Human Head Lice

External Parasite-Lice 1

LicePediculus humanus capitis (Head lice) are responsible for the disease pediculosis. Human lice are not passed to pets or birds. Each species has its own preference in body temperature. For example a human’s body temperature is about 98.6, a dog or cats 101.5 and a bird’s is around 105 degrees Fahrenheit.

External Parasite-Lice 2

Adult human head lice (Anoplura)

Picture references: https://www.superhomeremedies.com/pictures-of-head-lice-3b.html

Modes of Transmission is usually contact with a person who is already infested (i.e., head-to-head contact).  Contact is common during play (sports activities, playgrounds, at camp, and slumber parties) at school and at home. Less commonly, transmission via fomites may occur.  Wearing clothing, such as hats, scarves, coats, sports uniforms, or hair ribbons worn by an infested person; using infested combs, brushes or towels; or lying on a bed, couch, pillow, carpet, or stuffed animal that has recently been in contact with an infested person may result in transmission.  Of note, both nymph and adult lice forms need to feed on blood to live.  If an adult louse does not have a blood meal, it can die in 2 days.

Symptoms of head lice: The majority of infestations are asymptomatic.  When symptoms are noted they may include a tickling feeling of something moving in the hair, itching, caused by an allergic reaction to louse saliva, and irritability.  Secondary bacterial infection may be a complication.

External Parasite-Lice 3

Human head lice nits on hair

Picture reference for nits on hair: https://www.merckmanuals.com/professional/multimedia/Photo2sec10ch121.html?Ref=n&RefId=x&Plugin=WMP&Speed=256&ItemId=Photo2sec10ch121

Treatment: There are several over-the-counter treatments available. We also have a natural shampoo called Lice Arrest available, and I often recommend dog flea shampoo with a few drops of clove essential oil in it although I’m sure the FDA would frown on that. In the pictures below we see an enlarged view of a head louse and a person’s hair with tiny white “nits” in it (more evident in the upper right part of the picture).