Avian tuberculosis is a chronic infection of bacteria that spreads through a flock slowly. All bird species tend to be susceptible, but although turkeys rarely succumb to the disease, pheasants seem particularly susceptible.
The condition is more prevalent in captivity than wild birds, but due to the methods of poultry farming and their limited life span, it is rare in poultry flocks.
Tuberculosis was found in emus and other ratites, and other species of animals such as pigs, sheep, rabbits, mice, and calves, have also been shown to be cross-infected.
Adult cattle can bear the bacterium asymptomatically and have been isolated from individuals with acquired immunodeficiency syndrome.
Symptoms typically don’t occur until late in the infection, and the hens affected are usually older than one year. Gradual weight loss, sluggishness and occasionally lameness characterize the illness in birds.
Wattles and combs shorten and become pale. The disease causes numerous granulomas to develop in a variety of organs, primarily in the liver, spleen, intestine and bone marrow (a small mass of firm tissue formed as a result of inflammation).
What is responsible for avian tuberculosis?
The bacterium Mycobacterium avium causes avian tuberculosis. This bacterium is closely linked to TB bacteria in humans and bovine animals.
For as long as four years in the soil or when protected by organic matter, it may live. It is also acid and alkali resistant. Infected birds excrete bacteria in their faeces with advanced granulomas.
If consumed, infected dead birds and offal are likely to kill pen mates, rodents and predators. Bacteria are capable of spreading from bird to bird, from animal to bird, and from bird to animal. The duration of the incubation is several weeks to months.
Avian Tuberculosis Prevention and Treatment
Avian tuberculosis is not being treated. Control, including rodent control, isolation from other birds, screening against wild birds, and animals and good sanitation, is achieved through depopulation and good biosecurity practices.
Dirt-floored houses should remove several inches of the floor from a place where poultry has not been preserved and replace it with dirt.