Pulmonary aspergillosis causing right ventricular failure and ascites in meat-type chickens.

Experimentally induced pulmonary aspergillosis in one-day-old chicks resulted in some with no clinical signs or little damage while others developed marked interstitial pneumonia. Chicks with severe lung damage died from respiratory failure (60%) or developed pulmonary hypertension followed by right ventricular hypertrophy and dilation, right ventricular failure from valvular insufficiency, portal hypertension and ascites (10.7%). Chicks that developed ascites before day 16 (13/31) had shown mouth-breathing and other signs of hypoxia and developed pulmonary hypertension, probably from hypoxia-induced polycythaemia. Most chicks that developed ascites after day 16 (18/31) had not shown an increased depth or rate of respiration indicating that they had not been significantly hypoxic. Microscopic examination of lung tissue indicated that in these chicks the pulmonary hypertension was caused by lung consolidation and fibrosis restricting blood capillary space and resulting in cor pulmonale.