ENTEROBIUS VERMICULARISHuman Pinworm

Causes enterobiasis or oxyuriasis Not fatal but worms might go beyond

perianal region Intestinal nematode Meromyarian – in somatic muscles,

there are two to five cells per dorsal or ventral half

PARASITE BIOLOGY

Adults have cuticular alar expansions at the anterior and a prominent esophageal bulb

Female has a long pointed tail and uteri is distended with eggs

Males have a curved tail and a single spicule and because they

die after copulation Rhabditiform larva has esophageal bulb and no cuticular expansion on the anterior end

PARASITE BIOLOGY

Eggs are asymmetrical with one side flat and the other side convex

Translucent shell consists of an outer, triple albuminous covering and embryonic lipoidal membrane

Ovum develops into a tadpole-like embryo Eggs are resistant to disinfectants but succumb to dehydration and strive in moist environments

PATHOGENESIS AND CLINICAL MANIFESTATIONS

An innocuous parasite, rarely produces serious lesions

Attachment of worms=Mild catarrhal inflammation of the intestinal mucosa

Mechanical irritation and secondary bacterial invasion= inflammation of the deeper layers of the intestines

Migration of egg-laying females to the anus= irritation of perianal region

Intense itching = secondary bacterial infection

Pruritus= insomia Adult worm migration= appendicitis,

endometritis, salpingitis and peritonitis Other signs: poor appetite, weight loss,

irritability, grinding of teeth, abdominal pain

Familial disease

DIAGNOSIS

Perianal itching Microscopic examinations Graham’s scotch tape swab or perianal

cellulose tape swab

TREATMENT

Pyarantel pamoate, albendazole, mebendazole Secondary dose may be necessary Cure only after seven perianal smears Egg reduction rate are hard to determine

because eggs are from perianal area and not from feces

Contradictions to drugs: pregnancy and hypersensitivity

Effects of drugs: gastrointestinal distrubance, headache

EPIDEMIOLOGY

Both temperate and tropical Both developed and under developed

countries Cannot be controlled by sanitary

disposal of human feces Contaminate underwear and beddings

EPIDEMIOLOGY

route of infection: mouth, respiratory system -> anus Retroinfection: when they go back to

large intestine 208.8 million people are infected In Philippines: 29% schoolchildren from

private schools; 56% from public school

EPIDEMIOLGY

Prevalence is higher in females Eggs from nails Migration of female worms to perianal

area during night time

PREVENTION AND CONTROL

Personal cleanliness and hygeine Short nail Frequent handwashing

PREVENTION AND CONTROL

Showers and not bath tubs Underwear, night clothes, blankets

bedsheets- handled with care, boiled, laundered

Chemotherapy for entire family

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