Which of the following is NOT considered an etiologic agent?

Etiologic agents are factors that contribute to the development of a disease or health condition. Typically, this includes biological pathogens like viruses, bacteria, and parasitic worms, which can directly cause infections or diseases in hosts.

Viruses and bacteria are well-known etiologic agents because they can lead to a range of illnesses, from mild to severe, through infection and replication within the host organism. Parasitic worms also fit into this category as they can invade and damage host tissues, leading to various health issues.

Pesticides, on the other hand, are chemical substances used to eliminate or control pests. While they can certainly be harmful and lead to health issues indirectly (e.g., through environmental exposure or poisoning), they do not cause diseases in the same way that viruses, bacteria, or parasitic worms do. Therefore, pesticides do not fit the traditional definition of an etiologic agent since they are not pathogens that cause disease by infection or invasion.

This distinction clarifies why pesticides are categorized separately from the other options presented, as they relate more to environmental health concerns rather than direct disease causation.