Con la finalidad de determinar la presencia de Cryptosporidium so. y su asociación con cuadros de diarrea en becerros neonatos, se desarrolló una investigación en una finca comercial ubicada en el Municipio Rosario de Perijá, estado Zulia, Venezuela. Se colectaron muestras fecales de 57 becerros de ambos sexos, alojados en becerreras individuales, cuyas edades oscilaron entre 2 y 27 días. Las muestras fueron analizadas mediante la preparación de frotis coloreados con la técnica de kinyoun modificada y observadas a una magnificación de 1000X. Todas las muestras positivas para Cryptosporidium con kinyoun fueron confirmadas con la técnica de inmunofluorescencia directa utilizando anticuerpos monoclonales marcadas con isotiocianato de fluoresceína específicos para oocistos de Cryptosporidium. Del total de muestras examinadas, 29 resultaron positivas a Cryptosporidium (50,8%), observándose la asociación significativa (P<0,05) entre la presencia del parasito y la edad por semana de los becerros. En los casos positivos a Cryptosporidium solo se presentaron 6 animales con diarrea (20,6%), no encontrándose asociación significativa entre la presencia de Cryptosporidium y ésta. Los resultados del presente estudio indican un alto porcentaje de infección con Cryptosporidium sp. en los becerros neonatos de la hacienda La Esperanza, sin embargo, su presencia no fue determinante en el desarrollo del cuadro de diarrea.213 - [email protected] order to establish the presence of Cryptosporidium sp. and its association with diarrhea cases in newborn calves, a commercial farm in the Rosario de Perijá county, Zulia state, Venezuela was surveyed. Fecal samples were collected directly from the rectum of a total of 57 individually housed calves with ages ranging from 2 to 27 days. For the detection of Cryptosporidium oocysts fecal smears were stained with a modified Kinyoun technique and subsequently examined by light microscopy at X1000 magnification. All oocyst-positive samples were further stained with monoclonal antibodies labeled with fluorescein isothiocyanate (FITC-Mabs) and examined by epifluorescence microscopy to confirm the presence of Cryptosporidium. Among all samples, 29 (50.8%) were Cryptosporidium positive, and the percentage of occurrence in newborn calves was significantly associated with the age in weeks of the animals (P<0.05). Only six (20.6%) of the animals examined had diarrhea and no association was found between illness and Cryptosporidium occurrence. The resulted of this research showed that a high percentage of the calves were infected with Cryptosporidium sp., however the presence of this protozoan parasite was not responsible for the development of cases of diarrhea
