Enterobius vermicularis

2. Enterobius vermicularis

4. Introduction:
• Enterobius vermicularis, also called pinworm, is one of
the most common nematode infections in the world.
Originally, E. vermicularis was named Oxyuris
vermicularis. Humans are the only natural host for this
infection.
• Transmission occurs in people who are living in crowded
environments and usually occurs within families.
• The worms are tiny, thread-like, and whitish.
• The worm is named after the characteristic pin-like
tail present on the posterior part of female worms.

5. • Pinworm infestation usually occurs in children.
Transmission is via direct contact with contaminated
items or even during sexual contact. Most infections
are asymptomatic. While the cure rate is high,
recurrences are common.
• Infection most commonly occurs in children, but
any individual is susceptible to E. vermicularis
infection.
• People from tropical climates and school-aged
children are the most vulnerable. Infection is
caused by the ingestion of the pinworm eggs.
• Transmission is most commonly through the
fecal-oral route.

6. • Risk factors for pinworms include poor hygiene, eating
after touching contaminated items and living with an
individual who is identified as egg positive
• Female Enterobius vermicularis, measuring 8 to 13 mm
long by 0.4 mm wide.
• They are characterized by the presence of wing like
expansions (alae) of the body wall at the anterior end,
distension of the body .
• Due to the large number of eggs in the uteri, and a
pointed tail.

7. • Males egg’s smaller in size, are 2 to 5 mm long
and possess a curved tail.
• Enterobiasis is considered the most common roundworm
infection in the United States.
• Commonly occurs as a result of nail biting, poor
hygiene, or inadequate hand-washing
• The life span of the adults is about two months.

8. Enterobius, commonly known as
pinworm or seat worm, is parasitic
only to humans.

9. LIFE CYCLE OF ENTEROBIUS

10. LOCATION:
Sexually mature worms usually inhabit the ileocaecal
area of the human intestinal tract, but they can
spread to adjacent regions of the small and large
intestines
MIGRATION:
Adhering to the mucosa, the worms feed on bacteria
and epithelial cells. Males die following copulation, while
egg-bearing females, with up to 15,000 eggs in their
uteri, migrate to the perianal and perineal regions.

11. DEPOSTION OF EGGS:
There, stimulated by lower temperature and aerobic
environment, they deposit their eggs and then also die.
More eggs are released when the female’s body ruptures.
Each egg contains, upon deposition, an immature larva.
THIRD STAGE LARVA:
The infective, third-stage larva completes development
within the egg several hours after leaving the body of
the female worm.

12. HOW INFECTION OCCURS
Infection and re-infection occur when eggs containing the
infective larvae are ingested by the host. This may happen
when eggs are picked up on the hands from bedclothes or
beneath fingernails contaminated when the host scratches
the perianal zone to relieve itching caused by nocturnal
migration of the female worms.
It may be airborne infection because these eggs are light
weight and can be spread through air.

13. After ingestion a new cycle starts.
LIFE SPAN:
The life cycle of E. vermicularis spans about 2 months

14. Enterobius vermicularis
Life Cycle
Epidemiology
Symptomatology and Diagnosis
Chemotherapy
Prevention

15. Symptomatology
 Pinworms are not highly pathogenic.
Clinical symptoms
Such as itching and irritation are
caused by the migration of gravid females around the
perianal, perineal, and vaginal area.
Heavy infections
In children may also produce such
symptoms as sleeplessness, weight loss, hyperactivity,
grinding of teeth, abdominal pain, and vomiting.

16.  Gravid females
may also migrate up the female
reproductive tract, become trapped in the tissues, and
cause granulomata in the uterus and fallopian tubes.
They may also migrate to the appendix, the
peritonealcavity, or even the urinary bladder.

17. Diagnosis
• Diagnosis is verified when adult worms and/or eggs are
detected.
• Female worms emerge at night and are frequently visible
in the perianal and perineal regions. Adult worms can
• often be observed on feces as well; however, eggs are
found in feces in only about 5% of cases.

18. • The most reliable procedure for finding eggs is to press a
strip of scotch tape on the perianal
skin, remove it, and place it on a clean microscope slide
for examination.
• Negative results from this protocol for seven consecutive
days constitute confirmation that the patient is free of
infection

19. Chemotherapy
 Following positive diagnosis in any individual, treatment
should be administered to all
 members of the household.
 Several relatively inexpensive and essentially nontoxic
drugs are available. Either pyrantel pamoate, albendazole,
or mebendazole, usually administered
 Mebendazole and albendazole are contraindicated for
pregnant women since they are teratogenic in
experimental animals.

20. prevention
Complete eradication of pinworm infection from a population
is highly unlikely.
Scrupulous personal hygiene is the most effective deterrent.
Fingernails should be cut short, and hands should be washed
thoroughly after toilet use and before food is prepared or
eaten.
Since infection is most prevalent in urban areas where
relatively large populations intermingle education of parents
has proven most effective.

21. prevention
Parents should be informed that it is a self-limiting,
nonfatal infection, widespread among children and that no
social stigma should be attached to it.
There is no evidence that dogs can transmit the infection.
Infected children as well as other members of the household
should be treated promptly. Bedclothes, towels, and
washcloths from infected homes should be carefully laundered
in hot water and
aired in sunlight.