Assessing the burden and spatial distribution of Taenia solium human neurocysticercosis in Ecuador (2013-2017)

Background

Estimating the burden of neglected tropical diseases is a valuable tool to support policymakers in the resource allocation for control and elimination of these diseases. Spatial analysis allows to identify the geographical distribution patterns of infectious and parasitic diseases within a country and allows to assess their possible correlation with other health disorders. Despite being neurocysticercosis (NCC) considered as the most important parasitic disease of the nervous system, few efforts have been addressed to assess the real burden of NCC in endemic countries, to date, there are no studies estimating the burden of NCC in South America. In this study we aimed to use the Disability Adjust Life Years (DALY) and spatial indicators as tools to measure the impact of human neurocysticercosis in Ecuador between 2013 and 2017.

Methods

Mortality, morbidity and spatial data from the national agency of statistics were used to estimate the burden of disease of NCC during a five-year period (2013–2017). NCC cases and its two main sequelae, epilepsy and migraine headache, were stratified by sex and age group to calculate the DALY associated to NCC using the DALY package in R. SATSCAN software was used to assess spatial clusters of NCC and its possible neurological sequelae as epilepsy, status epilepticus, migraine and hydrocephalus.

Principal findings

The burden of human neurocysticercosis ranged from 56201 [95% CI 29961–89333] to 59612 [95% CI 31854–94689] DALY per year, corresponding to 3.54 to 3.56 DALY per 1000 population. Average yearly incidence rates per 10 000 person-years were 0.23 [95% CI 0.21–0.26] for NCC, 4.89 [95% CI 4.78–5.00] for epilepsy, 0.130 [95% CI 0.11–0.15] for status epilepticus, 0.62 [95% CI 0.58–0.66] for migraine headache, and 1.02 [95% CI 0.98–1.07] for hydrocephalus. Most important significant spatial clusters (p<0.0001) were located in the southern region of the highlands of the country.

Conclusion/Significance

This is the first study in South America to calculate estimates for burden of NCC and one of the few using spatial analysis to show the importance of sequelae other than epilepsy that play an important role in the impact of human neurocysticercosis.

Taenia solium-neurocysticercosis (NCC) is a neglected parasite infection in humans causing a variety of neurological sequelae like epilepsy, and chronic headache. The purpose of this study was to estimate the burden of NCC in Ecuador using official nation-wide databases from the National Institute of Statistics and Census (INEC) for the period of 2013–2017, and to assess for spatial clusters of four neurological disorders associated with NCC. The burden of NCC measured in Disability Adjusted Life Years (DALY) was estimated in 3.54 to 3.56 DALY per 1000 population. Several significant spatial clusters for augmented risk of disease were identified along the country for NCC and its sequelae, most of which converged in the southern Sierra provinces. Our study suggests a possible spatial correlation between the presence of NCC cases and a higher prevalence of neurological conditions like epilepsy, status epilepticus, migraine, and hydrocephalus in several ‘hot spots’ of the southern provinces of Ecuador, indicating possible areas where the application of preventive measures is necessary to reduce cysticercosis transmission rates.

Historical perspective: The British contribution to the understanding of neurocysticercosis

Neurocysticercosis, or brain infestation with the larval stage of Taenia solium, is the most common risk factor for epilepsy in many endemic regions of the world. Hardly any cases are seen in Western developed countries, including Britain. However, a sizeable number (n = 450) was seen among British soldiers returning from deputation to India, then a British colony, first reported by Col. MacArthur at the Queen Alexandria Military Hospital in 1931. Here, we review the influence of the perceptive observations of British Army medics on the understanding of the parasitic disorder. The majority of these people presented with epilepsy. Among the contributions of the army medics were establishing the diagnosis, initially by histological examination of subcutaneous and muscular infestation, and later by radiography, clarifying the prognosis and the role of medical and surgical treatments and uncovering the close relationship between the larval (cysticercosis) and adult (intestinal tapeworm) stages of T. solium.

Headaches More Common among Epilepsy Sufferers with Neurocysticercosis than Other Structural Brain Lesions

Neurocysticercosis is a leading cause of seizures and epilepsy in the developing world. Cysticercosis is endemic in many regions of Central and South America, sub-Saharan Africa, India, and Asia. Neurocysticercosis is of emerging importance because globalization has increased travel between Hawai'i and disease-endemic areas. Headache and epilepsy are two of the most common complications of neurocysticercosis infection. Currently, it is not known if epilepsy patients with neurocysticercosis are more likely to have headaches than those with other structural brain lesions or those with no structural brain abnormalities. This study was designed to investigate whether epilepsy patients with neurocysticercosis report co-morbid headaches more frequently than those with other or with no structural brain lesions. A retrospective cross-sectional study of all patients treated at a community based neurology clinic for epilepsy during a three-month period was performed. One-hundred sixty patients were included in the analytical study. Co-morbid headaches were more commonly present among those with neurocysticercosis (40%) than those with other structural lesions and those with no structural brain abnormalities (19% and 22%, respectively; P = .031). Headache frequency among those reporting co-morbid headaches did not differ significantly between the groups. Prevalence of co-morbid headaches is greater among epilepsy patients with neurocysticercosis than those with other structural brain lesions or no structural brain abnormality. Epilepsy patients with neurocysticercosis may be especially vulnerable to development of headaches and a thorough headache history should be obtained to help screen for affected individuals.

Neurocysticercosis presenting as a 'Stroke Mimic'

A 62 year old Nepalese gentleman presented with left sided weakness and sensory loss. Initial brain CT scanning was suggestive of acute infarction but a subsequent MRI scan showed cysts with oedema. Cysticercosis serology was positive and a diagnosis of neurocysticercosis was made. The patient made almost a complete recovery after treatment with albendazole, praziquantel and steroids. Neurocysticercosis should be considered in the diffierential diagnosis when patients originating from endemic areas present with focal neurological deficit.

Three cases of imported neurocysticercosis in Northern Italy

BACKGROUND

Neurocysticercosis (NCC) is an important cause of adult-onset seizures in endemic areas, whereas it is emerging in some nonendemic areas as well because of extensive immigration.

METHOD

We describe three cases of imported NCC recently admitted to San Bortolo Hospital in Vicenza, located in Northern Italy.

