Guinea Pigs

The fur louse

Fig. 105. The fur mite, Trimenopon jenningsi and its eggs. (Seguy)

Trimenopon jenningsi. A biting louse. It is 1.7 mm long and seen throughout the body of the guinea pig. It causes itching and does not infect humans.

Gliricola Porcelli. Another species of the biting louse. It is up to 1.7 mm long and very thin. It is found throughout the body, causing itching and hair loss. Harmless to humans.

Gyropus ovalis. A third species of the biting louse. It only 1 mm long, and is found on the neck as well as on the back of the head. It causes itching and dull fur. It does not infect humans.

Chirodiscoides caviae

Fig. 107. The mite Chirodiscoides caviae. (Baker & Wharton)

The guinea pig itch mite, Sarcoptes scabiei. P.122. Symptoms include thickened skin and itching. It can transfer pseudo scabies to humans.

Chirodiscoides caviae. A mite that lives like Listrophorus gibbus on the rabbit. It is mostly seen in the groin and armpits of the guinea pig and may cause itching and hair loss. It does not infect people.

Gliricola Porcelli and Gyropus ovalis

Fig. 106. Gliricola Porcelli (left) and Gyropus ovalis (right). ( Seguy)


The rabbit flea

Fig. 103. Rabbit fleas. (Seguy)

Rabbit louse, Haemodipsus ventricosus. It sucks the blood of its host animal. Is up to 2 1/2 mm long, and causes itching. This mite does not infect humans. Rabbits do not have biting lice.

Rabbit Flea, Spilopsyllus cuniculi. It is a rather small, blood sucking flea and is found in groups on the inside of the ears of, preferably in wild rabbits. The rabbit flea may bite people. It is a vector for a contagious, fatal infection in rabbits.

Rabbit fur mite, Cheyletiella parasitovorax, P.128. Feeds on the top layer of the skin and possibly on other mites. It rarely causes symptoms in the host rabbits. It is common and can bite humans.

Rabbit follicle mite, Demodex cuniculi. Feed on the sebum and usually causes no symptoms. It does not infect humans.

Rabbit louse

Rabbit louse

Rabbit itch mite, Sarcoptes scabiei. P.122. Feed on the top layer of the skin, forming burrows in the skin on the head and legs. It causes thickening of the skin, itching and hair loss in rabbits. It causes mild symptoms in humans.

The small notoedric mite in rabbits, Notoedres cuniculi. It feeds on the top layer of the skin, especially on the nose, head and genitals. I causes itching, thickening of the skin and hair loss. Does not infect humans.

Rabbit ear mite, Psoroptes cuniculi. Is found in the auditory canal, where it chews on the top layer of the skin. It causes itching and rash inside the ear. It does not infect humans.

Listrophorus gibbus. A mite that feeds on sebum, etc., found in the coat on the entire body. It is common and harmless to both rabbits and humans.


Cat lice, Felicola subrostrata. P.36. Feeds on the skin of the head, neck and back of the cat. Normally, without discomfort to the cat. Does not bother humans. Cats have no blood sucking lice.

Cat flea, Ctenocephalides felis. P.96.   The cat flea sucks blood. The same species are seen in dogs and transmits between dogs and cats. It will bite people when given the opportunity. The larvae live in carpets and in the cat’s sleeping place.

Cat fur mite, Cheyletiella blakei. P.128.   Feeds on the top layer of the skin. Cats are usually asymptomatic. When in contact with humans, it can bite. It is not transmittable to dogs.

Cat follicle mite, Demodex cati. P.123. The follicle mites in cat feed of sebum rarely causes symptoms in cats and cannot be transmitted to humans or dogs.

The cat itch mite, Sarcoptes scabiei. P.122. Feeds on the top layer of the skin, causing thickening of the skin as well as itching. Humans can be infected, however, the symptoms are mild.

The small notoedric mite, Notoedres cati, P.xx.  Its way of life is similar to that of the cat itch mite. Can possibly infect dogs, but probably not humans. This species of mites is rare.

Cat ear mite, Otodectes cynotis. P.125. Same species and symptoms as the dog ear mite. Can transmit between dogs and cats.

Lice in cats

Cat biting louse

Cat biting louse

Cat biting lice are quite small

Fig. 11. Cat biting lice are quite small and are distinguished by their almost triangular heads. (Seguy)

There is only one species of feline lice: Felicola subrostrata, also called feline chewing louse. This louse will get up to 1.3 mm long and is characterized by its triangular head. As a biting lice, it is quite peaceful as it eats skin flakes, etc. This does not usually bother the cat. However, biting lice are active, and if there are many of them it bothers the cat. The feline chewing lice are uncommon in domestic, well-nourished cats and more common in wild cats, especially during the winter. Fighting is rarely necessary, however, if necessary, the same treatments as used on canine lice can be applied. Be aware that cats may be intolerant of some treatments.

