Treatment of neurocysticercosis: current status and future research needs

Disruption of the blood-brain barrier in pigs naturally infected with Taenia solium, untreated and after anthelmintic treatment

Neurocysticercosis is a widely prevalent disease in the tropics that causes seizures and a variety into of neurological symptoms in most of the world. Experimental models are limited and do not allow assessment of the degree of inflammation around brain cysts. The vital dye Evans Blue (EB) was injected to 11 pigs naturally infected with Taenia solium cysts to visually identify the extent of disruption of the blood-brain barrier. A total of 369 cysts were recovered from the 11 brains and classified according to the staining of their capsules as blue or unstained. The proportion of cysts with blue capsules was significantly higher in brains from pigs that had received anthelmintic treatment 48 and 120h before the EB infusion, indicating a greater compromise of the blood-brain barrier due to treatment. The model could be useful for understanding the pathology of treatment-induced inflammation in neurocysticercosis.

A new parasiticidal compound in T. solium cysticercosis

The effect of 16α-bromoepiandrosterone (EpiBr), a dehydroepiandrosterone (DHEA) analogue, was tested on the cysticerci of Taenia solium, both in vitro and in vivo. In vitro treatment of T. solium cultures with EpiBr reduced scolex evagination, growth, motility, and viability in dose- and time-dependent fashions. Administration of EpiBr prior to infection with T. solium cysticerci in hamsters reduced the number and size of developed taenias in the intestine, compared with controls. These effects were associated to an increase in splenocyte proliferation in infected hamsters. These results leave open the possibility of assessing the potential of this hormonal analogue as a possible antiparasite drug, particularly in cysticercosis and taeniosis.

Increased accumulation of regulatory granulocytic myeloid cells in mannose receptor C type 1-deficient mice correlates with protection in a mouse model of neurocysticercosis

Neurocysticercosis (NCC) is a central nervous system (CNS) infection caused by the metacestode stage of the parasite Taenia solium. During NCC, the parasites release immunodominant glycan antigens in the CNS environment, invoking immune responses. The majority of the associated pathogenesis is attributed to the immune response against the parasites. Glycans from a number of pathogens, including helminths, act as pathogen-associated molecular pattern molecules (PAMPs), which are recognized by pattern recognition receptors (PRRs) known as C-type lectin receptors (CLRs). Using a mouse model of NCC by infection with the related parasite Mesocestoides corti, we have investigated the role of mannose receptor C type 1 (MRC1), a CLR which recognizes high-mannose-containing glycan antigens. Here we show that MRC1(-/-) mice exhibit increased survival times after infection compared with their wild-type (WT) counterparts. The decreased disease severity correlates with reduced levels of expression of markers implicated in NCC pathology, such as interleukin-1β (IL-1β), IL-6, CCL5, and matrix metalloproteinase 9 (MMP9), in addition to induction of an important repair marker, fibroblast growth factor 2 (FGF2). Furthermore, the immune cell subsets that infiltrate the brain of MRC1(-/-) mice are dramatically altered and characterized by reduced numbers of T cells and the accumulation of granulocytic cells with an immune phenotype resembling granulocytic myeloid-dependent suppressor cells (gMDSCs). The results suggest that MRC1 plays a critical role in myeloid plasticity, which in turn affects the adaptive immune response and immunopathogenesis during murine NCC.

Neurocysticercosis

Cysticercosis, an infection caused by the cystic larvae of the pork tapeworm Taenia solium, is one of the most frequent parasitic infections of the human nervous system (neurocysticercosis). It is endemic in most of Latin America, the sub-Saharan Africa, and vast parts of Asia, including the Indian subcontinent. It has also been increasingly diagnosed in developed countries because of migration of people from endemic zones and exposure in travelers. The life cycle involves the development of the adult tapeworm in the human small intestine (after ingesting infected pork with cysts) and larval infection in pig tissues (after ingesting human stools containing the eggs of the tapeworm). Humans get infected by the fecal-oral route, most often from a direct contact with an asymptomatic Taenia carrier. Most common clinical presentations are seizures (particularly late-onset seizures), chronic headaches, and intracranial hypertension. However, cysticerci can locate anywhere in the human nervous system, thus potentially causing almost any neurological syndrome and making clinical diagnosis a difficult task. Neuroimaging is the main diagnostic tool, and specific serology confirms the diagnosis and helps to define the diagnosis when images are unclear. Factors such as location (extraparenchymal versus intraparenchymal), number, size and evolutive stage of the parasites determine the clinical manifestations, therapeutic approach, and prognosis. Management includes symptomatic drugs (analgesics, antiepileptic drugs, anti-inflammatory agents) and in many cases cysticidal drugs, either albendazole or praziquantel. In recent years, efforts have focused on transmission control and potential elimination in endemic regions.

Tamoxifen treatment in hamsters induces protection during taeniosis by Taenia solium

Human neurocysticercosis by Taenia solium is considered an emergent severe brain disorder in developing and developed countries. Discovery of new antiparasitic drugs has been recently aimed to restrain differentiation and establishment of the T. solium adult tapeworm, for being considered a central node in the disease propagation to both pigs and humans. Tamoxifen is an antiestrogenic drug with cysticidal action on Taenia crassiceps, a close relative of T. solium. Thus, we evaluated the effect of tamoxifen on the in vitro evagination and the in vivo establishment of T. solium. In vitro, tamoxifen inhibited evagination of T. solium cysticerci in a dose-time dependent manner. In vivo, administration of tamoxifen to hamsters decreased the intestinal establishment of the parasite by 70%, while recovered tapeworms showed an 80% reduction in length, appearing as scolices without strobilar development. Since tamoxifen did not show any significant effect on the proliferation of antigen-specific immune cells, intestinal inflammation, and expression of Th1/Th2 cytokines in spleen and duodenum, this drug could exert its antiparasite actions by having direct detrimental effects upon the adult tapeworm. These results demonstrate that tamoxifen exhibits a strong cysticidal and antitaeniasic effect on T. solium that should be further explored in humans and livestock.

