Identifying Common Ectoparasites in Animals Quiz

Ctenocephalides canis is not host specific and can infest multiple mammals. It is laterally compressed, aiding movement through hair, and has six legs like all insects. It is zoonotic and serves as an intermediate host for Dipylidium caninum. Incorrect options either list eight legs, which is incorrect for insects, or misstate host specificity and zoonotic status, making them scientifically inaccurate.

Trichodectes canis is the biting louse specific to dogs. It feeds on skin debris rather than blood and is host specific. Other options are lice of sheep or horses or fleas, which are not lice at all. Correct identification relies on host specificity and feeding behavior, making Trichodectes canis the correct answer.

Felicola subrostratus is a biting louse found in cats. It has chewing mouthparts and causes irritation and hair loss. Fleas and ticks are blood-sucking ectoparasites, while mosquitoes are flying insects. The question tests classification, and Felicola subrostratus is clearly a louse, not a flea or tick.

Trombicula autumnalis larvae are orange-red and have six legs, unlike nymphs and adults which have eight. The larvae are the parasitic stage responsible for irritation. Other options list incorrect leg counts or colors. Knowledge of mite life stages is essential to answer this question accurately.

Sarcoptes scabiei causes sarcoptic mange by burrowing into the skin. It has a round body and short legs, producing intense pruritus. The other options are ticks or lice that do not burrow and have different body morphology. The description matches Sarcoptes scabiei exactly.

Demodex canis inhabits hair follicles and sebaceous glands of dogs. Other Demodex species are host specific to cats or horses. The question evaluates host specificity, which is a key concept in parasitology. Therefore, Demodex canis is the only correct option.

Psoroptes equi has long legs with suckers and pointed mouthparts, enabling surface feeding on horses. The other options are internal parasites or ticks with different feeding mechanisms. Morphology and host species confirm Psoroptes equi as the correct answer.

Otodectes cynotis has an oval body with eight legs and suckers on some legs. It commonly infests the ear canals of dogs and cats. Other descriptions do not match its morphology. Accurate identification relies on leg number and sucker placement.

Cheyletiella species are known as walking dandruff mites due to their movement on the skin surface. They have a distinct waist and comb-like structures on their legs. Fleas, ticks, and lice do not share these characteristics, making walking dandruff mite the correct common name.

Ctenocephalides felis is the most common flea in cats and frequently infests dogs as well. It is adaptable and widespread. Other fleas are less common or host restricted. This question tests epidemiological prevalence rather than strict host specificity.

Sarcoptes scabiei causes severe itching due to hypersensitivity reactions. Demodex causes hair loss with minimal itching, while Otodectes affects ears. Intensity of pruritus is a key differentiator, making Sarcoptes scabiei the correct choice.

Demodex canis has a cigar-shaped body adapted to living in hair follicles. This morphology is unique among mites listed. Other mites are round or oval and live on the skin surface. Shape and habitat confirm Demodex canis as correct.

Ixodes hexagonus is commonly associated with hedgehogs and is adapted to burrow-dwelling hosts. Ixodes ricinus is more common on livestock and dogs. Ixodes scapularis is primarily found in North America. Host preference and ecological niche confirm Ixodes hexagonus as the correct answer.

Notoedres cati causes feline mange and produces concentric, thumbprint-like markings on the dorsal surface. This unique feature distinguishes it from Sarcoptes scabiei and fungal or bacterial skin diseases. The pattern is a classic diagnostic clue used in veterinary dermatology.

Cheyletiella species are zoonotic and can cause transient dermatitis in humans. Demodex and Otodectes are host specific. Zoonotic potential and temporary human infestation distinguish Cheyletiella from the other options.