Avian mycobacteriosis, also known as avian tuberculosis (ATB), is an important chronic, contagious disease that affects both domestic and wild birds worldwide. The disease is caused by infection with Mycobacterium avium
or M. genavense
. M. avium
is capable of infecting any species of bird, as well as other mammals, including humans. In cattle and goats, M. avium
subsp. paratuberculosis (MAP) is responsible for causing paratuberculosis (PTB), also known as Johne's disease. Chickens that are stressed or have poor immune systems are more susceptible to infection with M. avium
Avian Mycobacteriosis Risk Factors
Risk factors include overcrowded living conditions, inadequate or unbalanced nutrition, adverse weather or environmental conditions such as drought, extreme cold or heat, chronic inflammation, internal or external parasites, or infection with an existing disease.
Clinical Signs of Avian Mycobacteriosis
Avian mycobacteriosis has a slow disease course, and symptoms of illness may last for several weeks to months in affected birds. The most common signs include:
- Progressive weight loss
- Loss in condition
- Muscle atrophy along the keel bone
- Roosters may develop a change in voice, such as making hoarse attempts at crowing.
How Avian Mycobacteriosis is Transmitted
is transmitted primarily by infected wild birds or newly introduced, older adult domesticated poultry, which shed the organism into the environment through their droppings. Susceptible chickens become infected by ingesting or inhaling the organism from the contaminated environment.