Tomografía computarizada experimental en el cerdo

Se describe una técnica original para la obtenci6n de imágenes tomografías simples y contrastadas de encéfalo de cerdos parasitados con la fase larvaria de la Taenia solium

Spatial Distribution of Taenia solium Porcine Cysticercosis within a Rural Area of Mexico

Cysticercosis is caused by Taenia solium, a parasitic disease that affects humans and rurally bred pigs in developing countries. The cysticercus may localize in the central nervous system of the human, causing neurocysticercosis, the most severe and frequent form of the disease. There appears to be an association between the prevalence of porcine cysticercosis and domestic pigs that wander freely and have access to human feces. In order to assess whether the risk of cysticercosis infection is clustered or widely dispersed in a limited rural area, a spatial analysis of rural porcine cysticercosis was applied to 13 villages of the Sierra de Huautla in Central Mexico. Clustering of cases in specific households would indicate tapeworm carriers in the vicinity, whereas their dispersal would suggest that the ambulatory habits of both humans and pigs contribute to the spread of cysticercosis. A total of 562 pigs were included in this study (August–December 2003). A global positioning system was employed in order to plot the geographic distribution of both cysticercotic pigs and risk factors for infection within the villages. Prevalence of pig tongue cysticercosis varied significantly in sampled villages (p = 0.003), ranging from 0% to 33.3% and averaging 13.3%. Pigs were clustered in households, but no differences in the clustering of cysticercotic and healthy pigs were found. In contrast, the presence of pigs roaming freely and drinking stagnant water correlated significantly with porcine cysticercosis (p = 0.07), as did the absence of latrines (p = 0.0008). High prevalence of porcine cysticercosis proves that transmission is still quite common in rural Mexico. The lack of significant differentiation in the geographical clustering of healthy and cysticercotic pigs weakens the argument that focal factors (e.g., household location of putative tapeworm carriers) play an important role in increasing the risk of cysticercosis transmission in pigs. Instead, it would appear that other wide-ranging biological, physical, and cultural factors determine the geographic spread of the disease. Extensive geographic dispersal of the risk of cysticercosis makes it imperative that control measures be applied indiscriminately to all pigs and humans living in this endemic area

Characterization of S3Pvac Anti-Cysticercosis Vaccine Components: Implications for the Development of an Anti-Cestodiasis Vaccine

Background: Cysticercosis and hydatidosis seriously affect human health and are responsible for considerable economic loss in animal husbandry in non-developed and developed countries. S3Pvac and EG95 are the only field trial-tested vaccine candidates against cysticercosis and hydatidosis, respectively. S3Pvac is composed of three peptides (KETc1, GK1 and KETc12), originally identified in a Taenia crassiceps cDNA library. S3Pvac synthetically and recombinantly expressed is effective against experimentally and naturally acquired cysticercosis.Methodology/ Principal Findings: In this study, the homologous sequences of two of the S3Pvac peptides, GK1 and KETc1, were identified and further characterized in Taenia crassiceps WFU, Taenia solium, Taenia saginata, Echinococcus granulosus and Echinococcus multilocularis. Comparisons of the nucleotide and amino acid sequences coding for KETc1 and GK1 revealed significant homologies in these species. The predicted secondary structure of GK1 is almost identical between the species, while some differences were observed in the C terminal region of KETc1 according to 3D modeling. A KETc1 variant with a deletion of three C-terminal amino acids protected to the same extent against experimental murine cysticercosis as the entire peptide. on the contrary, immunization with the truncated GK1 failed to induce protection. Immunolocalization studies revealed the non stage-specificity of the two S3Pvac epitopes and their persistence in the larval tegument of all species and in Taenia adult tapeworms.Conclusions/ Significance: These results indicate that GK1 and KETc1 may be considered candidates to be included in the formulation of a multivalent and multistage vaccine against these cestodiases because of their enhancing effects on other available vaccine candidates

Evaluation of the impact of a control program against taeniasis-cysticercosis (Taenia solium).

Objetive. The impact of a control program is evaluated to eventually eradicate taeniasis-cysticercosis (Taenia solium) based on education and vaccination of pigs. Materials and methods. The prevalence of porcine cysticercosis was estimated using tongue inspection, ultrasound and determination of antibodies, before and three years after the application in three regions of the state of Guerrero. Results. A significant reduction in the prevalence of porcine cysticercosis of 7 to 0.5% and 3.6 to 0.3% estimated by tongue examination or ultrasound respectively (p menor que 0.01) and a no significant decrease in seroprevalence from 17.7 to 13.3% were observed. Conclusions. The reduction of the prevalence of taeniasis-cysticercosis establishes the program’s effectiveness in preventing infection. The sustained presence of antibodies, compatible with contact of Taenia solium or other related helminths, underlines the importance of maintaining interventionsto achieve eradication

Teniosis y detección de anticuerpos anticisticerco en personas de una comunidad rural del estado de Guerrero

OBJETIVO: Determinar la frecuencia de portadores de Taenia sp. y su relación con el diagnóstico de cisticercos en humanos en una comunidad rural del estado de Guerrero, México. MATERIAL Y MÉTODOS: Para detectar portadores de Taenia sp. se analizaron 403 muestras de heces de personas, por medio de ELISA para coproantígenos de Taenia sp., así como 92 muestras de suero para detectar anticuerpos anticisticerco mediante inmunoelectrotransferencia. El diseño del estudio fue transversal y se llevó a cabo durante 1998. Se hizo estadística descriptiva y se estimó razón de momios. RESULTADOS: De 403 muestras de heces evaluadas, cinco resultaron positivas (1.2 %). Sólo en dos de las cinco personas positivas se obtuvo el cestodo adulto. En 3 (3.26%) de los 92 sueros se encontraron anticuerpos anticisticerco. Del total de sueros, 17 fueron de las personas con diagnóstico positivo a teniosis por coproantígenos o que cohabitaban con ellos (primer grupo), los restantes 75 provenían de personas en quienes no se detectaron casos en las viviendas (segundo grupo). En el primer grupo se detectaron 2 (11.8%) sueros positivos, mientras que en el segundo sólo 1 (1.3%) (RM= 9.87, I.C 0.64-295.56, p= 0.086). CONCLUSIONES: La dificultad para obtener el parásito adulto en las personas positivas a coproantígenos puede deberse a características propias de éste que dificultan su expulsión, a que la permanencia del cestodo en su huésped es menor a la esperada o a que el tratamiento fue insuficiente para obtener el parásito, o bien, a problemas de especificidad de la prueba. Es necesario realizar estudios tendientes a evaluar estas posibilidades, lo cual permitiría conocer mejor la dinámica de transmisión de esta parasitosis, con el fin de establecer medidas de prevención y control, además de poder comparar con mayor veracidad la eficacia de las pruebas diagnósticas en condiciones de campo