RESULTS

All patients were immigrants. One patient was human immunodeficiency virus positive with severe immunosuppression. The diagnosis of NCC was made on the basis of magnetic resonance results; failure of anti-Toxoplasma, antitubercular, and antifungal therapy; and regression of the cystic lesions after empiric therapy with albendazole. Serology was positive in only one case. In one patient, NCC was diagnosed by biopsy of the brain lesion.

CONCLUSION

In nonendemic countries, NCC should be included in the differential diagnosis of all patients coming from endemic areas with seizures, hydrocephalus, and compatible lesions on brain imaging. Long-term follow-up is required but may be difficult to implement because these patients tend to move in search of employment. Screening of patient's household contacts for Taenia solium infection should always be carried out.

Neurocysticercosis among resettled refugees from Burma

Taenia solium is the most common helminthic infection of the central nervous system and a leading cause of epilepsy in developing nations. Little is known about neurocysticercosis in refugees from Southeast Asia which is endemic for T solium. We present two cases in a single household of refugees from Burma.

Neurocysticercosis: local and systemic immune-inflammatory features related to severity

Neurocysticercosis (NC) is caused by the establishment of Taenia solium cysticerci in the central nervous system. Previous studies have established that neuroinflammation plays a key role in the severity of the disease. However, the relationship between peripheral and local immune response remains inconclusive. This work studies the peripheral and local immune-inflammatory features and their relationships, toward the identification of potential peripheral immunologic features related to severity. A panel of cytokines was measured in paired cerebrospinal fluid (CSF) and in the supernatant of antigen-specific stimulated peripheral blood mononuclear cells samples (SN) in a total of 31 untreated inflammatory and non-inflammatory NC patients. Increased clinical and radiologic severity was associated with an increased cerebrospinal fluid cell count. A peripheral proliferative depression that negatively correlates with CSF cellularity and TNFα and that positively correlates with SN IL5 was observed in severe NC patients. These results provide evidences to support the systemic proliferative response as a biomarker to monitor the level of neuroinflammation, of possible value in the patients' follow-up during treatment.

[Neurocysticercosis in Israel]

BACKGROUND

Neurocysticercosis is the most common cause of adult onset seizures in developing countries. In recent years, with the rise in the number of immigrants to developed countries and travelers to endemic areas, neurocysticercosis is increasingly diagnosed in non-endemic countries.

AIMS OF THE STUDY

The authors describe the clinical and epidemiologic characteristics of patients diagnosed with neurocysticercosis acquired in Israel or in immigrants to Israel from endemic countries.

METHODS

A retrospective national survey of patients diagnosed with neurocysticercosis during 1994-2009 was conducted. Clinical and epidemiologic data were recorded. Case definition consisted of roentgenologic, serologic and pathologic features.

RESULTS

In all, 17 cases of neurocysticercosis were diagnosed in Israel during the study period. Nine (53%) cases were diagnosed in travelers to endemic areas, and six (35%) in immigrants from endemic areas. Two cases were native Israelis who had never traveled to an endemic area. Most immigrants suffered from multiple brain lesions. Two immigrants underwent brain biopsy.

CONCLUSIONS

This is the first report of the clinical and epidemiologic characteristics of patients diagnosed with neurocysticercosis acquired in Israel or diagnosed in immigrants to Israel. Neurocysticercosis must be included in the differential diagnosis of seizures, headache or neurologic deficit with single or multiple brain lesions, especially in immigrants from endemic countries. Invasive procedures may be obviated by appropriate clinical diagnosis, imaging and serology.

Use of statewide hospital discharge data to evaluate the economic burden of neurocysticercosis in Los Angeles County (1991-2008)

Statewide hospital discharge data were used to assess the economic burden of neurocysticercosis in Los Angeles County (LAC) from 1991 through 2008. A neurocysticercosis hospitalization was defined as having a discharge diagnosis of cysticercosis in addition to convulsions, seizures, hydrocephalus, cerebral edema or cerebral cysts. This study identified 3,937 neurocysticercosis hospitalizations, with the number of annual hospitalizations remaining relatively unchanged over the study period (R(2) = 0.01), averaging 219 per year (range 180-264). The total of all neurocysticercosis hospitalization charges over the study period was $136.2 million, averaging $7.9 million per year. The average charge per patient was $37.6 thousand and the most common payment method was Medicaid (43.9%), followed by private insurance (24.5%). The average length of stay was 7.2 days. The substantial number of hospitalizations and significant economic cost underscore the importance of neurocysticercosis in LAC.

[Tropical causes of epilepsy]

INTRODUCTION

Eighty-five percent of all epileptics live in tropical regions. Prenatal risk factors, traumatic brain injuries and different parasitic infestations of the central nervous system (CNS) are the reasons behind the high prevalence of epilepsy. This work reviews the main parasitic infestations causing epilepsy in the tropics.

DEVELOPMENT

Neurocysticercosis is the main cause of focal epilepsy in early adulthood in endemic areas (30-50%). All the phases of cysticerci (viable, transitional and calcified) are associated with epileptic seizures. Anti-cysticercus treatment helps get rid of cysticerci faster and reduces the risk of recurrence of seizures in patients with viable cysts. Symptomatic epilepsy can be the first manifestation of neuroschistosomiasis in patients without any systemic symptoms. The pseudotumoral form can trigger seizures secondary to the presence of granulomas and oedemas in the cerebral cortex. The eggs of Schistosoma japonicum are smaller, reach the CNS more easily and trigger epileptic seizures more frequently. Toxocariasis and sparganosis are other parasitic infestations that can give rise to symptomatic seizures. The risk factors for suffering chronic epilepsy after cerebral malaria are a positive familial history of epilepsy and a history of episodes of fever and cerebral malaria that began with coma or which progressed with multiple, prolonged epileptic seizures. About 20% of patients with cerebral infarction secondary to Chagas disease present late vascular epilepsy as a complication.

CONCLUSIONS

Very few studies have been conducted to examine the prognosis, risk of recurrence and modification of the natural course of seizures associated with tropical parasitic infestations, except for the case of neurocysticercosis.

