Pulmonary hypertension syndrome in broilers caused by Enterococcus faecalis

A field strain of Enterococcus faecalis was administered to broiler chicks at doses of 0, 3 X 10(6), 1.5 X 10(7), and 2 X 10(7) bacteria/bird either i ntra-abdominally or intravenously. In trials 1 to 3, birds were reared comm unally in a broiler house on pine shaving litter. In trial 4, challenged an d control birds were maintained in separate isolation rooms in metal cages with raised wire floors. Challenged birds exhibited a characteristic cavity or depression in the external wall of the right ventricle. A subjective sc oring system was devised to quantify challenge effects by assigning each he art a score of I to 4. The average number of birds, over all trials and ove r all dose levels, exhibiting the ventricular cavity was 93%. This value in controls was 5%. The average heart score for challenged birds was 3.1, and that for controls was 0.20. Heart scores of challenged and control chicks were not different in birds reared communally or in separate isolation room s. Additionally, both routes of administration were equally effective. Resu lts suggest that challenge with E. faecalis caused pulmonary hypertension.