A widespread group of viruses known to cause Tenosynovitis and Malabsorption Syndrome
In general, reoviruses are most likely to infect birds three to eight weeks-of-age. Tenosynovitis, also known as Viral Arthritis, attacks the tendons and legs of the birds. Malabsorption Syndrome, or Pale Bird Syndrome, causes a number of problems, although mortality rates tend to be relatively low.
Symptoms of tenosynovitis include swelling and inflammation of (and a yellowish fluid in) the hock joint. As the inflammation progresses, scar tissue may form and fuse tendons and sheaths together. Bones of the joint may become eroded or pitted. Also, the gastrocnemius tendon may rupture.
Symptoms of Malabsorption Syndrome include stunted growth, unthriftiness, poor feed conversions, a generally sick appearance, orange-tinted diarrhea and loss of color in the legs and beak, as well as various feather problems.