[Clinical manifestations of neurocysticercosis]

INTRODUCTION

Cysticercosis is a common parasitic infection caused by the larval phase of the Taenia solium, it infects humans as well as pigs. Considered an endemic parasitosis in developing countries including Latin America, Asia and Africa. Clinical manifestations of the disease can be influenced by ambient factors, host individualities and the infectious agent itself. Neurocysticercosis can be asymptomatic or present with various signs and symptoms that can vary in severity.

OUTLINE

This review is focused on analyzing the various presentations of Neurocysticercosis throughout different age groups, and special populations. We found asymptomatic presentations to be the most common form, followed by various grades of severity including in its most severe form death. The most common alterations include: epilepsy (60-90%), intracraneal hypertension (14-27%), as well as neuropsychiatric symptoms (5-52%), and focal neurological deficits (4-19%). The heterogeneity of the clinical scenario relies upon parasite factors (number, localization and stage of central nervous system [CNS] disease), host particularities (gender, age and immunologic response), and finally environmental factors.

CONCLUSIONS

The most common form of infection is asymptomatic although there are various forms of clinical manifestations that rely upon different factors including environment, host response and the parasite itself.

The immune response in Taenia solium neurocysticercosis in pigs is associated with astrogliosis, axonal degeneration and altered blood-brain barrier permeability

Immunohistochemistry was used to examine the immuno-pathological changes and the extent of neuronal damage caused by either viable or dead Taenia solium cysticerci during porcine neurocysticercosis. Thirty pig brains with cerebral cysticercosis and 5 brains from T. solium free pigs were used in this study. Results revealed extensive astrogliosis, neuronal and mostly axonal damage in both early (grade I) and late (grades III and V) lesions as evidenced by an increased expression of glial fibrillary acidic protein (GFAP) and neurofilament protein (NFP). In many late lesions, astrocyte end-feet formed glial scars that surrounded the dead parasite. Rapid angiogenesis resulted in blood vessels lacking astrocyte end-feet suggesting loss of blood-brain barrier (BBB) hence allowing an influx of peripheral blood immune cells such as eosinophils, macrophages, CD3+ T cells, B lymphocytes and plasma cells into lesions. This study showed that porcine NCC was associated with severe nervous tissue damage, the host response of which is a collaborative effort between the local and peripheral immune responses comparable to that observed in human NCC. Results further implied that porcine NCC could be a useful model for understanding the course of NCC in human as well as provide useful information for therapeutic and/or immune strategies.

Heart involvement in disseminated cysticercosis- a case report and review of literature

Heart involvement in cysticercosis is uncommon but is well described in literature. Most of the reports are in the form of autopsy studies. Here we describe a young female with asymptomatic involvement of the heart, diagnosed by echocardiography.

Differential release and phagocytosis of tegument glycoconjugates in neurocysticercosis: implications for immune evasion strategies

Neurocysticercosis (NCC) is an infection of the central nervous system (CNS) by the metacestode of the helminth Taenia solium. The severity of the symptoms is associated with the intensity of the immune response. First, there is a long asymptomatic period where host immunity seems incapable of resolving the infection, followed by a chronic hypersensitivity reaction. Since little is known about the initial response to this infection, a murine model using the cestode Mesocestoides corti (syn. Mesocestoides vogae) was employed to analyze morphological changes in the parasite early in the infection. It was found that M. corti material is released from the tegument making close contact with the nervous tissue. These results were confirmed by infecting murine CNS with ex vivo–labeled parasites. Because more than 95% of NCC patients exhibit humoral responses against carbohydrate-based antigens, and the tegument is known to be rich in glycoconjugates (GCs), the expression of these types of molecules was analyzed in human, porcine, and murine NCC specimens. To determine the GCs present in the tegument, fluorochrome-labeled hydrazides as well as fluorochrome-labeled lectins with specificity to different carbohydrates were used. All the lectins utilized labeled the tegument. GCs bound by isolectinB4 were shed in the first days of infection and not resynthesized by the parasite, whereas GCs bound by wheat germ agglutinin and concavalinA were continuously released throughout the infectious process. GCs bound by these three lectins were taken up by host cells. Peanut lectin-binding GCs, in contrast, remained on the parasite and were not detected in host cells. The parasitic origin of the lectin-binding GCs found in host cells was confirmed using antibodies against T. solium and M. corti. We propose that both the rapid and persistent release of tegumental GCs plays a key role in the well-known immunomodulatory effects of helminths, including immune evasion and life-long inflammatory sequelae seen in many NCC patients.

Neurocysticercosis (NCC) is a disease caused by the larval form of a tapeworm parasite that preferentially migrates to the brain. It is characterized by a long asymptomatic period thought to result from the parasite's ability to evade host immunity. To date, the mechanisms of host–parasite interaction before symptoms develop remain unknown. In this study we evaluate by multiple immunofluorescent techniques distinct stages of the infection, making use of a murine model that closely resembles the disease process observed in humans. We discovered that the array of molecules secreted by the parasite varies according to the phase of infection studied. Early in infection, the parasite permanently sheds distinct molecules, allowing a rapid establishment in the brain. As the infection ensues, the continuous release of different molecules appears to facilitate the persistence of the parasite by downregulating molecules involved in its recognition and destruction. Loss of such molecules when the parasite dies after drug treatment may explain sudden inflammatory responses in patients. Characterization of these molecules will lead to advances in our understanding of the complex immunoregulatory mechanisms used by parasites and to new approaches for therapeutic strategies.

