Clinical Signs
Disease may appear suddenly and morbidity typically reaches 100%. In the acute form birds are prostrated, debilitated and dehydrated. They produce a watery diarrhea and may have swollen feces-stained vent. Most of the flock is recumbent and have ruffled feathers. Mortality rates vary with virulence of the strain involved, the challenge dose, previous immunity, presence of concurrent disease, as well as the flock's ability to mount an effective immune response. Immunosuppression of very young chickens, less than three weeks of age, is possibly the most important outcome and may not be clinically detectable (subclinical). In addition, infection with less virulent strains may not show overt clinical signs, but birds that have bursal atrophy with fibrotic or cystic follicles and lymphocytopenia before six weeks of age, may be susceptible to opportunistic infection and may die of infection by agents that would not usually cause disease in immunocompetent birds.
Read more about this topic: Infectious Bursal Disease
Famous quotes containing the word signs:
“If family communication is good, parents can pick up the signs of stress in children and talk about it before it results in some crisis. If family communication is bad, not only will parents be insensitive to potential crises, but the poor communication will contribute to problems in the family.”
—Donald C. Medeiros (20th century)