Editing Paratuberculosis (section)

== Signs and symptoms ==
In cattle, the main signs of paratuberculosis are [[diarrhea]] and [[wasting]]. Most cases are seen in 2- to 6-year-old animals. The initial signs can be subtle, and may be limited to weight loss, decreased milk production, or roughening of the hair coat. The diarrhea is usually thick, without blood, mucus, or epithelial debris, and may be intermittent.  Several weeks after the onset of diarrhea, a soft swelling may occur under the jaw. Known as "bottle jaw" or intermandibular [[edema]], this symptom is due to [[protein]] loss from the bloodstream into the digestive tract. Paratuberculosis is progressive; affected animals become increasingly emaciated and usually die as the result of [[dehydration]] and severe [[cachexia]].{{citation needed|date=June 2020}}

Signs are rarely evident until two or more years after the initial infection, which usually occurs shortly after birth.  Animals are most susceptible to the infection in the first year of life. Newborns most often become infected by swallowing small amounts of infected [[manure]] from the birthing environment or [[udder]] of the mother.  In addition, newborns may become infected while in the [[uterus]] or by swallowing bacteria passed in [[milk]] and [[colostrum]].  Animals exposed at an older age, or exposed to a very small dose of bacteria at a young age, are not likely to develop clinical disease until they are much older than two years.{{citation needed|date=June 2020}}

The clinical signs are similar in other ruminants. In sheep and goats, the wool or hair is often damaged and easily shed, and diarrhea is uncommon. In deer, paratuberculosis can progress rapidly. Intestinal disease has also been reported in rabbits and nonhuman primates.{{citation needed|date=June 2020}}

Unlike cattle and sheep, infections in deer often present with clinical illness in animals under one year of age.{{citation needed|date=June 2020}}