RESUMO
Cysticerci of Taenia solium cause cysticercosis, with neurocysticercosis (NCC) as the major pathology. Sensible and specific recombinant antigens would be an source of antigen for immunodiagnosis. The objective of this work was the molecular characterization and evaluation, of three news recombinant antigens (TsF78, TsP43 and TsC28), obtained by screening of a Taenia solium cDNA library. The three cDNA were analysed by bioinformatic programs, subcloned and expresed. The purified proteins were evaluated in ELISA using cyst fluid as control. TsF78 is filamina, TsP43 a peroxidase and TsC28 collagen XV. The sensitivity and specificity of the recombinant proteins were; TsF78 93.8 % and 95.0 %, TsP62 91.7 % and 93.3 %, TsC28 85.4 % and 93.3 %, respectively, while the cyst fluid showed a sensitivity of 87.5 % and a specificity of 76.7 %. Given its high sensitivity and specificity, the recombinant proteins TsF78 and TsP62 could be used in the diagnosis of cysticercosis.
Assuntos
Antígenos de Helmintos/imunologia , Cisticercose/diagnóstico , Testes Imunológicos , Proteínas Recombinantes/imunologia , Taenia solium/imunologia , Teníase/diagnóstico , Animais , Antígenos de Helmintos/genética , Estudos de Casos e Controles , Cisticercose/imunologia , Cisticercose/microbiologia , Humanos , Proteínas Recombinantes/genética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Taenia solium/genética , Teníase/imunologia , Teníase/microbiologiaRESUMO
The enzyme-linked immunoelectrotransfer blot (EITB) assay to detect antibodies in serum is a complementary tool for the diagnosis of neurocysticercosis (NCC). Presence of at least one glycoprotein band corresponding to a Taenia solium (T. solium) antigen indicates a positive result; however, EITB assays have multiple glycoprotein bands, and previous work has suggested that band patterns may have additional diagnostic value. We included 58 participants with a definitive diagnosis of NCC who received care at the Instituto Nacional de Neurología y Neurocirugía in Mexico City. Three different EITB tests were applied to participants' serum samples (LDBio, France; US Centers for Disease Control and Prevention [CDC]; and Instituto de Diagnóstico y Referencia Epidemiológicos [InDRE]). There was substantial variability in specific glycoprotein band patterns among the three assays. However, in age- and sex-adjusted logistic regression models, the number of glycoprotein bands was positively associated with the presence of vesicular extraparenchymal cysts (InDRE adjusted odds ratio [aOR] 1.60 p < 0.001; CDC aOR 6.31 p < 0.001; LDBio aOR 2.45 p < 0.001) and negatively associated with the presence of calcified parenchymal cysts (InDRE aOR 0.63 p < 0.001; CDC aOR 0.25 p < 0.001; LDBio aOR 0.44 p < 0.001). In a sensitivity analysis also adjusting for cyst count, results were similar. In all three EITB serum antibody tests, the number of glycoprotein bands consistently predicted cyst stage and location, although magnitude of effect differed.
Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Glicoproteínas/análise , Proteínas de Helminto/análise , Neurocisticercose/diagnóstico , Taenia solium/isolamento & purificação , Animais , Anticorpos Anti-Helmínticos/análise , Antígenos de Helmintos/análise , Antígenos de Helmintos/imunologia , Feminino , França , Glicoproteínas/imunologia , Proteínas de Helminto/imunologia , Humanos , Masculino , México , Neurocisticercose/parasitologia , Razão de Chances , Sensibilidade e Especificidade , Taenia solium/crescimento & desenvolvimento , Taenia solium/imunologiaRESUMO
Immunodiagnosis has a supportive role in the diagnosis of neurocysticercosis (NCC). The aim of this study was to compare the validity of seven immunodiagnostic tests among serum samples from 58 patients with NCC, 26 patients with neurological diseases other than NCC, and 15 healthy controls. One test for viable parasite detection (HP10 antigen assay) and six for antibody detection were evaluated. For the entire sample, sensitivities ranged from 55.2% (NOVALISA) to 81.0% (enzyme-linked immunosorbent assay [ELISA] Taenia solium antibody), with the sensitivity of the latter test significantly higher than that of the in-house ELISA Taenia crassiceps, NOVALISA, enzyme-linked immunoelectrotransfer blot (EITB) CDC, and HP10. Overall, specificities were high, ranging from 85.4% (ELISA Ts) to 97.1% (NOVALISA), with no statistically significant differences. Detection of HP10 antigen was significantly associated with the presence of vesicular parasites. The simple and low-cost ELISA Taenia solium antibody Ab instead of EITB is recommended to support NCC diagnosis in both rural and hospital settings in Mexico.