In vitro analysis of albendazole sulfoxide enantiomers shows that (+)-(R)-albendazole sulfoxide is the active enantiomer against Taenia solium

Albendazole is an anthelmintic drug widely used in the treatment of neurocysticercosis (NCC), an infection of the brain with Taenia solium cysts. However, drug levels of its active metabolite, albendazole sulfoxide (ABZSO), are erratic, likely resulting in decreased efficacy and suboptimal cure rates in NCC. Racemic albendazole sulfoxide is composed of ABZSO (+)-(R)- and (-)-(S) enantiomers that have been shown to differ in pharmacokinetics and activity against other helminths. The antiparasitic activities of racemic ABZSO and its (+)-(R)- and (-)-(S) enantiomers against T. solium cysts were evaluated in vitro. Parasites were collected from naturally infected pigs, cultured, and exposed to the racemic mixture or to each enantiomer (range, 10 to 500 ng/ml) or to praziquantel as a reference drug. The activity of each compound against cysts was assayed by measuring the ability to evaginate and inhibition of alkaline phosphatase (AP) and parasite antigen release. (+)-(R)-ABZSO was significantly more active than (-)-(S)-ABZSO in suppressing the release of AP and antigen into the supernatant in a dose- and time-dependent manner, indicating that most of the activity of ABZSO resides in the (+)-(R) enantiomer. Use of this enantiomer alone may lead to increased efficacy and/or less toxicity compared to albendazole.

Transient cortical blindness as a manifestation of solitary cysticercus granuloma

Neurocysticercosis is recognised as a significant cause of neurological morbidity in endemic regions. The wide range of pleomorphic and non-specific neurological manifestations of neurocysticercosis must be kept in mind by physicians, as the disease has shown resurgence in developed countries. When an atypical presentation of an unusual tropical disease occurs in non-endemic regions, the diagnosis is often missed. We describe a case of a 4-year-old girl who presented with a history of transient bilateral loss of vision with headache and vomiting. Brain MRI revealed the presence of a single cysticercus granuloma in the occipital lobe. A diagnosis of symptomatic occipital lobe seizure secondary to neurocysticercosis was made. She was given a course of albendazole. There was no recurrence of symptoms at 3 years follow-up. Occipital seizures that are associated with ictal amaurosis closely mimic basilar migraine. Such cases benefit from neuroimaging in order to rule out the underlying structural causes.

Extraparenchymal neurocysticercosis in the United States

Neurocysticercosis (NCC) is endemic in the developing world but is becoming more common in the United States because of immigration. Although NCC is pleomorphic in its presentation, extraparenchymal NCC may be challenging to diagnose and treat. Extraparenchymal NCC is probably more frequent than previously thought. Neurologists and neuroradiologists in the United States are often unaware of the pretreatment/post-treatment radiographic patterns of extraparenchymal NCC and the potentially poor prognosis if not correctly diagnosed and managed. The review of this condition is important given increasing incidence in the United States.

Cerebral coenurosis in a cat caused by Taenia serialis: neurological, magnetic resonance imaging and pathological features

CLINICAL SUMMARY: A 4-year-old Birman cat was presented with marked obtundation and non-ambulatory tetraparesis. Two well-demarcated, intra-axial T2-hyperintense, T1-hypointense structures, which did not contrast enhance, were evident on magnetic resonance imaging (MRI). Histopathology of the structures revealed metacestodes that were morphologically indicative of larval stages of Taenia species. Polymerase chain reaction amplification of a fragment within the 12S rRNA gene confirmed the subspecies as Taenia serialis. PRACTICAL SIGNIFICANCE: This is the first report of MRI findings of cerebral coenurosis caused by T serialis in a cat. Early MRI should be considered an important part of the diagnostic work-up for this rare clinical disease, as it will help guide subsequent treatment and may improve the prognosis.

Neurocysticercosis in sub-Saharan Africa: a review of prevalence, clinical characteristics, diagnosis, and management

Neurocysticercosis has been recognized as a major cause of secondary epilepsy worldwide. So far, most of the knowledge about the disease comes from Latin America and the Indian subcontinent. Unfortunately, in sub-Saharan Africa the condition was neglected for a long time, mainly owing to the lack of appropriate diagnostic tools. This review therefore focuses on the prevalence of neurocysticercosis in sub-Saharan Africa, the clinical picture with emphasis on epilepsy, as well as the diagnosis and treatment of neurocysticercosis and its related epilepsy/epileptic seizures in African resource-poor settings.

Cestode infestations: hydatid disease and cysticercosis

Although humans can be definitive hosts for cestodes (tapeworms), major pathologic conditions occur during cestode larval stages when humans serve as the intermediate host for these parasites. The most relevant forms of human disease caused by cestode larvae are echinococcosis, caused by Echinococcus granulosus (cystic echinococcosis) and Echinococcus multilocularis (alveolar echinococcosis), and cysticercosis, caused by Taenia solium. These infections occur worldwide, but their relevance is particularly high in developing countries, where poor hygiene conditions facilitate the transmission of the parasites. The therapeutic approach is often complex, requiring surgery and/or chemotherapy or, in the case of cystic echinococcosis, percutaneous treatments.

Neglected infections of poverty in Texas and the rest of the United States: management and treatment options

In the poorest regions of the United States, especially along the Gulf Coast and in South Texas, are a group of endemic parasitic and related infections known as the neglected infections of poverty. Such infections are characterized by their chronicity, disabling features, and disproportionate impact on the estimated 46 million people who live below the U.S. poverty line. Today more Americans live in poverty than ever before in the half-century that the Census Bureau has been recording poverty rates. In association with that poverty, a group of major neglected infections of poverty have emerged in the United States. Here we describe the major neglected infections of poverty in the United States, with a brief overview of their significant epidemiological features, their links with poverty, and our approaches to their diagnosis, management, and treatment.

