Efecto de beauveria bassiana balsamo, 1835 (hipocreales: clavicipitaceae) en la reproducción de meccus pallidipennis stal, 1872 (heteroptera: reduviidae)

The health risk of triatomines as vectors of Trypanosoma cruzi is related to the domiciliation of originally wild species that manage to adapt to human habitats, finding varied sources of food and shelter. Residual fumigation with pyrethroid insecticides is used to control these insects, but due to the resistance of triatomines to chemical insecticides and high costs of permanent fumigation, the potential of some entomopathogenic fungi as biological controllers has been successfully tested. However, the effect of sub-lethal doses on reproductive parameters is unknown, as these factors are very important in population growth and colonization of new habitats. In this work we tested the effect of a low concentration of Beauveria conidia. bassiana (1 x 10⁸ conidia/ml) on the reproductive parameters of Meccus pallipennis females inoculated in the adult stage, counting daily the number of eggs laid and hatched in a period of 44 days. No inhibition of oviposition was recorded, all the females laid eggs, but the fungal infection reduced the fertility of the treated females by 63%. The reproductive yield of the control females was 56.7 ± 3.8 eggs/female/life while the yield of the infected females was 20.8 ± 2.9 eggs/female/life, finding significant differences between the means of the groups. (p<0.0008). No significant differences were detected in the hatching percentage between both groups (p=.3737). The reproductive system of the infected females did not present variation in the size of the structures, however, organisms without terminal filament, germium, and empty ovarioles were observed, with some oocytes detached from the yolk. We confirmed the presence of B. bassiana in genitalia and oocytes. During the experimental design it was observed that the males treated with B. bassiana did not complete the mating pattern.El riesgo sanitario de los triatominos como vectores de Trypanosoma cruzi está relacionado con la domiciliación de especies originalmente selváticas que logran adaptarse a hábitats humanos, encontrando variadas fuentes de alimento y refugio. Para el control de estos insectos se utiliza la fumigación residual con insecticidas piretroides, pero debido a la resistencia de los triatominos a insecticidas químicos y altos costos de fumigaciones permanentes, alternativamente se ha probado con éxito el potencial de algunos hongos entomopatógenos como controladores biológicos. Sin embargo, se desconoce el efecto de dosis sub letales sobre parámetros reproductivos, siendo estos factores muy importantes en el crecimiento poblacional y colonización de nuevos hábitats. En este trabajo probamos el efecto de una concentración de conidios baja de Beauveria. bassiana (1 x 10⁸ conidios/ml) en los parámetros reproductivos de hembras de Meccus pallipennis inoculadas en el estadio adulto, contabilizando diariamente el número de huevos puestos y eclosionados en un periodo de 44 días. No se registró inhibición de la oviposición, todas las hembras pusieron huevos, pero la infección fúngica redujo un 63% la fertilidad de las hembras tratadas. El rendimiento reproductivo de las hembras control fue de 56.7 ± 3.8 huevos /hembra/vida mientras que el rendimiento de las hembras infectadas fue de 20.8 ± 2.9 huevos /hembra/vida encontrando diferencias significativas entre las medias de los grupos. (p<0.0008). No se detectaron diferencias significativas en el porcentaje de eclosión entre ambos grupos (p=.3737). El sistema reproductor de las hembras infectadas no presento variación en el tamaño de las estructuras, sin embargo, se observaron organismos sin filamento terminal, germario, y las ovariolas vacías, con algunos ovocitos desprendidos del vitelario. Confirmamos la presencia de B. bassiana en la genitalia y ovocitos. Durante el diseño experimental se observó que los machos tratados con B. bassiana no completaron el patrón de cópula

Factores bióticos que determinan la seroprevalencia de anticuerpos contra Trypanasoma Cruzi en el municipio de Palmar de Bravo, Puebla, México

