INTRODUÇÃO: Durante muito tempo, foi questionada a importância da doença de Chagas no México onde muitos a consideravam um padecimento exótico. Considerando a grande diversidade genética existente, entre os isolados de Trypanosoma cruzi, a importância da caracterização biológica desses e o escasso número de informações sobre os aspectos clínicos e biológicos da doença de Chagas no México, o objetivo deste trabalho foi realizar a caracterização biológica e molecular de isolados de Trypanosoma cruzi originários de diferentes áreas endêmicas deste país, principalmente do Estado de Jalisco. MÉTODOS: Oito cepas mexicanas de Trypanosoma cruzi foram caracterizadas biologicamente e geneticamente (PCR específica para Trypanosoma cruzi, PCR-multiplex, amplificação do espaço não transcrito dos genes do mini-exon, amplificação das regiões polimórficas do gene do mini-exon, classificação pela amplificação de regiões intergênicas dos genes do spliced leader, RAPD - random amplified polymorphic DNA). RESULTADOS: Foram observados dois tipos de parasitemia: patente com picos máximos de parasitemia entre 4,6x10(6) e 10(7) parasitas/mL e subpatente. Além disso, todos os isolados foram capazes de infectar 100% dos animais. Observou-se tropismo predominante pelo músculo estriado (cardíaco e esquelético). As técnicas de PCR do gene do mini-éxon classificaram as oito cepas como TcI e a técnica de RAPD mostrou variação intra-especifica das mesmas, separando as cepas isoladas de humanos daquelas de triatomíneos e por origem geográfica. CONCLUSÕES: As cepas mexicanas de Trypanosoma cruzi são miotrópicas e correspondem ao TcI.

INTRODUCTION: For a long time, the importance of Chagas disease in Mexico, where many regarded it as an exotic malady, was questioned. Considering the great genetic diversity among isolates of Trypanosoma cruzi, the importance of this biological characterization, and the paucity of information on the clinical and biological aspects of Chagas disease in Mexico, this study aimed to identify the molecular and biological characterization of Trypanosoma cruzi isolates from different endemic areas of this country, especially of the State of Jalisco. METHODS: Eight Mexican Trypanosoma cruzi strains were biologically and genetically characterized (PCR specific for Trypanosoma cruzi, multiplex-PCR, amplification of space no transcript of the genes of the mini-exon, amplification of polymorphic regions of the mini-exon, classification by amplification of intergenic regions of the spliced leader genes, RAPD - (random amplified polymorphic DNA). RESULTS: Two profiles of parasitaemia were observed, patent (peak parasitaemia of 4.6×10(6) to 10(7) parasites/mL) and subpatent. In addition, all isolates were able to infect 100% of the animals. The isolates mainly displayed tropism for striated (cardiac and skeletal) muscle. PCR amplification of the mini-exon gene classified the eight strains as TcI. The RAPD technique revealed intraspecies variation among isolates, distinguishing strains isolated from humans and triatomines and according to geographic origin. CONCLUSIONS: The Mexican T. cruzi strains are myotrophic and belong to group TcI.

As características físico-geográficas da região Ciénega, Jalisco, México a tornam propícia para transmissão do Trypanosoma cruzi, causador da doença de Chagas. Este trabalho caracteriza a prevalência de triatomíneos infectados pelo parasita, sua sazonalidade e distribuição nesta região. Foram analisados 328 triatomíneos no período de janeiro de 2005 a junho de 2007 procedentes de 13 municípios da região, sendo abril, maio e junho os meses de maior captura. Dos triatomíneos analisados, 57,3% foram positivos para Trypanosoma cruzi, correspondendo 15,4% para a área urbana e 84,6% para a área rural. A espécie mais freqüente foi Triatoma longipennis e a mais parasitada foi Triatoma barberi com índice de infecção de 83,3% quando comparada a Triatoma longipennis (67,5%) (p<0,05). A infecção natural dos vetores capturados pode indicar alta exposição das pessoas ao Trypanosoma cruzi. O achado recente do Triatoma dimidiata positivo nesta região, sugere a adaptação de novas espécies às condições ecológicas destas populações.

