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

Diarrhea is a major cause of mortality in young calves under once month. Bovine neonatal gastroenteritisis 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 diagnosisof the etiological agent of diarrhea can only be preformed in the laboratory because clinical sign donot allow to differentiate between the different mlcroorganisms.In order to survey of frequency of infectious (rotavirus, coronavirus, E.coli 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 micro plate for 60 minutes at room temprature. after thisfirst incubation step, the plate was washed and incubated for 60 minutes with the conjugate. after thissecond 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 micro wells were substracted from the corresponding positive micro wells. the positive antigen supplied with the kit gave the refrence value. multiplying thisvalue by a specific conefficient it J:Vas 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. results are present in tables 1,2 and 3,4. Contamination with cryptosporidium was detected in 41 Cases (50%), rotavirus in 28 Cases (34%), cronavirus in 28 cases (34%) and E.colik99 in 24 cases (30%). so cryptosporidium is the most frequent agent was detected in this study.