Factors associated with Taenia solium cysticercosis: analysis of nine hundred forty-six Peruvian neurologic patients. Cysticercosis Working Group in Peru (CWG)

Prevalence and risk factors for neurocysticercosis in children with a first-onset seizure in rural North India

BACKGROUND

Neurocysticercosis (NCC) is a parasitic infection acquired by consuming food and water contaminated by the faeces of a Taenia solium tapeworm carrier. It is an important cause of acquired seizures and also the common identifiable cause of new-onset seizures in children.

METHODS

A hospital-based prospective cross-sectional study of NCC was undertaken in a medical college in north-west India. All patients aged 1-15 years admitted to the paediatric emergency room with a first-onset seizure were selected.NCC was diagnosed and staged on the basis of MRI findings. A structured, pretested schedule was administered to each patient's parent for analysis of risk factors for NCC.

RESULTS

Of 79 patients with first-onset seizure, 43 (54.4% were diagnosed with NCC based on MRI findings. The association of NCC with age and pig-rearing near the patients' homes was statistically significant (p = 0.01 and 0.02, respectively). The association between NCC and other risk factors such as gender, religion, father's occupation, parents' literacy, source and storage of drinking water, the washing and peeling of fruit and vegetables and distance of refuse disposal from residential areas was not statistically significant. Although open defaecation is an important risk factor for transmission of NCC, there was no significant association with NCC.

CONCLUSION

In India, NCC is a common cause of first-onset seizure. The major risk factors are poor environmental sanitation and poor food and drinking water hygiene. NCC can be controlled and prevented by generating awareness of hygienic consumption of food and water and the provision of good sanitation.

Neurocysticercosis presenting as focal hydrocephalus

A 40-year-old man presented with a 2-month history of headache, nausea and vomiting, with generalised seizures for the past 15 days. On examination he had bilateral papilloedema, visual acuity was 6/6 in both eyes but perimetry showed right homonymous inferior quadrantanopia. His MRI showed numerous small cystic lesions with eccentric nodules, diffusely distributed in bilateral cerebral and cerebellar hemispheres. There was also focal hydrocephalus involving occipital and temporal horns of the left lateral ventricle leading to its selective dilation. Stool examination showed ova of Taenia solium. He was treated with albendazole, prednisone and sustained release sodium valproate for 1 month. His headache resolved and he is free of seizures. Repeat perimetry at 1 month also showed resolution of visual field defect.

Awareness of neurocysticercosis: A study from northwest India

Background:

Neurocysticercosis (NCC) is a common cause of epilepsy in developing countries. In order to plan and implement prevention programs, it is essential to study the awareness of NCC.

Objective:

To study the awareness of NCC among patients with NCC and compare with age- and gender-matched controls without NCC.

Setting and Design:

Hospital based case–control study.

Materials and Methods:

Two hundred and fourteen subjects were studied (109 NCC patients, and 105 age- and gender-matched controls without NCC). The participants were selected from neurology and medical wards of a tertiary referral hospital in northwest India. They were interviewed by trained medical interns using a questionnaire.

Results:

64.2% of the NCC patients and 19% of control group had heard about NCC (P < 0.001). Knowledge regarding organ affected by NCC in the NCC group was 61.4% and in the control group was 80% (P = 0.09). Only 12.9% of the NCC group and none in the control group identified tape worm as a causative agent for NCC (P = 0.092). Negative effects of NCC on marriage and social life were more often cited by the NCC group but in the control group it was towards education (P = 0.004).

Conclusions:

The awareness of NCC was poor in both the groups. Educational programs are needed to improve the awareness about NCC among the patients and the public.

Anti-Taenia solium larval stage Ig G antibodies in patients with epileptic seizures

Background:

Cysticercosis is the most common differential diagnosis for epilepsy. The present study was carried out to assess the serological response among patients with epileptic seizures visiting JIPMER Hospital Puducherry.