Evidence for differential changes of junctional complex proteins in murine neurocysticercosis dependent upon CNS vasculature

The delicate balance required to maintain homeostasis of the central nervous system (CNS) is controlled by the blood-brain barrier (BBB). Upon injury, the BBB is disrupted compromising the CNS. BBB disruption has been represented as a uniform event. However, our group has shown in a murine model of neurocysticercosis (NCC) that BBB disruption varies depending upon the anatomical site/vascular bed analyzed. In this study further understanding of the mechanisms of BBB disruption was explored in blood vessels located in leptomeninges (pial vessels) and brain parenchyma (parenchymal vessels) by examining the expression of junctional complex proteins in murine brain infected with Mesocestoides corti. Both pial and parenchymal vessels from mock infected animals showed significant colocalization of junctional proteins and displayed an organized architecture. Upon infection, the patterned organization was disrupted and in some cases, particular tight junction and adherens junction proteins were undetectable or appeared to be undergoing proteolysis. The extent and timing of these changes differed between both types of vessels (pial vessel disruption within days versus weeks for parenchymal vessels). To approach potential mechanisms, the expression and activity of matrix metalloproteinase-9 (MMP-9) were evaluated by in situ zymography. The results indicated an increase in MMP-9 activity at sites of BBB disruption exhibiting leukocyte infiltration. Moreover, the timing of MMP activity in pial and parenchymal vessels correlated with the timing of permeability disruption. Thus, breakdown of the BBB is a mutable process despite the similar structure of the junctional complex between pial and parenchymal vessels and involvement of MMP activity.

[Strokes caused by infection in the tropics]

INTRODUCTION

Almost three out of every four people in the world who suffer a fatal stroke live in developing countries. A number of different tropical diseases may appear in Europe in the coming years as a consequence of the demographic change that is being brought about by migratory flows. We review the main infectious causes of strokes in the tropics.

DEVELOPMENT

There are estimated to be 500 million cases of malaria every year. Cerebral malaria can cause cerebral oedema, diffuse or focal compromise of the subcortical white matter and cortical, cerebellar and pontine infarctions. Chagas disease is an independent risk factor for stroke in South America. At least 20 million people have the chronic form of Chagas disease. The main prognostic factors for Chagas-related stroke are the presence of apical aneurysms, arrhythmia and heart failure. Vascular complications of neurocysticercosis include transient ischemic attacks, ischemic strokes due to angiitis and intracranial haemorrhages. The frequency of cerebral infarction associated with neurocysticercosis varies between 2% and 12%. Gnathostomiasis is a cause of subarachnoid haemorrhage in south-east Asia. Other less common causes of stroke are viral haemorrhagic fevers due to arenavirus and flavivirus.

CONCLUSIONS

Several diseases that are endemic in the tropics can be responsible for up to 10% of the cases of strokes in adults.

Neuro-endoscopic management of intraventricular neurocysticercosis (NCC)

OBJECTIVE

Various approaches including endoscopy have been used for the treatment of intraventricular and cisternal NCC. We present our technique of Neuro-endoscopic management of intraventricular NCC.

METHODS

Twenty-one cases, 13 females and 8 males (age range 12-50 years; mean, 25.7 years), of intraventricular NCC [lateral (n = 6), third (n = 6), fourth (n = 10) ventricles including a patient with both lateral and third ventricular cysts] producing obstructive hydrocephalus formed the group of study. Gaab Universal Endoscope System along with 4 mm 0 degrees and 30 degrees rigid telescopes were used through a frontal burr-hole for removal of intraventricular including intra-fourth ventricular (n = 10) NCC. Endoscopic third ventriculostomy (ETV) was done for internal cerebrospinal fluid (CSF) diversion. Average follow up was 18 months.

RESULTS

Complete (n = 18) or partial (n = 2) removal of NCC was done in 20 patients, while a cyst located at foramen of Monro slipped and migrated to occipital or temporal horn in 1 patient. Thirty-degree 4-mm rigid telescope provided excellent image quality with ability to address even intra-fourth ventricular NCC through the dilated aqueduct using a curved tip catheter. No patient required further surgery for their hydrocephalus. There was no operative complication and post-operative ventriculitis was not seen in any case despite partial removal of NCC.

CONCLUSION

Neuro-endoscopic surgery is an effective treatment modality for patients with intraventricular NCC. It effectively restores CSF flow and is capable of removing cysts completely or partially from accessible locations causing mass effect. Partial removal or rupture of the cyst does not affect the clinical outcome of the patients.

Expression and distribution of Toll-like receptors in the brain during murine neurocysticercosis

In a mouse model of neurocysticercosis, the expression and distribution of Toll-like receptors (TLRs) was investigated by using both gene array analyses and in situ immunofluorescence microscopy (IF). In the normal uninfected brain, mRNA of all the TLRs are constitutively expressed albeit TLR5, TLR7, TLR8 and TLR9 to a lesser extent. In these animals, however, expression of TLR1, TLR3, TLR4 and TLR9 proteins was not detected. In contrast, parasite infection increased both gene and protein level expression of all the TLRs several fold except TLR5 where only the mRNA was upregulated. Importantly, TLRs were differentially distributed among various central nervous system (CNS) cell types and infiltrating leukocytes. TLR2 was almost exclusively localized to nervous tissue cells, particularly astrocytes, while TLR1 and TLR9 proteins were essentially limited to infiltrating leukocytes. All other TLRs tested were detected in both CNS and immune cell types. Interestingly, ependymal cells and neurofilaments of the cerebellar white matter of infected mice exhibited a substantial upregulation of TLR7 and TLR8 proteins respectively. These data provide a comprehensive analysis of TLR expression in the normal and parasite infected brain and suggest a role for TLRs in the interplay of immune cells and CNS cells during infection.

Epidemiologic classification of seizures associated with neurocysticercosis: observations from a sample of seizure disorders in neurologic care in India

AIMS

To determine the etiologic role of neurocysticercosis (NC) in a hospital-based sample of epilepsies divided according to International League Against Epilepsy (ILAE) epidemiological criteria and number of seizures prior to presentation.

METHODS

A sample comprising 1026 consecutive patients with either definite seizures or epilepsy attending a Neurology Outpatient Service was divided into four subgroups: single seizure (n = 314), incident epilepsy (n = 127), prevalent epilepsy (n = 398) and recurrent acute symptomatic seizures (RASS) (n = 175). The etiologic contribution of NC to each of the subgroups was examined with imaging studies.

RESULTS

Neurocysticercosis was diagnosed on imaging studies in 34.6% of patients with seizure disorder of any type, 59.2% of those with a single seizure, 23.7% of those with recurrent seizure disorder, 92.0% of those with RASS, none of cases of incident epilepsy and 2.0% with prevalent epilepsy. A diagnosis of NC was significantly associated with single seizures (P < 0.001).

