Camille has just returned from a trip to Southeast Asia. A week later she is experiencing fever, severe headache, and abdominal pain. Lab analysis shows single celled organisms inside erythrocytes (red blood cells). Which type of pathogen is most likely responsible for these symptoms?

• A. Parasitic worms.
• B. Bacteria.
• C. Protozoans.
• D. Fungi.
• E. None of the above.

Answer: (C)

Verified step by step guidance

1. Step 1: Identify the symptoms and lab findings described: fever, severe headache, abdominal pain, and presence of single-celled organisms inside erythrocytes (red blood cells).
2. Step 2: Understand that erythrocytes are red blood cells, which typically do not contain organisms unless infected by certain pathogens.
3. Step 3: Recall that parasitic worms are multicellular organisms and would not be described as single-celled inside red blood cells.
4. Step 4: Recognize that bacteria are single-celled but usually do not live inside red blood cells; instead, protozoans are known to infect red blood cells directly.
5. Step 5: Conclude that the pathogen type most consistent with single-celled organisms inside erythrocytes causing these symptoms is protozoans.