Low seroprevalence of systemic cysticercosis among patients with epilepsy in Kerala--South India

Pediatric Neurocysticercosis

Neurocysticercosis is the most common helminth infection of nervous system in humans caused by the encysted larvae of Taenia solium. It is a major cause of epilepsy in tropical areas and the most common cause of focal-onset seizures in North Indian children. Children with neurocysticercosis have pleomorphic manifestations depending on the location, number and viability of the cysts and host response. In endemic areas, neurocysticercosis should be clinically suspected in any child with recent-onset seizures, headache or focal motor deficits where there is no other suggestion of an underlying neurological disorder. Diagnosis of neurocysticercosis is essentially based on neuroimaging; visualization of a scolex is diagnostic. Management includes use of cysticidal drugs usually albendazole, which seems to be effective for lesion resolution and seizure remission, use of steroids and anti-epileptic drugs. Single lesions portend good prognosis with resolution of lesions in >60% of the cases within 6 mo and good seizure control. Prognosis is guarded in cysticercus encephalitis, racemose and extraparenchymal neurocysticercosis.

The epidemiology of Taenia spp. infection and Taenia solium cysticerci exposure in humans in the Central Highlands of Vietnam

BACKGROUND

Vietnam is endemic for taeniasis and T. solium cysticercosis. Despite this, information on the epidemiological characteristics of the diseases in the Central Highlands of Vietnam are poorly described. The aims of this study were to determine the epidemiological characteristics of taeniasis (Taenia spp.) and T. solium cysticerci exposure in humans in Dak Lak province in the Central Highlands, Vietnam.

METHODS

This cross-sectional study was carried out in six villages in three districts of Dak Lak. A total of 190 households were visited. From each household, between one and five individuals were asked to donate a single faecal and blood sample and respond to a questionnaire. Serum samples were subjected to lentil lectin purified glycoprotein enzyme-linked immunoelectrotransfer blot assay to detect antibodies against T. solium cysticerci. Multiplex real-time PCR was used to detect Taenia spp. infection in faecal samples. A fixed-effects logistic regression model was developed to identify factors associated with the probability of Taenia spp. infection or T. solium cysticerci exposure risk. The contribution of each of identified factor was quantified using population attributable fractions.

RESULTS

The prevalence of seroexposure to T. solium in Dak Lak was 5% (95% CI 3% to 8%). Consumption of raw vegetables, sourcing drinking water from lakes, streams or ponds and the practice of outdoor defaecation were identified as primary risk factors for the prevalence of T. solium cysticerci exposure, while consuming undercooked pork and beef, pork tongue and observing Taenia proglottids in stool were associated with Taenia spp. infection. Consumption of raw vegetables attributed to 74% of T. solium cysticerci exposure-positive cases and consumption of undercooked beef attributed to 77% of taeniasis cases in these communities.

CONCLUSIONS

The prevalence of T. solium seroexposure in Dak Lak is consistent with those reported in other regions of Vietnam. The identified risk factors associated with the prevalence of T. solium seroexposure and taeniasis infection in Dak Lak are modifiable and thus advocate for targeted community intervention programs to mitigating these risks.

A Stratified Analysis of Clinical Manifestations and Different Diagnostic Methods of Neurocysticercosis-Suspected Tamilian Population Residing in and Around Puducherry

INTRODUCTION

Human beings are accidental hosts for Cysticercus cellulosae showing varied clinical manifestations based on the site harbored by the parasitic cyst because of which disease profile remains unexplored at large. Besides this, diagnosis of the disease with a single conventional method is problematic due to lack of specificity and sensitivity.

AIM

To assess the varied clinical manifestations and stratify based on imaging and serological methods for diagnosis of Neurocysticercosis (NCC) in our study population.

