Prevalence of anti-Taenia solium antibodies in sera from outpatients in an Andean region of Ecuador

Sera from 9,254 individuals that presented at one of three outpatient clinics in Quito, Ecuador were assayed by indirect hemagglutination for the presence of antibodies reactive with antigens from Taenia solium cysts. Immunoblot anlysis of 81 selected sera with IHA titers ranging from 0 to 1,028 showed that a titer of maior ou igual a 32 was suggestive of exposure to the parasite. Nine percent (9 %) of the 9,254 patients had titers of 32 or greater. Of 3,503 sera from one clinic, which included sera from food handlers undergoing yearly physicals, 390 (11 %) were positive. In addition, a correlation with age was seen in some, but not all, populations. In situations where age-related effects were noted, the highest incidence was seen in the youngest (0-20 years) and in the oldest (51-60 years) group. Thus, a resurgence of infection after a period of lower prevalence may be developing. Overall, this study shows that cysticercosis is relatively common and potentially a serious health problem in this region.

Vaccination against Taenia solium cysticercosis

Taenia solium is a parasite that causes human cysticercosis. Its life cycle includes the adult stage, the egg and the larval stage. Human cysticercosis is a disease related to underdevelopment, the main clinical manifestation is neurocysticercosis. Control measures include mass cestocidal treatment aimed to cure possible taeniosis cases. Although useful it has certain disadvantages, such as the generation of symptomatology in occult neurocysticercosis. Alternatively, health education has been shown to be highly effective since people become aware of the importance of human and porcine cysticercosis and the possibility of eliminating it. Nevertheless it has to be implemented by knowledgeable people. On the other hand, the life cycle can be controlled by avoiding swine cysticercosis. This review describes the studies performed to vaccinate pigs against T. solium and indicate that short time perspectives are very encouraging for the production of an optimal vaccine.

Isozyme analysis of Taenia solium isolates from Mexico and Colombia

Mexican and Colombian Taenia solium cysticerci and some species of Taenia adults were assayed using cellulose acetate electrophoresis to distinguish between isolates. Isozyme patterns for ARK, GOT, G3PD, GPI, and MPI were identical in all cysticerci suggesting homozygotic profiles. G6PD and MDH showed different patterns between Mexican and Colombian cysticerci, suggesting regional differences. ME activity was mainly detected in the adult stage suggesting that this enzyme is active in anaerobic environment, while MDH, detected in cysticerci, could be related to an environment that contains oxygen. Finally, the species of taeniid adults analyzed showed different patterns among them.

Taenia solium metacestode immunodominant peptides recognized by IgG antibodies in cerebrospinal fluid and serum paired samples from patients with active and inactive neurocysticercosis

The aim of this study was to test if serological distinction between patients with active and inactive neurocysticercosis (NCC), could be accomplished by the recognition of immunodominant peptides in total saline antigenic extract of Taenia solium metacestodes by IgG antibody in cerebrospinal fluid (CSF) and serum paired samples. CSF and serum samples of 10 each, active NCC patients, inactive NCC, and individuals with other neurological disorders, were used to recognize the antigenic peptides by western blot (WB). In the active NCC the 28-32 and 39-42 kDa peptides were more frequently detected in CSF than in sera (p < 0.05). The 47-52, 64-68, and 70 kDa antigens showed high frequencies in both samples from patients with active NCC. All the CSF samples of inactive NCC and other neurological disorder (control) patients tested negative, while serum samples from these last two groups recognized mainly the 80, 86, 95, and 98 kDa bands. This finding eliminates the use of the high molecular weigh bands (> 80 kDa) for diagnosis of NCC. The final conclusions were that the difference between active and inactive NCC may be done with the detection of peptides only in the CSF samples and that the 47-52, 64-68, and 70 kDa bands may be included as specific markers for active NCC when detected in CSF samples by WB using total saline extract of T. solium metacestode.

