Frequency study of rotavius, 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 gastroenterritis is a multifactorial disease. it can be caused by viruses: rotavirus or coronavirus by bacteria:salmonella or e-colik99, or by protozoan microoragnisms such as cryptosporidium parvum. The diagnosis of the etiologicak agent of diarrhea can only be preformed in the laboratory beacuse clinical sign donot allow to diffrentiate between the different microoganisms. in order to survey of frequency of (nfectious,coronavirvirus, E.coi K99 and parastic ( cryptosporidium) agent in calves diarrhea, 82 feces sample were collected of 12 indastrical diary herds in arak. we used ELISA metod for detection of above antigen in samples. the test used 96-well microtitration plates by specific antibadies for each agent. these antibodies allow a spicific capture of the corresponding pathogens which are present in the faces samples. feces were diluted in dilution buffr and incubated on the microplate for 60 minutes at room temprature. after htis first hncabation step, the plate was eashed and incubated for 60 minutes with the conjugate. after this second incubation the plate was washed again and the chromogen were added. enzymatic reacition 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 microwells. the positive antigen supplied withe the kit gave the refrence value. multiplying this valu by a sepcific conefficient it was possible to determin a limit of positivity for the kit. From 82 samples, 69 cases were positive and 13 cases were negative withe elisa metjod. results are present in table 1,2 and 3,4. contamination with cryptosporidium was detected in 41 cases(%50), rotaviros in 28 cass( %34), cronavirus in 28 cases ( %34), and E. colik 99 in 24 cases (%34), so cryptosporidium is the most frequent agent was detected in this study. From