Which fly is claimed by some to be the greatest threat to people's health due to disease transmission?

• A. Fruit fly
• B. House fly
• C. Blow fly
• D. Mosquito

Answer: (B)

The main idea here is how certain flies spread disease by contaminating surfaces and food. The house fly is especially concerning because it frequents waste, garbage, and animal feces, then lands on food and utensils. It carries bacteria on its body and in its gut and can regurgitate or defecate as it moves, transferring pathogens like Salmonella, E. coli, Shigella, and Campylobacter to foods and surfaces. This combination of crossing between waste and human food in everyday settings makes the house fly a leading disease-vector among common pests.

Fruit flies are more of a nuisance associated with fermenting fruit and don’t typically spread disease as widely. Blow flies are attracted to decaying meat and aren’t as common in typical home environments for contaminating everyday foods. Mosquitoes are also disease vectors, but their transmission is mainly through biting rather than contaminating food surfaces, so the house fly stands out as the greatest threat in terms of spreading pathogens to food and contact surfaces.