Comparative evaluation of different immunoassays for the detection of Taenia solium cysticercosis in swine with low parasite burden

Seven swine were experimentally infected with Taenia solium eggs and blood samples from each animal were periodically collected. At the end of the experiment (t140) the animals did not show clinical aspects of cysticercosis or parasites in tongue inspection. All animals were slaughtered and cut into thin slices in searching for cysts. The number of cysts found in each animal varied from 1 to 85. Enzyme-linked immunosorbent assay (ELISA) tests for antibody (Ab) detection and for antigen (Ag) detection were performed, which presented respectively 71 and 57% of positivity. By immunoblot (IB), using 18/14(T. crassiceps Ag) or lentil-lectin-purified glycoproteins from T. solium Ag (LLGP) as Ag, five (71%) and six (86%) animals were positive, respectively. The association between Ag-ELISA with any IB (18/14 or LLGP) allowed the detection of all animals at 140 days post-experimental infection (days p.e.i.). The use of IB 18/14 combined to the Ag-ELISA allowed the detection of all animals since 70 days p.e.i., and the association between IB LLGP and Ag-ELISA allowed the detection of all animals since 112 days p.e.i. While all animals could be considered healthy by conventional screening tests, the use of immunoassays for detecting Ab and Ag showed better accuracy; therefore it would be more useful than usual clinical examination for screening cysticercosis in slightly infected pigs.

Genetic polymorphism in Taenia solium metacestodes from different Brazilian geographic areas

The aim of the present study is to investigate genetic polymorphisms in Taenia solium metacestodes from different Brazilian geographical areas and to relate them to antibody recognition in serum samples of neurocysticercosis (NC) patients. Metacestodes were obtained from the Distrito Federal (DF), Bahia, Minas Gerais (MG) and São Paulo (SP) regions of Brazil. Samples of human sera from 49 individuals with NC, 68 individuals with other helminthiasis and 40 healthy volunteers were analysed (157 individuals in total). Antigens were prepared and used in enzyme-linked immunosorbent assay and western blotting assays to detect specific immunoglobulin G antibodies. Genetic distances between metacestode populations were analysed using random amplified polymorphic DNA (RAPD) analysis. Our results show that there was a higher frequency of reactivity in the DF region in the sera from NC patients (p < 0.05), while discrimination between active and inactive NC was seen only in extracts from the MG and SP regions (p < 0.05). Using RAPD, the sample from the DF region presented a greater increase compared to the other regions. A relationship between genetic polymorphisms among T. solium metacestodes from different areas in Brazil and the differences in antibody detection in patients with NC were established.

Serodiagnosis of human neurocysticercosis using antigenic components of Taenia solium metacestodes derived from the unbound fraction from jacalin affinity chromatography

The aim of the present study was to analyse Taenia solium metacestode antigens that were derived from the unbound fraction of jacalin affinity chromatography and subsequent tert-octylphenoxy poly (oxyethylene) ethanol Triton X-114 (TX-114) partitioning in the diagnosis of human neurocysticercosis (NCC). Immunoassays were designed to detect T. solium-specific IgG antibodies by ELISA and immunoblot. Serum samples were collected from 132 individuals who were categorised as follows: 40 had NCC, 62 presented Taenia spp or other parasitic diseases and 30 were healthy individuals. The jacalin-unbound (J unbound ) fraction presented higher sensitivity and specificity rates than the jacalin-bound fraction and only this fraction was subjected to subsequent TX-114 partitioning, resulting in detergent (DJ unbound ) and aqueous (AJ unbound ) fractions. The ELISA sensitivity and specificity were 85% and 84.8% for J unbound , 92.5% and 93.5% for DJ unbound and 82.5% and 82.6% for AJ unbound . By immunoblot, the DJ unbound fraction showed 100% sensitivity and specificity and only serum samples from patients with NCC recognised the 50-70 kDa T. solium-specific components. We conclude that the DJ unbound fraction can serve as a useful tool for the differential immunodiagnosis of NCC by immunoblot.