CONCLUSIONS

Imaging abnormalities consistent with NC are frequently noted in persons presenting with a single seizure in neurologic care in NC-endemic countries like India. The probability of diagnosing NC diminishes with increasing numbers of seizures. Among samples of individuals with recurrent-unprovoked seizures, it is rare for imaging to demonstrate lesions of NC.

Breakdown of the blood brain barrier and blood–cerebrospinal fluid barrier is associated with differential leukocyte migration in distinct compartments of the CNS during the course of murine NCC

Brain homeostasis is normally protected by the blood brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCB), barriers that function in distinct CNS compartments and consist of different types of blood vessels including pial (subarachnoid spaces, leptomeninges), parenchymal (cerebral cortex) and ventricular vessels. In this study, a mouse model of neurocysticercosis was used to distinguish between changes in the permeability of the BBB and the BCB and determine the association of such alterations on leukocyte infiltration. Mice were intracranially infected with the parasite Mesocestoides corti and sacrificed at various times post infection. Different anatomical areas of infected brain were analyzed by three color immunofluoresence utilizing antibodies against serum proteins to assess brain barrier permeability, glial fibrillary acidic protein (GFAP) to detect astrocytes, and specific cell surface markers to determine the subpopulations of leukocytes infiltrating the CNS at particular sites. The results indicate increased permeability of all three types of vessels/structural sites as a result of infection evidenced by serum proteins and leukocyte extravasation but with considerable differences in the timing and extent of these permeability changes. Parenchymal vessels were the most resilient to changes in permeability whereas pial vessels were the least. Choroid plexus vessels of the ventricles also appeared less susceptible to increased permeability compared with pial vessels. In addition, parenchymal vessels appeared impermeable to particular types of immune cells even after extended periods of infection. Additionally, alterations in reactive astrocytes juxtaposed to blood vessels that exhibited increased permeability displayed increased expression of cytokines known to regulate brain barrier function. The results suggest that access of leukocytes and serum derived factors into the infected brain depend on several parameters including the anatomical area, type of vascular bed, cell phenotype and cytokine microenvironment.

Clinical aspects of neurocysticercosis

The clinical features of neurocysticercosis (NCC) largely depend on the number, type, size, localization and stage of development of cysticerci, as well as on the host immune response against the parasite. Seizures are widely reported to be the most common symptom, occurring in 70-90% of patients, while NCC is considered to be the main cause of late-onset epilepsy in endemic areas. When cysticerci lodge within the ventricular system, life-threatening acute intracranial hypertension secondary to hydrocephalus may develop. Cysts in the subarachnoid space may invade the Sylvian fissure and grow to large sizes (giant cysts) causing intracranial hypertension with hemiparesis, partial seizures or other focal neurological signs. Racemose cysts in the basal cisterns can cause an intense inflammatory reaction, fibrosis and progressive thickening of the leptomeninges at the base of the brain. In approximately 60% of the cases, there is an obstruction of the cerebrospinal fluid (CSF) circulation, resulting in hydrocephalus and intracranial hypertension. When hydrocephalus secondary to cysticercotic meningitis is present, the mortality rate is high (50%) and most patients die within 2 years after CSF shunting. Therefore, ventricular and basal cisternal locations are considered to be malignant forms of NCC. The diagnosis of NCC is based upon neuroimaging studies, laboratory analysis of the CSF and antibody detection in the serum. Nowadays, albendazole is considered the medication of choice for the therapy of NCC. Its main use is for symptomatic patients showing multiple viable brain parenchymal cysticerci.

Neurocysticercosis an uncommon intra-cerebral infection in Malaysia

Neurocysticercosis, infection of the central nervous system (CNS) by larvae of the pork tapeworm Taenia solium, is the commonest neuroparasitic infection in humans. However in countries as in Malaysia it poses a diagnostic problem as the disease in not seen amongst the local population; however with the arrival of immigrant workers, a number of cases have recently been diagnosed. There were 3 cases of neurocysticercosis reported in our centre over the last 5 years.

[Neurocysticercosis: up-dating in diagnosis and treatment]

Cysticercosis occurs when humans become intermediate hosts of Taenia solium after ingesting its eggs. It is the most common helminthic infection of the nervous system, and is endemic in Latin America, Asia and Africa, as well as in industrialized nations with a high immigrant influx of people coming from endemic areas. Neurocysticercosis is a pleomorphic disease due to individual differences in the number and location of the parasites within the nervous system as well as to differences in the severity of the host's immune reaction against the parasite. Common clinical manifestations include epilepsy, focal neurological signs, intracranial hypertension, and cognitive decline. Diagnosis require proper interpretation of clinical, neuroimaging, and serologic data, in the correct epidemiological context. Neuroimaging studies show the parasites as well as the changes they induce in the nervous system. Tests developed to detect anticysticercal antibodies in serum or cerebrospinal fluid present problems inherent to lack of specificity or sensibility, and should not be used by themselves to confirm or exclude the diagnosis. Cysticidal drugs (albendazole and praziquantel) have improved the prognosis of this condition. However, some patients have torpid clinical courses despite therapy. Surgery plays an important role in the management of some forms of the disease, particularly hydrocephalus and intraventricular cysts.

Relationship between the clinical heterogeneity of neurocysticercosis and the immune-inflammatory profiles

Human neurocysticercosis is caused by the establishment of Taenia solium cysticerci in the central nervous system. Neurocysticercosis may be asymptomatic or manifested by non-specific mild to severe neurological symptoms. Host factors may be involved in this heterogeneous clinical picture. An immune-inflammatory profile that underlies neurocysticercosis presentation was determined in 45 cerebral spinal fluid (CSF), from clinical and radiologically characterized neurocysticercosis patients, measuring specific IgG subclasses and cytokines. Severity related with increased cellularity in the CSF which was characterized by increased levels of IgG subclasses, IL6/IL5/IL10, proteins, and eosinophils. Multiple neurocysticercosis showed higher levels of IL5/IL6 than single neurocysticercosis. Women presented increased IL6/IL5/IL10 levels pointing out immunological differences due to gender. Severe symptomatology was found when cysticerci were located intraventricular or in the subarachnoid space of the base, inducing an exacerbated response in the CSF. These results constitute an integrative insight to understand the immune-inflammatory response that underlies symptomatic neurocysticercosis.

