Which common household pest is associated with transmitting anthrax, dysentery, cholera, typhoid, and tuberculosis?

• A. The cockroach
• B. The common fruit fly
• C. The house fly
• D. The spider

Answer: (C)

The key idea is that some pests spread disease by physically carrying pathogens from waste or contaminated material to food. The house fly is a classic example of a mechanical vector: it feeds in garbage, feces, and rotting matter, then lands on human food. While it’s on food, it can regurgitate and defecate, depositing microbes on the surface. Pathogens such as those causing anthrax, dysentery, cholera, typhoid, and tuberculosis can hitch a ride on the fly’s body or in its gut and be transferred to people, which is why this insect is strongly associated with these diseases.

Cockroaches can contaminate food as well, but they’re not as iconic for transmitting this particular group of diseases. Fruit flies are linked to spoiled fruit and general contamination, not specifically the listed diseases. Spiders don’t play a role in transferring these pathogens. So the house fly best fits the connection to those diseases.