micro sheet #9 of Dr 7assan - Muna Yanis

All the parasites that we have took so far are endoparasites; where they live inside the lumen of the organ or the tissue . and today we will discuss the ectoprasites ( which live outside the body ).
These parasites (ectoparasites) live on the body not necessary all the time they come and feed on the person by sucking their blood, OR they can live on the body as part of their life cycle.
The first group we will talk about is lice ( pleural ) /louse (single).
Lice in literature means being tired
The medical term of infected with lice is Pediculosis.
Lice eggs always associated with them (they known as nits)
We have three variety of lice:
1) Pediculosis capities : live on the head (head lice).
2) Pediculosis humans :live on the body(body lice). These species have very similar morphology to the first group.
You will find actually some of them live on the body and some of them live on the head.
3) pubic louse : live on the pubic hair called “ pubic lice or crab lice or (phthirus pubic). Morphologically they are different from the 1st & 2nd groups. They are shorter, smaller and broader like crap.
Pediculosis capities or head lice live in association with head hair.
crab lice live in association with pubic hair.
As far as the body lice don’t live actually on the body, they live in the clothes , but they come out and feed on the body. (الدرزات)
But the site of their living (incidence) is on the clothes.
When we talk about head lice you can see their eggs are stuck to the hair and these eggs have operculum. So when you look for pediculosis capitis you look for eggs for diagnosis because we can't see the lice unless there is a lots of them which look like swimming in the hair or falling from the shoulders and transmitted from one person to another.
It is very difficult to see that so you look for nets(eggs) where they are usually stuck to the hair. White things on the hair may be “ dandruff/ قشرة " or “nits” ; the nits are smaller, where the dandruff are not stuck to hair.
The infected patient use special comb.

Pediculosis capitis very common in school ,in winter seasons (they are near each other in sake of warm) specially in girls.
Girls are more prone to be infected with pediculosis capitis.
When you look for nits you look in the area behind the ears.
If you are not sure then you can use ultraviolet light and the nits will fluoresce and look like shinny purple. (it called wood lamp (not sure)).
Associated with overcrowding. (more probably to get head lice
It doesn’t really matter is immune !!!(I am not sure ) but if one is infected he can transmit to lots of people in school and family.

Main symptom is etching /irritation bcs when lice come and bite then become allergic to saliva of the lice.
Sometimes become oblivious, they become tolerant to it so there is no itching at all.
Sometimes there is 2nd infection with bacteria for example.
You make diagnosis then give him treatment.
Head lice don’t transmit any disease. They don’t act as a vector for transmit any disease. Cause only local disease .

When we move to body lice they actually live in the clothes, and the way of transmission either close associated with crowded places where there is bad hygiene (clothes in very crowded places like prisons) OR in wars (dikes) >>> bad hygiene and no time to wash themselves or change their clothes.

Body lice are associated with bad hygiene, overcrowding (mode of transmission)

Body Itching is symptom.
The body lice is more dangerous because it can transmit disease to person who is infected which cause production of epidemics of disease like rikettsia, relapsing fever, poleria recarantis (spirochete ), relapsing ferver (recurrent , bacteria spirochet), typhos!!!!(not sure)

Head lice don’t transmit disease where body lice do.
Done by : Mona Waheed
Date of lecture:10/5/2011