Lice are small, wingless insects that live as external parasites. The specific species of louse that infests domestic cats worldwide is the chewing louse, Felicola subrostratus. This cat louse is the only species that targets felines, and infestations can cause discomfort for your pet.
Why Cat Lice Do Not Infest Humans
Cat lice are highly host-specific, meaning they are biologically adapted to survive and reproduce only on their feline hosts. The simple answer is no; cat lice cannot establish a sustainable population on a person. This species-specific nature is due to several biological incompatibilities with the human body environment.
The Felicola subrostratus louse is a chewing louse, feeding on skin flakes and hair debris found on the cat’s coat. They are not adapted to feed on human blood, which is necessary for parasite survival. Furthermore, the claws on the louse’s legs are specifically designed to grasp the diameter and spacing of cat hair shafts.
The texture and spacing of human hair follicles, along with differences in body temperature, make the human body an unsuitable habitat. While a cat louse might briefly transfer to a person during handling, it cannot complete its life cycle or feed adequately. If separated from its feline host, the louse will die within a few days.
Recognizing Cat Lice Infestation
Infestations are typically seen in sick, elderly, or stray cats that struggle with regular grooming. The most direct way to identify an infestation is by visually spotting the parasites or their eggs. Adult lice are small, flattened, wingless insects, usually pale in color and measuring about 2 to 4 millimeters long, which can be seen slowly moving through the fur.
Owners often first notice the nits, which are the louse eggs. These eggs appear as tiny white or yellowish oval casings that are firmly glued to individual hair shafts close to the skin. Unlike dandruff, nits cannot be easily brushed or shaken off the hair.
The presence of lice causes several symptoms in the cat. Constant irritation can lead to hair loss or secondary skin infections in severe cases.
Symptoms of Infestation
- Excessive scratching, biting, and rubbing of infested areas.
- Poor coat condition, including matted, dry, or patchy fur.
- Infestation concentrated around the ears, head, neck, and tail base.
Treating the Cat and Preventing Spread
A veterinary consultation is necessary to confirm the diagnosis, as symptoms can mimic other skin conditions. The veterinarian will recommend an appropriate insecticide treatment, often a topical spot-on application or medicated shampoo. Products containing ingredients like fipronil or selamectin are commonly used and effective.
Treating the cat typically requires only a single application of a persistent product, which remains active long enough to kill newly hatched nymphs. To prevent re-infestation, it is necessary to manage the immediate environment. This involves thoroughly washing all bedding, grooming tools, and contaminated items in hot water.