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Faecal specimens from 36 scouring neonatal calves from two dairy farms located in the Al Ain region of the UAE were screened with pathogen-specific antigen ELISA for Cryptosporidium parvum, Escherichia coli K99, rotavirus, and coronavirus. Additionally, faecal smears were stained with modified-acid-fast for Cryptosporidium oocysts, and the VITEK 2 system plus Gram's stain used to identify bacteria isolated from the faecal samples. Farm management practices were also evaluated during a farm visit. Of the 36 calves, 29, 13, 5, and 6 were positive for C. parvum, E. coli K99, bovine coronavirus, and rotavirus antigens respectively, while 27 were positive for Cryptosporidium oocysts. In various combinations, mixed infections were detected in 20/36 calves. This is the first report of C. parvum, E. coli K99, Salmonella spp., rotavirus, and coronavirus in ≤14-days-old scouring neonatal dairy calves from the UAE. Molecular characterization of these pathogens and nationwide epidemiological calf scour studies are recommended., Competing Interests: Declaration of Competing Interest All authors of this manuscript declare there are no financial and personal relationships with other people or organizations that could inappropriately influence the intellectual work presented in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Despite many reports on the shedding of Giardia parasites by scouring calves, the role of Giardia as a cause of calf diarrhea is still controversial. To elucidate the role of Giardia duodenalis in calf scours, diagnostic samples from 189 scouring calves were tested by different assays during a 1-year-study period. Giardia antigens were detected in 22/189 scouring calves by a fecal-based enzyme-linked immunosorbent assay and 10 of these were positive for assemblage E, G. duodenalis by polymerase chain reaction. Giardia trophozoites were demonstrated by immunohistochemistry in intestinal sections from five calves in which the parasites were spatially distributed in areas of microscopically detectable enteritis. Our data suggest that under certain circumstances, Giardia may cause intestinal lesions leading to calf scours. Gnotobiotic calf-based infectivity studies are needed if the pathogenicity of Giardia in calves is to be definitively determined.