Bacteriological and molecular study of Salmonella spp and rotavirus isolated from diarrheal calves

Neonatal calf diarrhea represents an essential health challenge for livestock care because of its profound financial loss and extensive death rates among neonatal calves. A purpose of this research was to separate and identify bacterial and viral pathogens, explicitly focusing on the Detection of Salmonella spp. and rotavirus, from diarrheic fecal samples of calves less than three months old. Three hundred diarrheic fecal samples were gathered from different cattle farms throughout Babylon Province in Iraq. The research involved bacterial isolation using various media types, followed by confirmation of the presence of Salmonella spp, through biochemical identification tests by Viyk2. The detection method for rotavirus involved the use of reverse transcription polymerase chain reaction (RT-PCR) to evaluate the highly conserved VP6 gene. The tested samples revealed that rotavirus infected 5% of the specimens, as confirmed by protein band analysis of the 237 bp VP6 gene fragment through gel electrophoresis. VP6 gene expression levels dropped significantly in positive samples, as determined by quantitative RT-PCR analysis; however, testing revealed different viral loads. The study of VP6 sequences with SNP detection revealed various gene mutations that resulted in both functional and non-functional changes in protein configuration. The biological classification of VP6 sequences produced two genetically divergent clusters, indicating the different evolutionary rates of rotavirus strains, similar to those of Salmonella spp. Isolates successfully succeeded in testing. Molecular and microbiological diagnostic methods prove vital to understand the causes of calf diarrhea. The reduction of enteric infectious burden in calves depends on both persistent surveillance and specific intervention approaches such as vaccination and antimicrobial care practices.