Assuntos
Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/imunologia , Testes Diagnósticos de Rotina/métodos , Neurocisticercose/diagnóstico , Taenia solium/imunologia , Adulto , Animais , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Humanos , Testes Imunológicos/métodos , Masculino , México , Neurocisticercose/imunologia , População Rural , Sensibilidade e EspecificidadeRESUMO
Echinococcus granulosus is a taeniid cestode and the etiological agent of an infectious zoonotic disease known as cystic echinococcosis (CE) or hydatid disease. CE is a serious public health concern in many parts of the world, including the Americas, where it is highly endemic in many regions. Echinococcus granulosus displays high intraspecific genetic variability and is divided into multiple genotypes (G1-G8, G10) with differences in their biology and etiology. Of these, genotype G1 is responsible for the majority of human and livestock infections and has the broadest host spectrum. However, despite the high significance to the public and livestock health, the data on genetic variability and regional genetic differences of genotype G1 in America are scarce. The aim of this study was to evaluate the genetic variability and phylogeography of G1 in several countries in America by sequencing a large portion of the mitochondrial genome. We analysed 8279bp of mtDNA for 52 E. granulosus G1 samples from sheep, cattle and pigs collected in Argentina, Brazil, Chile and Mexico, covering majority of countries in the Americas where G1 has been reported. The phylogenetic network revealed 29 haplotypes and a high haplotype diversity (Hd=0.903). The absence of phylogeographic segregation between different regions in America suggests the importance of animal transportation in shaping the genetic structure of E. granulosus G1. In addition, our study revealed many highly divergent haplotypes, indicating a long and complex evolutionary history of E. granulosus G1 in the Americas.
Assuntos
DNA de Helmintos/genética , DNA Mitocondrial/genética , Equinococose/parasitologia , Echinococcus granulosus/genética , Animais , DNA de Helmintos/análise , DNA Mitocondrial/análise , Equinococose/epidemiologia , Genótipo , México/epidemiologia , Epidemiologia Molecular , Filogeografia , América do Sul/epidemiologiaRESUMO
MAIN CONCLUSION: The Taenia solium HP6/TSOL18 antigen was produced in carrot cells, yielding an immunogenic protein that induced significant protection in an experimental murine model against T. crassiceps cysticercosis when orally administered. This result supports the potential of HP6/TSOL18-carrot as a low-cost anti-cysticercosis vaccine candidate. Cysticercosis is a zoonosis caused by Taenia solium that can be prevented by interrupting the parasite life cycle through pig vaccination. Several injectable vaccine candidates have been reported, but the logistic difficulties and costs for its application limited its use in nationwide control programs. Oral plant-based vaccines can deal with this limitation, because of their easy administration and low cost. A stable expression of the HP6/TSOL18 anti-T. solium cysticercosis protective antigen in carrot calli transformed with an optimized transgene is herein reported. An antigen accumulation up to 14 µg g(-1) of dry-weight biomass was achieved in the generated carrot lines. Mouse immunization with one of the transformed calli induced both specific IgG and IgA anti-HP6/TSOL18 antibodies. A statistically significant reduction in the expected number of T. crassiceps cysticerci was observed in mice orally immunized with carrot-made HP6/TSOL18, in a similar extent to that obtained by subcutaneous immunization with recombinant HP6/TSOL18 protein. In this study, a new oral plant-made version of the HP6/TSOL18 anti-cysticercosis vaccine is reported. The vaccine candidate should be further tested against porcine cysticercosis.
