Head louse

Head louse

Head louse

(Latin:  Pediculus humanus var. capitis)

The head louse attaches its eggs firmly to hairs close to the scalp. The eggs are extremely tenacious and can only be removed from the hair by using a fine comb and much effort. Even frequent washing of the hair may not be sufficient to remove them.

The empty eggshells remain on the hair and move outwards as it grows. Under a lens they can be distinguished from unhatched eggs, because they are more transparent and they lack the ‘lid’.

As already mentioned, lice require a blood meal twice a day, and at ordinary room temperatures a head louse can only survive a couple of days when not living on a human.

Head lice do not transmit diseases.

They can be controlled by special preparations, but these do not usually kill the eggs, so treatment has to be repeated several times at intervals of 4-5 days.

Body louse

( Latin: Pediculus humanus var. corporis )

Found only on the body and in clothing, the body louse lays its eggs in the seams and in similar sheltered places. It is somewhat hardier than the head louse and at 23° C it can live for 4 days without access to blood.

The best conditions for the spread of these lice are when humans are living close together under primitive conditions.

They do not thrive among people who maintain a good standard of hygiene with frequent changing and washing of clothes.

Body lice are important as vectors of typhus fever, trench fever and louse-borne relapsing fever. In populations where these diseases do not occur, the only effect of louse bites is the resultant annoying itch.