Recent advancements and new perspectives in animal models for Neurocysticercosis immunopathogenesis

Neurocysticercosis (NCC), one of the most common parasitic diseases of the central nervous system, is caused by Taenia solium. This parasite involves two hosts, intermediate hosts (pig and human) and a definitive host (human) and has various stages in its complex life cycle (eggs, oncosphere, cysticerci and adult tapeworm). Hence, developing an animal model for T. solium that mimics its natural course of infection is quite challenging. We have reviewed here the animal models frequently used to study immunopathogenesis of cysticercosis and also discussed their usefulness for NCC studies. We found that researchers have used mice, rats, guinea pigs, dogs, cats and pigs as models for this disease with varying degrees of success. Mice and rats models have been utilized extensively for immunopathogenesis studies due to their relative ease of handling and abundance of commercially available reagents to study these small animal models. These models have provided some very exciting results for in‐depth understanding of the disease. Of late, the experimentally/naturally infected swine model is turning out to be the best animal model as the disease progression closely resembles human infection in pigs. However, handling large experimental animals has its own challenges and limitations.     

脑囊尾蚴病的病理改变及分期

近些年,由于显微技术和影像学技术的广泛应用以及脑囊尾蚴病的高发病率引起人们的高度重视,越来越多的人关注于其发病机制及病理变化,而关于脑囊尾蚴病的分型及分期各文献报道却不一致,该文针对其病理改变及分型分期作一综述.     

MRI在诊断退变期脑实质型脑囊虫病同小转移瘤的鉴别价值

目的：通过常规MRI序列与DWI序列,鉴别退变期脑实质型脑囊虫病与小病灶环形强化转移瘤。方法回顾29例脑囊虫病患者与30例多发小病灶转移瘤患者的M R检查,观察两者的影像学表现及测量ADC值进行统计学处理。结果常规T2 WI退变期脑囊虫病组和小转移瘤组病灶出现低信号环的比例分别为91．9％和9．1％,诊断敏感性为90．7％（78/86）、特异性90．9％（60/66）、准确性90．8％（138/152）;DWI退变期脑囊虫病组和转移瘤组病灶出现低信号所占比例分别为95．4％和69．7％,诊断敏感性95．4％（82/86）、特异性30．3％（20/66）、准确性67．1％（102/152）。退变期脑囊虫组病灶ADC值（1．54±0．42）×10^-3 s/mm^2,脑转移瘤病灶组ADC值（1．12±0．36）×10^-3 s/mm^2,两者比较具有统计学差异（ P ＜0．01）。结论 T2 WI病灶周围连续的低信号和完整规则的环形强化是退变期脑囊虫病的特殊表现。DWI序列对退变期脑囊虫病和小病灶转移瘤的鉴别具有一定的价值。     

Prevalence of neurocysticercosis among people with epilepsy in rural areas of Burkina Faso

Purpose: To estimate the lifetime prevalence of neurocysticercosis (NCC)–associated epilepsy and the proportion of NCC among people with epilepsy in three Burkina Faso villages. Methods: Three villages were selected to represent three types of pig‐rearing methods: (1) Batondo, where pigs are left to roam; (2) Pabré, where pigs are mostly tethered or penned; and (3) Nyonyogo, where the majority of residents are Muslim and few pigs are raised. In Batondo and Nyonyogo, all concessions (a group of several households) were included. Half of the concessions in Pabré were randomly chosen. All households of selected concessions were included, and one person per household was randomly selected for epilepsy screening and serologic testing for cysticercosis. Self‐reported cases of epilepsy were also examined and confirmed cases included in analyses other than the estimate of NCC‐associated epilepsy prevalence. Epilepsy was defined as ever having had more than one episode of unprovoked seizures. Individuals with medically confirmed epilepsy had a computerized tomography (CT) scan of the brain before and after contrast medium injection. The diagnosis of NCC was made using a modification of the criteria of Del Brutto et al. Key Findings: Thirty‐nine (4%) of 888 randomly selected villagers and 33 (94%) of 35 self‐reported seizures cases were confirmed to have epilepsy by medical examination. Among the 68 participants with epilepsy who had a CT scan, 20 patients were diagnosed with definitive or probable NCC for a proportion of 46.9% (95% confidence interval [CI] 30.2–64.1) in Batondo and 45.5% (95% CI 19.0–74.1) in Pabré. No cases of NCC were identified in Nyonyogo. Significance: All the definitive and probable cases of NCC were from the two villages where pig breeding is common. Prevention policies intended to reduce the burden of epilepsy in this country should include measures designed to interrupt the life cycle of Taenia solium.     

