Lice are small, wingless parasites that live on the skin, hair, or feathers of mammals and birds. They are divided into biting lice (which feed on skin and debris) and sucking lice (which feed on blood). While some species affect humans, others are host-specific to animals like cattle, horses, and poultry. This list covers 17 different types of lice, each with unique characteristics, hosts, and health impacts.
1. Head Louse (Pediculus humanus capitis)
The Head Louse is a tiny, wingless parasitic insect that lives exclusively on the human scalp. It feeds on blood several times a day and spreads primarily through direct head-to-head contact. It is especially common among school-aged children.
Identification
- Color: Grayish-white to tan (becomes reddish after feeding)
- Size: 2–3 mm long
- Body Shape: Elongated with six legs
- Antennae: Short and straight
- Eggs (Nits): White or yellowish, firmly attached to hair shafts
Habitat and Behavior
Lives on the scalp, behind the ears, and near the nape of the neck. It cannot jump or fly, relying on crawling from one host to another.
Health Impact
Though not known to spread disease, infestations cause intense itching, scalp irritation, and social discomfort. Treatment involves medicated shampoos, fine-toothed combs, and careful nit removal.
2. Body Louse (Pediculus humanus humanus)
The Body Louse is closely related to the head louse but differs in behavior and habitat. It lives in clothing seams and only moves to the skin to feed. Body lice are typically associated with poor hygiene and overcrowded living conditions.
Identification
- Color: Grayish-white
- Size: 2.3–3.6 mm
- Body Shape: Elongated with well-developed claws for clinging to fabric
- Eggs: Laid on clothing fibers rather than on hair
Habitat and Behavior
Found in clothing folds, especially near the waist, underarms, or necklines. Comes into contact with skin only to feed several times a day.
Health Risk
Capable of transmitting diseases such as trench fever, epidemic typhus, and louse-borne relapsing fever. Eradication involves improved hygiene, laundering clothes, and insecticide treatments.
3. Pubic Louse (Pthirus pubis)
The Pubic Louse, also known as the crab louse, infests coarse body hair, including the pubic region, armpits, chest, and sometimes eyelashes. It is primarily spread through close personal or sexual contact.
Identification
- Color: Pale gray or tan
- Size: 1–2 mm (smaller than head and body lice)
- Body Shape: Broad, crab-like with large front claws
- Eggs: Laid on hair shafts, close to the skin
Habitat and Behavior
Clings tightly to coarse body hairs. Moves slowly and feeds on blood several times a day.
Health Effects
Causes intense itching and visible irritation. Not known to spread diseases but requires prompt treatment with medicated lotions or shampoos. Eyelash infestations may need manual removal or prescription ointments.
4. Hog Louse (Haematopinus suis)
The Hog Louse is the largest louse species affecting domestic animals and exclusively infests pigs. It feeds on the host’s blood and can lead to discomfort, reduced growth, and disease transmission in swine.
Identification
- Color: Grayish to bluish-black
- Size: Up to 6 mm (very large for a louse)
- Body Shape: Broad, flat, and heavily wrinkled
- Legs: Equipped with strong claws for clinging to coarse hair
- Eggs: Cemented to pig bristles, especially behind the ears and on the neck
Habitat and Behavior
Found mainly on the neck, jowls, flanks, and inside legs of pigs. Prefers colder seasons and is more active when pigs are housed closely.
Health Impact
Can transmit swine pox and lead to anemia in heavy infestations. Control involves insecticidal sprays or pour-on treatments.
5. Dog Louse (Trichodectes canis)
The Dog Louse is a chewing louse that lives on dogs and wild canines. It feeds on skin debris and hair rather than blood, causing irritation and discomfort in infested animals.
Identification
- Color: Pale yellow with dark bands
- Size: 1.5–2 mm
- Body Shape: Flattened, broad head wider than the thorax
- Legs: Short with blunt claws
- Eggs: Found attached to the base of dog hair shafts
Habitat and Behavior
Commonly found around the head, neck, and tail base of dogs. Spread occurs through direct contact or shared bedding and grooming tools.
Risk to Pets
May cause intense itching, hair loss, and secondary infections. It can also act as an intermediate host for the dog tapeworm (Dipylidium caninum). Treatment includes veterinary-recommended shampoos or topical medications.
6. Cat Louse (Felicola subrostratus)
The Cat Louse is the only louse species that affects domestic cats. It is a chewing louse, meaning it feeds on skin debris and fur rather than blood. While rare, infestations may occur in neglected or stray cats.
