higher than that of ELISA (96.2%) and both reported higher specificity than sensitivity denoting that both tests are good positive to rule in the presence of infection at 40% prevalence. Conclusion: Cryptosporidium infection is significantly higher among cancer colon patients reinforcing that it might be considered as a likely risk factor for the development cancer colon.     

抗微小隐孢子虫单克隆抗体免疫保护作用的研究

目的：探讨抗隐孢子虫单克隆抗体（ＭｃＡｂ）的免疫保护作用。方法：在细胞培养的基础上进行体外中和试验,筛选具有保护作用的ＭｃＡｂ,并通过大鼠及ＭＤＣＫ细胞接种隐孢子虫子孢子（ＣＰＳ）进行动物实验和受染ＭＤＣＫ细胞透射电镜观察证实。结果：Ｚ３Ｄ２可显著降低ＣＰＳ在大鼠肠粘膜表面定植的隐孢子虫虫体及卵囊数。可使隐孢子虫各发育期的虫体减少,使ＭＤＣＫ细胞的超微结构受损减轻。结论∶ＭｃＡｂＺ３Ｄ２具有良好的保护作用。     

人隐孢子虫IbA19G2基因亚型蒙古沙鼠感染模型的建立

人隐孢子虫Cryptosporidium hominis是人类的主要感染虫株,目前已获取且传代保存的国内分离株较少,在生物学特性研究也未见报道.在本试验自感染前第10天起至排卵囊结束后14天,采用胃管灌服地塞米松(0.75 mg/(只·2天))抑制蒙古沙鼠免疫力,对国内C.hominis Ib亚型分离株生物学特性进行研...     

新现人兽共患兔隐孢子虫病的病原学研究进展

兔隐孢子虫是新近发现的人兽共患隐孢子虫种,已引起全球关注.本文对其分类地位、流行病学及分子特征研究等方面进行综述.