Body louse

• Body louse are a parasitic louse that infests the body of human beings of the genus, Pediculus, species humanus.
• Body lice frequently lay their eggs on or near the seams of clothing.
• Body lice must feed on blood and usually only move to the skin to feed.
• Body lice exist worldwide and infest people of all races.
• Body lice infestations can spread rapidly under crowded living conditions where hygiene is poor (the homeless, refugees, victims of war or natural disasters).
• In the United States, body lice infestations are found only in homeless transient populations who do not have access to bathing and regular changes of clean clothes.
• Infestation is unlikely to persist on anyone who bathes regularly and who has at least weekly access to freshly laundered clothing and bedding.

Morphology

Body lice have three forms: the egg (also called a nit), the nymph, and the adult.

• Nit: Nits are lice eggs. They are generally easy to see in the seams of an infested person’s clothing, particularly around the waistline and under armpits. Body lice nits occasionally also may be attached to body hair. They are oval and usually yellow to white in color. Body lice nits may take 1–2 weeks to hatch.
• Nymph: A nymph is an immature louse that hatches from the nit (egg). A nymph looks like an adult body louse, but is smaller. Nymphs mature into adults about 9–12 days after hatching. To live, the nymph must feed on blood.
• Adult: The adult body louse is about the size of a sesame seed, has 6 legs, and is tan to greyish-white. Females lay eggs. To live, lice must feed on blood. If a louse falls off of a person, it dies within about 5–7 days at room temperature.

Geographic distribution

• Body lice generally are found on clothing and bedding used by infested people.
• Sometimes body lice are be seen on the body when they feed. Body lice eggs usually are seen in the seams of clothing or on bedding. Occasionally eggs are attached to body hair.
• Lice found on the head and scalp are not body lice; they are head lice.

Transmission of diseases

• Body lice can spread epidemic typhus, trench fever, and louse-borne relapsing fever.
• Although louse-borne (epidemic) typhus is no longer widespread, outbreaks of this disease still occur during times of war, civil unrest, natural or man-made disasters, and in prisons where people live together in unsanitary conditions.
• Louse-borne typhus still exists in places where climate, chronic poverty, and social customs or war and social upheaval prevent regular changes and laundering of clothing.

Multiplication

• Body lice are spread through direct physical contact with a person who has body lice or through contact with articles such as clothing, beds, bed linens, or towels that have been in contact with an infested person.
• In the United States, actual infestation with body lice tends to occur only in persons, such as homeless, transient persons, who do not have access to regular (at least weekly) bathing and changes of clean clothes, such as homeless, transient persons.

Signs and symptoms

• Intense itching (“pruritus”) and rash caused by an allergic reaction to louse bites are common symptoms of body lice infestation.
• As with other lice infestations, intense itching leads to scratching which can cause sores and secondary bacterial infection of the skin.
• When body lice infestation is long lasting, heavily bitten areas of the skin can become thickened and darkened, particularly in the mid-section of the body.
• This condition is called “vagabond’s disease.”
• Body lice are known to transmit disease such as epidemic typhus, trench fever, and epidemic relapsing fever etc.

Diagnosis

• Body lice infestation is diagnosed by finding eggs and crawling lice in the seams of clothing.
• Sometimes a body louse can be seen crawling or feeding on the skin.
• Although body lice and nits can be large enough to be seen with the naked eye, a magnifying lens may be necessary to find crawling lice or eggs.

Treatment

• A body lice infestation is treated by improving the personal hygiene of the infested person, including assuring a regular (at least weekly) change of clean clothes.
• Clothing, bedding, and towels used by the infested person should be laundered using hot water (at least 130°F) and machine dried using the hot cycle.
• Sometimes the infested person also is treated with a pediculicide, a medicine that can kill lice; however, a pediculicide generally is not necessary if hygiene is maintained and items are laundered appropriately at least once a week. A pediculicide should be applied exactly as directed on the bottle or by your physician.
• If you choose to treat, guidelines for the choice of the pediculicide are the same as for head lice.

Prevention & Control

• Body lice are spread most commonly by direct contact with an infested person or an infested person’s clothing or bedding.
• Body lice usually infest persons who do not launder and change their clothes regularly.

Steps to take for prevention:

• Bathe regularly and change into properly laundered clothes at least once a week; launder infested clothing at least once a week.
• Machine wash and dry infested clothing and bedding using the hot water (at least 130°F) laundry cycle and the high heat drying cycle. Clothing and items that are not washable can be dry-cleaned OR sealed in a plastic bag and stored for 2 weeks.
• Do not share clothing, beds, bedding, and towels used by an infested person.
• Fumigation or dusting with chemical insecticides sometimes is necessary to control and prevent the spread of body lice for certain diseases (epidemic typhus).

Body louse Resources
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