The physical and geographical characteristics of the Ciénega region, Jalisco, Mexico make it suitable for transmission of Trypanosoma cruzi, the causative agent for Chagas disease. This study characterizes the prevalence of triatomines infected by this parasite, their seasonality and their distribution in this region. A total of 328 triatomines were evaluated between January 2005 and June 2007, from 13 municipalities in the region. April, May and June were the months with the highest capture levels. Among the triatomines examined, 57.3% were positive for Trypanosoma cruzi, corresponding to 15.4% in urban areas and 84.6% in rural areas. The species with greatest prevalence was Triatoma longipennis and the species with the highest parasitism rate was Triatoma barberi, with an infection rate of 83.3%, whereas the rate for Triatoma longipennis was 67.5% (p<0.05). This natural infection in the captured vectors may indicate that individuals in this region have high exposure to Trypanosoma cruzi. The recent findings of positive Triatoma dimidiata in this region suggest that new species are becoming adapted to the ecological conditions of these populations.

Aspects related to hatching, lifetime, number of blood meals for molting, mortality, feeding time, and postfeeding defecation delay were evaluated and compared in each instar of three North American Triatominae: Triatoma gerstaeckeri, Triatoma lecticularia and Triatoma protracta, all of them fed on rabbits. No significant differences (p > 0.05) were found among the three species regarding mean hatching rate, which was close to 20 days. Egg-to-adult development times were significantly shorter (p < 0.05) for T. lecticularia. Number of blood meals for molting to next instar ranged from one to five for T. protracta, and from one to six for T. gerstaeckeri and T. lecticularia. Mortality rates were higher in younger nymphs of T. lecticularia and T. protracta, while rates in T. gerstaeckeri were higher in fifth-instar nymphs. Mean feeding time was longest in T. gerstaeckeri, followed by T. lecticularia. More than twice the number of T. gerstaeckeri nymphs completed the development process, if compared to the nymphs from the other two species. Defecation delay was less than 10 min for T. lecticularia, T. protracta and the youngest nymphs of T. gerstaeckeri. Results point out that these three species may be important potential vectors of Trypanosoma cruzi for human populations, in areas of Mexico where these species are currently present.

Aspects related to hatching, life time, number of blood meals to molt, mortality, feeding time and postfeed defecation delay for each instar of Meccus phyllosomus, M. mazzottii, and M. bassolsae, life-cycle were evaluated and compared in two cohorts of each of those three species, fed on hens or rabbits. No significant (p > 0.05) differences were recorded among cohorts fed on hens respect to cohorts fed on rabbits in M. phyllosomus and M. mazzottii and the average time of hatching was 21.5 days for cohorts fed on hens and 22.5 for cohorts fed on rabbits. Average egg-to-adult development times were no significant (p > 0.05) different between both cohorts of M. phyllosomus and M. mazzotti, independent of the blood meal source. The average span in days for each instar fed on hens was not significantly different to the average span for each instar fed on rabbits, when comparisons were made by species. The number of blood meals at each nymphal instar varied from 1 to 6 in both cohorts of each species. The mortality rates were higher on older nymphs, in both cohorts of M. phyllosomus and M. bassolsae, whereas they were higher on first instar nymphs on M. mazzottii. Mean feeding time was no significant (p > 0.05) different in triatomines fed on hens or fed on rabbits, when each species were compared separately. A similar number of nymphs of each cohort, completed the cycle. Defecation delay was no significant (p > 0.05) different when cohorts fed on hens and fed on rabbits were compared by species. Most of the studied parameters showed no significant (p > 0.05) differences among those cohorts fed on hens and for fed on rabbits, which could mean a high degree of association of those species with birds as much as mammals, under wild conditions, increasing their capacity to colonize human dwellings.

The present study is an epidemiologic environmental trial aimed at isolating and identifying Listeria monocytogenes from dammed up waters. It was conducted at the lagoon of Zapotlán, which is an important tourist resort in the southern region of the state of Jalisco. It also provides neighboring cities and populations with fish. Moore's pledget was used to isolate Listeria spp. from the samples obtained in 3 canals with sewage coming from 2 nearby municipalities. Pledgets had 2 exposure times (1 h and 24 h). A total of 60 samples were taken from September 1997, to February 1998. The 2 exposure times were considered in each sample. Of the 60 studied samples, 42 (70 %) were positive for Listeria ssp. and 40 (66.6 %) for Listeria monocytogenes. The latter was the most frequently found with 133 of the 150 isolated strains. It is obvious that the species are widely distributed in the zone and may disseminate themselves very easily in the region and in the country. Though the results do not show significant differences for the 2 exposure times, they suggest that when the pledget is exposed for 24 hours there is a higher probability of attaining isolation than when it is exposed during 1 hour.