Assuntos
Antígenos de Helmintos/imunologia , Cisticercose/veterinária , Daucus carota/metabolismo , Taenia solium/imunologia , Administração Oral , Animais , Cisticercose/parasitologia , Cisticercose/prevenção & controle , Daucus carota/genética , Feminino , Imunização , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes , Suínos , Transgenes , VacinasRESUMO
La neurocisticercosis es una enfermedad neurológica causada por la presencia de cisticercos de Taenia solium en el sistema nervioso central. La clonación de genes del parásito es importante para la identificación y estudio de moléculas claves en la biología del parásito, en diagnóstico, protección y en las relaciones parásito-hospedador. En T. solium, ocurre un mecanismo alternativo en el procesamiento de algunos ARNm, denominado trans-splicing, en el cual una pequeña molécula de ARN (Spliced Leader, SL) es añadida al extremo 5´ de una molécula de pre-ARNm, formando diferentes ARNm maduros que contienen un extremo 5´ común. El objetivo de este trabajó fue realizar el análisis de las secuencias de algunas moléculas que utilizan este procesamiento, para conocer mejor este mecanismo en T. solium. Para ello, se realizó un cribado mediante PCR de genotecas de expresión de cisticerco de T. solium utilizando como cebador directo SL y como reverso ZAP-3´UP, oligonucleótido que hibrida con la secuencia del vector. Se obtuvieron diferentes ADN complementarios (ADNc), que fueron clonados en el plásmido pGEM-T-easy, secuenciados y comparados con las bases de datos (GenBank). Un total de 14 moléculas diferentes fueron obtenidas, las cuales muestran similitud principalmente con proteínas de T. solium, Echinococcus sp. e Hymenolepis sp. Se obtuvieron transcriptos completos que codifican una variedad de proteínas que forman parte de la biología propia de organismos vivos, tales como; enzimas, transportadores, proteínas estructurales, entre otras. Aunque no fue posible determinar si existen grupos específicos de ADNc (con funciones comunes), escogidos para llevar a cabo esta modificación post-transcripcional, se pudo observar que el proceso de trans-splicing ocurre en una gran variedad de ARN que codifican diferentes proteínas de importancia biológica para T. solium.
Neurocysticercosis is a neurological disease caused by the presence of Taenia solium cysticerci in the central nervous system. T. solium uses an alternative mechanism for processing some mRNAs, known as trans-splicing, in which a small RNA molecule (Spliced Leader, SL) is added to the 5' end, of one pre-mRNA molecule, leading to the formation of different mature mRNAs that all contain a common 5' end. The aim of this study was to analyze the sequences of some of the molecules that undergo this type of post-transcriptional processing in order to learn more about this mechanism in T. solium. Expression libraries of T. solium cysticerci were screened using PCR with SL as the forward primer and ZAP 3' UP, an oligonucleotide that hybridizes to the vector sequence, as the reverse primer. Different cDNAs were obtained which were cloned in the pGEM-T-easy plasmid, sequenced and then compared with sequences in databases (GenBank). A total of 14 different molecules showing similarities to T. solium, Echinococcus sp. and Hymenolepis sp. proteins were obtained. Complete transcripts encoding a variety of proteins that are part of the biology of living organisms, such as enzymes, transporters and structural proteins, were also identified. Although we could not determine whether specific cDNA groups (with common functions) are selected to carry out this post-transcriptional modification, we were able to observe that the process of trans-splicing occurs in a variety of RNAs that code for several proteins biologically important for T. solium.
RESUMO
Taenia solium cysticercosis is a major parasitic disease that affects the human health and the economy in underdeveloped countries. Porcine cysticercosis, an obligatory stage in the parasite life cycle, is a suitable target for vaccination. While several recombinant and synthetic antigens proved to be effective as vaccines, the cost and logistic difficulties have prevented their massive use. Taking this into account, a novel strategy for developing a multi-epitope low-cost vaccine is herein explored. The S3Pvac vaccine components (KETc1, KETc12, KETc7, and GK1 [KETc7]) and the protective HP6/TSOL18 antigen were expressed in a Helios2A polyprotein system, based on the 'ribosomal skip' mechanism mediated by the 2A sequence (LLNFDLLKLAGDVESNPG-P) derived from the Foot-and-mouth disease virus, which induces self-cleavage events at a translational level. This protein arrangement was expressed in transgenic tobacco cells. The inserted sequence and its transcript were detected in several Helios2A lines, with some lines showing recombinant protein accumulation levels up to 1.3 µg/g of fresh weight in leaf tissues. The plant-derived Helios2A vaccine was recognized by antibodies in the cerebral spinal fluid from neurocysticercosis patients and elicited specific antibodies in BALB/c immunized mice. These evidences point to the Helios2A polyprotein as a promising system for expressing multiple antigens of interest for vaccination and diagnosis in one single construction.
