Diagnosis Of Human Cysticercosis Research Articles

Evaluation of ELISA kit for detection of serum specific IgG antibodies against Taenia solium in diagnosis of human cysticercosis

To evaluate the ELISA kit for detection of IgG antibodies against Taenia solium cysticercus in humans, so as to provide a reference for its application in clinical practice. The sera collected from the patients with neurocysticercosis, echinococcosis, taeniasis and healthy people, respectively, were checked by ELISA for specific IgG antibodies against T. solium cysticercus, as described in the instruction of the kit. Of the 30 patients with neurocysticercosis at active stage, 28 showed seropositive reaction, indicating a sensitivity of 93.33%. There were no positive reactions in the 100 healthy people. Two of the 42 persons with taeniasis were seropositive with an infection rate of 4.76%. Forty-one of the 60 persons with echinococcosis showed positive reactions, suggesting that the cross reaction rate of the kit with echinococcosis was 68.33%. The assessed ELISA kit has a reasonably high sensitivity but a poor specificity, and the cross reaction rate with echinococcosis is very high. It is urgent to improve the sensitivity and specificity of the diagnostic kit for detection of T.solium cysticercosis in China.

Utility of a Protein Fraction with Cathepsin L-Like Activity Purified from Cysticercus Fluid of Taenia solium in the Diagnosis of Human Cysticercosis

Neurocysticercosis, an endemic parasitic disease in most developing countries, is caused by Taenia solium and compromises the human central nervous system. Cathepsin L-like proteases are secreted by several parasites including T. solium and constitute important antigens for immunodiagnostics. A protein fraction with cathepsin L-like activity was purified from the cysticercus fluid by size exclusion and ion exchange chromatography. Cathepsin L-like activity was measured fluorometrically by detecting the hydrolysis of the fluorogenic substrate Z-Phe-Arg-AMC. The purified protein fraction included antigens of 53 and 25 kD that were tested in a Western immunoblot and in an enzyme-linked immunosorbent assay (ELISA) for detection of human cysticercosis. The sensitivity of the Western immunoblot was 96% for patients infected with multiple cysts and 78% for patients with a single cyst. Specificity was 98%. The sensitivity of the ELISA was 98% in patients with multiple cysts and 84% in patients with a single cyst. Specificity was 92.7%.

A Novel Taenia solium Protein That Resembles Troponin T Proteins

Taenia solium Linnaeus, 1758 is responsible for taeniasis and cysticercosis, which are 2 serious health problems, particularly in developing countries. The attempt to identify a 22.5kD possible protective oncospheral antigen by 2-dimensional gel-electrophoresis, micro-sequencing, and cDNA library screening produced a protein of 42kD that possesses a conserved domain similar to that of troponin T. Five variants that showed differences at the 5' end were observed at the cDNA level. Hyper-immune rabbit sera developed against recombinant GST fused protein identified the protein exclusively on activated oncospheres. The 42kD protein was tested in an enzyme-linked immunoassay (ELISA) alone and then together with the Tso31 protein for the diagnosis of human cysticercosis. When both antigens were combined, the test was found to be 85% sensitive and 65% specific. The 42kD is a novel T. solium protein that is present exclusively on activated oncospheres of this parasite, with poor diagnostic activity against taeniasis or human cysticercosis.

