Pullorum disease mortality is most common in which age group of chicks?

Pullorum disease mortality is most common in which age group of chicks?

• A. 2-3 weeks old chicks
• B. Adult birds
• C. Neonatal day-old chicks
• D. All ages equally

Answer: (A)

Mortality from Pullorum disease is highest in the youngest chicks because the infection causes septicemia in neonates and their immune systems are not yet fully developed. Salmonella pullorum is often transmitted vertically through the egg, so day-old chicks hatch already exposed. The bacteria spread rapidly, especially in the yolk sac and bloodstream, leading to high death rates within the first days after hatch. As chicks age, their immune defenses strengthen and maternal antibodies wane, reducing mortality. Adults can harbor the organism and may be asymptomatic carriers rather than dying from the disease. So the age group with the greatest mortality is neonatal day-old chicks.

Mortality from Pullorum disease is highest in the youngest chicks because the infection causes septicemia in neonates and their immune systems are not yet fully developed. Salmonella pullorum is often transmitted vertically through the egg, so day-old chicks hatch already exposed. The bacteria spread rapidly, especially in the yolk sac and bloodstream, leading to high death rates within the first days after hatch. As chicks age, their immune defenses strengthen and maternal antibodies wane, reducing mortality. Adults can harbor the organism and may be asymptomatic carriers rather than dying from the disease. So the age group with the greatest mortality is neonatal day-old chicks.