Evaluation of a New Immunochromatographic Test Using Recombinant Antigen B8/1 for Diagnosis of Cystic Echinococcosis.

Diagnosis of cystic echinococcosis (CE) is based on the identification of the cyst(s) by imaging, using immunodiagnostic tests mainly as complementary tools in clinical settings. Among the antigens used for immunodiagnosis, previous studies described a good performance of the recombinant antigen B8/1 (rAgB) in an enzyme-linked immunosorbent assay (ELISA) format; however, in remote parts of areas where the disease is endemic, the implementation of an ELISA is difficult, so a more simple, rapid, and reliable method such as the immunochromatographic test (ICT) is required. In this study, using a set of 50 serum samples from patients with surgically confirmed CE, we compared the performance of an ICT and that of an ELISA using the rAgB. The overall sensitivities of ICT and ELISA were not statistically different (78% versus 72%; P = 0.36). The overall agreement between both tests was moderate (κ = 0.41; P < 0.01). Concordance between ICT and ELISA was substantial or almost perfect for patients with liver involvement (κ = 0.65; P < 0.001) and patients with more than one hydatid cyst (κ = 0.82; P < 0.001), respectively. Moreover, specificity analysis using a total of 88 serum samples from healthy individuals (n = 20) and patients (n = 68) with other parasitic infections revealed that ICT had a specificity of 89.8%. ICT and ELISA had similar performance for the detection of specific antibodies to E. granulosus, and ICT had a high specificity, opening the possibility of using ICT as a screening tool in rural settings.

Simple and reliable preparation of immunodiagnostic antigens for Taenia solium cysticercosis.

SUMMARY Cysticercosis caused by infection with the larval stage of Taenia solium is an important cause of neurological disease worldwide and immunodiagnosis is important for the control and elimination of cysticercosis. In the present study, we established a simple and reliable preparation of immunodiagnostic low-molecular-weight antigens (LMWAgs) from T. solium cyst fluids by a cation-exchange chromatography (CEC). Banding patterns of LMWAgs on SDS-PAGE were different between isolates from Ecuador and China. All cysticercosis patient sera and some echinococcosis patient sera recognized both LMWAgs by enzyme-linked immunosorbent assay (ELISA), but sera from healthy persons were not positive. There was no statistical difference in immunodiagnostic performance of LMWAgs prepared from different geographical isolates. These results indicated that these novel immunodiagnostic antigen preparations could contribute the control and prevention of cysticercosis in endemic areas, especially developing countries.

A possible nuclear DNA marker to differentiate the two geographic genotypes of Taenia solium tapeworms.

Cysticercosis caused by infection with embryonated eggs of the pork tapeworm Taenia solium is an important cause of neurological disease worldwide. Based on the phylogenetic analysis of mitochondrial DNA, the pathogen has been divided into two geographic clades, corresponding to Afro-American and Asian genotypes. In this study the genotyping of T. solium was carried out by using the nuclear DNA sequences of the immunodiagnostic antigen genes Ag1V1 and Ag2. The two geographic genotypes were supported by the Ag2 sequences, especially showing unique substitutions in each of the genotypes. It seems likely that the Ag2 may be a novel nuclear DNA marker to distinguish the two geographic genotypes of T. solium.

Echinococcus vogeli infection in a hunter, French Guiana.

Echinococcus vogeli infection in a hunter from the rain forest of French Guiana was confirmed by imaging and mitochondrial DNA sequence analysis. Serologic examination showed typical patterns for both alveolar and cystic echinococcosis. Polycystic echinococcis caused by E. vogeli may be an emerging parasitic disease in Central and South America.

Molecular identification of Echinococcus isolates from Peru.

Genetic variations in tapeworms causing cystic echinococcosis in Peru were investigated. Seventy one larval isolates collected from different intermediate hosts and geographic regions were identified by the DNA sequencing of genes for mitochondrial cytochrome c oxidase subunit 1 (cox1) and nuclear elongation factor 1 alpha (ef1a). The G7 genotype (E. canadensis pig strain) was found for the first time in pigs reared in the city of Lima. Echinococcus granulosus sensu stricto (sheep strain or G1) was the most prevalent in human patients, sheep, and cattle and the G6 genotype (E. canadensis camel strain) was found in goats and in one human patient. These findings may inform prevention strategies and control programs against echinococcosis in Peru.

