Enterobius vermicularis Flashcards
Common Name
- Seatworm
- Pinworm
- Society worm
- “Tiwa”
Other Name
Oxyuris Vermicularis
Final Host
Humans
Infective Stage
Embryonated Egg
Habitat
Large Intestine
Epidemiology
Considered as most common nematode
infection in the world
Shape
Spindle-shaped
Tails
Males have curve tails; have a spicule Females have pointed tails
Notable Parts
It has cephalic alae
a wing-like structure
cephalic alae
on its anterior portion that is used during migration
cephalic alae
Shape of Eggs
D shaped / lopsided / football shaped
(flattened one side)
Egg Production
Approx. 11,000 eggs per day
Eggs Structure
It has 2 layers:
- Outer albuminous
layer
- Inner lipodial layer
Inside is a tadpole looking larva
Embryonation
After 4-6 hours
MOT
Oral, Air-borne, Retroinfection,
Autoinfection
Enterobius vermicularis : Life Cycle
There are different ways we get the infection but primarily, main mode of transmission is ____________
Ingestion of eggs
Enterobius vermicularis : Life Cycle
After ingesting, it would hatch and release larva in the _________ and they will find its way to the ______ and become adults.
- small intestine
- large intestine
Enterobius vermicularis : Life Cycle
The gravid female would travel from large intestine to the _________ to lay eggs
perianal area
Enterobius vermicularis : Life Cycle
The female migrates during the _____ to lay eggs
night
v
They will ___ after laying eggss
die
Enterobius vermicularis : Life Cycle
Within _____ hours in the perianal area, they will already be embryonated and mature
4 to 6
Enterobius vermicularis : Life Cycle
Within the eggs are the tadpole-like larvae and are considered as _____
L1 larva
Enterobius vermicularis : Life Cycle
Eggs can be found in the _______ where
the child is sleeping
bed sheets
Enterobius vermicularis : Life Cycle
There is also a possibility of ________ when cleaning the bed of an infected person if the eggs are suspended in the air.
inhalation
Enterobius vermicularis : Life Cycle
_______ is another mode of infection in which case the larva hatched in the perianal area and will go back into the anus and be infected again by the parasite.
Retrofection
Enterobius vermicularis: Pathology
Disease caused
Enterobius vermicularis: Pathology
Enterobius vermicularis : Life Cycle
In autoinfection, one symptoms is _____________ which causes the infected to scratch their butt and eggs can be found between the nails infecting themselves or other.
nocturnal pruritus ani
Enterobius vermicularis: Pathology
Patients experience:
Nocturnal Pruritus Ani
○ Insomnia
○ Secondary Bacterial infection
○ Loss of Appetite,
○ Abdominal Pain
○ Vulvovaginitis
○ Appendicitis.
○ Ectopic deposition of the eggs
Enterobius vermicularis: Pathology
(eggs can be found in the vagina and cause inflammation)
Vulvovaginitis
Enterobius vermicularis: Pathology
In some rare cases, the eggs can be deposited not in the perianal area but in the ______ or _____
lungs or liver
Enterobius vermicularis: Pathology
If one is infected in the family, best course of treatment is to treat __________ in the Family
everyone
Enterobius vermicularis: Treatment
First drug of choice
Mebendazole
Second drug of choice
- Albendazole
- Pyrantel Pamoate
Enterobius vermicularis: Diagnosis
__________ is not recommended due to low recovery rate (only about 5%)
Stool examination
Commonly used:
Scotch tape Swab/Cellophane
Anal Swab/NIH Swab
Other method of collection:
- Swellengrebel
- Graham’s technique
- Petrolatum
Collection should be done early in the morning before ______ and ________
defecating and taking a bath
Collect the specimen wearing ____
PPE
Use of scotch tape or cellulose acetate with
a tongue depressor or slide
Scotch tape swab
Use of scotch tape with a tongue depressor
Graham’s technique
Use of moisten pestle. Pestle is slowly rolled on the perianal area, and the eggs will adhere to the moisten pestle
Swellengrebel technique
Use of a glass-rod; wherein on top has a cellophane paper (clear-type)
NIH swab
The _______ is applied to the perianal area - rolled on the area to collect the eggs and examine under the microscope.
NIH swab
cellophane part
You can put it on a test tube.
NIH swab
Based on the guidelines, at least __ negative (-) NIH swabs should be done before reporting it as negative
7
Enterobius vermicularis : Epidemiology
More common among
females(Locally)
Cosmopolitan
Cannot be controlled by _____________
sanitary disposal of waste
