Laboratory Diagnosis of Neurocysticercosis (Taenia solium).

Neurocysticercosis accounts for approximately 30% of all epilepsy cases in most developing countries. The immunodiagnosis of cysticercosis is complex and strongly influenced by the course of infection, the disease burden, the cyst location, and the immune response of the host. The main approach to immunodiagnosis should thus be to evaluate whether the serological results are consistent with the diagnosis suggested by imaging. Antibody detection is performed using lentil lectin-purified parasite antigens in an enzyme-linked immunoelectrotransfer blot format, while antigen detection uses a monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA). Promising new assay configurations have been developed for the detection of both antibody and antigen, including assays based on synthetic or recombinant antigens that may reduce costs and improve assay reproducibility and multiplex bead-based assays that may provide simultaneous quantitative results for several target antigens or antibodies.

[Transverse myelitis associated with toxocariasis and the importance of locally produced antibodies for diagnosis]. / Toksokariyaza bagli bir transvers miyelit olgusu ve tanida yerel antikor üretiminin önemi.

Toxocariasis caused by Toxocara canis or less frequently by T.catis is a common parasitic infection worldwide. Clinical spectrum in humans can vary from asymptomatic infection to serious organ disfunction depending on the load of parasite, migration target of the larva and the inflammatory response of the host. Transverse myelitis (TM) due to toxocariasis is an uncommon illness identified mainly as case reports in literature. In this report, a case of TM who was diagnosed as neurotoxocariasis by serological findings has been presented. A 44-year-old male patient complained with backache was diagnosed as TM in a medical center in which he has admitted two years ago, and treated with pregabalin and nonsteroidal drugs for six months. Because of the progression of the lesions he readmitted to another center and treated with high dose steroid therapy for three months. After six months of follow up, improvement has been achieved, however, since his symptoms reccurred in the following year he was admitted to our hospital. Magnetic resonance imaging (MRI) examination revealed a TM in a lower segment of spinal cord. He was suffering with weakness and numbness in the left lower extremity. There was no history of rural life or contact with cats or dogs in his anamnesis. Physical examination revealed normal cranial nerve functions, sensory and motor functions. There has been no pathological reflexes, and deep tendon reflexes were also normal. Laboratory findings yielded normal hemogram and biochemical tests, negative PPD and parasitological examination of stool were negative for cysts and ova. Viral hepatitis markers, anti-HIV, toxoplasma-IgM, CMV-IgM, rubella-IgM, EBV-VCA-IgM, VDRL, Brucella tube agglutination, echinococcus antibody, autoantibody tests and neuromyelitis optica test were negative. Examination of CSF showed 20 cells/mm3 (mononuclear cells), 45 mg/dl protein and normal levels of glucose and chlorine. In both serum and CSF samples of the patient Toxocara-IgG antibodies were detected by Western blot (WB) assay. Low molecular weight bands (30-40 kDa) were detected in both of the samples by repeated WB testing. CSF revealed more intense bands suggesting local antibody production. Therefore the patient was diagnosed as neurotoxocariasis, and treated with steroid and mebendazole for six weeks. Clinical improvement was detected in the case and thoracic MRI revealed significant improvement in myelitis signs two months after treatment. In conclusion, toxocariasis should be considered in the differential diagnosis of TM although the involvement of central nervous system is rare and serological testing should be performed properly in the serum and CSF samples for the diagnosis.

Toxocara encephalitis presenting with autonomous nervous system involvement.

Human toxocariasis has been reported to cause a broad spectrum of neurological syndromes, including encephalitis, meningitis and meningo-radiculitis. Nevertheless, cerebral infection by Toxocara may go undiagnosed due to its rarity, elusive symptoms and lack of availability of appropriate testing. We report the case of a 54-year-old man who presented with abdominal pain and paralytic ileus approximately 3 weeks after having eaten raw snails (a folk remedy for peptic ulcer). Three weeks later, marked eosinophilia ensued, associated with mental clouding, nystagmus, diplopia, peripheral limbs ataxia, urinary retention, slackened deep tendon reflexes, arthralgias and myalgias. Cerebrospinal fluid (CSF) examination demonstrated an eosinophilic meningitis, and Toxocara canis cerebral infection was diagnosed by positive serology and by the detection of T. canis DNA in the CSF. The patient made a full recovery following treatment with albendazole and corticosteroids. Physicians should be aware of this rare presentation of toxocariasis, whose diagnosis is, today, facilitated by molecular biology techniques. A history of ingestion of raw snails may alert the clinician to consider the possibility of such an uncommon condition.

Meningitis by Toxocara canis after ingestion of raw ostrich liver.

