[Identification of immunodominant components of an isolate of Trypanosoma cruzi by immunoblot and its standardization for diagnostic purposes]. / Identificación de componentes inmunodominantes de un aislado de Trypanosoma cruzi por inmunoblot y su estandarización con fines diagnósticos.

INTRODUCTION: Conventional serology was used for the detection of Trypanosoma cruzi infection, with diverse sensitivity and specificity results. Due to the number of samples with doubtful results, it is necessary to develop additional confirmation tests such as the immunoblot. OBJECTIVE: The aim of this study was identify major immunogenic proteins of T. cruzi isolate and establish criteria for immunoblot positivity with diagnostic purposes. METHODS: Immunoblot initial standardization was performed, determining optimal concentrations of antigen, serum, and second antibody. Thirty-five positive and thirty negative sera were assayed to evaluate different criteria of positivity and determine which provides greater sensitivity and specificity. RESULTS: Immunoblot of T. cruzi positive sera shared a rich pattern of components with molecular weights between 10-250 kDa. Twelve components had a recognition rate higher than 50%, of which the polypeptides of 27, 32, 34, and 38 kDa were close to 100%. Of the positivity criteria evaluated, the recognition of the components of 27 and 32 kDa provided sensitivity and specificity of 100%. DISCUSSION: The Immunoblot is suitable for confirmation of infection by T. cruzi, so it is strongly recommended for confirmation and discrimination of discordant cases.

Triatoma mexicana (Hemiptera: Reduviidae) in Guanajuato, Mexico: house infestation and seasonal variation.

Triatoma mexicana was described by Herrich-Schaeffer in 1848. In 1940, a male specimen was found in Hidalgo. In 1970, this species was recorded in the state of Queretaro. Later, it was registered in Guanajuato and San Luis Potosi. In the present paper we performed an investigation in 545 dwellings from three counties in the state of Guanajuato, Mexico, from March 2003 to May 2004. The search and capture of triatomines were seasonally performed indoors and outdoors. Entomological indexes were calculated. The risk and no risk relations between triatomine presence and housing construction materials were analyzed. Fourteen triatomines were collected indoors and 151 outdoors. The vectors were collected in houses built with either risky and non-risky materials. Adults go indoors but do not settle there, hence, no relationship was found between the building materials and infestation of houses. Conventional interventions like house improvement or insecticide spraying are not efficient for the control of T. mexicana, because its developmental cycle is accomplished outdoors in the area surrounding the houses.

Triatoma mexicana (Hemiptera: Reduviidae) in Guanajuato, Mexico: house infestation and seasonal variation

Triatoma mexicana was described by Herrich-Schaeffer in 1848. In 1940, a male specimen was found in Hidalgo. In 1970, this species was recorded in the state of Queretaro. Later, it was registered in Guanajuato and San Luis Potosi. In the present paper we performed an investigation in 545 dwellings from three counties in the state of Guanajuato, Mexico, from March 2003 to May 2004. The search and capture of triatomines were seasonally performed indoors and outdoors. Entomological indexes were calculated. The risk and no risk relations between triatomine presence and housing construction materials were analyzed. Fourteen triatomines were collected indoors and 151 outdoors. The vectors were collected in houses built with either risky and non-risky materials. Adults go indoors but do not settle there, hence, no relationship was found between the building materials and infestation of houses. Conventional interventions like house improvement or insecticide spraying are not efficient for the control of T. mexicana, because its developmental cycle is accomplished outdoors in the area surrounding the houses.