Neurocysticercosis in pregnancy: not just another headache

Infection with pork tapeworm, or Taenia solium, affects approximately 50 million people worldwide. The most important and potentially devastating form of the infestation, neurocysticercosis, occurs when the parasite invades the central nervous system. There has been a significant increase in the number of cases in the United States due to immigration from endemic areas. This case study of a pregnant woman in the 35th week of gestation exemplifies the serious consequences of this infection in pregnancy, and discusses an evidence-based approach to the diagnosis, treatment and eradication of this preventable disease.

Corticosteroid use in neurocysticercosis

The cystic larvae of Taenia solium commonly infect the human nervous system, resulting in neurocysticercosis, a major contributor to seizure disorders in most of the world. Inflammation around the parasites is a hallmark of neurocysticercosis pathophysiology. Although mechanisms regulating this inflammation are poorly understood, anti-inflammatory drugs, particularly corticosteroids, have been long used alone or with anthelmintics to manage disease and limit neurological complications and perhaps damage to neural tissues. Only scarce controlled data exist to determine when and what type of corticosteroids and the treatment regime to use. This article revisits the mechanisms of action, rationale, evidence of benefit, safety and problems of corticosteroids in the context of neurocysticercosis, as well as alternative anti-inflammatory strategies to limit the damage caused by inflammation in the CNS.

Neurocysticercosis: a review

Neuroysticercosis is the most common helminthic infection of the nervous system, and a leading cause of acquired epilepsy worldwide. The disease occurs when humans become intermediate hosts of Taenia solium by ingesting its eggs from contaminated food or, most often, directly from a taenia carrier by the fecal-to-oral route. Cysticerci may be located in brain parenchyma, subarachnoid space, ventricular system, or spinal cord, causing pathological changes that are responsible for the pleomorphism of neurocysticercosis. Seizures are the most common clinical manifestation, but many patients present with focal deficits, intracranial hypertension, or cognitive decline. Accurate diagnosis of neurocysticercosis is possible after interpretation of clinical data together with findings of neuroimaging studies and results of immunological tests. The introduction of cysticidal drugs have changed the prognosis of most patients with neurocysticercosis. These drugs have shown to reduce the burden of infection in the brain and to improve the clinical course of the disease in most patients. Further efforts should be directed to eradicate the disease through the implementation of control programs against all the interrelated steps in the life cycle of T. solium, including human carriers of the adult tapeworm, infected pigs, and eggs in the environment.

Medical management of neurocysticercosis

INTRODUCTION

Neurocysticercosis (NCC) is considered to be the most common cause of acquired epilepsy worldwide. Formerly restricted to palliative measures, therapy for NCC has advanced with the advent of two drugs that are considered to be effective: praziquantel (PZQ) and albendazole (ALB).

AREAS COVERED

All available articles regarding research related to the treatment of NCC were searched. Relevant articles were then reviewed and used as sources of information for this review.

EXPERT OPINION

Anticysticercal therapy has been marked by intense controversy. Recent descriptions of spontaneous resolution of parenchymal cysticercosis with benign evolution, risks of complications and reports of no long-term benefits have reinforced the debate over the usefulness and safety of anticysticercal therapy. High interindividual variability and complex pharmacological interactions will require the close monitoring of plasma concentrations of ALB and PZQ metabolites in future trials. Given the relative scarcity of clinical trials, more comparative interventional studies - especially randomized controlled trials in long-term clinical evolution - are required to clarify the controversy over the validity of parasitic therapy in patients with NCC.

Progesterone induces mucosal immunity in a rodent model of human taeniosis by Taenia solium

More than one quarter of human world's population is exposed to intestinal helminth parasites. The Taenia solium tapeworm carrier is the main risk factor in the transmission of both human neurocysticercosis and porcine cysticercosis. Sex steroids play an important role during T. solium infection, particularly progesterone has been proposed as a key immunomodulatory hormone involved in susceptibility to human taeniosis in woman and cysticercosis in pregnant pigs. Thus, we evaluated the effect of progesterone administration upon the experimental taeniosis in golden hamsters (Mesocricetus auratus). Intact female adult hamsters were randomly divided into 3 groups: progesterone-subcutaneously treated; olive oil-treated as the vehicle group; and untreated controls. Animals were treated every other day during 4 weeks. After 2 weeks of treatment, all hamsters were orally infected with 4 viable T. solium cysticerci. After 2 weeks post infection, progesterone-treated hamsters showed reduction in adult worm recovery by 80%, compared to both vehicle-treated and non-manipulated infected animals. In contrast to control and vehicle groups, progesterone treatment diminished tapeworm length by 75% and increased proliferation rate of leukocytes from spleen and mesenteric lymph nodes of infected hamsters by 5-fold. The latter exhibited high expression levels of IL-4, IL-6 and TNF-α at the duodenal mucosa, accompanied with polymorphonuclear leukocytes infiltration. These results support that progesterone protects hamsters from the T. solium adult tapeworm establishment by improving the intestinal mucosal immunity, suggesting a potential use of analogues of this hormone as novel inductors of the gut immune response against intestinal helminth infections and probably other bowel-related disorders.

Short report: A calcified Taenia solium granuloma associated with recurrent perilesional edema causing refractory seizures: histopathological features

We describe the first detailed histological description of an excised calcified Taenia solium granuloma from a patient who developed recurrent seizures associated with perilesional edema surrounding a calcified cysticercus (PEC). The capsule, around a degenerated cysticercus, contained marked mononuclear infiltrates that extended to adjacent brain, which showed marked astrocytosis, microgliosis, and inflammatory perivascular infiltrates. The presence of large numbers of mononuclear cells supports an inflammatory cause of PEC. Immunosuppression or anti-inflammatory measures may be able to treat and prevent PEC and recurrent seizures.

