Which set of diseases could be included in the differential for poultry mortality in a flock?

• A. Marek's Disease And Infectious Laryngotracheitis
• B. Highly Pathogenic Avian Influenza And Newcastle Disease
• C. Marek's Disease And Newcastle Disease
• D. A, B, And C

Answer: (D)

When evaluating poultry mortality, think of a broad differential that includes major viral diseases known to cause sudden illness and death in flocks. Marek's disease can lead to mortality through tumor formation and immunosuppression; Infectious Laryngotracheitis causes acute respiratory disease and significant losses, especially in susceptible flocks; Highly Pathogenic Avian Influenza can produce abrupt, high mortality with severe systemic illness; Newcastle disease often presents with respiratory and/or nervous signs and can also cause rapid death. Because any of these pathogens could be the culprit in a mortality event, the differential should encompass all of them rather than a subset. Therefore, the comprehensive set that includes Marek's, Infectious Laryngotracheitis, HPAI, and Newcastle disease is the best fit. In practice, you’d pursue confirmatory testing (necropsy findings, PCR, culture, serology) to distinguish among them.