Effect of dexamethasone on Mycobacterium paratuberculosis infection in hamsters

Sixty hamsters were randomly divided into 4 equal groups: group 1--given only dexamethasone, group 2--given dexamethasone and exposed to Mycobacterium paratuberculosis, group 3--exposed to M paratuberculosis but not treated, and group 4--used as normal controls. Group 2 hamsters (treated with dexamethasone and exposed to the bacterium) had significantly higher bacterial counts in spleen and aggregated lymphatic nodules (Peyser's patches) than did those in group 3. None of the hamsters exposed to M paratuberculosis (groups 2 and 3) developed clinical signs of disease. All hamsters treated with the drug (groups 1 and 2) grew more slowly than did the hamsters not treated.