Cysticercosis of the central nervous system: how should it be managed?

PURPOSE OF REVIEW

Taenia solium neurocysticercosis (NCC) has been long recognized as an important cause of neurological morbidity in most of the world. Unwarranted generalization of diagnostic and treatment recommendations made it difficult to assess individual prognosis and responses for each type of NCC. Understanding of the main clinical presentations (dependent on number, location, size, and stage of parasites, as well as on the immune response of the host) allows a better view of treatment options and expected outcomes.

RECENT FINDINGS

Current treatment options are still limited and involve symptomatic agents, antiparasitic agents, or surgery. The importance of adequate symptomatic management, the potential for improved antiparasitic treatment regimes, in particular combination therapy, and the increasingly important role of minimally invasive neurosurgery are also reviewed in this article.

SUMMARY

Treatment decisions in NCC should be individualized in relation to the type of NCC. Initial measures should focus on the symptomatic management before considering antiparasitic therapy when appropriate. Appropriate patient categorization, new antiparasitic regimes, and minimally invasive surgery are improving the prognosis of patients with NCC.

Diagnosis and treatment of neurocysticercosis

Neurocysticercosis is a parasitic disease caused by the larval (cystic) form of the pork cestode tapeworm, Taenia solium, and is a major cause of acquired seizures and epilepsy worldwide. Development of sensitive and specific diagnostic methods, particularly CT and MRI, has revolutionized our knowledge of the burden of cysticercosis infection and disease, and has led to the development of effective antihelminthic treatments for neurocysticercosis. The importance of calcified granulomas with perilesional edema as foci of seizures and epilepsy in populations where neurocysticercosis is endemic is newly recognized, and indicates that treatment with anti-inflammatory agents could have a role in controlling or preventing epilepsy in these patients. Importantly, neurocysticercosis is one of the few diseases that could potentially be controlled or eliminated-an accomplishment that would prevent millions of cases of epilepsy. This Review examines the rationale for treatment of neurocysticercosis and highlights the essential role of inflammation in the pathogenesis of disease, the exacerbation of symptoms that occurs as a result of antihelminthic treatment, and the limitations of current antihelminthic and anti-inflammatory treatments.

Extraparenchymal neurocysticercosis in Albuquerque, New Mexico

BACKGROUND

neurocysticercosis (NCC) prevalence is increasing throughout the United States mainly because of immigration from Latin America. Clinicians may fail to recognize the extraparenchymal disease because they do not consider the diagnosis.

METHODS

to analyze neuroimaging and clinical characteristics of extraparenchymal NCC, we retrospectively reviewed all such cases presenting to a major general medical school hospital in the State of New Mexico.

RESULTS

eleven (30%) of our 37 cases of NCC diagnosed using standard criteria from 1998 through 2004 had extraparenchymal disease. On neuroimaging, 36% of the patients lacked parenchymal cysts, 64% had intraventricular cysticerci, 64% had subarachnoid cysticerci, and 64% had hydrocephalus due to either basal arachnoiditis or direct obstruction of intraventricular pathways. Lumbar puncture was performed in 6 patients. All had a cerebrospinal fluid (CSF) pleocytosis, none had CSF or blood eosinophilia, and CSF antibody to NCC could be absent while present in serum. Response to treatment was frequently suboptimal.

CONCLUSIONS

extraparenchymal NCC is more frequent than previously thought. Because clinicians outside the Southwest United States are often unfamiliar with NCC as a cause of chronic meningitis, chronic ventriculitis, or hydrocephalus without obvious cysts, the diagnosis of extraparenchymal NCC often depends on the correct interpretation of neuroimaging.

Short-course of prednisolone in solitary cysticercus granuloma: a randomized, double-blind, placebo-controlled trial

PURPOSE

To determine the effect of administration of a short course of prednisolone on seizure and radiologic outcome in patients with solitary cysticercus granuloma (SCG).

METHODS

One hundred forty-eight subjects presenting with new-onset seizures (<15 days duration) and with SCG demonstrated on imaging studies were randomly allocated to either treatment with prednisolone (40-60 mg/day for 2 weeks) or placebo in addition to standard antiepileptic drug therapy. The subjects were followed up for seizure recurrence for 9 months. Repeat computed tomography (CT, at 3 months) and magnetic resonance imaging (MRI, at 6 months) to evaluate resolution and calcification of the lesion.

KEY FINDINGS

There was no difference in the proportion of subjects with seizure recurrence during the follow-up period in the treatment (n = 16, 21.9%) and control (n = 19, 25.33%) groups (p = 0.7). However, generalized seizures occurred in a significantly lesser proportion of subjects in the treatment group (n = 3, 15.79%) in comparison to the control group (n = 12, 60.00%) (p = 0.015). There were no significant differences in the proportion of subjects with complete resolution of the SCG on repeat CT at 3 months [treatment group (27, 46.7%) and control group (23, 39.8%); p = 0.453] and repeat MRI at 6 months [treatment group (28, 46.7%) and control group (21, 38.9%); p = 0.402].

SIGNIFICANCE

The administration of a short course of prednisolone does not offer significant improvement in seizure control, although a benefit in terms of reducing the likelihood of generalized seizures is possible. Furthermore, it does not improve the chances of resolution of the SCG on follow-up imaging studies.

Albendazole-praziquantel interaction in healthy volunteers: kinetic disposition, metabolism and enantioselectivity

AIM

This study investigated the kinetic disposition, metabolism and enantioselectivity of albendazole (ABZ) and praziquantel (PZQ) administered alone and in combination to healthy volunteers.