Evaluation of purified Taenia solium glycoproteins and recombinant antigens in the serologic detection of human and swine cysticercosis.

Cysticercosis caused by infection with embryonated eggs of Taenia solium is an important cause of neurological disease worldwide. On the basis of mitochondrial DNA analysis, T. solium is divided into 2 (African/American and Asian) genotypes. Glycoproteins (GPs) in cyst fluid purified from the 2 genotypes of T. solium were characterized and compared with the recombinant chimeric T. solium-Ag1V1/Ag2 protein (Rec-Ag1V1/Ag2) as serodiagnostic antigens. Immunoblot analysis revealed that banding patterns of GPs differed between the 2 genotypes because of posttranslation modification, especially glycosylation. The comparison of native GPs with Rec-Ag1V1/Ag2 by enzyme-linked immunosorbent assay demonstrated that there was no statistical difference in sensitivity. In addition, the conservation of the genes encoding Ag1V1 and Ag2 in T. solium worldwide was verified. These results indicate that Rec-Ag1V1/Ag2 has great potential for usefulness in serodiagnosis as an alternative to native antigens.

Short report: Evidence and potential for transmission of human and swine Taenia solium cysticercosis in the Piracuruca region, Piauí, Brazil.

The study conducted in the Cocal dos Alves municipality, located in the Piracuruca region of Piauí State, Brazil in November of 2003 was based on both a socio-behavioral survey and analysis of serum antibodies and parasitic materials. Pig raising is the main economic activity with 91.4% using extensive farming. On the studied population, 54.3% of people did not apply any sanitary measures to wastewater, 45.7% used septic tanks, and 69.1% consumed water without treatment. The data collected indicated the occurrence and active transmission of the taeniasis-cysticercosis complex in the region. One of seven voluntary persons was positive in antibody-ELISA tests using both native and recombinant antigens. Multiplex PCR and DNA sequencing of cyst samples obtained from a pig revealed the presence of the Afro-American genotype of Taenia solium. This study revealed the occurrence of human and porcine cysticercosis in the Piracuruca region of Piauí State, middle-north of Brazil.

Prevalence of toxocariasis in northeastern Brazil based on serology using recombinant Toxocara canis antigen.

To evaluate the prevalence of toxocariasis in children in Jaboatão dos Guararapes, Pernambuco in northeastern Brazil, 215 serum samples were examined by an enzyme-linked immunosorbent assay (ELISA) using a recombinant Toxocara canis antigen. In the ELISA, 26 (12.1%) of 215 subjects were positive. In a dot-blot assay using 53 of 215 serum samples, the diagnostic results correlated with those obtained by the ELISA. Moreover, it has been confirmed that the recombinant T. canis antigen was highly specific for toxocariasis by ELISA using serum samples positive for antibody to Ascaris lumbricoides. Considering the specificity of the recombinant antigen to toxocariasis, the ELISA or dot-blot assay using the recombinant T. canis antigen is recommended in tropical and sub-tropical regions where various parasitic infections are commonly endemic.

Infection of rats with Taenia taeniformis metacestodes increases hepatic CYP450, induces the activity of CYP1A1, CYP2B1 and COH isoforms and increases the genotoxicity of the procarcinogens benzo[a]pyrene, cyclophosphamide and aflatoxin B(1).

Infection of rat liver by Taenia taeniformis metacestodes produced an increase in total CYP450 content and induced activity of the CYP1A1, CYP2B1 and COH isoforms. Variations in activity and p450 total content were found with increasing time of infection. During increased activity of p450 isoforms, rats were challenged with carcinogens metabolized by the mentioned isozymes and an increased amount of genotoxic damage was found when benzo[a] pyrene, cyclophosphamide and aflatoxin B(1) were used. No change was seen in CYP2E1 activity. These results support previous findings regarding an increased susceptibility to genotoxic damage of infected organisms.