Assuntos
Antígenos/genética , Cisticercose/imunologia , Epitopos/genética , Vacinas/imunologia , Animais , Antígenos/biossíntese , Cisticercose/parasitologia , Cisticercose/prevenção & controle , Epitopos/imunologia , Vírus da Febre Aftosa/genética , Humanos , Imunização , Camundongos , Células Vegetais , Proteínas Recombinantes/genética , Ribossomos/genética , Suínos , Taenia solium/genética , Taenia solium/patogenicidade , Vacinas/genéticaRESUMO
BACKGROUND & OBJECTIVES: Several studies have demonstrated genetic heterogeneity in populations of Trypanosoma cruzi that allowed the identification of six different discrete typing units (DTU) classified as TcI, TcII, TcIII, TcIV, TcV and TcVI. Furthermore, some characterization studies have described genetic variability within TcI isolates from endemic regions. The objective of the present study was to analyze Venezuelan T. cruzi isolates, obtained from triatomine-vectors, mammal-hosts including infected humans, detected in both rural and urban areas from diverse geographic origins. METHODS: Molecular characterization of 44 Venezuelan T. cruzi isolates, obtained from triatomine-vectors, mammalian hosts and human patients from both rural and urban areas of different geographic origins, were carried out. Samples were analyzed by PCR amplification of the intergenic region of the mini-exon gene, 24Sα rDNA and 18S rDNA, followed by sequencing of the amplification products. RESULTS: The TcI amplification pattern was found in 42 out of 44 (95.5%) isolates; a TcIII strain and one possible TcIV were also found. The sequence analysis of the TcI Venezuelan isolates showed genetic variability among them. Urban isolates formed a homogeneous group, with differences in their sequences, when compared to rural isolates. INTERPRETATION & CONCLUSION: The results showed genetic heterogeneity in Venezuelan TcI strains, probably in response to different environmental conditions.
Assuntos
Doença de Chagas/parasitologia , Variação Genética , Trypanosoma cruzi/genética , Animais , Sequência de Bases , DNA Intergênico/genética , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Éxons/genética , Genótipo , Humanos , Análise de Sequência de DNA , Trypanosoma cruzi/isolamento & purificação , VenezuelaRESUMO
La cisticercosis es una enfermedad causada por el estadio larvario (cisticerco) de Taenia solium. El diagnóstico de la enfermedad se ve limitado por la disponibilidad de antígenos del parásito, donde una alternativa sería la clonación de genes codificantes de antígenos. En T. solium, al igual que en otros parásitos, ocurre un mecanismo alternativo en el procesamiento de algunos ARNm, denominado trans-splicing, en el cual una pequeña molécula de ARN conocida como Spliced Leader (SL) es añadida al extremo 5´ de una molécula de pre-ARNm, formando diferentes ARNm maduros que contienen un extremo 5´ común. Debido a las limitaciones que presenta el diagnóstico, además del interés en el estudio de este mecanismo, el objetivo de este trabajo fue clonar moléculas que utilizan este procesamiento posttranscripcional. Para ello, se realizó un cribado mediante PCR a partir de genotecas de expresión de cisticerco de T. solium utilizando como cebador directo TSSL-DW2 y como reverso ZAP-3´UP que hibridan con la secuencia SL y con la del vector, respectivamente. Se obtuvieron productos de ADNc de diferentes tamaños, que fueron clonados en un plásmido de mantenimiento (pGEM-Teasy). Posteriormente, mediante PCR de colonias se verificó la presencia de los insertos y se estimó su tamaño, obteniendo un total de 56 clones de tamaño variable (150-1200 pb). Este diseño permitió la identificación de genes de T. solium que utilizan el mecanismo de trans-splicing; y además de ser una estrategia fácil para clonar moléculas completas, abre camino para futuras investigaciones enfocadas en el diagnóstico de cisticercosis.