METHODS

A randomized crossover study was carried out in three phases (n= 9), in which some volunteers started in phase 1 (400 mg ABZ), others in phase 2 (1500 mg PZQ), and the remaining volunteers in phase 3 (400 mg ABZ + 1500 mg PZQ). Serial blood samples were collected from 0-48 h after drug administration. Pharmacokinetic parameters were calculated using a monocompartmental model with lag time and were analyzed using the Wilcoxon test; P ≤ 0.05.

RESULTS

The administration of PZQ increased the plasma concentrations of (+)-ASOX (albendazole sulphoxide) by 264% (AUC 0.99 vs. 2.59 µg ml(-1) h), (-)-ASOX by 358% (0.14 vs. 0.50 µg ml(-1) h) and albendazole sulfone (ASON) by 187% (0.17 vs. 0.32 µg ml(-1) h). The administration of ABZ did not change the kinetic disposition of (+)-(S)-PZQ (-)-(R)-4-OHPZQ or (+)-(S)-4-OHPZQ, but increased the plasma concentration of (-)-(R)-PZQ by 64.77% (AUC 0.52 vs. 0.86 µg ml(-1) h).

CONCLUSIONS

The pharmacokinetic interaction between ABZ and PZQ in healthy volunteers was demonstrated by the observation of increased plasma concentrations of ASON, both ASOX enantiomers and (-)-(R)-PZQ. Clinically, the combination of ABZ and PZQ may improve the therapeutic efficacy as a consequence of higher concentration of both active drugs. On the other hand, the magnitude of this elevation may represent an increased risk of side effects, requiring, certainly, reduction of the dosage. However, further studies are necessary to evaluate the efficacy and safety of this combination.

A cross-sectional study of people with epilepsy and neurocysticercosis in Tanzania: clinical characteristics and diagnostic approaches

Neurocysticercosis (NCC) is a major cause of epilepsy in regions where pigs are free-ranging and hygiene is poor. Pork production is expected to increase in the next decade in sub-Saharan Africa, hence NCC will likely become more prevalent. In this study, people with epilepsy (PWE, n = 212) were followed up 28.6 months after diagnosis of epilepsy. CT scans were performed, and serum and cerebrospinal fluid (CSF) of selected PWE were analysed. We compared the demographic data, clinical characteristics, and associated risk factors of PWE with and without NCC. PWE with NCC (n = 35) were more likely to be older at first seizure (24.3 vs. 16.3 years, p = 0.097), consumed more pork (97.1% vs. 73.6%, p = 0.001), and were more often a member of the Iraqw tribe (94.3% vs. 67.8%, p = 0.005) than PWE without NCC (n = 177). PWE and NCC who were compliant with anti-epileptic medications had a significantly higher reduction of seizures (98.6% vs. 89.2%, p = 0.046). Other characteristics such as gender, seizure frequency, compliance, past medical history, close contact with pigs, use of latrines and family history of seizures did not differ significantly between the two groups. The number of NCC lesions and active NCC lesions were significantly associated with a positive antibody result. The electroimmunotransfer blot, developed by the Centers for Disease Control and Prevention, was more sensitive than a commercial western blot, especially in PWE and cerebral calcifications. This is the first study to systematically compare the clinical characteristics of PWE due to NCC or other causes and to explore the utility of two different antibody tests for diagnosis of NCC in sub-Saharan Africa.

Neurocysticercosis, a preventable and treatable disease, is one of the main causes of epilepsy in low income countries. In these countries, the diagnosis of epilepsy is often based on clinical presentation and interviews as neuroimaging is rarely available. It is crucial to distinguish people with epilepsy due to neurocysticercosis from other people with epilepsy by clinical symptoms and/or serology, because the former warrants a specific approach both in terms of diagnosis and treatment. The authors compared the demographic and clinical data of the two groups and found that people with epilepsy due to neurocysticercosis are older, more likely to consume pork, and respond better to anti-epileptic treatment. Additionally, the authors compared two antibody tests for cysticercosis with computed tomography images, which showed a higher sensitivity of the CDC electroimmunotransfer blot compared to a commercial western blot. The number of neurocysticercosis lesions was significantly associated with a positive antibody result in both tests. In summary, this research describes clinical characteristics of people with epilepsy and neurocysticercosis and assesses the usefulness of two immunoblots in those patients. This has implications not only for the diagnosis of neurocysticercosis in low income countries, but also for future epidemiological research.

Hemorrhagic cerebrovascular events and neurocysticercosis: a case report and review of the literature

Cerebrovascular complications have been reported to occur in patients with neurocysticercosis (NCC). We report a patient who presented with relapsed subarachnoid hemorrhage possibly linked to NCC. In addition, we performed a literature review of all of the reported cases of aneurysmal and non-aneurysmal hemorrhagic cerebrovascular events associated with NCC. We identified 11 such cases. The majority of the individuals were young males (mean: 38 years; 70% males). Four cases (36%) had aneurysms. Four (36%) others had negative cerebral angiograms and therefore classified as non-aneurysmal, while the remaining three (28%) did not report sufficient information to classify them. All cases with aneurysmal hemorrhage underwent successful surgical repair of the aneurysms. Seven patients received albendazole (including three who had had surgery). Three patients died; all three presented in the pre-albendazole era. In summary, neurocysticercosis should be considered in the differential diagnosis of hemorrhagic cerebrovascular events in young patients without classical vascular risk factors who have lived or visited NCC-endemic areas.

