Ileitis is widespread in swine herds of different production systems worldwide. This disease is present in every single country that has a significant commercial swine production industry. It was the most frequent cause of disease in grower/finisher pigs reported in the 2000 National Animal Monitoring System survey, occurring on more than one-third of all sites and reported on 75% of large sites (10,000 or more total inventory) (Highlights, 2002).
Studies have shown that the prevalence of PE positive herds ranges from 15 to 100% in different countries, depending on the diagnostic test used.