Parasitic worms of the central nervous system: an Australian perspective

Abstract
The diagnosis and management of parasitic diseases of the central nervous system (CNS) is difficult, even for infectious diseases physicians and neurologists. Furthermore, few overviews of the spectrum of causative helminths and clinical syndromes have been published. In the present study, we review the seven most common parasitic diseases of the CNS: (i) cysticercosis, (ii) neuroschistosomiasis, (iii) paragon­imiasis, (iv) angio-strongyliasis, (v) hydatid disease, (vi) sparganosis and (vii) gnathostomiasis. Major syndromes of parasitic disease of the CNS and their differential causes are discussed, including: (i) cystic lesions, (ii) enhancing granulomas (with and without creeping subcutaneous eruptions), (iii) eosinophilic meningoencephalitis and (iv) spinal cord disease. Specific risk factors that predispose to these infections are also discussed and particular attention is drawn to the situation in Australia. (Intern Med J 2002; 32: 541−553)     

Cerebral cysticercosis: A case report

A case of cerebral cysticercosis is reported in a 49-year-old female who presented with headache, nausea, and vomiting. Lumbar CSF showed the findings of mild aseptic meningitis. CT scan revealed an enlargement of the left ambient cistern and a small cystic lesion in the left frontal cortex. MRI demonstrated multilobular cysts in the left ambient cistern with enhancement of their capsules, which compressed and distorted the midbrain. The cysts were surgically excised, and histological examination of the specimen disclosed characteristic features of cysticercus with viable larva. An excellent value of MRI in the diagnosis of intracisternal cysticercosis is emphasized.     

Bilateral Multifocal Intraocular Cysticercosis

A 47-year-old male from India was treated for the rare condition of bilateral multifocal intraocular infestation with Cysticercus cellulosae, the larval form of Taenia solium. The intravitreous parasite in the left eye was removed via pars plana vitrectomy. A subretinal cysticercus in the right eye, which caused a rhegmatogenous retinal detachment, was removed via sclerotomy during the scleral buckling procedure. An additional peripapillary subretinal cyst could not be removed. A subconjunctival cysticercus was incidently found and removed at the time of surgery. The patient returned to India six weeks after surgery and is doing well.     

Hydrocephalus and racemose cysticercosis: surgical alternative by endoscopic third ventriculostomy

BACKGROUND AND PURPOSE: Hydrocephalus is a frequent and potentially serious complication of neurocysticercosis. Its treatment often requires ventricular shunting. The complication rate is high due to obstruction or material infection, which may justify endoscopic third ventriculostomy (ETV). OBSERVATION: We report a case of obstructive hydrocephalus in a 46-year-old man in the context of racemose cysticercosis, presenting with headaches and transient disorders of consciousness. Imaging showed cystic lesions of the cisterna magna, responsible for hydrocephalus which was treated effectively by ETV. Treatment with albendazole decreased the volume of the cisterna magna cysts. RESULTS: The patient was followed for 6 years after ETV with no recurrence of hydrocephalus despite two more symptomatic episodes of the disease with extension of the cysts into the lumen of the fourth ventricle and into the perispinal subarachnoid spaces, effectively treated by albendazole each time. CONCLUSIONS: Treatment of obstructive hydrocephalus secondary to cerebral racemose cysticercosis by ETV seems to be an effective and safety technique. The role of ETV should be evaluated in this indication.     