Neurocysticercosis

Neurocysticercosis (NCC) is the most common cause of acquired epilepsy in developing countries. It can present variably depending on the location and stage of cysts in the nervous system, and the host immune response. The most common presentation of parenchymal NCC is with seizures that are usually focal and brief; status epilepticus occurs in some cases. About a third of cases have headache and vomiting. Diagnosis is made by either CT or MRI. Single, small, contrast enhancing lesions are the most common; visualization of a scolex is diagnostic. Some cases have multiple cysts with a characteristic starry-sky appearance. Although treatment with cysticidal therapy continues to be debated, there is increasing evidence that it helps through increased and faster resolution of CT lesions; whether there is any improvement in long-term seizure control needs further study. It should not be used in cysticercus encephalitis or in ophthalmic NCC and used with caution in extraparenchymal NCC. It is of no use in calcified lesions. Corticosteroids are used simultaneously to reduce cerebral oedema. Seizures respond well to a single antiepileptic, and the seizure recurrence rate is low in cases with single lesions; those with multiple, persistent or calcified lesions usually have recurrent seizures. Extraparenchymal NCC is often associated with intracranial hypertension, hydrocephalous and chronic meningitis; it has a guarded prognosis; surgical intervention is required in many cases. Management of NCC needs to be individualized. NCC is potentially eradicable; proper sanitation, hygiene and animal husbandry are warranted.

Neurocysticercosis in Houston, Texas: an update

Neurocysticercosis, one of the most common parasitic infections of the human nervous system, has emerged as an important infection in the United States. Neurocysticercosis causes significant morbidity associated with acute seizures, chronic epilepsy, and hydrocephalus.We retrospectively identified patients with definitive or probable neurocysticercosis seen at Ben Taub General Hospital, the largest public teaching hospital in Houston, Texas, from September 1997 through December 2005. We collected demographic, clinical, therapeutic, and outcome variables. Neurocysticercosis was classified according to the location of cysts in imaging studies. We compared cases with parenchymal and extraparenchymal disease.We included 111 patients (48 had definitive and 63 probable neurocysticercosis). The mean age was 28.6 years (standard deviation, 13.6 yr), and the male to female ratio was 2:1. Most patients (93%) were Hispanic immigrants. Sixty (54%) patients had parenchymal disease, 22 (20%) intraventricular, 13 (12%) subarachnoid disease, and 13 (12%) had calcifications only. Additionally, 2 patients had hydrocephalus only, and 1 had ocular cysticercosis. Thirteen (40%) of 32 patients with parenchymal disease and 3 (30%) of 10 patients with calcifications had relapsed seizures at follow-up. Extraparenchymal disease was associated with longer duration of hospitalization compared with parenchymal disease. No deaths were identified in our series during a median follow-up of 1 year.Neurocysticercosis has emerged as an important parasitic infection in developed countries as a result of increased migration. With current management, mortality is limited, but there continues to be significant morbidity. Further studies of the epidemiology and pathophysiology of the infection are urgently needed to develop better preventive and therapeutic strategies.

Seizure in people with newly diagnosed active or transitional neurocysticercosis

PURPOSE

The aim of this study is to describe seizure as a presenting symptom in individuals with recently diagnosed neurocysticercosis (NCC).

METHODS

Using logistic regression, we examined the probability of having seizures as a presenting symptom among those with active or transitional NCC by host age and gender, and by number of cysts, location of the cysts in the brain, and phase of evolution of the encysted parasite.

RESULTS

We found that the odds of having seizures as presenting symptom for those in the youngest age group (3-24 years old) were 12.9 times that of the oldest participants (age 55-82 years) (p=0.006). People with cysts in parenchymal locations had a significantly higher odds of seizures compared to those with all their cysts elsewhere (ventricles or subarachnoid) (OR=6.2, p=0.028); and the number of cysts was significantly associated with having seizures (OR=1.1, p=0.026). Host gender and cyst phase were not significantly associated with having seizures after adjusting for confounders and covariates.

CONCLUSION

Children, those with cysts in parenchymal locations, and those with a higher number of cysts appear to be more likely to experience seizure when they have NCC cysts in the active or transitional stage.

STAT6⁻/⁻ mice exhibit decreased cells with alternatively activated macrophage phenotypes and enhanced disease severity in murine neurocysticercosis

In this study, using a murine model for neurocysticercosis, macrophage phenotypes and their functions were examined. Mesocestoides corti infection in the central nervous system (CNS) induced expression of markers associated with alternatively activated macrophages (AAMs) and a scarcity of iNOS, a classically activated macrophage marker. The infection in STAT6(-/-) mice resulted in significantly reduced accumulation of AAMs as well as enhanced susceptibility to infection coinciding with increased parasite burden and greater neuropathology. These results demonstrate that macrophages in the helminth infected CNS are largely of AAM phenotypes, particularly as the infection progresses, and that STAT6 dependent responses, possibly involving AAMs, are essential for controlling neurocysticercosis.

Sensitive in vitro system to assess morphological and biochemical effects of praziquantel and albendazole on Taenia solium cysts

Neurocysticercosis resulting from Taenia solium infections is a major cause of adult-acquired seizures worldwide. Disease is caused by larval cysts, and treatment consists of the anthelmintic drugs albendazole or praziquantel. There are no standard methods to assess drug activity to T. solium cysts in vitro. Morphological, functional, and biochemical changes that might reflect damaging (inhibiting, cytotoxic) drug effects were analyzed after exposure of cysts to albendazole sulfoxide (ABZ-SO), the major active metabolite of the drug in vivo, praziquantel (PZQ), or combinations of both. PZQ exposure led to a decrease in cyst size and inhibition of evagination, whereas ABZ-SO exposure resulted in minimal changes. Alkaline phosphatase (AP) is normally secreted by cysts, and both drugs inhibited AP secretion at concentrations of 5 and 50 ng/ml for PZQ and ABZ-SO, respectively. Some combinations of both drugs resulted in additive and/or synergistic activities. Parasite-specific antigen, detected in the cerebrospinal fluid and blood of infected patients, is also normally secreted by T. solium cysts. Antigen secretion was similarly inhibited by ABZ-SO and PZQ and a combination of both drugs, suggesting that inhibition of secretion is a common downstream consequence of the activities of both drugs. These studies establish quantitative methods to measure in vitro anthelmintic activity and suggest combination therapy with ABZ-SO and PZQ may have clinical benefit.