Genetic variation in the Cytbgene of human cerebral Taenia soliumcysticerci recovered from clinically and radiologically heterogeneous patients with neurocysticercosis

Neurocysticercosis (NC) is a clinically and radiologically heterogeneous parasitic disease caused by the establishment of larval Taenia solium in the human central nervous system. Host and/or parasite variations may be related to this observed heterogeneity. Genetic differences between pig and human-derived T. solium cysticerci have been reported previously. In this study, 28 cysticerci were surgically removed from 12 human NC patients, the mitochondrial gene that encodes cytochrome b was amplified from the cysticerci and genetic variations that may be related to NC heterogeneity were characterised. Nine different haplotypes (Ht), which were clustered in four haplogroups (Hg), were identified. Hg 3 and 4 exhibited a tendency to associate with age and gender, respectively. However, no significant associations were found between NC heterogeneity and the different T. solium cysticerci Ht or Hg. Parasite variants obtained from patients with similar NC clinical or radiological features were genetically closer than those found in groups of patients with a different NC profile when using the Mantel test. Overall, this study establishes the presence of genetic differences in the Cytb gene of T. solium isolated from human cysticerci and suggests that parasite variation could contribute to NC heterogeneity.

Testing pigs of non-technified rearing farms for serum antibodies against Taenia solium in a region of the state of São Paulo, Brazil

Abstract: Taenia solium is a zoonotic tapeworm of great importance in developing countries, due to the occurrence of human taeniasis and cysticercosis. Pigs have an important role in the biological cycle of the parasite as intermediate hosts. The scientific literature has been describing risk factors associated with the occurrence of this disease that must be avoided in countries with poor sanitation, in order to reduce the exposure of swine to the parasite eggs. This research focused on testing pigs of non-technified rearing farms for serum antibodies against Taenia solium in the region of Jaboticabal municipality, in the state of São Paulo, Brazil. The found prevalence was 6.82% (CI 95% 4.18 - 9.45) at animal level and 28.87% (CI 95% 16.74 - 40.40) at herd level. These figures are probably associated with low technification adoption during animal rearing in the studied area, which increased the exposure of the animals to risk factors associated with the occurrence of Taenia solium complex. The results found based on serological evidences of swine cysticercosis in the studied region serves as a warning to public sanitary authorities to improve public health and control T. solium.

Taenia solium transmission in a rural community in Honduras : an examination of risk factors and knowledge

Taenia soliurn taeniasis and cysticercosis are recognized as a major public health problem in Latin America. T. soliurn transmission not only affects the health of the individual, but also social and economic development, perpetuating the cycle of poverty. To determine prevalence rates, population knowledge and risk factors associated with transmission, an epidemiological study was undertaken in the rural community of Jalaca. Two standardized questionnaires were used to collect epidemiological and T. soli urn general knowledge data. Kato-Katz technique and an immunoblot assay (EITB) were used to determine taeniasis and seroprevalence, respectively. In total, 139 individuals belonging to 56 households participated in the study. Household characteristics were consistent with conditions of poverty of rural Honduras: 21.4% had no toilet or latrines, 19.6% had earthen floor, and 51.8% lacked indoor tap water. Pigs were raised in 46.4% of households, of which 70% allowed their pigs roaming freely. A human seroprevalence rate of 18.7% and a taeniasis prevalence rate of 2.4% were found. Only four persons answered correctly 2: 6 out of ten T. soliurn knowledge questions, for an average passing score of 2.9%. In general, a serious gap exists in knowledge regarding how humans acquire the infections, especially neurocysticercosis was identified. After regression analysis, the ability to recognize adult tapeworms and awareness of the clinical importance of taeniasis, were found to be significant risk factors for T. soliurn seropositivity. These results demonstrate a high level of transmission and a low level of kn~,wledge about Taenia soliurn in Jalaca. Consequently, intervention measures integrated with health education are necessary to decrease the burden caused by this parasite.