Materials and Methods:

A total of 934 serum samples were collected from patients with epileptic seizures. A standardized questionnaire was designed to obtain information on the demographic, socioeconomic, environmental, and behavioral characteristics related to the transmission of infection. An enzyme-linked immunosorbent assay (ELISA) was used to detect the anti-Taenia solium larval stage IgG antibodies. Samples found reactive and inconclusive by ELISA were further tested by the enzyme immunotransfer blot (EITB).

Results:

The frequency of antibodies in the serum samples of the above-mentioned population was 16.2% by EITB. Anti-Taenia solium larval stage antibodies were detected in serum samples of 163 patients, out of which 27 (16.56%) patients belonged to the 0 – 15-year age group, 82 (50.30%) patients were in the 16 – 40-year age group, and 52 (31.90%) patients were above 41 years, respectively. Although the sera from males had higher OD values than those from females, the difference was not statistically significant. Out of 163 seropositive by ELISA, 152 (93.25%) were found to be positive by EITB. Out of the 152, 61 (40.13%) were farmers and 79 (51.97%) were office or factory workers.

Conclusions:

In conclusion, the results indicate a probable endemic situation and a high prevalence of cysticercosis in patients with epileptic seizures. Living in poor sanitary conditions seems to be an important factor related to human cysticercosis in Puducherry and the neighboring districts of Tamil Nadu.

Neurocysticercosis: risk and primary prevention strategies update

Neurocysticercosis results from the infestation of the central nervous system with invading tapeworm larvae. Though uncommon in the US prior to 1965, new cases are currently being diagnosed at an unprecedented rate. Drawing on environmental health, intervention and risk data retrieved from standard/alternative databases and in-country sources, we present an update and summary of modifiable risk factors and field-tested primary prevention measures. While points of intervention, subpopulations at risk and overall magnitude of the problem are addressed, particular attention is paid to defining risk reduction measures that can be adopted by individuals and high risk groups in the near-term to interrupt or eliminate pathways of exposure leading to disease transmission. Though global eradication is not attainable in the near future, effective preventative measures exist and should be taken now by international travellers and workers, US/foreign government agencies, and individuals living in endemic regions to reduce human suffering.

Detection of Cysticercus antigens and antibodies in cerebrospinal fluid of patients with chronic meningitis

Chronic meningitism is a less frequent manifestation of neurocysticercosis caused by Taenia solium cysticerci. In the present study we used Co-agglutination (Co-A), a simple and rapid slide agglutination test to detect specific Cysticercus antigen in the 67 cerebrospinal fluid (CSF) samples from patients with chronic meningitis of unknown etiology. The results were compared with that of ELISA for detection of antibodies. Among these samples four (5.97%) were positive for Cysticercus antigen by Co-A test and six (8.95%) were positive for antibodies by ELISA. Two samples were positive by both Co-A and ELISA, two were positive only by Co-A and four were positive only by ELISA. In the present study, although Cysticercus antigen and antibodies were present in CSF samples from eight (11.94%) patients, we cannot affirm that all the cases of chronic meningitis are due to cysticercosis, but for any case of chronic meningitis of unknown origin, it would be useful to consider the possibility of cysticercal meningitis.

Contribution of immunodiagnostic tests to epidemiological/intervention studies of cysticercosis/taeniosis in Mexico

Cysticercosis is acquired when swine ingest human faeces contaminated with Taenia solium eggs. Humans become tapeworm carriers when they ingest infected pork meat. They can also develop cysticercosis after inadvertently swallowing T. solium eggs. Human neurocysticercosis (NCC) is considered as a public health problem in Mexico and in several countries around the world, mainly developing ones. The development of immunodiagnostic techniques has promoted the conduct of seroepidemiological studies. This review provides insight into the evolution of these techniques, their predictive values and their use in field studies, and summarizes evidence supporting health care practice and policy related to cysticercosis/taeniosis in Mexico. Serological studies in rural and urban settings have demonstrated that close proximity with a tapeworm carrier is the main risk factor for acquiring cysticercosis. Research focusing on the tapeworm carrier generated an ELISA for the detection of Taenia coproantigens and facilitated the evaluation of intervention measures. Health education and self-identification of tapeworm carriers were shown to be successful. However, cestodial treatment as a community-based intervention was not as successful. Current immunodiagnostic techniques can be used to pinpoint transmission foci so that appropriate and effective interventions can be applied. In this way, sustainable control, and even eradication of T. solium may be envisioned.

