SEROPOSITIVITY FOR ASCARIOSIS AND TOXOCARIOSIS AND CYTOKINE EXPRESSION AMONG THE INDIGENOUS PEOPLE IN THE VENEZUELAN DELTA REGION

The present study aimed at measuring seropositivities for infection by Ascaris suum and Toxocara canis using the excretory/secretory (E/S) antigens from Ascaris suum (AES) and Toxocara canis (TES) within an indigenous population. In addition, quantification of cytokine expressions in peripheral blood cells was determined. A total of 50 Warao indigenous were included; of which 43 were adults and seven children. In adults, 44.1% were seropositive for both parasites; whereas children had only seropositivity to one or the other helminth. For ascariosis, the percentage of AES seropositivity in adults and children was high; 23.3% and 57.1%, respectively. While that for toxocariosis, the percentage of TES seropositivity in adults and children was low; 9.3% and 14.3%, respectively. The percentage of seronegativity was comparable for AES and TES antigens in adults (27.9%) and children (28.6%). When positive sera were analyzed by Western blotting technique using AES antigens; three bands of 97.2, 193.6 and 200.2 kDas were mostly recognized. When the TES antigens were used, nine major bands were mostly identified; 47.4, 52.2, 84.9, 98.2, 119.1, 131.3, 175.6, 184.4 and 193.6 kDas. Stool examinations showed that Blastocystis hominis, Hymenolepis nana and Entamoeba coli were the most commonly observed intestinal parasites. Quantification of cytokines IFN-γ, IL-2, IL-6, TGF-β, TNF-α, IL-10 and IL-4 expressions showed that there was only a significant increased expression of IL-4 in indigenous with TES seropositivity (p < 0.002). Ascaris and Toxocara seropositivity was prevalent among Warao indigenous.     

Respiratory atopic disease, Ascaris-immunoglobulin E and tuberculin testing in urban South African children

BACKGROUND: Epidemiological relation of intestinal helminth infection and atopic disease, both associated with a T-helper (Th) 2 immune response, is controversial, as it has been reported that helminth infection may either suppress or pre-dispose to atopic disease. This relation has not been tested in an area with a high burden of Mycobacterium tuberculosis (MTB) infection, a known Th1-stimulating infection. OBJECTIVE: To study the association of intestinal helminth infection and atopic disease in a community where helminth infection is endemic and MTB infection is high. METHODS: Three-hundred and fifty-nine randomly selected children aged 6-14 years from a poor urban suburb were tested with allergy questionnaire, skin prick test (SPT) to common aeroallergens, Ascaris-specific IgE (Ascaris-sIgE), fecal examination for pathogenic intestinal helminths and tuberculin skin testing (TST). Histamine bronchoprovocation was tested in the group of children aged 10 years and older. RESULTS: were corrected for demographic variables, socioeconomic status, parental allergy, environmental tobacco smoke (ETS) exposure in the household, recent anthelminthic treatment and for clustering in the sampling unit. Results Ascaris-sIgE was elevated in 48% of children, Ascaris eggs were found in 15% and TST was positive in 53%. Children with elevated Ascaris-sIgE had significantly increased risk of positive SPT to aeroallergens, particularly house dust mite, atopic asthma (ever and recent), atopic rhinitis (ever and recent) and increased atopy-related bronchial hyper-responsiveness. In children with negative TST (<10 mm), elevated Ascaris-sIgE was associated with significantly increased risk of atopic symptoms (adjusted odds ratio (OR(adj)) 6.5; 95% confidence interval (CI) 1.9-22.4), whereas in those with positive TST (>/=10 mm) this association disappeared (OR(adj) 0.96; 95% CI 0.4-2.8). CONCLUSIONS: These results suggest that immune response to Ascaris (Ascaris-sIgE) may be a risk factor of atopic disease in populations exposed to mild Ascaris infection and that MTB infection may be protective against this risk, probably by stimulation of anti-inflammatory networks.     