Cysticercosis is caused by the larval stage of Taenia solium (cysticercus). The diagnosis of the disease is limited by the availability of parasite antigens; an alternative would be the cloning of gene encoding antigens. In T. solium, as in other parasites, an alternative mechanism in the processing of some mRNAs called trans-splicing occurs, in which a small RNA known as Spliced Leader (SL) is added to the 5´ end of pre-mRNA molecules, forming a common 5´-terminal exon of the mature mRNAs. Due to limitations for diagnosing the disease, in addition to the interest in the study of this mechanism, the aim of this work was to clone molecules that use this posttranscriptional processing. In this study we did a screening by PCR from cDNA library of T. solium cysticerci using the forward primer TSSL-DW2 and the reverse primer ZAP-3´UP that hybridize with SL and vector sequence, respectively. cDNAs of different sizes were obtained that were cloned in maintenance plasmids (pGEM-T-easy). The presence of inserts and their sizes were estimated by colony PCR, obtaining a total of 56 clones of different sizes (500-1200 bp). This design allows the identification of of T. solium genes using the trans-splicing mechanism; and besides being an easy strategy to clone complete molecules, it opens the way for future investigations on the diagnosis of cysticercosis.
RESUMO
To study diagnostic epitopes within the Taenia solium 8 kDa antigen family, six overlapping synthetic peptides from an 8 kDa family member (Ts8B2) were synthesized and evaluated by ELISA and MABA with sera from patients with neurocysticercosis (NCC), from infected pigs and from rabbits immunized with recombinant Ts8B2 protein. The pre-immune rabbit sera and the Ts8B2 recombinant protein served as negative and positive controls, respectively. A similar analysis was done with the already described antigenic peptides from another member of the 8 kDa family, highly similar to Ts8B2, the CyDA antigen. Surprisingly, neither the Ts8B2 peptides nor the CyDA peptides were recognized by infected human and porcine sera. However, the entire Ts8B2 recombinant, as well as amino and carboxy-terminal halves were recognized by the positive serum samples. The observed lack of recognition of linear Ts8B2 peptides suggests that the principal serological response to the Ts8B2 family is focused on conformational epitopes in contrast to the previously observed antigenicity of the CyDA peptides. This differential antigenicity of 8 kDa family peptides could be related with parasite antigenic variability. The fact that rabbits experimentally immunized with Ts8B2 did make anti-peptide antibodies to peptides Ts8B2-6 and CyDA-6, located in the carboxy-terminal region demonstrated that the Ts8B2 peptides are not intrinsically non-immunogenic.
Assuntos
Antígenos de Helmintos/imunologia , Cisticercose/diagnóstico , Epitopos/imunologia , Taenia solium/imunologia , Sequência de Aminoácidos , Animais , Variação Antigênica , Antígenos de Helmintos/química , Antígenos de Helmintos/genética , Clonagem Molecular , Cisticercose/imunologia , Cisticercose/parasitologia , Cysticercus/genética , Cysticercus/imunologia , Cysticercus/isolamento & purificação , Ensaio de Imunoadsorção Enzimática , Epitopos/química , Epitopos/genética , Regulação da Expressão Gênica , Humanos , Immunoblotting , Coelhos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Sensibilidade e Especificidade , Alinhamento de Sequência , Suínos , Taenia solium/genética , Taenia solium/isolamento & purificaçãoRESUMO
This study evaluates five synthetic peptides derived from four, potentially protective, Taenia saginata oncosphere molecules for the serodiagnosis of T. solium cysticercosis/neurocysticercosis in three distinct Venezuelan endemic regions. The peptides, all of which have been described previously, are designated HP6-3, Ts45W-1, Ts45W-5, Ts45S-10 and TEG-1. In clinically verified and seropositive hospital cases, combining the results of three of the individual peptide-based ELISAs (HP6-3, Ts45W-1 and Ts45W-5) afforded the best balance between sensitivity (85%) and specificity (83.5%), a significant improvement on the 63.6% specificity obtained with the routinely employed T. solium cyst-fluid-based ELISA. Similarly, in the seropositive Venezuelan endemic zone samples, 89.09% of Amerindians, 77.27% of symptomatic rural subjects and 67.83% of non-symptomatic rural subjects were also classed as seropositive by the combined peptide-based ELISAs. The profile of antibody recognition to individual peptides varied between the different groups of samples examined. The relevance of the above findings for the serology and prognosis of T. solium cysticercosis/neurocysticercosis in hospital- and field-based situations is discussed.
