No abstract

These data indicate the presence of multiple sources of Salmonella infection in the DCC, posing a complex situation for infection control.

SUMMARYThe presence of Salmonella enterica and serologic evidence of infection by Leptospira interrogans, were detected in the opossum Didelphis virginiana in a semi-urban locality of the Yucatán State, México. Ninety-one opossums were captured during the period April 1996 and May 1998. From a total of 17 feces samples, four Salmonella enterica subsp. enterica serotypes (Sandiego, Newport, Anatum, and Minnesota), and one Salmonella enterica subsp. arizonae serovar O44: Z4,Z23:-were isolated. Some opossums presented mixed infections. From 81 sera samples, four (4.9%) were positive to antibodies to Leptospira serovars pomona and wolfii. Both animals infected with Salmonella enterica and those serologically positive to Leptospira interrogans were captured in peridomestic habitat. Opossums infected with Salmonella enterica, were captured in dry season, and those seropositive to Leptospira interrogans during the rainy season. The implications of infection and reactivity of these zoonotic pathogens in D. virginiana in the Yucatan state are briefly discussed. KEYWORDS: Didelphis virginiana; Salmonella enterica; Leptospira interrogans; Yucatán; México.Opossums of the genus Didelphis have been frequently found infected with several zoonotic diseases 7 . Didelphis virginiana occurs widely in México including the Yucatán Peninsula where this opossum is abundant in the peridomestic habitat, thus bringing a risk to transmit zoonotic diseases such as Chagas disease to the human populations 8 . In this paper, we report for the first time in México data on the infection by Salmonella enterica and the seroprevalence of antibodies against Leptospira interrogans in D. virginiana. This information constitutes a contribution to the knowledge of the epidemiology of zoonotic diseases in México, where in spite the abundance of this mammal in peridomestic habitat, its role in the epidemiology of many zoonotic diseases has not been evaluated.The data of infection by S. enterica and L. interrogans in opossum, were obtained during a populational study of this mammal to evaluate its importance as a reservoir of Trypanosoma cruzi, the etiologic agent of Chagas disease 8 . Opossums were captured from April 1996 to May 1998 in Dzidzilché (21°08'51.76" and 89°41'28.24"), a semiurban small village located 25 km northwestern Mérida, the capital of the Yucatán State, México (Fig. 1). Thorny and low forest, and scarce remains of low deciduous forest characterized the vegetation of the study area. Many abandoned sisal fields doted the surroundings of the village. Fruit trees such as Mangifera inca (mango), Manilkara achras (gumtree), Spondias purpurea (plum), Citrus aurantium (orange), and Carica papaya (papaya), were common in the courtyards. The climate was predominantly warm and humid, with a mean annual temperature of 25.4 °C. During the study period, the rainy season ranged from June to October, and the average annual rainfall was 449 mm.The capture of opossums was carried out following the capture-markingrecapture scheme in a grid of 4 x 4 Tom...

Introducción. Algunos serotipos de Salmonella contienen plásmidos asociados a la virulencia (spv). La presencia de estos plásmidos aumenta la virulencia en ratones infectados experimentalmente, aunque en humanos aún no se ha establecido su papel durante la infección. La mayoría de los estudios realizados hasta la fecha se ha hecho en modelos experimentales, en los cuales las cepas de Salmonella producen septicemia en ratones, pero falla en producir grastroenteritis. Además, son muy pocos los trabajos donde se ha investigado si la presencia de estos plásmidos y/o de los genes codificados en los mismos guardan relación con la presencia de diarrea en humanos. El objetivo del trabajo fue determinar la frecuencia del gen spvB en cepas de Salmonella spp. aisladas de niños y establecer la relación que guarda con la presencia de diarrea en éstos. Materiales y Métodos. Se estudiaron 170 cepas de Salmonella aisladas de niños con diarrea (50) y sin diarrea (120). A todas se les aplicó la técnica de PCR, para amplificar un fragmento de 200 pb que correspondía a la parte central del gen spvB. Resultados. De las 50 cepas de niños con diarrea, 16 fueron positivas a la presencia del gen spvB y 34 negativas. De 120 cepas aisladas de los niños sin diarrea, en 20 se amplificó el gen y en 100 no. De esta forma 36 (21.18%) cepas fueron positivas a la presencia del gen spvB, mientras que 134 (78.82%) fueron negativas (χ2= 4.09509, p = 0.0430). Conclusión. Existe una asociación entre la presencia del gen spvB y la presencia de diarrea en los niños.