Identification
- Color: Pale yellow to tan
- Size: 1–1.5 mm
- Body Shape: Flattened with a triangular head
- Legs: Short with clawed ends
- Eggs: Firmly attached to cat hair, especially near the neck and shoulders
Habitat and Behavior
Lives on the skin surface, especially in areas where cats can’t groom effectively. Spread through direct contact with infested animals or bedding.
Clinical Signs
May cause itching, scruffy coat, hair loss, and skin irritation. Most common in elderly, ill, or poorly groomed cats. Treatment includes flea combing and veterinary-prescribed insecticides.
7. Cattle Biting Louse (Bovicola bovis)
The Cattle Biting Louse is a chewing louse found on cattle worldwide. It feeds on skin flakes and hair, causing irritation and discomfort, especially in the winter months when coats are thick.
Identification
- Color: Reddish-brown with dark stripes on the abdomen
- Size: 1.5–2 mm
- Body Shape: Broad head wider than the thorax
- Legs: Short and sturdy
- Eggs: Cemented to hair shafts, especially along the neck, shoulders, and back
Habitat and Behavior
Prefers cooler seasons and thick coats. Spread through close contact between animals, shared grooming tools, or crowded housing.
Impact on Livestock
Heavy infestations lead to rubbing, hair loss, and reduced weight gain or milk production. Control includes pour-on insecticides and good animal husbandry practices.
8. Cattle Sucking Louse (Haematopinus eurysternus)
The Cattle Sucking Louse is one of the largest lice species affecting cattle. Unlike biting lice, it feeds directly on blood, causing irritation, anemia, and reduced productivity in heavily infested animals.
Identification
- Color: Dark bluish-gray
- Size: Up to 4 mm
- Body Shape: Long and narrow with a pointed head
- Legs: Equipped with claws for gripping hair
- Eggs: Found near the base of hair shafts, especially around the neck, dewlap, and brisket
Habitat and Behavior
Most active during colder months. Infestations are common in winter and early spring when cattle are housed close together.
Health Impact
Causes blood loss, stress, and weakened immunity. Can lead to secondary skin infections. Treated with systemic pour-on or injectable insecticides.
9. Horse Biting Louse (Bovicola equi)
The Horse Biting Louse is a chewing louse species found on horses and donkeys. It feeds on skin debris, dander, and hair, especially in long-coated animals during winter or poor grooming conditions.
Identification
- Color: Pale yellow to reddish-brown
- Size: 1–2 mm
- Body Shape: Flattened with a broad head
- Legs: Short and strong
- Eggs: Laid on hair shafts, often along the neck, back, and flanks
Habitat and Behavior
Spreads through direct contact or shared tack, blankets, and brushes. Often found on neglected or undergroomed horses.
Clinical Signs
Causes itching, hair loss, and scabby skin. Affected horses may rub or bite at infested areas. Treatment includes topical insecticides, grooming, and disinfecting equipment.
10. Horse Sucking Louse (Haematopinus asini)
The Horse Sucking Louse is a blood-feeding louse that infests horses, donkeys, and mules. It is less common than the horse biting louse but more damaging due to its blood-sucking behavior.
Identification
- Color: Dark gray to bluish-black
- Size: 3–4.5 mm
- Body Shape: Elongated with a narrow head and large abdomen
- Legs: Strong with clawed ends for gripping hair
- Eggs: Attached near the roots of coarse hairs, especially on the mane and tail
Habitat and Behavior
Found along the mane, tail base, and inner thighs. Prefers cooler months and heavily coated animals. Spread through close contact and shared grooming gear.
Effects on Horses
Causes anemia, skin irritation, and restlessness. Heavily infested horses may lose weight or show poor coat condition. Treatment includes insecticidal washes and decontaminating equipment.
11. Goat Louse (Bovicola caprae)
The Goat Louse is a chewing louse species that primarily affects domestic goats. It feeds on skin scales and hair, leading to irritation and behavioral changes in infested animals.
Identification
- Color: Light reddish-brown
- Size: 1.5–2 mm
- Body Shape: Broad head, shorter body
- Legs: Compact, adapted for movement through coarse goat hair
- Eggs: Found glued to hairs, often along the neck, shoulders, and back
Habitat and Behavior
Most common in cold seasons when goats have thick coats. Spread through close contact and contaminated grooming tools or enclosures.
Health Impact
Infestation causes itching, excessive rubbing, and patchy hair loss. May also contribute to reduced weight gain or milk production. Controlled with topical insecticides and improved herd hygiene.