Assuntos
Antígenos de Helmintos/imunologia , Cisticercose/diagnóstico , Taenia solium/imunologia , Animais , Anticorpos Anti-Helmínticos/sangue , Cisticercose/epidemiologia , Doenças Endêmicas/estatística & dados numéricos , Ensaio de Imunoadsorção Enzimática/métodos , Epitopos , Humanos , Neurocisticercose/diagnóstico , Neurocisticercose/epidemiologia , Prognóstico , Saúde da População Rural , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , Venezuela/epidemiologiaRESUMO
Gnathostomiasis is a rare nematode disease acquired by travelers to endemic areas. The most common clinical presentations are cutaneous forms; however, neurologic involvement can also occur. We present two cases of gnathostomiasis, one of them with severe neurologic complications, in Spanish travelers to Thailand and Mexico, who consumed local food and became infected.
Assuntos
Gnathostoma , Doenças do Sistema Nervoso/etiologia , Dermatopatias Parasitárias/etiologia , Infecções por Spirurida/complicações , Viagem , Adulto , Albendazol/uso terapêutico , Animais , Anti-Helmínticos/uso terapêutico , Feminino , Gnathostoma/isolamento & purificação , Humanos , Masculino , México , Doenças do Sistema Nervoso/diagnóstico , Dermatopatias Parasitárias/diagnóstico , Espanha , Infecções por Spirurida/diagnóstico , Infecções por Spirurida/tratamento farmacológico , Infecções por Spirurida/microbiologia , Tailândia , Resultado do TratamentoRESUMO
This study investigated the protective capacity of the recombinant Taenia saginata Tso18 antigen administered as a DNA vaccine in the Taenia crassiceps murine model of cysticercosis. This Tso18 DNA sequence, isolated from a T. saginata oncosphere cDNA library, has homologies with Taenia solium and Echinococcus sp. It was cloned in the pcDNA3.1 plasmid and injected once intramuscularly into mice. Compared to saline-vaccinated control mice, immunization reduced the parasite burden by 57.3-81.4%, while lower levels of non-specific protection were induced in control mice injected with the plasmid pcDNA3.1 (18.8-33.1%) or a plasmid with irrelevant construct, pcDNA3.1/3D15 (33.4-38.8%). Importantly, significant levels of protection were observed between the pcDNA3.1/Tso18 plasmid and pcDNA3.1/3D15 plasmid immunized mice. Mice immunized with pTso18 synthesized low levels of, primarily IgG1 sub-class, antibodies. These antibodies were shown to recognize a 66 kDa antigen fraction of T. crassiceps and T. solium. Splenocytes enriched in both CD4+CD8- and CD4-CD8+ T cells from these vaccinated mice proliferated in vitro when exposed to antigens from both T. solium and T. crassiceps cestodes. Immunolocalization studies revealed the Tso18 antigen in oncospheres of T. saginata and T. solium, in the adult tapeworm and in the tegument of T. solium cysticerci. The protective capacity of this antigen and its extensive distribution in different stages, species and genera of cestodes points to the potential of Tso18 antigen for the possible design of a vaccine against cestodes.
Assuntos
Antígenos de Helmintos/imunologia , Cisticercose/prevenção & controle , DNA de Helmintos/imunologia , Taenia saginata/imunologia , Taenia/imunologia , Animais , Células Cultivadas , Reações Cruzadas , Cisticercose/imunologia , DNA de Helmintos/genética , Estágios do Ciclo de Vida/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Baço/citologia , Linfócitos T/imunologia , Vacinação , Vacinas de DNARESUMO
The potential value of PCRs in the species-specific diagnosis of have been investigated, using samples of T. saginata and T. solium from different geographical areas. The PCRs examining inter-species differences were based on the sequence of the HDP2 DNA fragment, specific for T. saginata/T. solium, and the sequence of the rDNA internal transcribed spacer 1 and spacer 2 (ITS-1 and ITS-2). This PCR analysis of DNA isolates confirmed morphologic diagnosis and allowed the speciation of samples too small or fragmented for morphologic identification, with clear and consistent inter-species differences between T. saginata (twenty-two) and T. solium (three) geographical isolates. Possible intra-species genomic variability, within these species, was similarly studied through analysis of PCR amplification products (PCR-RFLP) and only encountered one exceptional T. saginata isolate from Kenya, which yielded a unique PCR-RFLP pattern, different from T. saginata DNA of Mexican (one sample) and Spanish (seven samples) origin.