Recently reports on toxocariasis are increasing by serodiagnosis in Korea. A previously healthy 17-yr-old boy complained of headache, fever, dyspnea, and anorexia. He showed symptoms and signs of eosinophilic meningitis with involvement of the lungs and liver. Specific IgG antibody to Toxocara canis larval antigen was positive in serum and cerebrospinal fluid by ELISA. He took raw ostrich liver with his parents 4 weeks before the symptom onset. His parents were seropositive for T. canis antigen but had no symptoms or signs suggesting toxocariasis. This is the first report of toxocariasis in a family due to ingestion of raw ostrich liver in Korea.

Human neurocysticercosis: comparison of different diagnostic tests using cerebrospinal fluid.

Neurocysticercosis (NC), caused by the larval stage of Taenia solium, is one of the most common parasitic diseases of the central nervous system. The diagnosis of NC is mostly based on costly brain neuroimaging (computed tomography and/or nuclear magnetic resonance), which is rarely accessible in most affected areas. The most sensitive and specific tools for NC diagnosis are imagery techniques. The identification of specific antibodies and antigens is currently used only to support NC diagnosis due to their limited specificity and sensitivity. This study was performed to compare immunodiagnostic assays (antibody detection by enzyme-linked immunosorbent assay [ELISA] and enzyme-linked immunoelectrotransfer blotting [EITB] and HP10 antigen detection by ELISA) with the detection of parasite DNA by PCR amplification of a repetitive element of the parasite genome in the cerebrospinal fluid (CSF) of 121 radiologically and clinically characterized NC patients. Patients were divided into six groups according to the stage of the parasites and their localization. The CSF cellularity of each patient was also recorded. When all patients were considered, PCR exhibited the highest sensitivity (95.9%) and variable specificity (80% or 100%) depending on the controls used. The sensitivities of antibody detection by ELISA and EITB were not significantly different, and ELISA identified HP10 antigen mostly when vesicular cysticerci were located in the subarachnoideal basal cisterns. These results can help in the selection of different individual assays or combinations of assays to be used in NC diagnosis according to different requirements.

Bioactive molecules of Taenia solium metacestode, a causative agent of neurocysticercosis.

Neurocysticercosis (NC), an infection of the CNS with Taenia solium metacestode, exemplifies formidable public health concerns associated with significant morbidity and mortality. The disease is a complex phenomenon involving molecular cell biological cross-talks between the parasite and human host. To effectively combat NC, specific diagnosis and proper management are prerequisites. Bioactive molecules implicated in host-parasite interactions and parasitic homeostasis should be elucidated. This article provides an overview of currently available serological biomarkers, especially those comprising low-molecular-weight proteins, and discusses available immunoproteomics for identification of such molecules. T. solium metacestode bioactive molecules, which might be critically implicated in the progression of NC disease, are summarized. Comprehensive understanding of the biochemical properties and biological functions of bioactive molecules may contribute to the development of novel intervention strategies against NC.

Case Report: Angiostrongylus cantonensis Meningoencephalitis in a 9-Month-Old Baby in Vietnam.

Meningoencephalitis is not a rare disease in small children. However, eosinophilic meningitis due to Angiostrongylus cantonensis is unusual in a baby. We describe the case of a 9-month-old baby from North Vietnam with eosinophilic meningoencephalitis. The baby lived in a rural area, where farming is widespread, and presented with fever and seizures. Laboratory results showed peripheral eosinophilia (16.1%), cerebrospinal fluid (CSF) white blood cell count 220/mm3 (26% eosinophils), CSF antibody test positive for Ascaris, CSF ELISA positive for Angiostrongylus cantonensis, and blood ELISA positive for A. cantonensis. A mobile worm was identified in the CSF. The presentation was consistent with a diagnosis of A. cantonensis eosinophilic meningitis. The baby recovered fully after administering albendazole (200 mg/day for 2 weeks), and intravenous dexamethasone (0.6 mg/kg/day every 8 hours) and mannitol (1.5 g/kg/day every 8 hours) for the first 3 days, followed by 5 days of oral prednisolone (2 mg/kg/day).

Saline extract of Taenia saginata metacestodes as an alternative antigen for the immunodiagnosis of neurocysticercosis in human cerebrospinal fluid.