Helminth infections of the central nervous system occurring in Southeast Asia and the Far East

Although helminth infections of the central nervous system (CNS) are rare, their public health implications must not be neglected. Indeed, several helminth species can cause cerebrospinal infections, especially if humans serve as intermediate or non-permissive host. The diagnosis of cerebrospinal helminthiases is difficult, and the detection of parasites in cerebrospinal fluid is rarely successful. Cerebrospinal helminth infections therefore often remain undetected, and hence prognosis is poor. Increases in tourism and population movements are risk factors for cerebrospinal helminthiases and infections pose particular challenges to clinicians in non-endemic areas. In this review, we focus primarily on food-borne helminthiases that are endemic and often emerging in Southeast Asia and the Far East, namely angiostrongyliasis, gnathostomiasis, sparganosis, paragonimiasis and cysticercosis. Additionally, we discuss neuroschistosomiasis, a disease that is transmitted through human-water contact. For each disease, we describe the pathogen, its transmission route and possible mechanisms for entering the CNS. We also summarise common signs and symptoms, challenges and opportunities for diagnosis, treatment, clinical management, geographical distribution and epidemiology. The adoption of a comprehensive set of diagnostic criteria for different cerebrospinal helminthiases is proposed, including epidemiological history, typical signs and symptoms, neuroimaging and laboratory findings. Finally, risk factors, and research needs for enhanced patient management and population-based control measures are discussed.

Mechanisms regulating monocyte CXCL8 secretion in neurocysticercosis and the effect of antiparasitic therapy

Neurocysticercosis (NCC) due to infection with Taenia solium is a major cause of epilepsy worldwide. Larval degeneration, which may follow antiparasitic treatment, results in clinical symptoms due to inflammatory cell influx. Mechanisms regulating this are not well understood, but chemokines have a key role. Stimulation of human monocytes by cyst Ags from NCC-infected pigs showed that scolex and membrane Ags drive CXCL8 and CCL2 secretion. Antiparasitic treatment of pigs increased CXCL8 in response to brain, but not muscle, cyst Ags. Cyst-fluid Ags did not elicit monocyte chemokine secretion, inhibited LPS-induced CXCL8 by up to 89%, but did not alter CCL2 secretion. This effect was inhibited by anti-IL-10 Abs. Plasma CXCL8, TNF-α, IL-10, eotaxin, IL-1, IL-1ra, soluble IL-1R-II, and soluble TNFR-I and -II levels were evaluated in 167 NCC patients. Patients had lower plasma CXCL8 and TNF-α concentrations than control subjects. In summary, larval Ags from brain and muscle cysts differentially regulate chemokine secretion. Cyst-fluid inhibits CXCL8, and this is blocked by anti-IL-10 Abs. CXCL8 concentrations are decreased in patient plasma. Following anti-parasitic therapy, scolex and membrane Ags are exposed, and cyst fluid is decreased, leading to inflammatory cell influx. Taken together, the cellular, porcine, and human data may explain, in part, why NCC is usually asymptomatic but may cause proinflammatory symptoms, particularly following treatment.

Epileptiform seizures revealing neurocysticercosis: report of two clinical cases in Libreville, Gabon

Neurocysticercosis (NCC) is the most common helminth infection of the central nervous system. It is caused by the larval form of the tapeworm Taenia solium and is increasingly recognized as a major cause of neurologic disease worldwide. Epilepsy is the usual mode of revelation. Neuroimaging, including computed tomography and magnetic resonance imaging, combined with serodiagnostic techniques have led to this increased recognition. We report on two cases (one co-infected with the HIV) of NCC diagnosed in 2006 and 2008 at the Omar Bongo Ondimba Army Teaching Hospital. New-onset epilepsy revealed the two cases. Medical treatment with albendazole, anti-epileptic drugs and corticosteroids led to full recovery. NCC should be considered in tropical countries as a leading cause of epilepsy. Moreover, NCC should be included in the differential diagnosis of neurologic infections in HIV patients in endemic populations.

Epilepsy and neurocysticercosis in sub-Saharan Africa

Over the last decades, studies in sub-Saharan Africa have indicated that epilepsy is a highly prevalent neurological disorder. Causes may be varied with infections of the central nervous system playing an important role. Neurocysticercosis (NCC) has recently been recognised as an emerging public health problem and a growing concern throughout sub-Saharan Africa and has been estimated to be responsible for 30-50% of acquired epilepsy. NCC is closely linked with porcine cysticercosis and human taeniosis, the former reaching a prevalence of almost 50% in some pig populations. In this review, we first summarize prevalence data on epilepsy and highlight some special aspects of the disorder within sub-Saharan Africa. We then focus on the prevalence of NCC, clinical signs and symptoms and diagnostic criteria for NCC with special reference to sub-Saharan Africa. This is followed by a section on the latest developments regarding serodiagnosis of cysticercosis and a section on care management of people infected with NCC. NCC clearly represents a major risk factor of epilepsy, thus detecting and treating NCC may help cure epilepsy in millions of people in sub-Saharan Africa.

Mesocestoides corti intracranial infection as a murine model for neurocysticercosis

Neurocysticercosis (NCC) is the most common parasitic disease of the central nervous system (CNS) caused by the larval form of the tapeworm Taenia solium. NCC has a long asymptomatic period with little or no inflammation, and the sequential progression to symptomatic NCC depends upon the intense inflammation associated with degeneration of larvae. The mechanisms involved in these progressive events are difficult to study in human patients. Thus it was necessary to develop an experimental model that replicated NCC. In this review, we describe studies of a murine model of NCC in terms of the release/secretion of parasite antigens, immune responses elicited within the CNS environment and subsequent pathogenesis. In particular, the kinetics of leukocyte subsets infiltrating into the brain are discussed in the context of disruption of the CNS barriers at distinct anatomical sites and the mechanisms contributing to these processes. In addition, production of various inflammatory mediators and the mechanisms involved in their induction by the Toll-like receptor signaling pathway are described. Overall, the knowledge gained from the mouse model of NCC has provided new insights for understanding the kinetics of events contributing to different stages of NCC and should aid in the formulation of more effective therapeutic approaches.