Control of Taenia solium cysticercosis/taeniosis

Cysticercosis is emerging as a serious public health and agricultural problem in many poorer countries of Latin America, Africa, and Asia. Caused by the pork tapeworm, Taenia solium, this zoonotic disease forms larval cysts in humans and pigs that can lead to epilepsy and death in humans, reduces the market value of pigs and makes pork unsafe to eat. It occurs where pigs range freely, sanitation is poor, and meat inspection is absent or inadequate, and is thus strongly associated with poverty and smallholder farming. Although theoretically easy to control and declared eradicable cysticercosis remains neglected in most endemic countries due to lack of information and awareness about the extent of the problem, suitable diagnostic and management capacity, and appropriate prevention and control strategies. Human neurocysticercosis occurs when the larval cysts develop in the brain. It is considered to be the most common parasitic infection of the human nervous system and the most frequent preventable cause of epilepsy in the developing world. Thus far the infection has not been eliminated from any region by a specific program, and no national control programs are yet in place. We consider the tools available for combating cysticercosis and suggest simple packages of interventions, which can be conducted utilizing existing services and structures in the endemic countries to provide appropriate and sustainable control of the disease.

Control of the taeniosis/cysticercosis complex: Future developments

Cysticercosis is due to the establishment of the larval stage of the zoonotic cestode parasite Taenia solium. The infection causes substantial human morbidity and mortality, particularly in several Latin American countries and parts of Africa and Asia, as well as economic losses in pig husban dry due to condemnation of infected pork meat. The life cycle of T. solium includes human beings as definitive hosts and pigs as intermediate hosts. Cysticercosis is acquired by the ingestion of eggs released by human tapeworm carriers, who become infected after ingesting pork meat contaminated with cysticerci. Taenia solium transmission has been associated with poverty, lack of sanitary services and practices of rearing backyard pigs with free access to the areas that villagers use as toilets, as well as cultural behaviour. Nonetheless, due to the recent increase of migration and tourism, industrial countries are also reporting cases of human cysticercosis. There are many epidemiological studies that have been conducted mainly in Latin American countries that have evaluated intervention measures for control of cysticercosis including the development and testing of vaccines. Furthermore, the involvement of international agencies and institutions, such as the World Health Organization, the Food and Agriculture Organization and the International Livestock Research Institute, as well as the commitment of policymakers, scientists and field workers, are key means for the sustainable control and, hopefully, eradication of T. solium infections.

An epidemiological study of familial neurocysticercosis in an endemic Mexican community

Neurocysticercosis (NC) caused by Taenia solium is a frequent parasitic disease of the central nervous system. It is highly endemic in many developing countries, where many people are exposed but few become infected. Here, the relevance of age, gender, and genetic and exposure factors on NC susceptibility was studied in 649 inhabitants of a rural community of Mexico. Endemicity was confirmed by the high prevalence of pig cysticercosis (32.8%) and human seroprevalence (43.8%). Human NC cases were diagnosed by computerised tomography scans. A questionnaire to evaluate risk factors was applied and familial relationships between participants were registered. An overall NC frequency of 9.1% (59/649) was found. NC frequency increased with age but did not associate with gender. Most NC cases were asymptomatic. None of the evaluated risk factors were associated with NC. No familial aggregation was detected when studying all cases, although a significant relationship between mother and child in cases with multiple parasites was found. These findings point to the fact that human NC in high exposure conditions is not simply related to exposure factors and they do not support the participation of a major gene in single-cyst NC. Rather, our results point to a complex interaction of genetic and environmental factors involved in NC.