人囊虫病T淋巴细胞亚群及血清IgE的变化

应用直接ＳＰＡ菌花环法对２７例囊虫病患者外周血Ｔ淋巴细胞亚群进行检测，同时用ＥＬＩＳＡ法测定血清ＩｇＥ水平。发现患者ＣＤ３＋，ＣＤ４＋细胞的百分率明显降低，ＣＤ４／ＣＤ８比值明显下降，血清ＩｇＥ含量显著升高。经分析，患者ＣＤ４细胞、ＣＤ４／ＣＤ８比值与ＩｇＥ对数值呈负相关。揭示囊虫病患者Ｔ细胞亚群比例失调，免疫功能紊乱。本文对可能的免疫调节机制和发病机理进行了探讨。     

Evidence for high seroprevalence of Taenia solium cysticercosis in individuals from three rural communities in Venezuela

A serological study was undertaken in 1998 to evaluate levels of Taenia solium cysticercosis in 3 rural Venezuelan communities. Infection with viable metacestodes was diagnosed with a trapping enzyme-linked immunosorbent assay (ELISA) that detects a secreted product of viable parasites. Anti-metacestode antibodies were assayed by ELISA using T. solium vesicular fluid as antigen. A total of 1254 sera was collected from 3 communities (Canoabo, Sanare, and Rio Tocuyo) where previous studies had suggested the presence of T. solium. Our results demonstrate an unusually high seroprevalence of cysticercosis, indicating an attendant risk of transmitting the disease to other areas. The seroprevalence of infection with viable cysts, as indicated by detection of circulating parasite antigen, was 9.1% in Canoabo, 6.1% in Sanare, and 5.7% in Rio Tocuyo. The corresponding frequency of antibodies to T. solium cyst antigens was 36.5% in Canoabo, 36.5% in Sanare, and 4% in Rio Tocuyo. As these communities are probably representative of many others in Venezuela, T. solium cysticercosis may be a significant public health problem and more work is certainly indicated. An important finding was that local knowledge of the disease and its transmission do not necessarily guarantee diminished disease prevalence, indicating a lack of appropriate vigilance towards disease control.     

特异性单克隆抗体测定脑囊虫病人血清中循环抗原的临床研究

对１３０例临床初诊脑囊虫病人血清中循环抗原及抗体进行了测定。结果发现，６７例抗体阳性患者中有３４例抗原阳性，阳性率为５０．７％；３４例抗原阳性患者中有２０例头颅ＣＴ证实为活动性病变；３３例抗体阳性而抗原阴性患者中有２６例头颅ＣＴ证实为１～２个或多个钙化灶，这表明脑囊虫患者特异性抗原检测可以比较客观地反映脑囊虫病变的不同程度与ＣＴ检查之间的关系，而且可以作为疗效观察的指标。     

小剂量Isovist脑室造影CT扫描诊断脑室系统非肿瘤性疾病的实验与临床研究

用乳胶囊制成脑积水和脑室囊虫病的模型，行Ｉｓｏｖｉｓｔ造影ＣＴ扫描。结果：造影剂浓度（Ｖ／Ｖ）０．５％～１％时，ＣＴ值６５．１～１２８．３Ｈｕ，造影效果良好，浓度过小，对比度不足，效果不佳，浓度过高，将有较多伪影，可淹没或掩盖病变。以０．５％～１％Ｉｓｏｖｉｓｔ脑室造影ＣＴ扫描４４例，４３例得到明确诊断，造影效果良好，其中交通性脑积水２例，室间孔粘连１例，导水管狭窄２例，正中孔粘连５例，脑室囊虫病３３例，经手术和病理证实诊断符合率为１００％。１例注入造影剂后距扫描时间过短，造影剂尚未扩散到病变部位而失败。     

二种快速ELISA用于检测囊虫病患者血清特异性抗体的实验观察

用快速ＩｇＧ－ＥＬＩＳＡ和快速ＳＰＡ－ＥＬＩＳＡ检测囊虫病人血清抗体，其阳性率分别为９０．００％和９４．２９％，两虫之间无显著性差异（Ｐ＞０．０５）。两法假阴性率分别为１．４３％和２．８６％，对包虫病人血清出现较强交叉反应，对肝吸虫、肺吸虫病人血清出现一定程度的交叉反应，而对血吸虫病人、绦虫病人血清未出现交叉反应。若两种方法同时使用可提高敏感性。两种方法均较简便，在包虫病非流行区可作为较好的流行病学调查筛检方法，亦可用于临床