Do helminths cause epilepsy?

Both helminthiases and epilepsy occur globally, and are particularly prevalent in developing regions of the world. Studies have suggested an association between epilepsy and helminth infection, but a causal relationship is not established in many helminths, except perhaps with neurocysticercosis. We review the available literature on the global burden of helminths, and the epidemiological evidence linking helminths to epilepsy. We discuss possible routes that helminths affect the central nervous system (CNS) of humans and the immunological response to helminth infection in the CNS, looking at possible mechanisms of epileptogenesis. Finally, we discuss the current gaps in knowledge about the interaction between helminths and epilepsy.

Progesterone induces scolex evagination of the human parasite Taenia solium: evolutionary implications to the host-parasite relationship

Taenia solium cysticercosis is a health problem in underdeveloped and developed countries. Sex hormones are involved in cysticercosis prevalence in female and male pigs. Here, we evaluated the effects of progesterone and its antagonist RU486 on scolex evagination, which is the initial step in the development of the adult worm. Interestingly, progesterone increased T. solium scolex evagination and worm growth, in a concentration-independent pattern. Progesterone effects could be mediated by a novel T. solium progesterone receptor (TsPR), since RU486 inhibits both scolex evagination and worm development induced by progesterone. Using RT-PCR and western blot, sequences related to progesterone receptor were detected in the parasite. A phylogenetic analysis reveals that TsPR is highly related to fish and amphibian progesterone receptors, whereas it has a distant relation with birds and mammals. Conclusively, progesterone directly acts upon T. solium cysticerci, possibly through its binding to a progesterone receptor synthesized by the parasite.

Intraventricular and subarachnoid basal cisterns neurocysticercosis: a comparative study between traditional treatment versus neuroendoscopic surgery

OBJECTIVE

The purpose of this study was to evaluate the efficacy of traditional treatment and minimal invasive flexible endoscopy surgery (MIFNES) in the treatment of intraventricular and subarachnoid basal cisterns neurocysticercosis (NCC).

METHODS

This was an observational comparative study of two independent series with a total of 140 patients with extremely severe forms of NCC from two different institutions. All 83 patients submitted for traditional treatment series received albendazole, and some of them received additionally praziquantel. Each cycle of both regimens lasted 4 weeks. The majority of these patients had at least one ventriculoperitoneal (VP) shunt. The rest 57 patients were submitted to the MIFNES treatment. The follow-up period was at least 6 months.

RESULTS

In all patients of both series cysticercal cysts disappeared, became calcified, or were removed. Symptoms of 136 patients improved. Four patients died. The average in the quality of life measured using the Karnofsky scale improved from a mean of 52.22 and 52.44 at the beginning to 85.48 and 90.37 at 6 months (p < 0.003), in the traditional treatment and MIFNES series, respectively. From traditional treatment, almost all patients remained with at least one VP shunt, and from the MIFNES series only 12 patients.

CONCLUSIONS

The authors postulate that MIFNES is a good alternative for the management of intraventricular and subarachnoid basal cisterns NCC because it allows removal of most of the parasites, rapid recovery of the patients, and removal and placement of shunt under direct vision when necessary. Traditional treatment is a second option where the MIFNES procedure is not available.

MyD88-deficient mice exhibit decreased parasite-induced immune responses but reduced disease severity in a murine model of neurocysticercosis

The symptomatic phase of neurocysticercosis (NCC), a parasitic disease of the central nervous system (CNS) in humans, is characterized by inflammatory responses leading to neuropathology and, in some cases, death. In an animal model of NCC in which mice were intracranially inoculated with the parasite Mesocestoides corti, the infection in mice lacking the myeloid differentiation primary response gene 88 (MyD88(-/-)) resulted in decreased disease severity and improved survival compared with that in wild-type (WT) mice. The CNS of MyD88(-/-) mice was more quiescent, with decreased microgliosis and tissue damage. These mice exhibited substantially reduced primary and secondary microglial nodule formations and lacked severe astrogliotic reactions, which were seen in WT mice. Significantly reduced numbers of CD11b(+) myeloid cells, alphabeta T cells, gammadelta T cells, and B cells were present in the brains of MyD88(-/-) mice in comparison with those of WT mice. This decrease in cellular infiltration correlated with a decrease in blood-brain barrier permeability, as measured by reduced fibrinogen extravasation. Comparisons of cytokine expression indicated a significant decrease in the CNS levels of several inflammatory mediators, such as tumor necrosis factor alpha, gamma interferon, CCL2, and interleukin-6, during the course of infection in MyD88(-/-) mice. Collectively, these findings suggest that MyD88 plays a prominent role in the development of the hyperinflammatory response, which in turn contributes to neuropathology and disease severity in NCC.

Diagnosis and treatment of neurocysticercosis

Neurocysticercosis, the infection caused by the larval form of the tapeworm Taenia solium, is the most common parasitic disease of the central nervous system and the most common cause of acquired epilepsy worldwide. This has primarily been a disease that remains endemic in low-socioeconomic countries, but because of increased migration neurocysticercosis is being diagnosed more frequently in high-income countries. During the past three decades improved diagnostics, imaging, and treatment have led to more accurate diagnosis and improved prognosis for patients. This article reviews the current literature on neurocysticercosis, including newer diagnostics and treatment developments.