Which statement best identifies Newcastle disease virus (APMV-1) as a disease reservoir?

• A. It primarily affects mammals
• B. It is primarily a disease of birds
• C. It is primarily a plant pathogen
• D. It does not affect birds

Answer: (B)

The key idea here is recognizing which group keeps the virus circulating in nature—the natural reservoir. Newcastle disease virus (APMV-1) is maintained primarily in bird populations, including both domestic poultry and wild birds. These birds shed the virus and sustain transmission within and between flocks, making them the main reservoir. Other species can become infected, but they are not the ongoing source that keeps the virus in the environment. So, describing it as primarily a disease of birds best reflects its natural maintenance and transmission pattern.

The other statements don’t fit because they imply birds aren’t involved or that another group is the main host, which isn’t accurate for this virus.