Protozoan infections can be transmitted by ingestion.

• A. Transmitted by vectors
• B. Fecal-oral
• C. Ingested
• D. Direct contact

Answer: (C)

When protozoan infections are described as being transmitted by ingestion, the key idea is that the pathogen enters the body by swallowing contaminated material. The best way to express that concept is that the protozoa are ingested. Ingestion refers to taking something into the body through the mouth, such as cysts or trophozoites in contaminated water or food. This directly matches the idea of how the pathogen gains entry.

Some protozoa are spread by different routes, like via vectors (for example, mosquitoes) or by direct contact, which are separate transmission modes and not what's described in this statement. A fecal-oral description is related to how contamination occurs before ingestion, but the action that leads to infection is the ingested parasite. Classic examples include Giardia and Entamoeba, which cause infection after ingestion of contaminated water or food.