Infectious bursal disease and spirochetosis in pullet chicks.
A disease characterized by inappetence, yellowish diarrhoea, weakness and prostration developed in a flock of 100 pullets at 6 weeks of age; 39 died within 5 days. The flock had received Newcastle disease B1 vaccine and infectious bursal disease (IBD) vaccine at one day of age. Examination of 6 birds revealed engorged Argas persicus larvae all over the body, subcutaneous haemorrhages, haemorrhages in muscles, caecal tonsils, proventriculus and intestines, urate-filled kidney tubules, and congested or necrotic bursa fabricii. Blood smears contained Borrelia anserina, and bursal homogenates were positive for IBD virus antigens. Acaricides and penicillin were used to control the outbreak.