Public Health Vectors and Pests

 Body Lice

Common Name Body Lice

Scientific Name Pediculus humanus humanus
Size The adult body louse is about the size of a sesame seed.
Colour Grey in colour and red after feeding on blood
  • Nit: Nits are body lice eggs. They are about the size of the mark at the end of this arrow .       They are oval and usually yellow to white. Nits may take 30 days to hatch.
  • Nymph: The egg hatches into a baby louse called a nymph. It looks like an adult body louse, but is smaller.
  • Adult: The adult body louse is about the size of a sesame seed, has 6 legs, and is tan to greyish-white. To live, adult lice need to feed on blood.
  • Adult lice have six legs that bear claws for grabbing hair.
  • Their abdomens are longer than wide and dirty white to grayish-black in colour, depending on the colour of the host.
  • Body lice are found on the body and on clothing or bedding used by infested people.
  • Lice found on the hair and head are not body lice; they are head lice.
  • A body louse cements its eggs to clothing fibres and seams. Eggs hatch in five to nine days.
  • The louse nymphs (immature) feed on the blood and moult three times before becoming sexually mature adults.
  • Body lice deposit 275 to 300 eggs. Both nymphs and adults feed on blood several times a day, injecting irritating saliva into the wound causing intense itching.
  • The entire life cycle requires about 21 to 27 days.
  • The adult body louse can survive no longer than eight to ten days off the host, and all stages, including eggs, die within 30 days away from the host.
  • Under normal conditions the eggs will hatch in about a week. Below 74 degrees F, most eggs will not hatch.
  • Newly hatched nymphs must feed within 24 hours or die.
  • Adults may survive 3 to 5 days without a blood meal. Normally a young louse will mature to an adult in 3 to 5 weeks.
Disease Transmitted
  • Body lice infestations
  • Typhus
  • Relapsing fever
  • Itching and rash are common; both are the body's allergic reaction to the lice bite.
  • Long-term body lice infestations may lead to thickening and discolouration of the skin, particularly around the waist, groin, and upper thighs.
  • Sores on the body may be caused by scratching. These sores can sometimes become infected with bacteria or fungi.
  • Intense itching, rashes, and red welts on the skin.
  • A long and severe infestation can lead to a general darkening and thickening of the skin. If left untreated, scratching can lead to bacterial infection

Relapsing Fever: generalised body aches, headache, chills sweats, vomiting, photophobia, rash, neck pain, dry cough and dizziness.

Typhus: sever headache , chills, high fever , stupor, skin rash, muscle aches, swollen and lymph nodes

  • Body lice are spread by direct contact with infested people, and their bedding or clothing.
  • To prevent infestation, avoid sharing clothes and bedding and close, prolonged contact with an infested person
  • Infested people do not need to be quarantined to avoid spreading body lice.
  • Proper sanitation is critical in lice control.
  • Bedding and undergarments machine laundered, clean clothing worn and the premises thoroughly vacuumed.
  • Laundering, using hot water or dry cleaning infested bedding and garments will kill all kinds of body lice.
  • Regular changes to properly laundered clothing will soon eliminate body lice.
  • Thoroughly vacuum carpets, rugs, pillows, mattresses, etc. to remove fallen hairs with attached nits.
  • Body lice can survive for several days on clothing removed from a person. In regions of the world where louse-borne infections occur, quarantines, mass inspections and treatments.
  • Body lice live on clothing, not on the body so may be prevented by bathing regularly and changing clothes daily.
  • Washing clothing in hot water will usually kill adult lice and prevent eggs from hatching.
  • Body lice that are present on the skin usually go away on their own with daily bathing and wearing clothes that are not contaminated.
  • Body lice are relatively easy to control by implementing a few simple steps. Regular changing and laundering of clothes (especially underwear), or disposal of affected clothing, will control lice.
  • Using hot water wash on clothes, followed by ironing will ensure all lice and nits have been killed. An increased level of personal hygiene with regular bathing or showering is essential for control.
  • Regular bathing, shampooing and laundering of clothing and bedding discourage the establishment of human lice.
  • Dry cleaning or tumble drying affected items at >60oC for 15 minutes is another method of effectively killing lice and eggs
  • Schools, jails, hospitals, boarding houses and other crowded living quarters need a public health educational program for effective lice control.
  • Back-to-school is an excellent time to educate teachers, parents, children and the community about lice.
  • Diagnosis and treatment of louse infestations should be done under the supervision of trained medical personnel.

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