Control of Taenia solium taeniasis/cysticercosis: From research towards implementation

Theoretically, considering the biology of its transmission and reservoirs, global eradication of Taenia solium taeniasis and cysticercosis is feasible. Recently much progress has been made in research on diagnosis, treatment and prevention of human taeniasis and porcine cysticercosis, although more operational research is still needed. In spite of this, global eradication of T. solium infection is still unlikely in the near future. Major obstacles to practical implementation of control measures include low levels of sanitation and health education amongst endemic populations, ineffective health services infrastructure and inadequate socioeconomic development in these areas. The continued public health impact of neurocysticercosis, especially fatalities and epilepsy, force us to identify improved options for control. In order to implement control measures in highly endemic areas the active involvement of medical services in controlling T. solium infection and more effective collaboration between medical and veterinary services is necessary. A switch is suggested from total reliance on meat inspection to active diagnosis and treatment of human taeniasis, protection of pigs against infection, promotion of health education and improved surveillance preparing chemotherapeutic and/or sanitary interventions. This could be implemented in areas where active transmission causes substantial morbidity and mortality provided there is the political will, social support, better financing and an effective organizational framework.

Cysticercus antibodies and antigens in serum from blood donors from Pondicherry, India

The aim of the present study was to screen the serum of blood donors, which are apparently healthy and residing in Pondicherry or its neighboring districts of Tamil Nadu State, for specific detection of Cysticercus antigens and antibodies. A total of 216 blood samples were collected from blood donors at the Central Blood Bank, JIPMER Hospital, Pondicherry, India during January and February 2004. Enzyme-linked immunosorbent assay (ELISA) was used to demonstrate anti-Cysticercus antibodies and the Co-agglutination (CoA) was used to detect antigen in sera. 14 (6.48 %) males were positive for either anti-Cysticercus antibodies or antigens. Of these eight sera were positive for anti-Cysticercus antibodies and six were positive for antigens. Results of the present study show that serum Cysticercus antigen detection may be a useful adjunct to antibody testing for seroprevalence studies of cysticercosis in the community. The present study is the first kind of study, carried out to determine both cysticercal antibodies as well as antigens in the serum samples collected from the healthy blood donors.

Methods for assessing the burden of parasitic zoonoses: echinococcosis and cysticercosis

Cysticercosis and echinococcosis cause illness and productivity losses in human and agricultural animal populations. Recent studies suggest that these diseases have large societal impacts on endemic areas. Estimates of burden provide essential, evidence-based data for conducting cost-benefit and cost-utility analyses that will secure political will, and financial and technical resources. To evaluate the burden, the monetary and non-monetary impacts of these zoonoses on human health, agriculture and society must be considered comprehensively. In this article, we review the framework used to assess the burden of cysticercosis and echinococcosis, and the data needed to estimate the extent of the problem for societies.

Correlative MR imaging and histopathology in porcine neurocysticercosis

PURPOSE

To examine whether all the histopathologically seen features of cysticercus cysts excised from brain of swine naturally infected with neurocysticercosis during its evolution are actually visible on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Five swine naturally infected with cerebral cysticercosis were subjected to fast spin-echo (SE) T2, SE T1, fluid attenuated inversion recovery imaging, T1-weighted magnetization transfer (MT), and postcontrast T1-weighted MT sequences on MRI. These animals were sacrificed after imaging and ex vivo imaging of the intact excised brain using the same imaging protocol was also performed. Grossing of these brains was done similar to the ex vivo imaging planes. Numeral density and external appearance of each cyst and scolex were evaluated on each pulse sequence. Amount of pericystic edema, if present, was also assessed. On histopathology, cellular characteristics, inflammatory response, and the extent of edema, if present, in the brain parenchyma around the cysts were graded. Cysts were categorized into viable, early, and late degenerated on histopathology. The MRI features of each cyst were correlated with their histopathologic findings.

RESULTS

Out of 31 cysts, eight were found to be viable, 13 early degenerated, and 10 late degenerated on histopathology. T2-weighted imaging demonstrated all the cysts while T1-weighted imaging showed 97% of the cysts. Scolex was seen in 90.3% and 93.5% of the cysts on T2- and T1-weighted images, respectively. Minimal edema (grade I) and inflammation in degenerating cysts present on histopathology was not visible on MRI. All but one of eight degenerated cysts, which showed enhancement on postcontrast MRI, had edema on imaging as well as on histopathology.

