Enterobius vermicularis

1. Coming Soon! To a home theater near you! Enterobius vermicularis

2. History Accounts of pinworm infestation have existed in medical literature since the beginning of recorded time. A worm causing intense pruritus ani (perianal itch) was described in early Chinese, Indian, Arabic-Persian, and Greco-Roman populations, and even Hippocrates recorded his experience with the sleep disturbances caused by infestation with E. vermicularis. Direct evidence of enterobiasis in ancient populations emerged with the discovery of E. vermicularis eggs in dried fecal specimens (known as coprolites) found in archaeological sites. The oldest known eggs were recovered from the Danger Cave and Hogup Cave in western Utah from a 10,000-year old coprolite. Described by Fry and Moore in a 1969 article published in Science, the coprolites were positively identified as belonging to the prehistoric humans who inhabited the caves. The eggs reported in that article still represent the earliest recorded samples of E. vermicularis, although subsequent discoveries have been reported in many ancient populations around the world, including a recent discovery among ancient Egyptian mummies. Utah, but I’m taller.. Recovery of eggs from various prehistorical human coprolites has allowed researchers to trace the migratory patterns of the humans carrying the worm. Because the pinworm life cycle occurs entirely within humans and does not rely on specific soil or climatic conditions, it is likely that E. vermicularis was carried over by human migrations across the Bering Strait. Such an early spread of the worm in human populations helps explain its wide geographic distribution today.

3. So what is a pinworm? Pinworms are helminthic pathogens. The worms are white and spindle-shaped with a large, bulbar esophagus. Eggs are ovoid, thin-shelled, and flat on one side. Females are approximately 1 cm long and males are half that size. The curved posterior end of male worms has a single copulatory spicule. The males are rarely seen because they die shortly after copulation and are expelled. Eggs will not embryonate at temperatures below 23°C, but embryonated eggs can remain viable for several weeks under moist and cool conditions. Little is known about immune responses to pinworm infection. Infections are more common in children than in adults, suggesting that acquired immunity or some other type of age-related resistance develops. • Infections affect about 200 million worldwide. • 40 million cases in the U.S. and Canada. • Most common worm infection in the U.S. STATS Enterobius ova (Scotch tape prep)

4. Transmission & Pathophysiolgy Humans become infected by ingestion of infected embryonated eggs which reach the mouth by inhalation, hand to mouth transport, or in contaminated food or drink. Infections many times involve families living under crowded conditions. Sometimes the entire family may be infected. Enterobiasis (pinworm disease) is caused by the nematode worm Enterobius vermicularis. This organism has a worldwide distribution and can infect horses, mice and primates (man and monkeys). It does not infect cats and dogs. Pinworms reach maturity in the lower GI tract within 2 to 6 weeks. The female worm migrates to the perianal region (usually at night) to deposit ova. The sticky, gelatinous substance in which the ova are deposited and the movements of the female worm cause perianal pruritus. The ova can survive on fomites as long as 3 weeks at normal room temperature. Intestinal lesions are reported, but the worms usually cause little intestinal pathology. The parasite has been found in diseased appendices but is not necessarily the cause of the pathology. Pinworms can make their way to extraintestinal locations and cause complications. For example, the parasites may carry bacteria into other organs, resulting in abscess formation.

5. Diagnosis Children suffering sleepless nights because of perianal itching often have pinworms. Eggs are rarely found in the feces, and the diagnosis is made by finding eggs on perianal swabs made of Scotch tape. The tape is pressed first onto the perianal region and then onto a microscope slide, and is examined microscopically. Perianal specimens are best obtained in the morning before bathing or defecation. Three specimens should be taken on consecutive days before pinworm infection is ruled out.

