"This investigation involved the analysis of selected gastroenteritis viruses, adenovirus and bovine coronavirus, obtained from faecal samples, collected from hospital and diagnostic laboratories respectively in Cork city, Ireland. The viruses isolated from these samples were subjected to analysis using cell culture and nucleic acid extraction. In addition adenovirus was analysed using PCR and PCR followed by restriction endonuclease digest. Many samples contained more than one gastroenteritis virus, the virus of interest and a natural co-infection with rotavirus species. Rotavirus infections in Ireland have been extensively studied and we were interested in studying singly and doubly infect samples. Bovine enteric coronavirus samples were obtained from the Cork regional Veterinary Laboratory. This virus causes gastroenteritis in calves and is a major source of bovine morbidity and mortality. These samples were studied for their ability to infect various cell lines in vitro. Factors such as the presence or absence of trypsin in the cell culture media were investigated for their effects on cell culture infection and were found to affect the appearance of both uninfected and infected cells. These virus samples were also used to infect cells expressing the anti-apoptotic gene bcl-2. Human enteric adenovirus positive clinical samples were obtained from Cork University Hospital. These samples were filter-sterilized and the isolated virus used to infect a panel of selected cell lines in vitro. Adenovirus samples were shown to infect the cell lines HRT-18 and HT-29. The isolates were also tested by ELISA for adenovirus and rotavirus. The adenovirus isolates were also subjected to molecular analysis by two different PCR methods. The second PCR method was combined with a restriction digest of the PCR products. These restriction digests were subsequently preformed to establish whether Ad40 or Ad41 were present. All of the clinical samples examined were positive for human enteric adenovirus serotype Ad41. Cell culture passages of adenovirus were also examined by PCR and ELISA. These samples were identified as being positive for adenovirus."