CONCLUSION

T2-weighted MRI demonstrated all the cysts that were visible on histopathology. Non-enhancement of some of the degenerated cysts along with absence of edema on MRI is likely to underestimate the staging of neurocysticercosis evolution, and these early degenerating cysts may be misdiagnosed as in viable stage.

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

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

Vaccination against cestode parasites: anti-helminth vaccines that work and why

Highly effective recombinant vaccines have been developed against the helminth parasites Taenia ovis, Taenia saginata and Echinococcus granulosus. These vaccines indicate that it is possible to achieve a reliable, high level of protection against a complex metazoan parasite using defined recombinant antigens. However, the effectiveness of the vaccines against the taeniid cestodes stands in contrast to the more limited successes which characterise attempts to develop vaccines against other platyhelminth or nematode parasites. This review examines the features of the host-parasite relationships among the taeniid cestodes which have formed the basis for vaccine development. Particular consideration is given to the methodologies that have been used in making the cestode vaccines that might be of interest to researchers working on vaccination against other helminths. In developing the cestode vaccines, antigens from the parasites' infective larval stage contained within the egg (oncosphere) were identified as having the potential to induce high levels of protection in vaccinated hosts. A series of vaccination trials with antigen fractions, and associated immunological analyses, identified individual protective antigens or fractions. These were cloned from cDNA and the recombinant proteins expressed in Escherichia coli. This strategy was independently successful in developing vaccines against T. ovis and E. granulosus. Identification of protective antigens for these species enabled rapid identification, cloning and expression of their homologues in related species and thereby the development of effective vaccines against T. saginata, E. multilocularis and, more recently, T. solium. The T. saginata vaccine provides an excellent example of the use of two antigen components, each of which were not protective when used individually, but when combined they induce a reliable, high level of protection. One important contributing factor to the success of vaccine development for the taeniid cestodes was the concentration on studies seeking to identify native host-protective antigens, before the adoption of recombinant methodologies. The cestode vaccines are being developed towards practical (commercial) application. The high level of efficacy of the vaccines against T. solium cysticercosis and hydatid disease suggests that they would be effective also if used directly in humans.

Measures for the prevention and control of Taenia solium taeniosis and cysticercosis

Taeniosis and cysticercosis due to Taenia solium are public health problems in many developing countries. Many studies of this parasitic zoonosis have focused on clinical features, diagnosis, treatment, surveillance, epidemiology and risk factors analysis. More recently projects on community and mass intervention strategies had been conducted in several rural areas worldwide focused on pig vaccination, pig cysticercosis treatment, human mass treatment, infrastructure development, as well as health education campaigns. Their advantages, disadvantages and public health impact have been published. This document discusses the feasibility and limitations of these interventions in order to assist countries in selection the best strategy for the prevention and control of this disease; we emphasized the specific strategies that might be recommended in different demographical situations.

Characterization of the 8-kilodalton antigens of Taenia solium metacestodes and evaluation of their use in an enzyme-linked immunosorbent assay for serodiagnosis

The Western blot for cysticercosis, which uses lentil lectin purified glycoprotein (LLGP) antigens extracted from the metacestode of Taenia solium, has been the "gold standard" serodiagnostic assay since it was first described in 1989. We report that the diagnostic antigens at 14, 18, and 21 kDa, as well as some larger disulfide-bonded antigens, are actually all members of a very closely related family of proteins, the 8-kDa antigens. The genes for 18 unique, mature proteins have been identified. Nine of these were chemically synthesized and tested in an enzyme-linked immunosorbent assay with a battery of defined serum samples, including 32 cysticercosis-positive serum samples reactive with the 8-kDa antigens of LLGP on Western blotting, 34 serum samples from patients with other parasitic infections, and 15 normal human serum samples. One of the 8-kDa antigens, TsRS1, is 100% sensitive and 100% specific. TsRS1 will be one component of a cocktail of three to four synthetic or recombinant antigens, based on the diagnostic bands of the Western blot, which will be used for the serodiagnosis of cysticercosis.