Objetivo. Determinar la prevalencia de anticuerpos contra Trypanosoma cruzi y su relación con los factores bióticos y abióticos en Palmar de Bravo, Puebla, México. Material y métodos. Estudio transversal efectuado en agosto de 2000 a septiembre de 2001, con una muestra aleatoria simple de 390 voluntarios residentes en Palmar de Bravo, Puebla, México. Se hizo determinación de anticuerpos contra T cruzi con técnicas serológicas validadas, búsqueda del vector y de reservorios domésticos, así como determinación de asociación entre caso positivo y factores de riesgo bióticos y abióticos. El análisis estadístico consistió en índice Kappa para las pruebas diagnósticas, empleando tabla de contingencia de 2 x 2; ji cuadrada corregida de Yates, exacta de Fisher y la razón de posibilidad para estimar la significancia de la asociación de factores bióticos y abióticos. Resultados. La seroprevalencia fue de 4% en la población humana estudiada y de los reservorios (equinos, porcinos y caninos), sólo 10% de los caninos resultaron reactivos. Los vectores identificados fueron T barberi y T pallidipennis, con índice de dispersión e índice de colonización de 55 y 40%, respectivamente. Los factores de riesgo más importantes fueron la altitud (>2 150 y <2 180 metros sobre el nivel del mar), los años de residencia, el pertenecer a un programa de asistencia social, la presencia de triatóminos y la edad. Conclusiones. En localidades ubicadas a una altitud mayor a los 2 000 metros sobre el nivel del mar se reconocieron vectores infectados con T cruzi, casos humanos y probablemente reservorios domésticos. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.htm

Factores bióticos y abióticos que determinan la seroprevalencia de anticuerpos contra Trypanosoma Cruzi en el municipio de Palmar de Bravo, Puebla, México Biotic and abiotic determinants of seroprevalence of antibodies against Trypanosoma cruzi in Palmar de Bravo, Puebla, Mexico

OBJETIVO: Determinar la prevalencia de anticuerpos contra Trypanosoma cruzi y su relación con los factores bióticos y abióticos en Palmar de Bravo, Puebla, México. MATERIAL Y MÉTODOS: Estudio transversal efectuado en agosto de 2000 a septiembre de 2001, con una muestra aleatoria simple de 390 voluntarios residentes en Palmar de Bravo, Puebla, México. Se hizo determinación de anticuerpos contra T cruzi con técnicas serológicas validadas, búsqueda del vector y de reservorios domésticos, así como determinación de asociación entre caso positivo y factores de riesgo bióticos y abióticos. El análisis estadístico consistió en índice Kappa para las pruebas diagnósticas, empleando tabla de contingencia de 2 x 2; ji cuadrada corregida de Yates, exacta de Fisher y la razón de posibilidad para estimar la significancia de la asociación de factores bióticos y abióticos. RESULTADOS: La seroprevalencia fue de 4% en la población humana estudiada y de los reservorios (equinos, porcinos y caninos), sólo 10% de los caninos resultaron reactivos. Los vectores identificados fueron T barberi y T pallidipennis, con índice de dispersión e índice de colonización de 55 y 40%, respectivamente. Los factores de riesgo más importantes fueron la altitud (>2 150 y OBJECTIVE: To establish the relationship between seroprevalence for antibodies against Trypanosoma cruzi and its relationship with biotic and abiotic factors. MATERIAL AND METHODS: A cross-sectional study was conducted between August 2000 and September 2001. The study population consisted of a simple random sample of 390 volunteers residing in Palmar de Bravo, Puebla, Mexico. Sample and data collection procedures included assaying antibodies against T cruzi with validated assays, and searching for domestic reservoirs and triatomine bugs. The relationship between biotic and abiotic factors with seropositivity was assessed. Statistical analysis was conducted using Kappa values for diagnostic tests; statistical significance was assessed with 2 x 2 tables, chi-squared test with Yates' correction, Fisher exact test, and odds ratios. RESULTS: The seroprevalence of T cruzi infection in humans was 4%; in domestic reservoirs (horses, pigs, and dogs) only 10% of canine reservoirs were positive. Vector species recognized were T barberi and T pallidipennis, with a Dispersion Area Index and a Colonization Index of 55% and 40%, respectively. The most important risk factors associated with positive serology were altitude (>2 150 y <2 180 meters above sea level), presence of triatomines, age, time of residence, and participation in a social assistance program. CONCLUSIONS: T cruzi infection was identified in human beings, vectors, and possibly in domestic reservoirs, in communities located over 2 000 meters above sea level

Fascioliasis and Intestinal Parasitoses Affecting Schoolchildren in Atlixco, Puebla State, Mexico: Epidemiology and Treatment with Nitazoxanide