gamma-Glutamyl transpeptidase activity in Ascaris suum

Using histochemical techniques γ-glutamyl transpeptidase activity has been localized mainly in the cuticle-hypodermis in Ascaris suum. The specific activity of γ-glutamyl transpeptidase was 3.87 ± 0.49 μmol h⁻¹ (g tissue)⁻¹ in cuticle-hypodermis as compared to gastrointestinal tract, where it was 0.07 ± 0.02 μmol h⁻¹ (g tissue)⁻¹, and muscle and reproductive tract where it was <0.001 μmol h⁻¹ (g tissue)⁻¹. When cuticle sections were incubated with labelled glutamine a large portion of the glutamine nitrogen was recovered as ammonia which indicated glutamine uptake and utilization by the cuticle-hypodermis. Collectively these histochemical and biochemical data support the fact that γ-glutamyl transpeptidase activity is found in the cuticle-hypodermis of A. suum and this may be an indication that amino acid absorption could occur through the cuticle via the γ-glutamyl cycle.     

蛔虫变应原致过敏性鼻炎豚鼠模型建立

为了建立蛔虫变应原致过敏性鼻炎的实验动物模型,将健康豚鼠３０只,随机分为致敏组（ｎ＝２０）和对照组（ｎ＝１０）。致敏组经腹腔、四肢皮下注射蛔虫变应原免疫４周后,鼻腔雾化吸入蛔虫变应原;对照组以生理盐水代替变应原。结果致敏组１８只出现鼻痒、喷嚏、流清涕等过敏性鼻炎的临床症状（评分〉５分）,鼻腔分泌物涂片见大量嗜酸性粒细胞,以及鼻粘膜水肿、粘膜嗜酸性粒细胞和肥大细胞浸润等组织学变化,而对照组无上述变化     

猪蛔虫不同发育期幼虫的收集方法研究

目的研究猪蛔虫不同发育期幼虫的收集方法。方法采用7.5%次氯酸钠氧化感染期蛔虫卵,37℃过夜后,用灭菌生理盐水离心数次,充分洗去次氯酸钠,将沉淀用玻璃珠在振荡器上振荡至全部卵壳破裂,幼虫孵出。用淋巴细胞分离液通过密度梯度离心法将幼虫与卵壳分离,最后收集底层的脱鞘第三期(L3)幼虫。在贝尔曼原理的基础上,在漏斗中加入低浓度(0.4%)琼脂凝胶,分别将绞碎的含幼虫的猪肝、肺和小肠内容物及其肠粘膜平均分装在数个漏斗中,放入40℃温箱中孵育3h,待大部分幼虫游离到管底,最后用400目分样筛过滤分离肝中的L3,用300目分样筛过滤分离肺中的L3,用200目分样筛过滤分离肠内容物及其粘膜上的第四期幼虫(L4)。结果次氯酸钠氧化加玻璃珠震荡法能够使感染期蛔虫卵几乎完全脱壳,配合淋巴细胞分离液的密度梯度离心法能收集到纯度较高且活力较强的体外脱鞘幼虫。与传统贝尔曼氏分离法相比,采用低浓度琼脂糖凝胶液能获得杂质少、高纯度的猪内脏中的不同发育期幼虫。结论次氯酸钠氧化加玻璃珠震荡法是体外脱鞘分离感染期幼虫的一种较为理想的方法,通过在漏斗内加低浓度的琼脂凝胶的方法是从猪内脏中获得高纯度的不同发育期幼虫的一种有效的方法。本方法不仅适用于猪蛔虫,而且对其它动物和人的寄生线虫幼虫的收集也有参考价值。     

Influence of physico-chemistry and mineralogy on the occurrence of geohelminths in geophagic soils from selected communities in the Eastern Cape,South Africa,and their possible implication on human health

Geophagic soils from selected communities in Eastern Cape, South Africa were characterised to determine their properties and geohelminth content. The soils were coarse-textured with cation exchange capacity values ranging from 6.35 to 18.94?cmol (+)/kg. Quartz was the dominant mineral in the samples with SiO₂, Al₂O₃, and Fe₂O₃(t) having the highest concentrations among major element oxides. The soil properties, mineralogical composition, and low amounts of particle binding substances may favour the survival of geohelminth ova in the soils. Seven of the samples contained at least one of the following geohelminths: Ascaris lumbricoides, Trichuris trichiura, Necator americanus, Ancylostoma duodenale and Strongyloides stercoralis. The presence of these geohelminths in the soils was attributed to agricultural and sanitary practices inherent in the communities and the soil properties. Communities need to be sensitised on the importance of safe sanitary and animal husbandry practices to reduce the prevalence of helminth infection among geophagists.     