A rare presentation of neurocysticercosis in a young child

Neurocysticercosis is the most common parasitic infestation of the central nervous system which manifests commonly as acute onset focal seizures. We report a rare clinical presentation of neurocysticercosis in a 1-year-old infant who presented with involuntary movements. Involuntary movements are not a common manifestation. Young children are rarely affected by this disease. In endemic areas, when a child presents with seizures or unusual neurological features and the CT scan shows contrast enhancing lesions or cystic lesions neurocysticercosis should be considered however young the child may be.

[Electroencephalograms (EEG) in 250 patients with epilepsy in a cysticercosis endemic area in Burundi]

OBJECTIVES

This work aimed at describing EEG abnormalities in epileptic patients living in areas endemic for cysticercosis, underlining the electroclinical correlations and discussing the interest of EEG examination in this context.

METHODS

During a case-control study, 250 EEGs from patients with epilepsy were recorded with a portable system. Types of seizures were assessed clinically and from information obtained through a standardised questionnaire, and along with EEG were related to the results of cysticercosis serological tests.

RESULTS

Among the 249 EEGs, 48% were normal, 5.2% had epileptic abnormalities, 6.8% showed an association between epileptic abnormalities and slow alterations. Slow theta and delta abnormalities were found in 21.8% of cases, and isolated deterioration of basic rhythms was observed in 17.3% of cases. Most seizures were generalized, and 61% of the patients had positive serology. One EEG was uninterpretable and another showed isolated spikes. Electroclinical agreement was considered to be satisfactory in 33 patients, and was better with the epileptic than with slow abnormalities. The existence of epileptiform EEG abnormalities confirmed clinically diagnosed epilepsy, but did not allow etiological diagnosis. Electroserological agreement was good in 24 patients. A significant association (Chi2, p = 0.03) existed between slow focal abnormalities and positive cysticercosis serology. Conversely, no significant association was detected between epileptic patterns and serology results.

CONCLUSION

While the EEG alone clearly does not allow aetiological diagnosis, its joint use with clinical and biological results was a key element of the etiological and therapeutic discussion. When it shows focal abnormalities in a patient with epilepsy living in a high prevalence cysticercosis area, it confirms the clinical suspicion of neurocysticercosis. Morphological imagery alone can provide etiological information on the seizures by showing the nature and localization of the parenchymal lesions.

[Cysticercosis as the main cause of partial seizures in children in Peru]

INTRODUCTION

Seizures are a common neurological problem in the pediatric population, and their etiologies in certain developing countries are still not clear. From previous studies it is well known that neurocysticercosis is the main cause of partial seizures in the adult population in Peru and in many developing countries, but the situation has not been clarified for the paediatric population yet.

PATIENTS AND METHODS

Fifty-four consecutive patients in pre- and school ages, with partial seizures, were evaluated in the outpatient clinics and emergency room of a public hospital in Lima. Evaluation consisted in clinical exam, computed tomography of the head, and in some cases serological evaluation.

RESULTS

Thirty-seven percent were diagnosed with neurocysticercosis, which was found to be the main cause.

CONCLUSIONS

The possible explanations may be the high incidence of neurocysticercosis in Peru, and the fact that epilepsy and seizures are the most common clinical manifestation of neurocysticercosis in children. These findings are also representative of the current situation in gravel developing countries.

Third Cranial Nerve Palsy From Midbrain Neurocysticercosis: Repeated Exacerbation on Tapering Corticosteroids

Third cranial nerve palsy is rare in neurocysticercosis and is usually caused by supratentorial or sub-arachnoid lesions with accompanying hydrocephalus or meningitis. We report a patient who presented with third cranial nerve palsy caused by neurocysticercosis involving the midbrain. The patient showed repeated exacerbation of symptoms on tapering corticosteroids. The experience with this patient indicates that tapering of corticosteroids should be performed very slowly in such cases.

Internuclear ophthalmoplegia: causes and long-term follow-up in 65 patients

OBJECTIVES

To analyze the causes and long-term clinical outcome of internuclear ophthalmoplegia (INO) in a consecutive series of 65 patients.

PATIENTS AND METHODS

From a clinical registry of a neuroophthalmological department, patients with diagnosis of INO were retrospectively identified. Patients were classified into three groups: unilateral INO, bilateral INO, and one-and-a-half syndrome.

RESULTS AND CONCLUSIONS

Thirty-three men (50.8%) and 32 women (49.2%), with a mean age of 38.4 years were included in the study. INO was unilateral in 36 patients (55.4%), bilateral in 22 (33.8%) and one-and-a-half syndrome in seven (10.8%). The most common causes were vascular (36.9%), multiple sclerosis (32.3%), and infectious diseases (13.8%). Resolution of INO was documented in 32 patients (49.2%): 15 patients showed INO resolution during the first 3 months and 17 patients in 3-9 months. INO persisted in 33 patients (50.8%) even after a follow-up longer than 12 months.

Neurocysticercosis in Oregon, 1995-2000

The unexpected death of a teenager from neurocysticercosis prompted an investigation of this disease in Oregon. We found 89 hospitalizations, 43 newly diagnosed cases, and 6 deaths from 1995 to 2000. At least five cases occurred in persons who had not traveled or lived outside the United States. Enhanced surveillance for neurocysticercosis is warranted.

[Multiple sclerosis and neurocysticercosis: a diagnostic dilemma]

INTRODUCTION

Both Multiple Sclerosis (MS) and Neurocysticercosis (NC) are two entities in which clinical manifestations, neuroimaging findings and immunoserologic assays are neither pathognomonic nor specific requiring for their diagnosis an accurate examination of the clinical history of patients and an adequate follow up.

CASE REPORTS

Two patients who consulted non neurologists about focal neurological symptoms. Neuroimaging findings revealed multiple lesions, some of them contrast enhanced. A diagnosis of neurocysticercosis was established, supported in one of the patients by positive serologic assays for cysticerci and antihelmintic therapy began to be administered. Observing the clinical evolution of the patients, monitoring their clinical history and considering the diagnostic criteria proposed by McDonald for MS and by Del Brutto for NC the patients were finally diagnosed of MS.