The aim of the present research was to test the application of Taenia saginata metacestodes as an alternative antigen for use in enzyme-linked immunosorbent assay (ELISA) and Western Blotting (WB) tests compared with the use of metacestodes antigen of Taenia solium in cerebrospinal fluid (CSF) samples. The samples were obtained from 35 patients with definitive neurocysticercosis (NCC)-group 1-and 44 patients with other neurological disorders (control)-group 2. The sensitivity and specificity of ELISA, using antigen obtained from T. solium, applied to the patients of group 1 yielded results of 100%. When the tests were conducted using T. saginata metacestodes, results were 100% and 93.2%, respectively. The 47-52-, 64-68-, and 70-kDa antigens showed high frequencies in CSF samples from patients with NCC when WB was conducted with both antigens. The results indicate that T. saginata metacestodes can be used as an alternative antigen for the diagnosis of human NCC in CSF samples.

Cognitive dysfunction, urinary retention, and a lesion in the thalamus--beware of possible toxocariasis of the central nervous system.

Toxocariasis of the central nervous system is usually characterized by an eosinophilic meningitis, encephalitis or myelitis. We here report a patient with an at least 7 years history of unexplained neurologic signs and symptoms. MRI showed a cystic lesion in the left thalamus, compatible with a parasitic infection. Blood and CSF analyses were positive for Toxocara canis IgG Western-blot, but were otherwise unremarkable. The case report raises the question whether there are chronic or late variants of this disease.

Reciprocal contribution of clinical studies and the HP10 antigen ELISA for the diagnosis of extraparenchymal neurocysticercosis.

To evaluate diagnosis of active neurocysticercosis, paired cerebral spinal fluid (CSF) and serum samples from 24 neurocysticercosis (NCC) patients and 17 control neurological patients were assayed in the HP10 Taenia antigen (Ag) ELISA. The CSF samples were also tested with an HP10 Lateral Flow Assay (LFA). The HP10 Ag was detected by ELISA in the CSF of 5/5 patients with Definitive extraparenchymal NCC, and in 4/5 of the corresponding sera. In the Definitive parenchymal group, on the other hand, the HP10 Ag was absent in 2/3 CSF (with a very low value in the one positive sample) and all the corresponding serum samples. Samples of CSF from 4/7 patients in the Probable parenchymal group, were also significantly HP10 Ag positive, suggesting the presence of extraparenchymal cysts not identified by the imaging studies. With the possible exception of one patient, the corresponding serum samples of the Probable parenchymal NCC group, were all HP10 Ag negative. Samples of CSF from 9 NCC patients diagnosed with Mixed parenchymal and extraparenchymal NCC were all significantly HP10 Ag positive, confirming the presence of extraparenchymal cysts, with only 7/9 of the corresponding serum samples being HP10 positive. Thus detection of the HP10 Ag indicates extraparenchymal and not parenchymal cyst localization and is more sensitive with CSF than serum. Three neurological patients clinically diagnosed as subarachnoid cyst, hydrocephalus and tuberculoma, respectively, were clearly positive for HP10 Ag. Of these, two were confirmed as NCC by subsequent imaging; the third died prior to further examination. Thus, a total of 8 patients had their clinical diagnosis questioned. Finally, there was good agreement between the HP10 Ag ELISA and LFA with CSF samples giving an optical density ≥0.4 in the ELISA assay. In conclusion, the HP10 Ag assay should provide a valuable and reciprocal tool in the clinical diagnosis and follow up of extraparenchymal NCC.

Detection of HP10 antigen in serum for diagnosis and follow-up of subarachnoidal and intraventricular human neurocysticercosis.

INTRODUCTION: Neurocysticercosis (NC), a parasitic disease caused by Taenia solium, may be either asymptomatic or show a mild to severe clinical picture with intracranial hypertension. The most severe form of the disease is caused when viable cysticerci are localised in the ventricles or in subarachnoidal cisterns at the base of the skull. Detection of the secreted metacestode antigen HP10 in cerebrospinal fluid is a sensitive and specific method for the diagnosis of these severe NC cases. OBJECTIVE AND METHODS: To evaluate the validity of HP10 antigen detection ELISA when applied to serum, using paired serum and cerebrospinal fluid samples from 116 radiologically and clinically characterised NC patients. RESULTS: The HP10 antigen assay exhibited a similarly high sensitivity in identifying severe NC cases from sera (84.8%) and CSF (91.3%). In contrast, HP10 antigen was rarely detected in asymptomatic or mild NC cases (3 of 57). Importantly, the HP10 antigen assay applied to serum showed high specificity (94%) when used in 126 serum samples of non-NC subjects from an endemic community with a confirmed coproparasitological diagnosis of intestinal parasitic infections. Finally, the HP10 assay also proved to be of value in the follow-up of treated patients. CONCLUSION: This study confirms that detection of the metacestode HP10 antigen in serum is a useful tool for diagnosis and follow-up of patients with severe forms of NC treated with cysticidal drugs.

