In Tennessee, cat fleas are a medical concern because they transmit which parasite?

• A. heartworm
• B. dog tapeworm
• C. plague
• D. roundworm

Answer: (B)

Cat fleas can carry the tapeworm Dipylidium caninum, known as the dog tapeworm. The flea acts as the parasite’s intermediate host: tapeworm eggs shed in a pet’s feces are eaten by flea larvae, the tapeworm develops inside the flea, and when a cat or dog grooms and swallows an infected flea, the worm takes up residence in the intestine. That’s why fleas on pets are a concern—they can introduce this tapeworm. The other options don’t fit because heartworm is spread by mosquitoes, not fleas; plague involves a bacterium transmitted by fleas but not through the same dog-tapeworm transmission route; and roundworms are transmitted mainly through ingestion of eggs from contaminated soil, not via fleas. So the parasite transmitted by cat fleas is the dog tapeworm.