El presente estudio es un ensayo epidemiológico ambiental el cual tuvo como objetivo aislar e identificar la Listeria monocytogenes de las aguas incorporadas a los embalses. Se realizó en la laguna de Zapotlán con importancia turística en la región sur del estado de Jalisco y que abastece de peces a ciudades y poblaciones vecinas del lugar. Se utilizó la torunda de Moore para el aislamiento de Listeria spp. de las muestras obtenidas de tres canales con aguas residuales que provenían de dos municipios aledaños al lugar. Se emplearon dos tiempos de exposición de las torundas (de 1 h y de 24 h). Se tomaron un total de 60 muestras distribuidas en los meses de septiembre de 1997 a febrero de 1998 y en cada muestra fueron considerados los dos tiempos de exposición. Se encontró de las 60 muestras estudiadas 42 (70 %) positivas a Listeria spp. y 40 (66,6 %) a Listeria monocytogenes. Esta última fue la que con más frecuencia se encontró con 133 de las 150 cepas aisladas. Es obvio que las especies están ampliamente distribuidas en la zona y pueden diseminarse con mucha facilidad en la región y en el país. Aunque los resultados no muestran diferencia significativa para los dos tiempos de exposición, sugieren que cuando la torunda se expone durante 24 h existe mayor probabilidad de lograr el aislamiento que cuando se expone 1 h.

Objective. To estimate the prevalence of iron deficiency, iodine deficiency and parasitosis in children attending the Instituto Alteño para el Desarrollo de Jalisco ((Highlands Institute for Development of Jalisco State, INADEJ), Arandas, Jalisco, Mexico. Material and Methods. A cross-sectional study was conducted between 1997 and 1999, among 432 children aged 12 to 120 months attending the INADEJ. Measurements included hematological values, urine iodine concentration, and presence of parasites. Student's t test chi square tests were used for parametric and non-parametric analysis. Results. The prevalence figures of anemia (20 vs 7.4%, p=0.007) and iron deficiency (60.9 vs 44.4%, p=0.02) were higher in preschool than in school children. Iodine deficiency was found in 29% (10.5% moderate or severe) and parasitosis in 47.2% of children, mainly E. histolytica (30.2%) and G. lamblia (28.9%). Low income, male gender and lack of social security policy holding were associated to parasitosis. Conclusions. The high prevalence rates of iron deficiency, iodine deficiency, and parasitosis, should be addressed by state health services with effective interventions to restrain these preventable diseases.

Objetivo. Estimar la prevalencia de deficiencia de hierro, yodo y parasitosis en niños que asisten al Instituto Alteño para el Desarrollo de Jalisco (Inadej), Arandas, Jalisco, México. Material y métodos. Estudio transversal efectuado entre 1997 y 1999 con 432 niños de 12 a 120 meses de edad, de nuevo ingreso al Inadej. Se determinaron variables hematológicas, yodo en orina y presencia de parásitos. Se utilizaron las pruebas Ji cuadrada y t de Student en variables no paramétricas y paramétricas. Resultados. Hubo más anemia (20 vs 7.4% p=0.007) y deficiencia de hierro (60.9 vs 44.4% p=0.02) en prescolares que en escolares. El 29% presentaron deficiencia de yodo (10.5% moderada o grave) y 47.2% parasitosis. Predominaron G. lamblia y E. histolytica. Bajo salario, sexo masculino y no tener seguridad social se asociaron con parasitosis. Conclusiones. La elevada prevalencia de deficiencia de hierro, yodo y parasitosis obliga al sector salud estatal a ejecutar medidas eficaces para abatir estas enfermedades prevenibles.

Objective. To estimate the prevalence of iron deficiency, iodine deficiency and parasitosis in children attending the Instituto Alteño para el Desarrollo de Jalisco ((Highlands Institute for Development of Jalisco State, INADEJ), Arandas, Jalisco, Mexico. Material and Methods. A cross-sectional study was conducted between 1997 and 1999, among 432 children aged 12 to 120 months attending the INADEJ. Measurements included hematological values, urine iodine concentration, and presence of parasites. Student's t test chi square tests were used for parametric and non-parametric analysis. Results. The prevalence figures of anemia (20 vs 7.4%, p=0.007) and iron deficiency (60.9 vs 44.4%, p=0.02) were higher in preschool than in school children. Iodine deficiency was found in 29% (10.5% moderate or severe) and parasitosis in 47.2% of children, mainly E. histolytica (30.2%) and G. lamblia (28.9%). Low income, male gender and lack of social security policy holding were associated to parasitosis. Conclusions. The high prevalence rates of iron deficiency, iodine deficiency, and parasitosis, should be addressed by state health services with effective interventions to restrain these preventable diseases.