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.

Eosinophilic meningitis associated with angiostrongyliasis: clinical features, laboratory investigations and specific diagnostic IgG and IgG subclass antibodies in cerebrospinal fluid.

Eosinophilic meningitis (EOM) associated angiostrongyliasis mostly induced by the nematode Angiostrongylus cantonensis, is a common disease with worldwide prevalence. Heavy infections can lead to chronic disabling disease and even death. This study was conducted to shed light on the overall specific IgG antibody response as well as the specific IgG antibody subclass responses in cerebrospinal fluid (CSF) of patients with EOM. Fifteen patients with EOM associated with angiostrongyliasis were included in the study. Sera were screened by immunoblotting for the presence of IgG antibody to the 29 kDaA. cantonensis antigenic polypeptide. CSF was examined by ELISA for the presence of specific IgG and IgG subclass antibodies. Patients presented with headache (100%), neck stiffness (20%), fever (40%), nausea (87%), vomiting (73%), paresthesia (7%), and muscle weakness (7%). Seven of 15 (47%) patients showed peripheral blood eosinophilia and all patients presented with eosinophils in CSF. A sensitivity of 80 % was obtained by combining the diagnostic values of immunoblotting in sera and IgG and IgG subclasses-based ELISA in CSF. The combination of a history of eating raw or semi-cooked infected foods, clinical features, complete blood count, differential cell counts, CSF profiles, and serum and CSF antibodies to A. cantonensis can be used to increase the sensitivity for the diagnosis of human angiostrongyliasis.

Evaluation of Taenia solium and Taenia crassiceps cysticercal antigens for immunodiagnosis of neurocysticercosis using ELISA on cerebrospinal fluid samples.

The efficacy of whole parasite and vesicular fluid antigen extracts from Taenia solium and Taenia crassiceps cysticerci for immunodiagnosis of neurocysticercosis was evaluated using ELISA on cerebrospinal fluid samples. Anticysticercal IgG antibodies were assayed in cerebrospinal fluid samples from 23 patients with neurocysticercosis and 35 patients with other neurological disorders. The ELISA reaction for the whole Taenia solium cysticercal extract showed 91.3% sensitivity and 94.3% specificity, whereas the sensitivity and specificity of the ELISA for the whole Taenia crassiceps cysticercal extract were 87% and 94.3%, respectively. The ELISA reactions for vesicular fluid from Taenia solium or Taenia crassiceps showed 91.3% sensitivity and 97.1% specificity. Considering the results obtained from the four antigen preparations, vesicular fluid from Taenia solium and Taenia crassiceps cysticerci may be useful as a source of antigens for immunological reactions that are used for detecting specific antibodies in cerebrospinal fluid samples from patients with neurocysticercosis.

Antigenic fractions from Taenia crassiceps metacestodes obtained by hydrophobicity for the immunodiagnosis of active and inactive forms of neurocysticercosis in human cerebrospinal fluid samples.

This study aimed to evaluate the total extract of Taenia crassiceps metacestodes (TC) and its antigenic fractions obtained by Triton X-114 fractionation techniques, such as detergent (DC) and aqueous (AC), in the immunodiagnosis of human neurocysticercosis (NCC). Cerebrospinal fluid samples were divided into two groups: Group 1 (n=40), which was further divided into active (n=20) and inactive (n=20) NCC, and Group 2 (control group), which comprised 39 CSF samples from patients who had another neurological disorder, were suffering from other infectious diseases of the brain or had other parasitic infections. The total extracts and antigenic fractions were tested by enzyme-linked immunosorbent assay (ELISA) to detect human IgG anti-Taenia solium. T. crassiceps fractions (DC and AC) showed the same value of sensitivity (Se), 100%, for active and inactive NCC and a specificity (Sp) of 97.4%. The DS fraction obtained from T. solium showed 100% Se for active NCC, 95% Se for inactive NCC and a 92.3% Sp. The AS fraction obtained from T. solium showed 100% Se for both active and inactive NCC and a 94.9% Sp. There was a positive correlation between the total saline extract of T. crassiceps (TC) and T. solium (TS) and their fractions (DC, AC, DS and AS). Positive predictive value, negative predictive value, diagnostic efficiency and Youden index were calculated. In conclusion, these results demonstrated that detergent and aqueous fractions obtained from T. crassiceps metacestodes are important sources of specific antigens and are efficient for immunodiagnosis of active and inactive NCC.

Intrathecal synthesis of specific immunoglobulin G antibodies in neurocysticercosis: evaluation of antibody concentrations by enzyme-linked immunosorbent assay using a whole cysticercal extract and cyst vesicular fluid as antigens.

