Salmonella typhimurium outbreak in broiler chicken flocks in Mexico.

A Salmonella typhimurium outbreak in 1-to-2-week-old broiler flocks in Mexico is reported. Clinical signs were growth retardation, blindness, twisted necks, and lameness. Gross lesions consisted of hypopyon, panophthalmitis, hepatomegaly with necrotic foci, enlarged spleen, pericarditis, coagulated and unabsorbed yolks, and purulent arthritis. Mortality and cull rates in different flocks ranged from 1.7% to 10.6% during the first two weeks of age. All internal organs, eyes, and hock joints of diseased chickens that were cultured were Salmonella-positive. The bacteria were also isolated from the breeder source flock. Disease was thought to be transmitted through eggs at hatch.