<div><p>Background</p><p>The Atlixco municipality, Puebla State, at a mean altitude of 1840 m, was selected for a study of <i>Fasciola hepatica</i> infection in schoolchildren in Mexico. This area presents permanent water collections continuously receiving thaw water from Popocatepetl volcano (5426 m altitude) through the community supply channels, conforming an epidemiological scenario similar to those known in hyperendemic areas of Andean countries.</p><p>Methodology and Findings</p><p>A total of 865 6–14 year-old schoolchildren were analyzed with FasciDIG coproantigen test and Lumbreras rapid sedimentation technique, and quantitatively assessed with Kato-Katz. Fascioliasis prevalences ranged 2.94–13.33% according to localities (mean 5.78%). Intensities were however low (24–384 epg). The association between fascioliasis and the habit of eating raw vegetables was identified, including watercress and radish with pronouncedly higher relative risk than lettuce, corncob, spinach, alfalfa juice, and broccoli. Many <i>F. hepatica</i>-infected children were coinfected by other parasites. <i>Entamoeba histolytica</i>/<i>dispar</i>, <i>Giardia intestinalis</i>, <i>Blastocystis hominis</i>, <i>Hymenolepis nana</i> and <i>Ascaris lumbricoides</i> infection resulted in risk factors for <i>F. hepatica</i> infection. Nitazoxanide efficacy against fascioliasis was 94.0% and 100% after first and second treatment courses, respectively. The few children, for whom a second treatment course was needed, were concomitantly infected by moderate ascariasis burdens. Its efficacy was also very high in the treatment of <i>E. histolytica</i>/<i>E. dispar</i>, <i>G. intestinalis</i>, <i>B. hominis</i>, <i>H. nana</i>, <i>A. lumbricoides</i>, <i>Trichuris trichiura</i>, and <i>Enterobius vermicularis</i>. A second treatment course was needed for all children affected by ancylostomatids.</p><p>Conclusions</p><p>Fascioliasis prevalences indicate this area to be mesoendemic, with isolated hyperendemic foci. This is the first time that a human fascioliasis endemic area is described in North America. Nitazoxanide appears as an appropriate alternative to triclabendazole, the present drug of choice for chronic fascioliasis. Its wide spectrum efficacy against intestinal protozooses and helminthiasis, usually coinfecting liver fluke infected subjects in human endemic areas, represents an important added value.</p></div

Maps showing the geographical distribution of localities surveyed in Atlixco municipality, Puebla, Mexico.

<p>A) Map of Mexico; B) Map of Puebla State; C) Map of Atlixco municipality showing Atlixco city and localities of the schools surveyed: 1 = Tenextepec; 2 = Alta Vista; 3 = Almazán; 4 = Huilotepec; 5 = San Juan Casstillotla; 6 = Juan Uvera; 7 = La Trinidad Tepango; 8 = San Felipe Xonacayucan; 9 = San Jerónimo Caleras; 10 = San Esteban Zoapiltepec.</p

Results of multivariate logistic regression analysis of vegetable food habits of children, potentially related to fascioliasis transmission and human fascioliasis and regression coefficients [Exp(B) = RR = relative risk] with significance in different models.

<p>Two models (Models 1–2) were used in the multivariate logistic regression analysis including presence/absence of fascioliasis as dependent variable:</p><p>- Model 1 including consumption of broccoli, spinach, lettuce, radish, corncob, alfalfa juice and watercress as independent variables.</p><p>- Model 2 including consumption of rice, flat maize pancake, beans and watercress & potato pancake as independent variables.</p

Prevalences by intestinal protozoa and helminths found in the 50 schoolchildren presenting fascioliasis among the total of children surveyed in the Atlitxco municipality, Puebla, Mexico, according to age.

*<p>Underestimating data due to the impossibility of using anal swabs for the detection of <i>E. vermicularis</i> eggs.</p

Sex distribution of <i>Fasciola hepatica</i> infection detected in the 865 6–14-year-old schoolchildren analyzed from the localities surveyed in Atlitxco municipality, Puebla State, Mexico, according to the different diagnostic techniques applied.

<p>Sex distribution of <i>Fasciola hepatica</i> infection detected in the 865 6–14-year-old schoolchildren analyzed from the localities surveyed in Atlitxco municipality, Puebla State, Mexico, according to the different diagnostic techniques applied.</p

Prevalences by intestinal protozoa and helminths found in the 865 schoolchildren surveyed in the Atlitxco municipality, Puebla, Mexico, and results obtained in nitazoxanide treatments.

*<p>Underestimating data due to the impossibility of using anal swabs for the detection of <i>E. vermicularis</i> eggs.</p

Age distribution of <i>Fasciola hepatica</i> infection detected in the 865 6–14-year-old schoolchildren analyzed from the localities surveyed in Atlixco municipality, Puebla State, Mexico.

<p>N = total studied; + = total infected; % = prevalence.</p