FFA Veterinary Science CDE Practice Test

Which of the following is an example of a vector in the transmission of animal diseases?

1. Utensils

2. Flies

3. Soil

4. Grass from Pasture

The correct answer is: Flies

Flies are a significant example of a vector in the transmission of animal diseases because they can carry pathogens from one host to another. Vectors are organisms that do not cause disease themselves but can spread infectious agents, such as viruses, bacteria, or parasites. Flies, particularly certain species like house flies, can land on contaminated food, waste, or other surfaces, picking up pathogens and transferring them to animals or surfaces where disease can spread. In contrast, utensils can be considered fomites as they can harbor and transfer pathogens but are not living organisms; soil may contain pathogens but does not actively transmit them to hosts in the way a vector does; and grass from pasture serves as a food source and can sometimes harbor pathogens but does not have the capacity to actively carry diseases to animals like flies do. Thus, the distinguishing feature of flies being living vectors that facilitate the direct transfer of diseases makes them the correct choice.