Neurocysticercosis: regional status, epidemiology, impact and control measures in the Americas

The analysis of epidemiological data concerning human cysticercosis point to important advances in understanding the magnitude and distribution of this parasitic disease in Latin America, as well as the relationship of the elements that conform the life cycle of Taenia solium. The data indicate that the main risk factor for acquiring human neurocysticercosis and swine cysticercosis is the presence of the tapeworm carrier in the household. Therefore, several intervention measures for the control of cysticercosis have been evaluated: mass treatment in order to cure tapeworm carriers, health education towards understanding the risk factors, pig control by restraining them, experimental vaccination of pigs and treatment of swine cysticercosis. In this paper, we review the information obtained in these areas. We hope it will be useful in other endemic countries that wish to elaborate an action plan for the control and ultimate eradication of T. solium.

Taeniasis and cysticercosis prevalence in a small village from Northeastern Brazil

Although not considered as an endemic region, the Northeast of Brazil has the necessary conditions for the development of taeniasis-cysticercosis complex. In a previous paper, we demonstrated that Mulungu do Morro municipality, in the State of Bahia, has a high seroprevalence to cysticercosis in epileptic patients.

OBJECTIVE

to determine the prevalence of taeniasis and positive cysticercosis serology in the population of Mulungu do Morro.

METHOD

blood and stool samples were collected from a random sampling of the population, by family. The identification of antibodies against T. solium cysticerci was made by EITB and T. solium antigens were identified using a polyclonal antibody-capture ELISA.

RESULTS

the cysticercosis seroprevalence was 1.6% (C.I. = 0.8 to 2.8%) and the taeniasis prevalence 4.5% (C.I. = 3.0 to 6.5%). Seropositivity to cysticercosis was higher among those who lived in a house of a person testing positive for coproantigen, p=0.017.

CONCLUSION

our results demonstrate that the taeniasis-cysticercosis complex is endemic in Mulungu do Morro. We believe that all areas in the world with the same socio-economic and sanitary characteristics are likely to have high prevalence of this parasite.

Evaluation of the enzyme-linked immunoelectrotransfer blot assay for diagnosis of neurocysticercosis in children

Neurocysticercosis is a common problem in developing countries, and it causes neurologic disorders in children. Immunodiagnosis with Taenia solium glycoproteins as an antigen has been validated in adults but not in children. The aim of this work was to evaluate a Taenia solium glycoproteins-based enzyme-linked immunoelectrotransfer blot assay in children with neurocysticercosis. Twenty-five confirmed cases of neurocysticercosis and 50 healthy children from the same community were included. The test had a sensitivity of 72% and a specificity of 96%. Sensitivity was higher (100%) in cases with multiple cysts and in multiple sites. Sensitivity was higher when cysts were in parenchyma (86%) than when they were in the subarachnoid space. The most frequently recognized proteins were 24, 39 to 42, and 50 kDa. Diagnosis was more efficient in serum than in cerebrospinal fluid. Western blot is a reliable method for serologic diagnosis of neurocysticercosis in children. Multiple cysts and infections in multiple sites elicited a stronger immune response.

Multiparametric quantitation of the perilesional region in patients with healed or healing solitary cysticercus granuloma

The purpose of this study was to compute T2 values and magnetization transfer (MT) ratios in the perilesional region of healing and healed cysticercus granulomas to determine if there are T2 abnormalities not apparent on conventional T2-weighted imaging and to determine the relationship between seizure control and the quantitative measures. Sixty-three patients were studied. T2 values and MT ratios were computed for the perilesional region and were compared with measurements from the contralateral normal-appearing region. A significantly increased T2 value was found for the perilesional region compared to the corresponding contralateral region despite the absence of qualitative abnormality on conventional T2-weighted magnetic resonance imaging. For patients showing normal-appearing perilesional regions on MT imaging, there was no significant difference in T2 and MT ratios between the perilesional and the normal contralateral regions. There was a statistically significant inverse correlation between perilesional T2 values and MT ratios, suggesting each was associated with perilesional gliosis. The study illustrates that quantitative evaluation of MT ratios and T2 augments the qualitative visual assessment of the perilesional region in healing or healed cysticercus granulomas.