Cysticercosis diagnostic methods in autopsies

Results: The cysticercosis occurred in 3.2% of the perfomed autopsies, and the NCC was specially more frequent in white man around 50 years old. However in non-white patients the cardiac cysticercosis was significantly more frequent, as well as the observation in other parasitic diseases. Macroscopically, the cysticercosis is a cystic lesion with area varying from 40.40 to 54.09 mm and with its characteristic membrane. The evolutive stages of the cysticerci were determined in macroscopy as well as in microscopy as VS, CVS, NGS and CNS. Using the morphometric analysis we verified that the cardiac cysticerci are significantly bigger than the encephalic ones. That happens probably because of the greater difficulty of the cyst’s growth in the intracranial cavity. For the first time in the literature, the use of the pericardic liquid for the post-mortem diagnosis of cysticercocis by ELISA was described confirming the anatomopathological data found. This study showed the importance of the imagenology in the post-mortem diagnosis of cysticercosis. Using the simple radiography of hearts and brains was possible to detect cysticerci present in the anatomopathological study. The same technique was used to find deep cysticerci that were not externally visible or at the surface of the organ. The host parasite interaction was studied by the analysis of the general pathologic processes and the evolutive characteristics of the cysticerci in the NCC as well as in the CC. This classification showed the correspondence between the macroscopic and microscopic diagnosis. Using the electronic microscopy the ultrastructure of the human and pork cysticerci was comparatively described. Many similarities between the C. cellulosae found in human and in pork were observed. The common structures found in the pork musculature and in the human brain were the tegument and the intern zone. A relevant aspect was that the basal membrane of the pork cysticerci was thinner than the human’s, probably because it was suffering the immunization process. Using the correct conservation of the cysts the extraction of the parasite’s DNA was possible and we used PCR technique to confirm the etiological agent. This diagnosis of human cysticercosis was possible even when we used material from autopsies conserved with formaldeid by several years. It is important to underline the use of the PCR as a method of diagnosis in cysticerci tissues that are in advanced evolutive stages making it possible to identify the taenia species.

Helminth antigens ( Taenia solium, Taenia crassiceps, Toxocara canis, Schistosoma mansoni and Echinococcus granulosus) and cross-reactivities in human infections and immunized animals

Helminth antigens were investigated in the search for accessible heterologous antigens capable to discriminate different helminthiases, by the enzyme linked immunosorbent assay (ELISA) and the immunoblot assay (IB). Antigens used were: Taenia solium cysticercus total saline (Tso); Taenia crassiceps cysticercus vesicular fluid (Tcra-VF); T. crassiceps cysticercus glycoproteins (Tcra-GP and Tcra-(18-14)-GP); Toxocara canis larva excretory-secretory (TES); Schistosoma mansoni adult total saline (Sm) and Echinococcus granulosus hydatid fluid (Eg). The assayed sera were from patients with: cysticercosis ( n=18); toxocariasis ( n=40); schistosomiasis ( n=19) and hydatidosis ( n=50) with proven clinical and laboratory diagnosis, and sera from rabbits immunized with Tso, Tcra-VF, TES and Eg. Cross-reactivity occurred mostly between infections caused by Taenia and Echinococcus or in immunized rabbits, by ELISA. Moreover, the cross-reactivity among helminthiases was found with the use of antigens belonging to phylogenetically related parasite species, Eg, Tso and Tcra-VF, by sharing same antigenic components. Lower cross-reactivities were obtained by IB technique, when only peptides were considered as antigens, and the use of T. crassiceps purified glycoproteins demonstrated high sensitivity and specificity in the diagnosis of human cysticercosis, similarly to that using homologous antigen (Tso) by the same technique.

Cysticercosis and epilepsy: a critical review.