MATERIALS AND METHODS

A hospital-based study was carried out at Jawaharlal Institute of Post-Graduate Medical Education and Research (JIPMER), the tertiary care centre caters patients from Puducherry and surrounding regions of Tamil Nadu. This is a cross-sectional analysis of clinically and radiologically suspected cases of NCC (n=119) for a period of three years (2012 to 2015). The collection of detailed clinical history and imaging findings (MRI or CT) along with the lifestyle parameters was done after obtaining informed consent. Enzyme-Linked Immune-Electro Transfer Blot (EITB) was carried out for the samples collected from study subjects.

RESULTS

Based on dietary and environmental factors non-vegetarians, pork eaters, raw vegetable consumers and open-field defecation showed significant seropositivity. The clinical manifestations like seizures, blurring of vision and chronic headache with nausea followed by neck pain, cognitive deficits and movement disorder have higher seropositivity respectively. Generalized seizures were found to be more than focal seizures. While comparing the imaging and serological tests for NCC diagnosis, the positivity rate was 46.2% considering positive by both methods; but 18.5% of sero-positive cases were imaging negative, and 16% of the sero-negative cases were imaging positive. The study showed a predominance of multiple cysts (62%) in cases with cystic lesions.

CONCLUSION

This study is first of its kind in associating varied and less commonly explored clinical manifestations with two different diagnostic measures in practice and its importance among our study settings. These manifestations must be considered as strong disease entities of NCC, which has to be suggested for differential diagnosis, and cannot be left ignored. Combinatorial diagnostic methods like serology and imaging techniques should be followed in diagnosis and assessing the disease burden.

The causal relationship between neurocysticercosis infection and the development of epilepsy - a systematic review

BACKGROUND

Neurocysticercosis (NCC) is a parasitic infection of the human central nervous system, the most common form of which involves infection of the brain parenchyma with the larval form of the Taenia solium tapeworm. A causal relationship between such an NCC infection and the development of epilepsy in infected individuals is acknowledged, in part supported by high levels of comorbidity in endemic countries worldwide.

METHODS

This study undertook a systematic review and critical analysis of the NCC-epilepsy relationship with the primary objective of quantifying the risk of developing epilepsy following NCC infection. A secondary aim was to analyse the proportions of NCC-associated epilepsy within different populations. Significant emphasis was placed on the importance of neuroimaging (CT or MRI) availability and use of clear guidelines for epilepsy diagnosis, in order to avoid overestimations of prevalence rates of either condition; a limitation identified in several previous studies.

RESULTS

A common odds ratio of 2.76 was identified from meta-analysis of case-control studies, indicating that an individual infected with NCC has almost a three times higher risk of developing epilepsy than an uninfected individual. Furthermore, meta-analysis of studies identified a common proportion of 31.54% of epilepsy cases associated with NCC infection which suggests that amongst epileptic populations in at risk countries, approximately one-third may be associated with NCC infection.

CONCLUSION

A significant finding was the lack of good clinical data to enable accurate determination of a causal relationship. Even studies that were included had noticeable limitations, including a general lack of consistency in diagnostics, and lack of accurate epidemiological data. This review highlights a need for consistency in research in this field. In the absence of reliable estimates of its global burden, NCC will remain of low priority in the eyes of funding agencies - a truly neglected disease.

Seroprevalence and risk factors of human cysticercosis and taeniasis prevalence in a highly endemic area of epilepsy in Bangoua, west Cameroon

Cysticercosis caused by the larvae of Taenia solium is a serious and emerging threat to public health in the endemic areas as well as in the non-endemic areas.　Neurocysticercosis, an affection of the central nervous system is a leading cause of epilepsy in endemic areas. This study was carried out to investigate human cysticercosis, taeniasis and risk factors, and also their association with epilepsy in Bangoua, west Cameroon where epilepsy is highly prevalent. Out of 384 people investigated, 12 (3.1%) exhibited antibody response against low molecular weight antigens of T. solium by ELISA. Immunoblot revealed that six persons (1.6%) were seropositive with the same antigens. Among 61 epileptic patients, only one was seropositive by immunoblot and the study did not find any statistically significant difference (P>0.05) in seropositivity to T. solium between epileptic persons (1/61, 1.6%) and non-epileptic group (5/323, 1.5%). In addition, cysticercosis was associated with households eating pork meat from pigs slaughtered at home, but not with other factors. The risk factors including pig farming, the consumption of pork meat, vegetables, and non-drinkable water were attenuated by the relatively good hygiene and pig husbandry practices of the population. No egg of Taenia was found in stool by microscopic examination. All data obtained in this study suggested that cysticercosis might not be the principal causative agent of epilepsy in this area.

