A number of insects are known to act as ectoparasite on humans.
The body louse is one such parasite easily found on the body of humans.
It belongs to phylum Arthropoda and class Insecta.
It is scientifically known as Pediculus humanus humanus and is sometimes Pediculus humanus corporis.
The condition of being infested with body lice, head lice or pubic lice is known as pediculosis.
The genetic analysis suggests that the human body lice evolved 107,000 years ago from the head louse when our ancestors started wearing clothes.
The head louse is believed to have originated about 770,000 years ago.
The body louse is indistinguishable in external appearance from the head louse and when both are kept under laboratory conditions both will interbreed.
However, in the natural conditions such type of interbreeding does not takes place and both the two subspecies occupy different habitats.
Body lice are adapted to attach their eggs on the human clothes while the head lice attach its eggs to the base of hairs.
They are known to lay their eggs on or near the seams of clothes.
They feed on blood so they move to the skin for feeding purposes.
Body lice are cosmopolitan in distribution and infest people of all races.
They grow rapidly in crowded areas with no hygienic conditions.
In United States the percentage of infestation is very rare as people take bath regularly and change their clothes frequently.
In United States only those persons who don't take regular bath and don't change their clothes are infested with body lice.
Attack of the body lice is very common among people who don't take bath regularly and change their clothes after a long interval.
Body lice are easily transmitted from one person to other through clothes, bed linens and even through body contact with an infected person.
Body lice are irritating and cause severe itching.
They also act as vectors of certain diseases.
They are known to spread epidemic typhus, trench fever, and louse-borne relapsing fever.
The louse-borne typhus is no longer widespread but was prevailing during the olden times.
Typhus spread by louse is still common in those areas where unhygienic conditions and overcrowding is present.
The life cycle includes three stages which are egg also known as nit, nymph and adults.
The eggs are easily visible in the seams of clothes of infested person especially around the waistline and armpits.
The nits may be occasionally found attached to the hairs.
The nits are oval, yellow to white in colour and take 1-2 weeks to hatch.
The eggs hatch out into immature nymphs.
It resembles the adult except its body size.
They take 9-12 days to become adult.
They feed on blood in order to survive.
The adult body louse is of the size of a sesame seed and tan to grayish white.
They need blood supply to stay alive.
If a body louse falls from the body of a person it dies soon at the room temperature.
The infestation of body lice can be reduced to a minimum by maintaining personal hygiene, regular changing of clothes as well as regular bathing practices.
The clothes and bedding of the infested person should be washed in hot water.
Infested person can be treated with peduliculicide but it should be applied after consulting a physician.
If hygienic conditions are established then there is no need of using the pediculicide.
Delousing can be performed by boiling the clothes and the bedding in hot water at 130°F.
This kills all the eggs as well as the nymphs and adults.
Use of insecticide can also give promising results like permethrin, DDT, malathion.
Drugs do not give promising results.
It is always advised to maintain hygienic conditions and regular changing of clothes and beddings in order to avoid infestation.