Neurocysticercosis (NC) remains a major public health problem in developing and some developed countries. Currently, the best procedures for diagnosing NC are neuroimaging studies. Immunoserologic assays, such as enzyme-linked immunoelectrotransfer blot assay (EITB) or enzyme-linked immunosorbent assay (ELISA), detect antibodies against Taenia solium, or cysticercus. Consequently, they are useful in identifying a population at risk of contact with the parasite but do not necessarily indicate a systemic active infection. Most seropositive individuals are asymptomatic. No data from prospective studies concern the proportion of these individuals that will develop seizures or other neurologic symptoms. There is a discrepancy between the results of serologic assays and neuroimaging studies: >50% of those individuals with NC diagnosed by computed tomography (CT) scan test EITB negative. Pathophysiologic classification of NC into active, transitional, and inactive forms permits a good correlation between clinical manifestations and neuroimaging procedures and facilitates medical and surgical management and research. The most frequent clinical manifestations of NC are seizures. We assume that NC is the main cause of symptomatic epilepsy in developing countries; however, no case-control or cohort studies demonstrate this association. Most patients with NC with seizures have a good prognosis; nevertheless, further studies analyzing factors related to recurrence of seizures and possibilities of discontinuation of antiepileptic medications (AEDs) are needed. Regarding treatment of NC with antihelminthic drugs, no controlled clinical trials exist that establish specific indications, definitive doses, and duration of treatment. The most effective approach to taeniasis/cysticercosis infection is prevention. This should be a primary public health focus for developing countries. We critically review the available information regarding the epidemiology and diagnosis of human cysticercosis, the physiopathology and imaging correlation of the parasite in the central nervous system (CNS) of the host, the relation between seizures or epilepsy and NC, and the issues surrounding the treatment and prognosis of NC, including the use of antihelminthic therapy.

Specificity of isoelectric focusing-purified antigens in the diagnosis of human cysticercosis.

Specific antigens were isolated from the cystic fluid of larval Taenia solium by preparative isoelectric focusing (PIEF). A total of 20 fractions were produced by a rotating ampholine column with pI 3-10 ampholytes. The specificity of each fraction (F) was tested by double-antibody enzyme-linked immunosorbent assay (ELISA) using antisera from patients suffering from cysticercosis or one of six other parasitic diseases. F8-F15 cross-reacted strongly with sera from patients with hydatidosis. F9 and F10 also cross-reacted with the antisera against ascariasis and F15, with antisera against angiostrongylosis. However, F16 and F17 were highly specific as they yielded no cross-reaction with any of the heterologous antisera. PIEF is a good method for the production of specific antigens from larval T. solium because it is easy to perform and relatively inexpensive to run.

Laboratory Diagnosis of Cysticercosss

Human cysticercosis is caused by cystic tissue larvae of Taenia solium acquired by ingesting the eggs of the T. solium tapeworm. The diagnosis of human cysticercosis can be made by radiologic imaging, tissue biopsy, or serology. Radiologic imaging, including MRI and CT, currently is the most effective means for diagnosis.

Taeniasis-cysticercosis in Honduras

Data on human taeniasis and human and animal cysticercosis from Honduras were gathered from laboratory, medical and slaughterhouse records, proglottid identification and surveys. The infection rate for human taeniasis was 2·7 1000 individuals at the University Hospital, 10 1000 in the southern provinces of Choluteca and Valle, and 0·6 1000 in Cortes and Atlantida in the north. In surveys, the rates found ranged from 14 to 62 1000 in 9 of 15 communities studied. Taenia solium was identified in 135 of 181 individuals (74·5%) who submitted proglottids for speciation, 23 of whom were children 0–5 years old. The male:female ratio of infection rate was 1:2. The rates of infection with cysticercosis in pigs and cattle at one abattoir in 1981–1986 were 5% and 0·05% respectively. Diagnosis of human cysticercosis at the University Hospital increased five-fold with the introduction of computerized tomography and an enzyme-linked immunosorbent assay: 22 cases were diagnosed in 1980–1984 and 107 cases in 1985–1988. Rates at the neurosurgical ward were higher ( 29 1000 patients) than in the general hospital census ( 1·6 1000 patients). Taeniasis-cysticercosis may be a serious health problem in some areas of Honduras.

Immunologic problems in the diagnosis of human cysticercosis.

Two types of Cysticercus are found in mamin : C. cellulosae, the most frequent, and C. racemosus. Antigenic differences have been observed between them being a possible cause ot false negative serology when using C. cellulosae only. A purified antigen of C. cellulosae must also be tested against sera of other parasitic diseases to eliminate cross reactions as well as against host antigens sometimes incorporated by the parasite and which may be also a source of error.