Pediatric neurocysticercosis: current challenges and future prospects

Neurocysticercosis (NCC) is an acquired infection of the nervous system caused by encysted larvae of Taenia solium. It is a major cause of epilepsy in the tropics and the commonest cause of focal seizures in North Indian children. T. solium teniasis-cysticercosis is considered a parasitic "Neglected Tropical Diseases" endemic throughout Southeast Asia. NCC in children has pleomorphic manifestations depending on the location, number and viability of the cysts, and host response. Even with advancing knowledge of the disease manifestations, many aspects related to diagnosis and treatment, particularly in children, still remain controversial and pose challenges to clinical practice. There is no gold standard test to diagnose NCC and the management recommendations are still emerging. This review provides an overview of diagnosis of NCC in children and its management with special focus on current challenges and future prospects.

Epilepsy in India I: Epidemiology and public health

Of the 70 million persons with epilepsy (PWE) worldwide, nearly 12 million PWE are expected to reside in India; which contributes to nearly one-sixth of the global burden. This paper (first of the two part series) provides an in-depth understanding of the epidemiological aspects of epilepsy in India for developing effective public health prevention and control programs. The overall prevalence (3.0-11.9 per 1,000 population) and incidence (0.2-0.6 per 1,000 population per year) data from recent studies in India on general population are comparable to the rates of high-income countries (HICs) despite marked variations in population characteristics and study methodologies. There is a differential distribution of epilepsy among various sociodemographic and economic groups with higher rates reported for the male gender, rural population, and low socioeconomic status. A changing pattern in the age-specific occurrence of epilepsy with preponderance towards the older age group is noticed due to sociodemographic and epidemiological transition. Neuroinfections, neurocysticercosis (NCC), and neurotrauma along with birth injuries have emerged as major risk factors for secondary epilepsy. Despite its varied etiology (unknown and known), majority of the epilepsy are manageable in nature. This paper emphasizes the need for focused and targeted programs based on a life-course perspective and calls for a stronger public health approach based on equity for prevention, control, and management of epilepsy in India.

Imaging and Serological-Evidence of Neurocysticercosis Among Patients with Seizures in Odisha, an Unexplored Eastern Coastal Province in India

INTRODUCTION

Neurocysticercosis being a potential to human transmitted disease, is the major cause of seizures and a public health problem in tropical countries. Though India is known to be highly endemic, there are many provinces where reports are still unavailable thereby underestimating its actual burden.

MATERIALS AND METHODS

Anti-Cysticercus IgG antibodies in sera from cases presenting with seizures were screened by ELISA in a preliminary study in Odisha state which is a province in Eastern coastal India that was never explored before. Patients presenting with recent onset of seizures within age group 5 to 50 years, either local residents of Odisha or inhabitants from other parts of the country living for at least one year period in the study area were included.

RESULTS

The present study showed 43.75% cases with seizures to be confirmed neurocysticercosis (NCC) based on serology and brain imaging. However, statistically no association was established between anti-Cysticercus antibody detection and radio imaging characteristics (location, number of lesions, and stage).

CONCLUSION

This is the first study in Odisha presenting a series of cases with serological evidence of exposure to the parasite along with imaging characteristics which was consistent with NCC. It is recommended that NCC must be considered for a differential diagnosis in each active epilepsy case irrespective of prior prevalence information in all unexplored provinces in India and other endemic regions; also a compulsory reporting is warranted in order to aid in quantifying its actual burden.