IMMUNE-SYSTEM DYSFUNCTION DURING EXPOSURE TO POULT ENTERITIS AND MORTALITY SYNDROME AGENTS

Poult Enteritis and Mortality Syndrome (PEMS) is a condition of yet un defined etiology. Affected flocks may exhibit 100% morbidity with mort ality up to 50% or more between 2 to 4 wk of age. The current study re ports the immune status of poults experimentally infected with PEMS ag ent(s) in various trials. When compared with the unchallenged controls , PEMS-infected poults had significant atrophy of the bursa (up to 2-f old), thymus (up to 11-fold), and spleen (up to 2-fold) (P less than o r equal to 0.05). When challenged with SRBC, PEMS-infected poults had 1 to 2 log(2) lower anti-SRBC antibody titers than the controls (P les s than or equal to 0.05). Responsiveness to a mitogenic lectin, phytoh emagglutinin-P, was reduced significantly in PEMS poults (P less than or equal to 0.05). These data show that the immune system of the poult s is compromised significantly during PEMS infection in terms of lymph oid organ integrity and humoral and cell-mediated immunity. These find ings imply, therefore, that immune dysfunction may contribute to the m ortality observed during PEMS outbreaks.