Enterobius vermicularis, commonly known as the pinworm, is a nematode parasite that infects the human intestine. The parasite has a worldwide distribution. It has a life cycle of 2-4 weeks that involves eggs being deposited around the anus by female pinworms at night and infecting new hosts if the eggs are ingested. Common symptoms of pinworm infection include itching around the anus and vagina, especially at night. Diagnosis involves examining perianal skin scrapings under a microscope for characteristic eggs. Treatment involves anti-parasitic medications and hygiene measures to prevent reinfection.

1. ENTEROBIUSENTEROBIUS
VERMICULARISVERMICULARIS
(Pinworm)(Pinworm)
Rahul raj ar

2. INTRODUCTIONINTRODUCTION
Enterobius vermicularis is a
nematode(roundworm) and a common
intestinal parasite in humans
It has a round body with cylindrical ends and a
complete digestive system including mouth
and anus
It has separate sexes, the female is usually
larger than a male
It has a worldwide distribution

3. MORPHOLOGYMORPHOLOGY
The body is covered with a highly resistant
coating called cuticle
The male worm is inconspicuous and has a
length of 2 to 5mm
The female is dominant and has a length of 8 to
13mm

4. GENERALGENERAL
CHARACTERISTICS OF THECHARACTERISTICS OF THE
EGGEGG
●Colourless .not bile stained
●Asymetrical in shape, being plano-convex.
(flattened on one side and convex on the
other
●Measure 50-60micrometer in length by
30micrometer in breadth
●Surrounded by transparent shell
●Contains a coiled tadpole like larva
●Floats in saturated solution of common salt

6. FEMALE PINWORMFEMALE PINWORM

7. LIFE CYCLELIFE CYCLE

8. ContdContd
Humans are the host
Infections occur by ingestion of eggs
The egg-shells are dissolved by the digestive
juices and larvae escape in the small intestine
The larvae develops into adolescent form
Fertilization occurs in the colon, after that
males die

9. ContdContd
Gravid female migrates nocturnally from the
small intestine down to the caecum and colon.
Through anus they came out at night and
deposit egg in the perianal skin
The eggs become infectious within 6 hours
The movement of the female worm and the
eggs cause itching
Scratching the area may result in retro infection
The whole life cycle is completed in 2-4 weeks
time

10. PATHOGENESIS AND CLINICALPATHOGENESIS AND CLINICAL
FINDINGSFINDINGS
Infection in man known as enterobiasis
MODE OF INFECTION
● Auto-infection
● Retrofection

11. Auto-infection
● Autoinfection occurs by scratching the
perianal area and transferring infective
eggs to the mouth with contaminated
hands by patients itself. Following
ingestion, eggs hatch and release larvae
in the small intestine

12. Retrofection
● Egg laid on the perianal skin immediately
hatch in to the infective stage larvae and
migrate through the anus to develop into
adolescent forms in the colon

13. PATHOGENESIS AND CLINICALPATHOGENESIS AND CLINICAL
FINDINGSFINDINGS
It is thought to be an allergic reaction to the
presence of either the adult female or the eggs
Itching of the perianal and vaginal area is
commonly notable, especially during night
Weight loss is also observed in severe infections
Scratching predisposes to secondary bacterial
infection

14. EPIDEMIOLOGYEPIDEMIOLOGY
Found worldwide.
Thumb sucking in and nail biting contributes to
the ingestion of eggs
Children younger than 12 years of age
are the most commonly affected
group

15. LABORATORY DIAGNOSISLABORATORY DIAGNOSIS
 The eggs are recovered from perianal skin by
using the scotch tape technique for microscopic
examination

17. ContdContd
Eggs are not found in the stool
Eggs are generally demonstrated in the
scrappings from the perianal skin by a NIH
swab.

18. TREATMENTTREATMENT
Mebandazole and albendazole can be used
These drugs are given in 1 dose at first, the
second dose is repeated after 2 weeks
Topical insecticide containing malathion can be
applied on the skin

19. PROPHYLAXISPROPHYLAXIS
Wash the anal area in the morning
Launder the bed sheets in hot water.
Don't scratch and avoid nail biting
Clean toilet seats daily.
Wash your hands.