Calcified neurocysticercosis lesions and hippocampal sclerosis: Potential dual pathology?

In areas where cysticercosis is endemic, calcified neurocysticercosis lesion(s) (CNL) and hippocampal sclerosis (HS) commonly coexist in patients with localization-related epilepsies. To understand the pathogenesis of HS associated with CNL, we compared the characteristics of three groups of patients with antiepileptic drug-resistant epilepsies: CNL with HS, CNL without HS (CNL alone), and HS without CNL (HS alone). In comparison to patients with CNL alone, those with CNL with HS had CNL more frequently located in the ipsilateral temporal lobe. Those with CNL with HS had a lower incidence of febrile seizures, older age at initial precipitating injury and at onset of habitual complex partial seizures, and more frequent clustering of seizures and extratemporal/bitemporal interictal epileptiform discharges as compared to patients with HS alone. Our study illustrates that HS associated with CNL might have a different pathophysiologic basis as compared to classical HS.     

Cysticercosis of the Fourth Ventricle Causing Sudden Death: A Case Report and Review of the Literature

A 15 years old girl of African origin was admitted with a history of headaches and a generalised tonic seizure. Her clinical examination including fundoscopy was normal. She claimed she had been assaulted. Within a few hours of her admission she was found dead in her bed during the ward round. Cardiopulmonary resuscitation was unsuccessful. At post-mortem, the major organs showed no pathological changes and neck dissection showed no abnormality. Neuropathological examination after formalin fixation revealed a cystic lesion in the fourth ventricle, ependymitis and acute hydrocephalus. Histology showed parts of the parasite Taenia solium and the diagnosis was neurocysticercosis. This case highlights the need for forensic and general pathologists as well as forensic medical examiners and paediatricians to be aware of neurocysticercosis as a possible cause of sudden death in the presence of normal clinical findings and negative autopsy, especially in patients from Asian, African or South American countries. As cysticercosis is the commonest cause of seizures in the developing world, neurocysticercosis needs to be considered as a cause of sudden and unexpected death in any patient with a history of headaches and/or seizures. Tibor Hortobágyi and Ali Alhakim are first authors who contributed equally to this work.     

Acute cysticercal meningitis—Missed diagnosis

Neurocysticercosis is the commonest CNS parasitic disease worldwide but cysticercal meningoencephalitis is relatively rare, especially in Indian patients. We herein report a girl with cysticercal meningitis that was initially not suspected and later diagnosed on the basis of cerebrospinal fluid (CSF) eosinophilia. The need for CSF examination with wright-giemsa staining to avoid missing CSF eosinophilia is discussed.     

Cerebral blood flow and sources of abnormal EEG activity (VARETA) in neurocysticercosis

OBJECTIVES: To compare two different functional procedures in the assessment of brain ischemia in patients with neurocysticercosis (NCC): (1) electroencephalography (EEG) evaluated by brain maps and EEG current sources in the frequency domain using variable resolution electromagnetic tomography and (2) blood flow analyzed by computerized tomography assessed with stable Xe (Xe-CT). METHODS: Eleven patients with NCC at different evolution stages were studied. CT and Xe-CT scans, as well as quantitative electroencephalography with source calculation in the frequency domain, were obtained. All patients showed cysts and in 6 of them there were also vascular complications: two of them presented calcifications of the middle cerebral artery, two other subjects showed calcifications of the vessels in the circle of Willis and the remaining two had brain infarctions. RESULTS: In the cyst areas important hypoperfused zones were observed, as intense as those observed in infarcted areas. Damage to the blood-brain barrier was originated by parasites in colloidal phase (final cysticerci stage) producing large areas of edema and hypoperfusion. Abnormal delta EEG activity was observed in very large lesions, probably generated by partial cortical deafferentation; and abnormal theta activity was mainly related to the presence of edema. CONCLUSIONS: Sources of abnormal EEG activity were very similar in topography to the hypoperfused areas.