Investigating serumic levels of antibodies against Mycobacterium avium subspecies paratuberculosis using the ELISA method in Holstein dairy cattle

Johne’s disease or paratuberculosis is an untreatable infectious disease of ruminants with a global distribution caused by Mycobacterium avium subspecies paratuberculosis (MAP). The disease is commonly spread by fecal-oral contamination of calves. Persistent diarrhea, weight loss and decrease in milk production are the most important signs in acute form of the disease and these signs are usually seen in cattle with over 2 years of age due to prolonged incubation period. The aim of the present study was to investigate the rate of infection to Johne’s disease by detecting antibody titers against MAP using the absorptive ELISA method. For this purpose, blood samples were collected from 738 randomly selected milking cattle of Moghan agro-business and animal husbandry complex and their sera were investigated using commercially available specific kit (ID.vet, Paras Company, Mont Pellie, France). The results indicated that 58 cattle had antibody titers against MAP with S/P percentage over 60% (infection rate of 7.86%) of which 25 cattle were positive (with S/P percentage over 70%) and 33 were suspicious (with S/P percentage between 60-70%). Because Johne’s disease is manifested as a subclinical disease and infected cattle seem to be apparently healthy, bacteria are shed through faeces and body secretions causing infection of the rest of the herd. This study demonstrated that the rate of infection to Johne’s disease in Iran is much higher compared to most other developed countries necessitating performing periodic herd screening tests and testing recently introduced animals alongside other preventive measures.