STUNTING SYNDROME IN TURKEY POULTS - ISOLATION AND IDENTIFICATION OF THE ETIOLOGIC AGENT

Stunting syndrome (SS) is an enteric disease of turkey poults that cau ses high morbidity including reduced growth, impaired feed efficiency, and diarrhea. The etiologic agent of this disease has not been previo usly reported. The objectives of the present study were to identify, i solate, and purify the etiologic agent of SS. Day-old poults were oral ly inoculated with a SS-inducing inoculum. The intestinal epithelial c ells (IECs) were isolated on the fourth day postinoculation. The IECs were lysed and filtered through 0.2-, 0.1-, and 0.02-mu m filters. The cell lysate filtrate (0.1 mu m) was subjected to density gradient ult racentrifugation. Intact IECs, filtrates from IECs (0.2, 0.1, and 0.02 mu m), and IEC lysate fractions from gradients (FRG) were used as ino cula to infect day-old turkey poults. The weight gain, jejunal maltase activity and gross intestinal lesions were used as the parameters of evaluation. Weight gain and maltase activity were reduced (P less than or equal to 0.001) by the isolated IECs, 0.2 and 0.1 mu m filtrates, and FRG when compared with corresponding controls. IEC lysate filtrate (0.1 mu m) and FRG were examined under transmission electron microsco pe (EM). Enveloped, pleomorphic particles varying in size from 60 to 9 5 nm were observed and termed stunting syndrome agent (SSA). Primary c ultures of turkey IECs were used to further isolate and propagate the SSA. Following the fifth passage in the turkey IECs, the cell lysate i nduced SS in day-old poults. SSA particles were observed under EM afte r the fifth passage. The results of this study provide evidence that a viral agent has been isolated and identified from IECs of SS-infected poults and is the etiologic agent of SS.