6. Treatment/Prevention The medications used for the treatment of pinworm are mebendazole, pyrantel pamoate, and albendazole. All three of these drugs are to be given in 1 dose at first and then another single dose 2 weeks later. Pyrantel pamoate is available without prescription. The second dose of medication is to eliminate possible re-infection since the first dose of medication. Health practitioners and parents should weigh the health risks and benefits of these drugs for patients under 2 years of age. Repeated infections should be treated by the same method as the first infection. In households where more than one member is infected or where repeated, symptomatic infections occur, it is recommended that all household members be treated at the same time. In institutions, mass and simultaneous treatment, repeated in 2 weeks, can be effective. • Wash in the morning. Because pinworms lay their eggs at night, washing the anal area in the morning can help reduce the number of pinworm eggs on your body. Showering may help avoid possible recontamination in bath water. • Change underwear and bed linen daily. This helps remove eggs. Launder in hot water. Wash bed sheets, nightclothes, underwear, washcloths and towels in hot water to help kill pinworm eggs. • Don't scratch. Avoid scratching the anal area. Trim your child's fingernails so there's less space for eggs to collect. Discourage nail biting. • Clean toilet seats daily. This helps remove eggs. Most Importantly…

7. …Wash Your Hands! When? How? -Before, during, & after preparing a -Wet hands with clean running water food and also before consumption. (hot or cold) and apply soap. -Before and after caring for someone -Rub your hands together to make a who is sick. lather and scrub them well; be sure -Before and after treating a wound or to scrub the back of your hands, cut. between your finger, & under nails. -After using the toilet. -Continue rubbing your hands for at -After blowing nose, sneezing, or least 20 seconds. (HINT) coughing. -Rinse hands well under running -After touching an animal, animal water. feed, or waste. -Dry your hands using a clean towel -After touching garbage. or air dry. *Hint- Need a timer? Try humming Happy Birthday to yourself two times.

8. What about hand sanitizer? Washing hands with soap and water is the best way to reduce the number of germs on them. If soap and water are not available, use an alcohol-based hand sanitizer that contains at least 60% alcohol. Alcohol-based hand sanitizers can quickly reduce the number of germs on hands in some situations, but sanitizers DO NOT eliminate all types of germs. How? • Applythe product to the palm of one hand (read the label to learn the correct amount). • Rubyour hands together. • Rubthe product over all surfaces of your hands and fingers until your hands are dry. ✔ ✔ ✔

9. Case Study Infection Sally became unknowingly infected by ingesting infective pinworm eggs. (Possibly from contaminated fingers, clothing, bedding, or by eating food that was prepared by an infected host who failed to perform proper sanitary practices after defecating.) After about a month and a half, Sally went to her physician complaining about difficulty sleeping due to an itchy rectum, particularly at night. Diagnosis After reporting her symptoms to her physician, he instructed her to touch her perianal skin with transparent tape first thing in the morning, to collect possible pinworm eggs. She was then to repeat this process for three consecutive days. Upon confirmation of a pinworms diagnosis, Sally’s physician prescribed the following treatment plan. Treatment Sally was advised to take Combantrin @ 125mg, 6 tablets (750mg) immediately and then repeat 2 weeks later to eliminate possible reinfection. She was then advised to take nonpharmacological steps to prevent reinfection.

10. BRAINS!! Will helminths be responsible for the zombie apocalypse? Why should we care? Even though the current symptoms of pinworms are relatively harmless, future evolution of the helminths could possibly result in more harmful symptoms. A second species, Enterobius gregorii has already been found in Europe, Africa, and Asia.

11. REFERENCES CDC (2013). Parasites-Enterobiasis. Retrieved from www.cdc.gov/parasites/pinworm/. (wash your hands/treatment/prevention/stats) Cross, John H. (2000). Enteric Nematodes of Humans. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK8261/. (pathophysiology/description/transmission) Dowshen, Steven (2009). Pinworms. Retrieved from http://wesleymc.com/your-health/kidshealth/22282/pinworms?mainCatergory=3. (pinworm soap image) Evaneko (2007). Avalace the Demon Worm. Retrieved from evaneko.deviantart.com.art.Avalace-the-Demon-Worm-59478396. (Imaginary worm and zombie images) Kiche, Anne O. (2011). Microbiology in the Physicians Laboratory. Retrieved from http://www.healthcare.uiowa.edu/cme/clia/modules.asp?testID=11. (diagnosis/tape procedure image/egg slide) Stanford (2006). History. Retrieved from http://www. Stanford.edu/class/humbio103/ParaSites2004/Enterobius/history.htm. (pinworm history) Thompson, Jason (2010). Attack of the Pinworms. Retrieved from www.theartofdad.blogspot.com/2010/05/attack-of-pinworms.html. (Pinworms image)