Detection of IgG in cerebrospinal fluid for diagnosis of neurocysticercosis: evaluation of saline and SDS extracts from Taenia solium and Taenia crassiceps metacestodes by ELISA and immunoblot assay

We compared saline (S) and sodium dodecyl sulphate (SDS) extracts from Taenia solium (homologous species - HO) and Taenia crassiceps (heterologous species - HE) metacestodes in order to detect Ige by ELISA and immunoblot assay (IBA) in cerebrospinal fluid (CSF) for the diagnosis of human neurocysticercosis (NC). CSF samples were obtained from 93 patients. of these, 40 had NC, five had a diagnosis of probable NC, nine had central nervous system schistosomiasis or strongyloidiasis and 39 had other neurological alterations. Samples were analysed by ELISA and the results were compared with IBA in all samples with confirmed and probable NC diagnosis, in all samples with other central nervous system parasitic infection, and in 10 of those with another neurological alterations. ELISA sensitivity was 100%, 85%, 95% and 87.5% for the S-HO, S-HE, SDS-HO and SDS-HE extracts, respectively, and ELISA specificity was 100% for S-HO, S-HE, SDS-HO extracts and 97.9% for SDS-HE antigen. Immunodominant peptides detected by IBA were, by decreasing percentage of recognition: 64-68 and 45 kDa for S-HO; 108-114, 92-95, 64-68, 83 and 88 kDa for S-HE; 64-68, 108-114, 77 and 86 kDa for SDS-HO; and 108-114, 88 and 92-95 kDa for SDS-HE. Overall the homologous antigenic extracts showed higher sensitivity than the heterologous extracts in the diagnosis of NC in CSF samples. The heterologous extracts contained most of the immunodominant peptides presented in the homologous extracts, which are recognized by Ige antibodies in CSF samples.

Taenia solium DNA is present in the cerebrospinal fluid of neurocysticercosis patients and can be used for diagnosis

Neurocysticercosis is the most frequent parasitic infection of the CNS and the main cause of acquired epilepsy worldwide. Seizures are the most common symptoms of the disease, together with headache, involuntary movements, psychosis and a global mental deterioration. Absolute diagnostic criteria include the identification of cysticerci, with scolex, in the brain by MRI imaging. We demonstrate here, for the first time, that T. solium DNA is present in the cerebrospinal fluid of patients. The PCR amplification of the parasite DNA in the CSF enabled the correct identification of 29/30 cases (96.7 %). The PCR diagnosis of parasite DNA in the CSF may be a strong support for the diagnosis of neurocysticercosis.

Comparative evaluation of an indirect ELISA test for diagnosis of swine cysticercosis employing antigen from Taenia solium and Taenia crassiceps metacestodes

Taenia solium cysticercosis is still a serious public health problem in several countries where poverty and lack of hygiene favor transmission. Because pigs are the primary intermediate hosts, prevalence of porcine cysticercosis is a reliable indicator of active transmission zones. Serological diagnostic methods are important tools for epidemiological studies since they can be applied to living animals on a large scale. Four antigen preparations (cyst fluid and crude) from T. solium and T. crassiceps metacestodes were compared for swine cysticercosis diagnosis by indirect ELISA (IE). Twenty-eight serum samples from swine naturally and experimentally infected by cysticerci of T. solium and 56 serum samples from swine reared in commercial herds were tested. Best results of overall sensitivity were obtained by the use of cyst fluid and crude antigen of T. crassiceps metacestode (100 and 96.4%, respectively). Using homologous antigen preparations we have observed higher specificity percentage (98.2% for cyst fluid and 96.4% for crude metacestode T. solium antigen). We concluded that sensitivity is of far more importance than specificity for identification of endemic areas in order to prevent transmission to man. We conclude, therefore, that IE performed with cyst fluid antigen of T. crassiceps metacestode is a better tool for that purpose. (C) 2000 Elsevier B.V. B.V. All rights reserved.