The bacteria can also be found in other tissues, including lymph nodes, uterine and mammary tissues. Milk from infected animals may also contain the bacteria. Johne s bacteria thrive in a damp environment, surviving in manure, soil and water. Direct sunlight, heat and some disinfectants kill the organism. Even with a normal appetite and good feed, affected animals lose weight.
Milk production is lessened and diarrhea develops.
The diarrhea occurs off and on, eventually becoming chronic and does not respond to treatment. A low grade fever may develop and some animals will have a swelling under the jaw. Animals can die within weeks to months after symptoms appear. In most cases of Johne s Disease, symptoms do not appear until the first or second lactation, even if the animal contracted the bacteria as a young calf. Age of the animal, amount of bacteria present, genetics and stresses such as calving or moving to a new environment may be determining factors as to when clinical disease or symptoms are noticed.