阳春市人体重点寄生虫感染状况调查及影响因素分析

目的 了解阳春市人体重点寄生虫感染状况及其影响因素,为制定符合当地实际的寄生虫防治措施提供科学依据.方法 采集3周岁以上常住居民粪便标本,采用改良加藤厚涂片法检测蛔虫、钩虫等重点寄生虫虫卵,同时采用透明胶纸法检查蛲虫虫卵,并对接受检查对象进行统一问卷调查.结果 共调查1 047人,查出感染者70人,总感染率为6.69％.蛔虫是主要的寄生虫感染虫种.0～岁年龄组儿童寄生虫感染情况较严重(x2=25.88,P＜0.05).经济类型(x2=8.41,P＜0.05)、文化程度(x2=34.30,P＜0.05)、饮水习惯(x2=14.22,P＜0.05)、洗手习惯(x2=9.95,P＜0.05)及厕所类型(x2=12.21,P＜0.05)是人群寄生虫感染的影响因素.结论 蛔虫是当地人体寄生虫感染的主要虫种,应针对重点地区、重点人群采取加大宣传、转变居民卫生习惯、促进农村改水改厕工程及改善生活环境相结合的综合性防治措施.     

江西农村社区蛔虫感染动态一年纵向研究

目的 :了解未加控制措施干预下农村社区蛔虫感染与传播动态。方法 :由 6次横断面调查组成的一年纵向研究。结果 :当地人群感染率常年稳定在 60 %以上 ,但年内社区感染率与感染度 ( EPG)有显著性波动。年龄分层分析进一步表明 ,感染的波动仅在部分儿童具显著性 ,而在几乎所有成人组波动不具显著性。蛔虫在土壤内的发育率变化与年内月平均温度的变化相一致。结论 :该地蛔虫感染呈相对稳定的地方性传播但存在明显季节波动 ,此种波动与季节对土壤中虫卵发育的影响有关 ,儿童是构成社区蛔虫感染波动的主要人群。     

Immuno-epidemiology of Ascaris lumbricoides infection in a high transmission community: antibody responses and their impact on current and future infection intensity

The role of the humoral immune system in human infection with Ascaris lumbricoides remains unclear. This study documents an epidemiological investigation in a highly endemic community in Vietnam, whereby serum antibody levels were assessed before treatment and after a 6-month reinfection period. These data were examined by correlation with infection status using an age-structured approach in an attempt to help shed light on the role of the humoral immune response. The first part of this study characterized levels of all serum antibody isotypes from the community in response to antigens of both adult and larval A. lumbricoides. Data were assessed in terms of their relation to host age and infection intensity with the aim to provide a broadly detailed account of immune responses to the parasite. In the second part, antibody responses to both life-stages of A. lumbricoides in serum samples collected before anthelmintic chemotherapy were analysed in relation to intensity of re-infection with the parasite 6 months following treatment. The results suggest that antibody responses may not confer protection from current infection or re-infection with A. lumbricoides and may not serve as reliable indicators of future infection intensity. Our results thereby lend support to the theory that immunity to A. lumbricoides may not be based on the humoral immune system.     

Esophageal space-occupying lesion caused by Ascaris lumbricoides

Ascaris lumbricoides is the largest intestinal nematode parasite of man, which can lead to various complications because of its mobility. As the esophagus is not normal habitat of Ascaris, the report of esophageal ascariasis is rare. An old female presented with dysphagia after an intake of several red bean buns and haw jellies. The barium meal examination revealed a spherical defect in the lower esophagus. Esophageal bezoar or esophageal carcinoma was considered at the beginning. The patient fasted, and received fluid replacement treatment as well as some oral drugs such as proton pump inhibitor and sodium bicarbonate. Then upper gastrointestinal endoscopy was done to further confirm the diagnosis and found a live Ascaris lumbricoides in the gastric antrum and two in the duodenal bulb. The conclusive diagnosis was ascariasis. The esophageal space-occupying lesion might be the entangled worm bolus. Anthelmitnic treatment with mebendazole improved patient's clinical manifestations along with normalization of the radiological findings during a 2-wk follow-up. Authors report herein this rare case of Ascaris lumbricoides in the esophagus, emphasizing the importance of awareness of this parasitic infection as it often presents with different and unspecific symptoms.