Which species is commonly associated with fleas affecting dogs and cats?

• A. Pulex irritans
• B. Ctenocephalides felis
• C. Ctenocephalides canis
• D. Xenopsylla cheopis

Answer: (B)

Fleas commonly found on both dogs and cats are most often the cat flea, Ctenocephalides felis. This species is highly adaptable and readily infests both companion animals, making it by far the most frequent culprit in canine and feline flea problems worldwide. Other flea species exist, but they are much less commonly seen on pets: Pulex irritans is mainly associated with humans, Xenopsylla cheopis with rats and other rodents, and Ctenocephalides canis on dogs tends to be outnumbered by C. felis on those animals. Practically, this means when you see fleas on dogs or cats, the likelihood that the infestations are due to Ctenocephalides felis is very high. Recognize that this flea can also transmit Dipylidium caninum if the pet ingests an infected flea, which adds to its clinical relevance.