Diseases Caused by Eukaryotic Pathogens

Steps:

• Recall the causative agents: cholera by Vibrio cholerae (bacterium), malaria by Plasmodium (protozoan), measles by rubeola virus, smallpox by variola virus.
• Classify pathogens: bacteria and viruses are prokaryotes or non-cellular; eukaryotes include protozoa, fungi, and helminths.
• Identify eukaryotes: Plasmodium is a single-celled eukaryotic parasite.
• Select the disease: malaria matches the eukaryotic criterion.

Why B is correct:

• Malaria is caused by Plasmodium species, eukaryotic protozoans that infect red blood cells, as defined by eukaryotic cells having nuclei and organelles unlike prokaryotes.

Why the others are wrong:

• A. Cholera is caused by the prokaryotic bacterium Vibrio cholerae.
• C. Measles is caused by the measles virus, a non-cellular entity.
• D. Smallpox is caused by the variola virus, a non-cellular entity.

Final answer: B