CONCLUSION

The first step to reach a diagnosis of MS is to consider such a possibility. The diagnosis is mainly based on clinical grounds and it is necessary to prove that symptoms disseminate or that alterations occur in neuroimaging findings both in time and space. It is of the utmost importance to establish a differential diagnosis with other conditions presenting with similar clinical manifestations, neuroimaging findings and cerebrospinal fluid tests results. Even with the latest criteria proposed for the diagnosis of MS and NC we may have doubts making it fundamental to cautiously interpret the clinical manifestations and tests results.

[Micturition dysfunction triggered by spinal intramedullary neurocysticercosis]

INTRODUCTION

Neurocysticercosis is the most common parasitic disease of the human nervous system. This case report describes the rare intramedullary form of spinal neurocysticercosis.

CASE REPORT

A 26-year-old male patient demonstrated sinistral brachialgia, arm paralysis and progressive disturbance of micturition with a weak urine stream and persisting residual urine. The cervical MRI revealed a large intramedullary space-occupying lesion in the spinal cord, which was excised. Histologically, parasitic structures were detected and the lesion classified as neurocysticercosis. Retrospectively, more detailed evaluation of the patient's medical history disclosed a number of subtle early neurological symptoms of the disease. The infection was probably acquired during a stay in South America 20 years earlier. The MRI revealed additional multiple small intramedullary lesions and a large lesion in the area of the conus medullaris, which could not be excised. The clinical course was partially dramatic and eventually resulted--apart from small neurological deficits--in complete failure of micturition due to a hyposensible, hypercontractile and instable detrusor muscle. In order for the patient to empty his bladder, sterile single catheterization under anticholinergic medication became necessary.

CONCLUSIONS

Diagnosis of neurocysticercosis on clinical grounds is difficult, especially in regions like Europe, where the disease is very rare. In patients with non-specific neurological symptoms, and radiological indication of an intraspinal tumor, a history of stays in endemic regions even a long time ago, neurocysticercosis should be considered in the differential diagnosis as a possible cause.

Ununsual manifestations of neurocysticercosis in MR imaging: analysis of 172 cases

PURPOSE: The typical manifestations of neurocysticercosis are described widely in the literature. The purpose of this study is to demonstrate the uncommon presentations of different forms of neurocysticercosis in MR imaging. METHOD: A retrospective analysis of 172 cases of neurocysticercosis in MR studies was carried out over a period of 13 years. One hundred and four males and 68 females with a mean age of 32 ± 3.7 years were studied. The studies were performed on 1.5 T GE MR units and T1 was used before and after gadolinium injection, T2 and gradient-echo (T2*) sequences. RESULTS: The authors divided the unusual manifestations of neurocysticercosis into: intraventricular, subarachnoid, spinal, orbital, intraparenchymatous, and reactivation of previously calcified lesions. The results obtained were: intraparenchymatous 95 cases (55.23%); intraventricular 27 cases (15.69%); subarachnoid 20 cases (11.63%); spinal 6 cases (3.49%); orbital 1 case (0.58%); reactivated lesion 1 case (0.58%); association of intraventricular and intraparenchymatous 12 cases (6.98%); association of subarachnoid and intraparenchymatous 6 cases (3.49%); association of subarachnoid and intraventricular, 4 cases (2.32%). CONCLUSION: MR imaging is a sensitive and specific method in the analysis of different forms of unusual manifestations of neurocysticercosis, which should appear in the differential diagnosis of parenchymal, ventricular, spinal, cisternal, and orbital lesions.

Intermittent symptoms in neurocysticercosis: could they be epileptic?

OBJECTIVES

Some patients with neurocysticercosis (NCC) develop perilesional gliosis during the course of healing and carry poor prognosis for the seizure control. We evaluated the clinical status of these patients during complete control of their original seizures on anti-epileptic drugs (AED).

MATERIAL AND METHODS

We studied 172 patients with solitary NCC, 45 with perilesional gliosis as visible on magnetization transfer spin echo (MTSE) magnetic resonance imaging and 127 without gliosis, for any abnormal symptom during the course of their "seizure-free" period. All of them received optimum doses of AED to control the original seizures.

RESULTS

Patients with gliosis had high incidence of abnormal symptoms with or without corresponding abnormalities on surface electroencephalogram (EEG). These symptoms disappeared on increasing the dose or adding a new AED. The symptoms, which were transient episodic in nature, included heaviness, dystonic posturing, weightlessness, numbness and alien limb phenomenon on the side of the body contralateral to cerebral lesion, and headache.

CONCLUSION

Patients with NCC who develop perilesional gliosis during the process of healing tend to suffer from disturbing intermittent symptoms during their apparent control of seizures. The symptoms are controllable with increased dosage of previously prescribed or addition of another AED. As these symptoms could possibly be epileptic in nature, their identification and treatment may have a bearing on long-term seizure control after stopping AED therapy.

[Neurocysticercosis in a paediatric population in Lima: an epidemiological and clinical analysis]

INTRODUCTION

Neurocysticercosis (NCC) in children is a clinical entity that was believed to be infrequent but, as methods of diagnosis by means of imaging techniques and immunological tests have improved, it has become possible to confirm more cases. This disease has been reported as being most prevalent in developing countries but over the past few years there has also been an increase in the incidence in developed countries.

PATIENTS AND METHODS

We examined the clinical records of paediatric patients admitted to the Hospital Cayetano Heredia, in Lima, Peru, between 1993 and 1998. The statistical analysis was performed with the SPSS software package.

RESULTS

A sample made up of 52 patients was obtained (n= 52), of which two were excluded because they were being treated at the same time with antituberculosis and anthelmintic drugs. Of these 50 patients, 22 were males (44%) and 28 females (56%). Average age was 7.86 years old (interval: 7 months 15 years). Diagnosis was definite in 26% of them, probable in 50% and possible in the remaining 24%. 36% reported that they raised pigs at home and had travelled to endemic areas. The convulsive syndrome was the most frequent clinical presentation, followed by endocranial hypertension. The single lesions were often identified in imaging studies (64.3%). 36.8% of the patients were found to be seropositive. 90% of the patients were receiving treatment with anticonvulsive drugs and almost 70% with albendazole and corticoids.