Objetivo. Estimar la prevalencia de deficiencia de hierro, yodo y parasitosis en niños que asisten al Instituto Alteño para el Desarrollo de Jalisco (Inadej), Arandas, Jalisco, México. Material y métodos. Estudio transversal efectuado entre 1997 y 1999 con 432 niños de 12 a 120 meses de edad, de nuevo ingreso al Inadej. Se determinaron variables hematológicas, yodo en orina y presencia de parásitos. Se utilizaron las pruebas Ji cuadrada y t de Student en variables no paramétricas y paramétricas. Resultados. Hubo más anemia (20 vs 7.4% p=0.007) y deficiencia de hierro (60.9 vs 44.4% p=0.02) en prescolares que en escolares. El 29% presentaron deficiencia de yodo (10.5% moderada o grave) y 47.2% parasitosis. Predominaron G. lamblia y E. histolytica. Bajo salario, sexo masculino y no tener seguridad social se asociaron con parasitosis. Conclusiones. La elevada prevalencia de deficiencia de hierro, yodo y parasitosis obliga al sector salud estatal a ejecutar medidas eficaces para abatir estas enfermedades prevenibles.

In 1987 the University of Guadalajara performed a seroepidemiological survey in order to know the prevalence of infection for Trypanosoma cruzi in the 124 counties of the state of Jalisco, Mexico in which appraisals of 21.6 for 100 inhabitants were gotten. From December of 1993 to June of 1994 was carried out a pursuit of some those individuals, studying it only to 2669 of they, of 50 municipalities of rural areas of the state. The causes off not survey of the not found was diverse, being between the most important the emigration (27.6%) and the not cooperation (14.8%). We found to 476 positives (17.8%) and 2193 negatives (82.2%). This second study allowed us detect 80 new cases (2.9%) the one which represents an appraisal of incidence of 30 for 100 inhabitants. However we found a seroconvertion in the studied individuals, since of 1007 individuals that were positives in 1987; 943 of them continues so, while 64 individuals became negative (2.3%), not being this attributable to flaws of laboratory, the prevalence of positivite detected in both studies was almost identical, 18.1 and 17.8 % respectly, for the one which we believe that the conditions in that the individuals of the rural towns of the state of Jalisco live favor to that the infections continue.

La Universidad de Guadalajara decidió realizar en 1987 un estudio seroepidemiológico para conocer la prevalencia de la infección por Trypanosoma cruzi en los 124 municipios del Estado de Jalisco, México, en el cual se obtuvieron tasas de 21,6 por 100 habitantes. De diciembre de 1993 a junio de 1994 se realizó un seguimiento de algunos de esos individuos, estudiándose sólo 2669 de ellos, de 50 municipios de áreas rurales del estado. Las causas de no encuesta de los faltantes fueron diversas, estando entre las más importantes la emigración (27,6) y la renuencia (14,8). Encontramos a 476 positivos (17,8%) y 2193 negativos (82,2%). Este segundo estudio nos permitió detectar 80 infectados nuevos (2,9%) lo que representa una tasa de incidencia de 30 por 1000 habitantes. Sin embargo, encontramos una seroconversión en los individuos estudiados, ya que de 1007 individuos que estaban positivos en 1987, 943 de ellos continúan así, mientras, que 64 individuos se negativizaron (2,3%), no siendo esto imputable a fallas de laboratorio, la prevalencia de positividad detectada en ambos estudios fue casi idéntica 18,1 y 17,8 % respectivamente, por lo que nosotros pensamos que las condiciones en que viven los individuos de las localidades rurales del Estado de Jalisco favorecen a que las infecciones continúen.

