Diagnosis of either HPAI or vND in the US is devastating because:

• A. Trade implications are costly
• B. The diseases are very contagious, most infected birds become ill, and most sick birds die.
• C. Because the diagnostic tests take so long to complete, the disease can spread before a diagnosis can be made
• D. A and B

Answer: (D)

The key idea is that the devastation comes from two powerful forces: economic impact on trade and the biology of the diseases themselves. When HPAI or virulent ND is suspected or detected in the US, many trading partners respond with immediate import suspensions and strict movement restrictions to prevent spread. That triggers widespread economic losses for producers, processors, and allied industries, along with costs for surveillance, depopulation, cleaning, and compensation. At the same time, these pathogens are highly contagious and cause severe illness and high mortality in affected flocks. Rapid spread means large portions of flocks can be wiped out quickly, requiring drastic control measures such as culling, quarantine, and extensive biosecurity efforts.

So, the worst impact isn’t just the time it takes to get a diagnostic result; it’s the combination of immediate, broad economic consequences from trade restrictions and the aggressive, high-mortality nature of the diseases themselves. Hence, the answer is that both trade implications and high contagion with high mortality explain why diagnosis of these diseases in the US is devastating.