Overview of Enterobius Vermicularis - Human Pinworm Infection

Enterobius vermicularis It is from the family: Oxyuridae. The common name is: human pinworm ,Seat worm or threadworm(UK andAustralia ) The common name was derived from the sharp- pointed tails, especially of females. Disease:Enterobiasis, pinworm infection, oxyuriasis Habitat: Large intestine ( cecum, appendix) Infective stage : Egg (embryonated egg) Method of infection: Oral- fecal or eggs inhaled. Hosts: Humans are the common host.

Morphology Males: 2-5mm long,widith by less then or equal o.3 mm and have a single spicule and a curved tail. Females: 8-13mm long by 4mm wide, and the posterior end extends into a long, slender point. In both sexes: 3 lips surround mouth, and creamy white colored. Spicule a minute sharp-pointed object or structure that is typically present in large numbers, such as a fine particle of male of E.vermicularis .

Eggs: 50-60um x 20-30um, elongate-oval, flattened on one side (D-shaped), embryonated when laid, became infective within 4-6 hrs)

Eggs:

Life Cycle:

Pathology and Symptomatology About one-third of pinworm-infected persons are asymptomatic, The adult worms may cause slight irritation of the intestinal mucosa. While Major symptom is anal pruritus(chronic itchy skin) , which associates with the nocturnal migration of the gravid females from the anus and deposition of eggs in the perianal folds of the skin. Restlessness, nervousness, and irritability, probably resulting from poor sleep associated with anal pruritus,. In young girls, migration of the worms may produce vaginitis.

Diagnosis Diagnosis depends on recovery of the characteristic eggs. The eggs and the female adults can be removed from the folds of the skin in the perianal regions by the use of the cellophane tape method (scotch tap method). The examination should be made in two three morning, before the patient has washed or defecated . Since the life span of the pinworm is less than two months, the major problem is reinfection. Include A retroinfection: infective pinworm eggs that migrate back into the host body develop and reproduce and becoming dislodged. Autoreinfection:if infective pinworm eggs are ingested via hand-to- mouth contamination.

Updating Humans are the only natural host of pinworms, However, in 2004, Chan et. al documented the existence of pinworm and Trichinella in cockroaches from hospitals and schools in Hawaii. While cockroaches are known carriers of bacteria and fungi that produce disease in humans, the link between cockroaches and pathogenic helminthes has not yet been illuminated, and this was the first report of pinworm infestation in naturally occurring cockroaches. In 2005, Tatfeng et. al isolated pinworm ova from cockroaches (Diploptera punctata), as well as the ova, cysts, oocysts, and mature parasites of several other parasites. This team trapped 234 cockroaches from areas in and around households in Ekpoma, Africa. The cockroaches were placed in containers of formol saline, which were then shaken vigorously to detach the parasites from the cockroaches. The fluid was then spun and examined under a microscope.

The findings from studies have great public health implications and detected pinworm in cockroaches. If they are indeed reservoirs for pinworms, control of cockroach populations and limiting contact with cockroaches could possibly greatly minimize not only the spread of pinworm infection, but of many other infectious diseases as well.

Control and Prevention: Thoroughly clean and wash bed linens, clothing, carpets, etc. Do not allow the eggs to become airborne. If infected, try not to scratch perianal region. Always wash hands before contact with other surfaces and mouth.