( Johne's disease, pronounced Yo-Knees)
This is also known as wasting away disease. What ever you call it, its a devastation all producers fear. This is a contagious and fatal gastrointestinal disease. Cows, sheep, goats, deer, elk and bison are included in the list of ruminants that can be effected. Johne's is caused by the bacterium “Mycobacterium avium subspecies paratuberculosis”.
According to Mercks Vet Manual, “The infection has also been recognized in omnivores and carnivores such as wild rabbits, foxes, weasels, pigs, and nonhuman primates”
“Paratuberculosis in cattle is characterized by weight loss and diarrhea in the late phases of infection, but infected animals can appear healthy for months to years. In cattle, diarrhea may be constant or intermittent; in sheep, goats, and other ruminants, diarrhea may not be seen. It typically does not contain blood, mucus, or epithelial debris and is passed without tenesmus. Throughout weeks or months, the diarrhea becomes more severe, further weight loss occurs, coat color may fade, and ventral and intermandibular edema may develop due to a protein-losing enteropathy. This leads to low concentrations of total protein and albumin in plasma, although gamma globulin levels are normal. In dairy cattle and goats, milk yield may drop or fail to reach expected levels. Animals are alert, and temperature and appetite are usually normal, although thirst may be increased. The disease is progressive and ultimately terminates in emaciation and death. In infected herds, the mortality rate may be low for a number of years, but as many as 50% of animals may be infected subclinically with associated production losses. The disease in sheep and goats is similar, but diarrhea is not a common feature, and advanced cases may shed wool easily. In cervids (deer and elk), the course of the disease may be more rapid.” ~ Merck vet manual
There are many places to read on this horrible disease. Testing is so unreliable but we stil encourage testing..doing both blood work and fecal testing any time you suspect an issue. Many test annually as a precaution, as sadly once you have it on your land..all animals have been exposed.
Zoonotic discussion: there are some that believe Johne's is related to Crohn's disease. Its advised to treat as contagious to humans until more research is done.
I think its important that we each do our research on diseases that effect our live stock, especially those that can effect our own health and the health of our families. Here are a few links to get you started. Understanding disease is the first step in avoiding it in our own herds and treating appropriately if the time comes.
This is a very good simple to read article on Johne's http://adga.org/johnes-disease/