12. Sheep Biting Louse (Bovicola ovis)
The Sheep Biting Louse is a chewing louse species that commonly infests sheep, particularly in colder climates. It causes severe irritation and fleece damage, which can affect wool quality and value.
Identification
- Color: Pale yellow with dark bands
- Size: 1.5–2 mm
- Body Shape: Broad, flat body with a wide head
- Legs: Short with small claws
- Eggs: Laid in the wool, usually along the shoulders, back, and flanks
Habitat and Behavior
Found on the skin surface beneath the wool, especially in thick or unshorn fleece. It thrives in winter and early spring.
Economic Impact
Heavy infestations lead to fleece matting, wool breakage, and reduced wool yield. Treatment includes shearing, insecticide dips, and regular monitoring.
13. Sheep Sucking Louse (Linognathus ovillus)
The Sheep Sucking Louse is a blood-feeding parasite that targets sheep, especially around the head and face. It is more damaging than biting lice due to its feeding habits and associated health risks.
Identification
- Color: Bluish-gray to dark brown
- Size: 2–3 mm
- Body Shape: Slender with a narrow, pointed head
- Legs: Adapted for gripping coarse wool
- Eggs: Firmly attached near the base of wool fibers, especially on the face and ears
Habitat and Behavior
Primarily found on the head, neck, and underbelly of sheep. Prefers cool temperatures and long wool coats.
Health Concerns
Can cause anemia, weight loss, and reduced growth in lambs. Proper dipping or pour-on insecticides are essential for control.
14. Human Eyelash Louse (Demodex folliculorum)
Although not a true louse, the Human Eyelash Louse is a microscopic mite often mistaken for lice due to its parasitic lifestyle. It lives in hair follicles, especially around the eyelashes and facial areas.
Identification
- Color: Transparent to pale white
- Size: 0.3–0.4 mm
- Body Shape: Long, worm-like with tiny legs near the head
- Legs: Four pairs near the front end
- Habitat: Resides inside hair follicles and sebaceous glands
Habitat and Behavior
Common in adults, especially in oily skin types. Often asymptomatic, but heavy infestations may cause irritation, itching, or blepharitis.
Health Significance
Generally harmless but can contribute to skin and eye conditions. Treatment may involve tea tree oil cleansers or prescription topical agents.
15. Chicken Body Louse (Menacanthus stramineus)
The Chicken Body Louse is a common ectoparasite of poultry, especially chickens. It is a chewing louse that feeds on skin debris, feathers, and sometimes blood from broken skin.
Identification
- Color: Yellowish to light brown
- Size: 1.5–2 mm
- Body Shape: Elongated with a rounded head
- Legs: Fast-moving, adapted for navigating feathers
- Eggs: Clustered at the base of feather shafts, especially around the vent and breast
Habitat and Behavior
Lives on the skin under feathers. Highly active and quickly spreads between birds through direct contact.
Poultry Impact
Heavy infestations cause feather damage, weight loss, reduced egg production, and stress. Controlled with poultry dusting powders, sprays, and good coop hygiene.
16. Pigeon Louse (Columbicola columbae)
The Pigeon Louse is a species of chewing louse that specifically infests pigeons and doves. It feeds on feathers and skin debris and is commonly found on domestic and wild pigeons.
Identification
- Color: Pale yellow to light brown
- Size: 2–2.5 mm
- Body Shape: Slender and elongated with a narrow head
- Legs: Adapted for crawling between feathers
- Eggs: Laid on feather shafts, particularly under the wings and around the vent
Habitat and Behavior
Inhabits the skin and feathers of pigeons. Spread through direct contact or contaminated nesting materials.
Effects on Birds
Can lead to feather wear, poor plumage condition, and discomfort. Regular cleaning of coops and treatment with bird-safe insecticides help manage infestations.
17. Elephant Louse (Haematomyrus elephantis)
The Elephant Louse is a rare and specialized sucking louse that exclusively parasitizes elephants. It is one of the largest lice species and is found on both Asian and African elephants.
Identification
- Color: Dark gray to black
- Size: Up to 6 mm
- Body Shape: Thick and robust with a rounded abdomen
- Legs: Strong, adapted to grip elephant skin folds
- Mouthparts: Piercing-sucking for blood feeding
Habitat and Behavior
Found in skin folds, behind ears, and along the underside of elephants. Lives directly on the host and is not known to infest other species.
Veterinary Concern
Usually causes minimal harm, but in heavy infestations, it may lead to irritation or secondary infections. Monitored in captive elephants and treated with veterinary antiparasitics if necessary.