Estudio de la respuesta inmune humoral en cerdos infectados con huevos y posoncósferas de taenia solium / Study on immune humoral response in pigs infected with eggs and posoncospheres of taenia solium

Due to the importance of cysticercosis in Mexico and Latin America and to the fact that in the last years another mechanism of infection for this disease has been proposed, i.e. through postoncospheres and immunosuppression of the host, we have considered relevant to perform the present work, which consisted in assessing the immune response induced by dexamethasone as well as that produced by parasites in pigs infected with T. solium eggs, or postoncosphere-infected, and in postoncosphere-infected and dexamethasone treated animals. We used 10 recently weaned pigs, three were used as controls, two of them without the drug and one with it; two were infected with T. solium eggs; five with postoncospheres receiving also dexamethasone three of them. We evaluated the humoral response against parasite antigen using indirect haemagglutination (IH) and ELISA methods. Results of the immune humoral response revealed titres of up to 1:128 in T. solium eggs infected animals, of 1:16 in postoncosphere infected animals. Absorbance titres with of 1:32 towards the end of the experiment in postoncosphere plus dexamethasone animals. Absorbance titres with Elisa confirmed these findings. Data obtained by IH show that the antibody titres of the pigs challenged with postoncospheres and postoncospheres plus dexamethasone are positive as compared to the titres obtained in the pigs infected with T. solium eggs. Results from the Elisa confirmed this finding, since, from weeks 14 to 17, the pigs became positive, behaving as those pigs that developed cysticercosis. This is revelant as it indicates that the antiposcosphere antibodies recognized antigens of T. solium larvae

Parasite search in strawberries from Irapuato, Guanajuato and Zamora, Michoacan (Mexico)

A seasonal research was carried out in Irapuato, Guanajuato and Zamora, Michaocan, Mexico, the location of the most important producers of strawberries, in order to assess fecal contamination through the findig of protozoan cysts and helminth eggs, specifically of Taenia sp eggs. Three techniques were used: direct observation, flotation and sedimentation. Low numbers of protozoan cysts and only one Ascaris egg were found. What is most interesting is that no Taenia eggs were identified. Results indicate that although strawberries are contaminated with human feces, contamination is minimal

Estudio cualitativo y cuantitativo de la presencia de posoncósferas de taenia solium en el tejido muscular de cerdos con y sin cisticercosis / Qualitative and quantitative study on taenia solium posoncospheres in pigs with and without cysticercosis in muscular tissues

It was determined the presence of posoncospheres in muscular tissues in 20 natural cysticercotic pigs and in 20 pigs apparently free of taenia solium metacestodes. Ten differents anatomical regions were dissected, giving 400 samples in total. The animals were slaugthered in Ecatepec, México State, México. The samples were kept in bottles with saline and were processed in the Laboratorio de Biología de Parásitos, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM); cysticercus were counted and later on the resulting muscular mass was grinded and observations were made in the sediment for posoncospheres search. Mann-Withney statistical method revealed meaningful differences between postoncospheres in cysticercotic pigs and not apparently cysticercotic pigs. The linear correlation analysis showed no relation between cysticercus quantity and postoncospheres quantity in the same samples. Postoncospheres were found in cysticercotic animals and in those apparently free of cysticercus, in the last group the quantity was bigger

Ensayo de la proliferación celular en cultivo de linfocitos de cerdo / Assay kinetics cell proliferations lymphocytes from pigs

Se reporta el cultivo de linfocitos de sangre periférica completa de cerdos sanos e infectados, para evaluar la cinética de proliferación celular; 0.5 ml de sangre fue cultivada en 6.0 ml de RPMI-11640 suplementado, en presencia de fitohemaglutinina y 5-BrdU, a 37§C. Al cabo de 48 horas de incubación se cosecharon y fueron teñidos de acuerdo a la técnica de fluorescencia más Giemsa, obteniéndose así células en diferentes etapas de diferenciación, identificándolas en primera, segunda y tercera división. La actividad proliferativa se midió bajo dos parámetros: índice mitótico e índice de replicación. Los resultados son reproducibles y se pueden diferenciar los efectos citotóxicos de los citostáticos sobre los linfocitos del huésped

Dermatitis verminosa reptante / Dermatitis cutaneous larva migrans

Se comunica un brote epidémico de Larva migrans cutánea, posterior a lluvias intensas al paso del huracán Celia, en siete estudiantes y un profesor de la Facultad de Ciencias. El diagnóstico se estableció clínicamente; se realizaron frotes sanguíneos para cuantificación de eosinófilos. Fueron tratados con albendazol a dosis convencionales y tiabendazol tópico