Em 1987, a Universidade de Guadalajara realizou um inquérito sorológico sobre a prevalência da doença de Chagas em 124 municípios do Estado de Jalisco, México, chegando a uma taxa de 21.6 por 100 habitantes. Entre dezembro de 1993 a junho de 1994, os autores estudaram 2238 indivíduos de 32 municípios da área rural desse mesmo estado. Encontraram 276 positivos (12.33%) a 1962 negativos (87.66%). Entretanto, as séries de diferenças sorológicas foram muito marcantes, uma vez que dos 655 indivíduos que testaram positivos em 1987, 276 permaneceram positivos, enquanto 50 (7.63%) tornaram-se soronegativos. Não houve falha de técnica laboratorial. Os autores acreditam que, ou a resposta imune dos mexicanos é diferente, ou então, que a virulência das cepas mexicanas de Trypanosoma cruzi não é tão intensa quanto aquela encontrada em países sul-americanos.

In 1987 the University of Guadalajara performed a seroepidemiological survey on the prevalence of Chagas’ disease in the 124 counties of the State of Jalisco, Mexico, arriving at a rate of 21.6 per 100 inhabitants. From December 1993 to June 1994, we studied 2238 individuals from 32 rural counties in this State. Of these, we found 276 positives (12.33%) and 1962 negatives (87.66%). Nevertheless, the series of serological differences found are very striking, since out of the 655 individuals that were seropositive in 1987, we noted that 276 individuals remained positive, while 50 individuals (7.63%) became negative. There were no flaws in the laboratory techniques. We believe that either the immune response of Mexicans is different or that the virulence of the Mexican strains of Trypanosoma cruzi may be not as great as that in the South America countries.

Em 1987, a Universidade de Guadalajara realizou um inquérito sorológico sobre a prevalência da doença de Chagas em 124 municípios do Estado de Jalisco, México, chegando a uma taxa de 21.6 por 100 habitantes. Entre dezembro de 1993 a junho de 1994, os autores estudaram 2238 indivíduos de 32 municípios da área rural desse mesmo estado. Encontraram 276 positivos (12.33%) a 1962 negativos (87.66%). Entretanto, as séries de diferenças sorológicas foram muito marcantes, uma vez que dos 655 indivíduos que testaram positivos em 1987, 276 permaneceram positivos, enquanto 50 (7.63%) tornaram-se soronegativos. Não houve falha de técnica laboratorial. Os autores acreditam que, ou a resposta imune dos mexicanos é diferente, ou então, que a virulência das cepas mexicanas de Trypanosoma cruzi não é tão intensa quanto aquela encontrada em países sul-americanos.

In 1987 the University of Guadalajara performed a seroepidemiological survey on the prevalence of Chagas’ disease in the 124 counties of the State of Jalisco, Mexico, arriving at a rate of 21.6 per 100 inhabitants. From December 1993 to June 1994, we studied 2238 individuals from 32 rural counties in this State. Of these, we found 276 positives (12.33%) and 1962 negatives (87.66%). Nevertheless, the series of serological differences found are very striking, since out of the 655 individuals that were seropositive in 1987, we noted that 276 individuals remained positive, while 50 individuals (7.63%) became negative. There were no flaws in the laboratory techniques. We believe that either the immune response of Mexicans is different or that the virulence of the Mexican strains of Trypanosoma cruzi may be not as great as that in the South America countries.

A Chagas Disease serological study was done frorn October 1991 to March 1992 and 3419 samples were takenfrom people who donated blood at 12 county areas of Jalisco, México and 8 urban hospitais, by means of indirect hemagglutination reaction. The results indicate that: 73.5% of the donors were from urban area, 26.5% were from rural areas; 1.28% of the donors (N=44) were considered infected. Thirty nine of them (1.14) were males and 5 females. According to the above mentioned data, we can confirm that the risk of transmission of Trypanosoma cruzi can occur by blood transfusion and this is potentially latent because of the growing urbanization of Chagas disease.

Durante el periodo de Octubre de 1991 a Marzo de 1992, se tomaron 3419 muestras de donadores de sangre de 12 localidades rurales y de 8 hospitales urbanos a los que se les realizo un estúdio serológico mediante la reacción de hemaglutinación indirecta encontrándose anticuerpos contra Trypanosoma cruzi en 44 indivíduos 39 masculinosy 5 femininos. El 90,9% de donantes fueron masculinos. De acuerdo a su procedencia, el 73,5% fué del área urbana y el 26,5% del área rural. De acuerdo a los resultados el riesgo de transmisión de T. cruzi por transfusión sanguinea está latente por la creciente urbanización de la enfermedad de Chagas.