The demonstration of intrathecal antibody production has proven useful for showing the involvement of the central nervous system (CNS) in several diseases. In the present study, the intrathecal synthesis of cysticercus-specific immunoglobulin G (IgG) antibodies was investigated in 30 patients with neurocysticercosis based on calculation of the specific IgG antibody index (AI(IgG)). An AI(IgG) > or =1.5 was considered to be indicative of intrathecal antibody production. Antibody concentrations in serum and cerebrospinal fluid samples were evaluated using an enzyme-linked immunosorbent assay with 2 antigen preparations from Taenia solium cysticerci, namely, a whole cysticercal extract (TsoW) and the vesicular fluid of the parasite (TsoVF). Intrathecal, cysticercus-specific IgG antibody synthesis was observed in 21 (70%) and 23 (76.6%) patients using the TsoW and TsoVF antigens, respectively. The detection of the intrathecal synthesis of specific antibodies may be a potentially useful tool in establishing the involvement of CNS in cysticercosis.

Necrotizing retinitis induced by Angiostrongylus cantonensis.

PURPOSE: To describe a case of bilateral necrotizing retinitis induced by Angiostrongylus cantonensis. DESIGN: Interventional case report. METHODS: A 52-year-old Asian woman developed eosinophilic meningitis after eating several undercooked snails. One week later, sudden onset of vision loss was noted in both eyes. Widespread yellow retinal exudates were accompanied by bullous retinal detachment in both eyes. RESULTS: Angiostrongylus cantonensis infection was confirmed by positive enzyme-linked immunosorbent assay of the serum and cerebrospinal fluid, and a positive Western blot test of the subretinal fluid. After treatment with mebendazole, levamisole, and corticosteroid, these necrotizing patches regressed gradually. However, the final visual acuity was no light perception. CONCLUSIONS: Angiostrongylus cantonensis infection should be considered as one of the causes of necrotizing retinitis.

Recombinant expression of Taenia solium TS14 antigen and its utilization for immunodiagnosis of neurocysticercosis.

In order to evaluate the potential use of TS14 antigen in an enzyme-linked immunosorbent assay (ELISA) for immunodiagnosis of neurocysticercosis (NC), its open reading frame (ORF) was amplified by RT-PCR from mRNA isolated from Taenia solium cysticerci. The ORF was subcloned into the expression vector pET-28a, and was used to transform Escherichia coli BL21 (DE3) cells to produce TS14 antigen. The His-tagged expressed protein was purified on a nickel affinity column. Using the HISTS14 as antigen, ELISA was positive for 100% of cerebrospinal fluid (CSF) and 97% of serum samples from NC patients. No positive results were observed with sera and CSF samples from control groups. Cross-reactivity with sera from patients with schistosomiasis and Chagas' disease was not observed. Serum samples from patients with taeniasis were evaluated and 2 of 13 cases showed reactivity in this assay. Our data indicate the usefulness of HISTS14 in ELISA for an accurate and rapid assay for diagnosis of NC and seroepidemiological studies.

Cerebral Sparganosis in Children: Epidemiologic and Radiologic Characteristics and Treatment Outcomes: A Report of 9 Cases.

BACKGROUND: Pediatric cerebral sparganosis has been seldom reported. In the current study, we retrospectively reviewed the clinicopathologic records of 9 consecutive pediatric cases of cerebral sparganosis and analyzed their epidemiologic characteristics and clinical outcomes. METHODS: Our cases included 6 boys and 3 girls, all from rural areas, and their median age at diagnosis was 9.4 (range, 5.8-12.9) years. The median duration of symptoms from onset to definite diagnosis was 21 months (range, 1 week to 3.7 years). RESULTS: Enzyme-linked immunosorbent assay revealed that serum anti-sparganosis antibody was positive in 9 of 9 patients and cerebrospinal fluid anti-sparganosis antibody was positive in 4 of 6 patients. Eight patients underwent craniotomy the removal of worms. The patients also received oral praziquantel. They were followed up for 2.2 years to 4.4 years. One patient died, and 8 patients survived. Three cases had poor outcomes whereas the outcome of the remaining 5 cases was satisfactory. CONCLUSIONS: Children are more at risk for sparganosis and cerebral sparganosis may be missed because of unclear epidemiologic history and nonspecific manifestations. Cerebrospinal fluid eosinophil counts and enzyme-linked immunosorbent assay for anti-sparganosis antibody and computed tomography/magnetic resonance imaging scans may be relied on for an early and accurate diagnosis before surgery.