[Neurocysticercosis: a clinical and pathological study of 27 necropsied cases]

Neurocysticercosis is the most frequent and widespread neuroparasitosis of the human being. The development of brain and leptomeningeal lesions, with subsequent symptoms, are mainly related with the immune status of the host, and to the number and evolutional phase of the parasites. We present the pathological findings in 27 necropsies of patients with neurocysticercosis, which accounted for 3.1% of the necropsies. 77% of the patients were male and the age ranged from 18 to 85 years. In 26% there was previous history of alcoholism. Clinicopathological study showed that 50% of the cases were classified as asymptomatic form, 11% epileptic form, 11% intraventricular form and 11% combined form. 33% of the patients presented seizures as a factor of aggravation of the clinical picture. There was a single cysticercus in 60% of the cases, the cellulosae form present in 82% and the racemous form in 7% of the cases; the remaining 11% had both forms present. In 30% of the patients the cause of death was directly related with the presence of the cysticercus in the central nervous system. Our findings confirm the high morbidity of this disease.

Taenia solium cysticercosis

Cysticercosis, the infection of the larval tissue stage of the pork tapeworm, Taenia solium, is endemic to most developing countries and increasingly is seen in industrialized countries because of immigration. Human infection is a major cause of acquired epilepsy, and porcine infection causes important economic losses to farm workers. Clinical manifestations vary because of the variable number, size, and location of the cysts and the immune response of the host. Diagnosis is based on imaging techniques (CT and MR imaging) and serology (immunoblot). Current research efforts are centered on control and eradication of the taeniasis cysticercosis complex in endemic areas.

Differentiating Taenia solium and Taenia saginata infections by simple hematoxylin-eosin staining and PCR-restriction enzyme analysis

Species-specific identification of human tapeworm infections is important for public health purposes, because prompt identification of Taenia solium carriers may prevent further human cysticercosis infections (a major cause of acquired epilepsy). Two practical methods for the differentiation of cestode proglottids, (i) routine embedding, sectioning, and hematoxylin-eosin (HE) staining and (ii) PCR with restriction enzyme analysis (PCR-REA), were tested on samples from 40 individuals infected with T. solium (n = 34) or Taenia saginata (n = 6). Microscopic examination of HE staining of sections from 24 cases, in which conserved proglottids were recovered, clearly revealed differences in the number of uterine branches. Distinct restriction patterns for T. solium and T. saginata were observed when the PCR products containing the ribosomal 5.8S gene plus internal transcribed spacer regions were digested with either AluI, DdeI, or MboI. Both HE histology and PCR-REA are useful techniques for differentiating T. solium from T. saginata. Importantly, both techniques can be used in zones of endemicity. HE histology is inexpensive and is currently available in most regions of endemicity, and PCR-REA can be performed in most hospital centers already performing PCR without additional equipment or the use of radioactive material.

Magnitude of the disease burden from neurocysticercosis in a developing country

Cysticercosis contributes to higher epilepsy rates in developing countries than in industrialized ones, yet no estimate exists for the associated burden of disease. We used epidemiological data on neurocysticercosis in Peru to calculate the burden of disease and applied our model to the other countries of Latin America where neurocysticercosis is endemic to determine a regional estimate. Analysis of 12 population-based community studies demonstrated that neurocysticercosis was endemic in highland areas and high jungles, with seroprevalences from 6% to 24%. In one community, the adult seizure disorder rate was 9.1% among seropositive persons versus 4. 6% among seronegative persons; we used this difference for estimates. On the basis of average prevalence rates in areas of endemicity of 6%-10%, we estimated that there are 23,512-39,186 symptomatic neurocysticercosis cases in Peru. In Latin America, an estimated 75 million persons live in areas where cysticercosis is endemic, and approximately 400,000 have symptomatic disease. Cysticercosis contributes substantially to neurological disease in Peru and in all of Latin America.

