Frequency Study Of Rotavirus, Coronavirlus , E.Coli K99 and Cryptospridium in calves diarrhea in dlliry farms of Arak city

Diarrhea is a major cause of mortality in young calves under once month. Bovine neonatal gastroenteritis is a multifactorial disease. it can be caused by viruses: rotavirus or coronavirus by bacteria: salmonella or E-colik99, or by protozoan microorganisms such as cryptosporidium parvum. The diagnosis of the etiological agent of diarrhea can only be preformed in the laboratory because clinical sign donot allow to differentiate between the different microorganisms. In order to survey of frequency of infectious (ro ta virus, coron a virus, Ecoli k99 and parasitic (cryptosporidium) agents in calves diarrhea, 82 feces samples were collected of 12 industrial dairy herds in Arak: We used ELISA method for detection of above antigen in samples. The test uses 96-well microtitration plates by specific antibodies for each agent. These antibodies allow a specific capture of the corresponding pathogens which are present in the feces samples. Feces were diluted in dilution buffer and incubated on the microplate for 60 minutes at room temprature. after this first incubation step, the plate was washed and incubated for 60 minutes with the conjugate. after this second incubation the plate was washed again and the enzyme substrate and the chromogen were added. enzymatic reaction was stopped by acidification and results were recorded by Elisa reader at 450 nm: the signals recorded for the negative control microwells were substracted from the corresponding positive m icro wells. the positive antigen supplied with the kit gave the refrence value. multiplying this value by a specific conefficient it was possible to determine a limit of positivity for the kit. - From 82 samples, 69 cases were positive and 13 cases were negative with elisa method. Contamination with cryptosporidium was detected in 41 Cases (50%), rotavirus in 28 Cases (34%), cronavirus in 28 cases (34%) and E.collk99 in 24 cases (30%)6 so cryptosporidium is the most frequent agent was detected in this study .