DISCUSSION

This study represents the first attempt to find out more about the epidemiological and clinical characteristics of the Peruvian infant population who are diagnosed as having NCC. The findings do not differ from those obtained in previous studies in other countries.

Neurocysticercosis: an update

Taeniosis and cysticercosis, diseases caused by the parasitic tapeworm Taenia solium, are distributed worldwide where pigs are eaten and sanitation is poor, and also in the more developed countries as a result of increasing migration. Neurocysticercosis is the commonest parasitic disease of the human nervous system. Immunological assays detect positivity for human cysticercosis in 8-12% of people in some endemic regions, which indicates the presence of antibodies against the parasite but not necessarily active or central-nervous-system infection. The only reliable tool for diagnosis of neurocysticercosis is imaging by CT or MRI. The presence of viable cysts with a mural nodule, associated with degenerative cysts and calcifications, is typical. Classification of neurocysticercosis into active, transitional, and inactive forms gives a good clinical-imaging correlation and facilitates medical and surgical treatment. The main clinical manifestations of neurocysticercosis are seizures, headache, and focal neurological deficits, and it can have such sequelae as epilepsy, hydrocephalus, and dementia. Treatment should be individually fitted for each patient, with antiepileptic drugs, analgesics, corticosteroids, or a combination of these. Anthelmintic drugs (praziquantel and albendazole) are used routinely, but so far no controlled clinical trial has established specific indications or definitive doses of treatment. Parenchymal forms of neurocysticercosis have a good prognosis in terms of clinical remission. The most effective approach to taeniosis and cysticercosis is prevention, which should be a primary public-health focus for less developed countries.

Sequential expression of the neuropeptides substance P and somatostatin in granulomas associated with murine cysticercosis

Neurocysticercosis, a parasitic infection of the human central nervous system caused by Taenia solium, is a leading cause of seizures. Seizures associated with neurocysticercosis are caused mainly by the host inflammatory responses to dying parasites in the brain parenchyma. We previously demonstrated sequential expression of Th1 cytokines in early-stage granulomas, followed by expression of Th2 cytokines in later-stage granulomas in murine cysticercosis. However, the mechanism leading to this shift in cytokine response in the granulomas is unknown. Neuropeptides modulate cytokine responses and granuloma formation in murine schistosomiasis. Substance P (SP) induces Th1 cytokine expression and granuloma formation, whereas somatostatin inhibits the granulomatous response. We hypothesized that neuropeptides might play a role in regulation of the granulomatous response in cysticercosis. To test this hypothesis, we compared expression of SP and expression of somatostatin in murine cysticercal granulomas by using in situ hybridization and immunohistochemistry. We also compared expression with granuloma stage. Expression of SP mRNA was more frequent in the early-stage granulomas than in the late-stage granulomas (34 of 35 early-stage granulomas versus 1 of 13 late-stage granulomas). By contrast, somatostatin was expressed primarily in later-stage granulomas (13 of 14 late-stage granulomas versus 2 of 35 early-stage granulomas). The median light microscope grade of SP mRNA expression in the early-stage granulomas was significantly higher than that in the late-stage granulomas (P = 0.008, as determined by the Wilcoxon signed rank test). By contrast, somatostatin mRNA expression was higher at later stages (P = 0.008, as determined by the Wilcoxon signed rank test). SP and somatostatin are therefore temporally expressed in granulomas associated with murine cysticercosis, which may be related to differential expression of Th1 and Th2 cytokines.

Surgical treatment of cerebral cysticercosis: long-term results and prognostic factors

OBJECT

Cysticercosis is the most frequent parasitosis of the central nervous system. Although anticysticercal drugs have proven efficient in some cases, many patients with NCC require palliative, occasionally curative, surgical procedures. The authors analyzed the data and prognostic factors obtained during the follow-up period (range 1-255 months, median 38 months) in 160 patients with cerebral cysticercosis who underwent surgical treatment.

METHODS

Different surgical approaches were indicated to control increased intracranial pressure (ICP) in most patients, and some patients had undergone decompressive surgery for local brain lesions. Most patients required more than one surgical procedure. Statistical analysis was performed using the Fisher exact, the log-rank, and the Kruskall-Wallis tests. Survival curves were calculated according the Kaplan-Meier method. The removal of a giant cyst from the parenchyma or cisterns for relief of increased ICP and for chiasm/optic nerve decompression improved most symptoms in patients. The removal of ventricular cysts was effective in the control of increased ICP in most patients. Patients with a ventricular cyst and ependymitis/arachnoiditis required placement of a ventriculoperitoneal (VP) shunt after the cyst was removed. This therapy effectively controlled increased ICP. Patients younger than 40 years of age at the time of treatment and male patients had worse outcomes. The outcome in patients who underwent VP shunt surgery or shunt surgery combined with reservoir implantation was worse than that in those who underwent cyst removal alone. Shunt-related infection was the most frequent complication, and the global mortality rate during the follow-up period was 21.2%. Although both complications were more frequent in the first 2 postoperative years, they occurred at any time.

CONCLUSIONS

Long-term prognosis in patients with cerebral cysticercosis who required surgery was not good. Cysts located in the basal cisterns and patient age younger than 40 years were poor prognostic factors.

Review of neurocysticercosis

In the neurosurgical services in many developing countries, treatment of neurocysticercosis (NCC) accounts for greater than 10% of brain surgical procedures and approximately 15% of neurological consultations. In these areas brain cysticercosis is the leading cause of hydrocephalus in adults and the first cause of late-onset epilepsy. During the last two decades, successful medical treatment has been established. Additionally, neuroimaging and immunological studies have clearly defined the topography, pathophysiological mechanisms, and biological status of these lesions. Thus, selection of cases for medical or surgical treatment has improved; in a significant number of cases, both interventions are required. New therapies with either albendazole or praziquantel have respectively reduced to 8 days and to 1 day the course of anticysticidal therapy, which now is fast, effective, inexpensive, atoxic, and convenient, particularly in endemic areas where most patients belong to the lower socioeconomic groups. Additionally, the rational use of steroid agents facilitates the treatment of inflammation, a conspicuous accompaniment in cases of NCC. A major effort, however, is still required to eradicate this disease.