Serological diagnosis of human cysticercosis by use of recombinant antigens from Taenia solium cysticerci

A Taenia solium metacestode cDNA expression library in the lambda ZAPII vector was screened with pooled sera from patients with neurocysticercosis. Sixty primary clones were identified and shown to belong to two classes. The clones NC-3 and NC-9 did not reveal any significant homologies to sequences deposited in the databases and were further characterized. Both recombinant antigens were expressed as glutathione S-transferase fusion proteins and applied for serological diagnosis of human cysticercosis. An enzyme-linked immunosorbent assay was established and evaluated with 27 serum samples of La Réunion and Madagascar patients with cysticercosis. Diagnosis in these patients was established with radiological and serological procedures. For antigen NC-3 a sensitivity of 96.3% and a specificity of 91.5% for the serodiagnosis were achieved. In contrast, the sensitivity of antigen NC-9 was only 33.3%.

Diagnosis of human neurocysticerocosis in endemic countries: a clinical study in Honduras

With the purpose of evaluating the available methodology for neurocysticercosis (NCC) diagnosis, 60 neurological patients were studied during a 4-year period in Honduras. Neurological evaluation, Computed Tomography (CT), cysticercosis Enzyme-Linked Immunoelectrotransfer blot (EITB) assay, electroencephalographic studies, and collection of epidemiological information were performed to assess a final diagnosis. The presenting clinical manifestations were: epileptic seizures (52%), headache without intracranial pressure (27%) and intracranial hypertension (10%). A protocol for the diagnosis of NCC is suggested. According to this protocol, patients with active (live) cysticercus and/or antibodies in Cerebrospinal fluid (CSF) were diagnosed as definitive cases of NCC, whereas those with only brain calcifications were diagnosed as probable cases. NCC diagnosis was definitive in 14 (23%) patients, probable in 32 (54%) and ruled out in 14 (23%). Of the patients with epileptic seizures, six (19%) had definitive and 20 (65%) had probable NCC. Overall seropositivity was 28%. EITB positivity varied from 14 to 100%, and from 20 to 35% in definitive and probable cases of NCC, respectively. When compared to CT, EITB overall sensitivity for definitive, active cases, was 50% in serum and 63% in CSF. These results suggest that brain images combined with neurological evaluation remains the best approach for neurocysticercosis diagnosis, and that EITB, even though its variable sensitivity, offers valuable information, especially if performed in CSF.

Subcutaneous cysticercosis

With the increasing numbers of immigrants coming to the United States from areas where Taeniasis and cysticercosis are endemic, it is important to be familiar with some of these more common entities. We present a patient with both neurologic and soft tissue cysticercosis as well as a review of the available literature.

Prevalence of taeniasis and cysticercosis in a population of urban residence in Honduras

To determine the prevalence of antibodies to Taenia solium and taeniasis in a population of urban residence, an epidemiological study was carried out in a military institution located in Tegucigalpa, the capital city of Honduras. A total of 404 persons were interviewed to collect epidemiological data, investigate antibodies to T. solium cysticercus by the enzyme-linked immunoelectrotransfer blot (EITB) assay and taeniasis by Ritchie's concentration technique. A total of 41 persons that were living at the headquarters and were traveling frequently to their rural hometowns were regarded as rural residents, the remaining 363 persons were considered urban residents. The seroprevalence of antibodies was 22% (9/41) in the rural residents and 15% (54/363) in the urban residents. The overall seroprevalence was 15.6% (63/404). Analyses of risk factors for seropositivity in the urban residents showed that seropositivity was statistically associated with poor household conditions such as raising pigs (odds ratio (OR), 5.39; 95% confidence interval (CI), 1.42-19.50), lack of potable water (OR, 3.66; CI, 1.25-9.94), lack of sanitary toilet (OR, 2.92; CI, 1.35-6.05) and earthen floor (OR, 2.48; CI, 1.28-4.73). Also seropositivity was associated with low academic education (OR, 2.5O; CI, 1.33-4.69) and lack of knowledge about the parasite (OR, 2.39; CI, 1.26-4.49). Out of 328 persons examined for intestinal parasites, two soldiers (0.6%) coming from rural areas were identified as Taenia sp. carriers. T. solium was identified in one case. Although T. solium infections originate and are more prevalent in rural villages, the high seroprevalence found in this study indicates that they can also be found at important levels in urban communities. Migration of tapeworm carriers from rural areas to the city grants the transmission of cysticercosis when poor environmental and social conditions are present.