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The abundance of total and pathogenic Vibrio parahaemolyticus (Vp) strains in American oysters (Crassostrea virginica) harvested in two different harvest sites from the Mandinga lagoon System was evaluated monthly for 1 year (January through December 2012). Frequencies of species-specific genes and pathogenic genes exhibited a seasonal distribution. The annual occurrence of Vp with the species-specific tlh gene (tlh(+)) was significantly higher during the winter windy season (32.50%) and spring dry season (15.0%), with the highest densities observed during spring dry season at 283.50 most probable number (MPN)/g (lagoon bank A, near human settlements), indicating the highest risk of infection during warmer months. Pathogenic Vp tlh(+)/tdh(+) frequency was significantly higher during the winter windy and the spring dry seasons at 22.50 and 10.00%, respectively, with highest densities of 16.22 and 41.05 MPN/g (bank A), respectively. The tlh/trh and tdh/trh gene combinations were also found in Vp isolates during the spring dry season at 1.25 and 1.3%, respectively, with densities of 1.79 and 0.4 MPN/g (bank A), respectively. The orf8 genes were detected during the winter windy season (1.25%) with highest densities of 5.96 MPN/g (bank A) and 3.21 MPN/g (bank B, near mangrove islands and a heron nesting area). Densities of Vp tdh(+) were correlated (R(2) = 0.245, P < 0.015) with those of Vp orf8(+). The seasonal dynamics of Vp harboring pathogenic genes varied with seasonal changes, with very high proportions of Vp tdh(+) and Vp orf8(+) isolates in the winter windy season at 46.2 and 17.0%, respectively, which suggests that environmental factors may differentially affect the abundance of pathogenic subpopulations. Although all densities of total Vp (Vp tlh(+)) were lower than 10(4) MPN/g, thus complying with Mexican regulations, the presence of pathogenic strains is a public health concern. Our results suggest that total Vp densities may not be appropriate for assessing oyster contamination and predicting the risk of infection. Evaluation of the presence of pathogenic strains would be a better approach to protecting public health.

No abstract

Objetivo. Determinar la frecuencia de Neospora caninum en dos Unidades de Producción Pecuaria con sistema búfalo/bovino de la zona central del estado de Veracruz, México. Materiales y Métodos. Fue un estudio de tipo transversal con muestreo no probabilístico por conveniencia. Se incluyeron dos Unidades de Producción Pecuaria (UPP), ambas con población bufalina y bovina ubicadas en la zona central del estado de Veracruz, México. Se incluyó el total de la población bufalina, bovina y canina, tomando muestras sanguíneas entre febrero-marzo, 2019, las cuales fueron procesadas con la prueba comercial ELISA (IDEXX®) y la prueba de inmunofluorescencia indirecta (VMRD, Pullman, WA, USA). En cada UPP, se aplicó una encuesta general y una individual para la colecta de datos. Los resultados se analizaron con el software STATA versión 14.0. Resultados. Del total de la población bóvida analizada, 63/138 animales presentaron anticuerpos contra N. caninum con frecuencia de 45.6% (IC95% 37.1-54.3). Con relación a las UPP, la población de búfalos presentó mayor presencia de anticuerpos contra N. caninum, 26/31 de la UPP Cotaxtla con 83.8% (IC95% 66.2-94.5) y 12/22 de la UPP Medellín con 54.5% (IC95% 32.2-75.6). Con relación a los perros, 4/6 resultaron positivos (66.6%). Se observó que de acuerdo con la especie animal 38/53 búfalos, presentaron la mayor frecuencia con 71.6% (IC95% 57.6-83.2). Conclusiones. Fue comprobada la presencia de anticuerpos contra N. caninum en población bovina y bufalina de las UPP estudiadas. Se confirmó que existe una mayor frecuencia de anticuerpos en búfalos de agua cuando cohabitan con bovinos y caninos.

The cattle tick Rhipicephalus microplus (Acari: Ixodidae) has demonstrated its ability to increase its distribution raising spatially its importance as a vector for zoonotic hemotropic pathogens. In this study, a global ecological niche model of R. microplus was built in different scenarios using Representative Concentration Pathway (RCP), Socio‐Economic Pathway (SSP), and a climatic dataset to determine where the species could establish itself and thus affect the variability in the presentation of the hemotropic diseases they transmit. America, Africa and Oceania showed a higher probability for the presence of R. microplus in contrast to some countries in Europe and Asia in the ecological niche for the current period (1970–2000), but with the climate change, there was an increase in the ratio between the geographic range preserved between the RCP and SSP scenarios obtaining the greatest gain in the interplay of RCP4.5‐SSP245. Our results allow to determine future changes in the distribution of the cattle tick according to the increase in environmental temperature and socio‐economic development influenced by human development activities and trends; this work explores the possibility of designing integral maps between the vector and specific diseases.