What is the main difference between Avian influenza and Newcastle disease?

What is the main difference between Avian influenza and Newcastle disease?

• A. Avian influenza causes higher mortality.
• B. Newcastle disease is associated with mild symptoms only.
• C. Both diseases have identical clinical signs.
• D. Newcastle disease has very high mortality.

Answer: (D)

The main concept here is how virulence and mortality can differ between two avian viral diseases, and how that affects what you see in outbreaks. Newcastle disease, especially the velogenic form, tends to produce very high mortality in infected flocks because it causes rapid, systemic, and severe disease. Birds can die quickly from neurologic and respiratory signs, and outbreaks can wipe out large numbers of birds, even with good control measures. In contrast, avian influenza outcomes vary a lot depending on the strain and the host. Some strains (especially low-pathogenic ones) cause mild illness, while highly pathogenic avian influenza can cause high mortality, but not universally across all outbreaks or species. So saying that Newcastle disease has very high mortality captures the typical severe impact seen with the more virulent forms of that disease, which is the point of contrast in this question. The other statements aren’t as accurate because avian influenza does not consistently cause higher mortality than Newcastle disease, Newcastle disease is not limited to mild symptoms, and the diseases do not share identical clinical signs.

The main concept here is how virulence and mortality can differ between two avian viral diseases, and how that affects what you see in outbreaks. Newcastle disease, especially the velogenic form, tends to produce very high mortality in infected flocks because it causes rapid, systemic, and severe disease. Birds can die quickly from neurologic and respiratory signs, and outbreaks can wipe out large numbers of birds, even with good control measures.

In contrast, avian influenza outcomes vary a lot depending on the strain and the host. Some strains (especially low-pathogenic ones) cause mild illness, while highly pathogenic avian influenza can cause high mortality, but not universally across all outbreaks or species. So saying that Newcastle disease has very high mortality captures the typical severe impact seen with the more virulent forms of that disease, which is the point of contrast in this question.

The other statements aren’t as accurate because avian influenza does not consistently cause higher mortality than Newcastle disease, Newcastle disease is not limited to mild symptoms, and the diseases do not share identical clinical signs.