Dog louse Dog biting lice Cat biting lice
Dog louse Dog biting lice Cat biting lice

Fig. 12. Lice on dogs and cats is not easy to see. Here, they are shown in actual size. The lice are generally harmless, but the discovery of lice on cats or dogs can be an opportunity to get an appointment for a checkup.

Lice in dogs

Dog louse

Dog louse

Dogs can have two different species of lice. One is a blood-sucking kind of louse, and the other is a biting kind of louse.

Difference between dog flea and dog's biting louse

Fig. 10. The dog flea (left) has a small head and a large, hairy abdomen. The dog’s biting louse (right) has a large, broad head. (Seguy)

The sucking louse, linagnathus setosus, sucks blood like the lice found on people. It lives on dogs and foxes and never bites humans. This species of canine lice can grow to become 2 1/2 mm long. The nits are l mm long and are glued to single hairs or locks of hair. Its bite causes itching, small wounds and a reddish rash in the skin. The lice especially like the area around the eyes and ears and on the chest, back, flanks and around the tail. This canine louse is not very common in Denmark. If the dog has this louse, it often also has the biting louse at the same time.

The other species of canine lice, the biting lice, Trichodectes canis, are more common than the sucking lice. It is not a bloodsucker; however, it still drinks blood. It bites a hole on the skin and drinks blood from the wound. The dog’s biting lice are up to 1.7 mm long and have a large, rounded head. They live on the head, neck and ears of the dog. With well-groomed, well-nourished dogs, this species of canine lice is rare.

Common to the two types of canine lice is that both glue their nits onto the hair close to the skin. There are three stages of nymphs as well as both female and male lice. The nits hatch after about a week but the nymph stages lasts longer than with human lice – 2-4 weeks. The total development time from nit to nit is then 3-5 weeks. You may suspect canine lice when the dog scratches itself more than usual. If this is the case examine the fur for lice and nits.

Dog biting louse

Dog biting louse

To eradicate lice from dogs, apply an insecticide throughout the fur. You only need two treatments a few days apart using treatments for fleas, ticks, lice, etc.


The treatments used against crab lice are the same as the once you use to eradicate head lice and body lice. Shampoos are most suitable because they do not sting the thin-skinned places. Apply on the body and on the scalp hair and eyebrows if these are also infected, however, do not apply on the eyelashes. For eradication of lice on the eyelashes, apply the eye ointment Ophtha twice a day for 8 days. The ointment as well as the other treatments for crab lice is available over the counter at pharmacies. Treatment for pubic lice should be applied on days 1, 5 and 10 (for the exact same reasons mentioned in the chapter about head lice).

Treat the whole family simultaneously. You can still infect others until after the third treatment. The surroundings do not need treatment, however, it makes sense to change clothes and linens every time you have treated the lice, i.e. on day l, 5 and 10 immediately after the treatment.


Many people only experience a little itching discover the crab lice by accident. For other, itching, especially in the crotch, is an outstanding symptom of crab lice. Itching in the groin area can have many other causes (among the animals, the flagellate Trichomonas vaginalis or pin worm Oxyuris vermicularis, may cause itching. These two kinds of animals are not affected by crab louse treatment).

The easiest way of detecting lice in beards, armpit hairs, chest hairs and pubic hair is to comb the hair with a fine-tooth comb. The comb will pull out the hairs which put up resistance and it is usually hairs with nits on them.

Spreading of crab lice

Crab lice are spread by intimate contact – either through intercourse or simply by sharing a bed with an infected person. However, there are cases of crab lice which cannot be explained by intercourse or sharing a bed. The lice rarely leave their host but they cause itching which can result in them being scratched off along with the hair they cling to. During the first few hours, those homeless crab lice might climb on to the other people who come into contact with the bedding, the clothing or the toilet seat on which the lice landed. Crab lice are no longer as common as they have been. This is attributed to the shaving of the pubic hair, which has become increasingly common and reduces the amount of hair for lice to live on.

Crab louse bites

The crab louse does not move much. When it has chosen its sucking place, it keeps the mouth inside the skin – also in the periods where it does not suck blood. Crab lice suck blood almost all the time. That is probably why they do not tolerate being away from their host for long periods of time. A single day without access to blood will cause them to die of hunger.

Crab louse bites and their symptoms are similar to those from the head louse. However, crab louse bites are characterized by blue-colored spots, which may appear where the lice bite. The spots, which are deep in the skin, appear a few hours after the bites. They may be 0.2 to 3 mm in diameter and will stay on the skin for a long time.


Crab lice in natural size

Fig. 9. Twelve medium-sized and large crabs as silhouettes in natural size.

The crab louse has adapted to sparse hair. The scalp hairs are too close (about 220 hairs / cm 2). The pubic hair (about 34 hairs / cm 2) is better suited for crab louse. The crab louse primarily live in pubic hair but is also seen in the hair on the chest and in armpits. On the head, crab louse live in the hair lines (neck and temples), in the scalp hair (thin-haired men), in beards and (especially with children) in eyebrows and eyelashes. There can be many crab lice in the eyelashes – up to 100. When there are many there may be inflammation of the eyelid edge.