In the ecological world of plants, insects, animals and humans interact and share for the benefit all. Not so with parasites. Dorland's Illustrated Medical Dictionary defines a parasite as an organism that lives off another entity for its own benefit while its host gains nothing in return. By biting into human skin, common parasitic insects get their needs met while causing their hosts discomfort, expense and inconvenience.
Significance
Contagion, one problematic property of the parasite, causes outbreaks among groups of people. School children, institutionalized individuals, nursing home residents and other groups that live together fall prey to these epidemics as the parasites migrate from person to person.
Types/Behaviors
Four common parasitic infections in the U.S. are lice, fleas, bedbugs and scabies.
Lice come in three varieties. Pediculis capitis or head lice lay their eggs on the heads of people. The eggs, numerous and white in color, cling to the hair shafts until they hatch and add to the louse population. Lice also infest another dense hairy area, the pubic region. Called pediculis pubis, they usually transfer between people through sexual contact. Pediculis corporis, or body lice, infects other areas of the body.
Fleas typically afflict humans who come into contact with pet dogs and cats who are infested. Bedbugs live in the cracks of floor boards and walls and the folds of bedding, according to the "Color Atlas and Synopsis of Clinical Dermatology." They come out one night a week to feed but can survive for six to 12 months without food and travel great distances in search of their prey -- humans.
Scabies, caused by a mite transmits from one person to another during sexual contact or when sleeping in infected sheets as in a hospital or nursing home setting. Scabies burrow under the skin and tunnel between and on the fingers or body folds.
Effects
All of these infestations cause unbearable itching. Intense scratching can lead to a secondary infection. According to Children's Hospital of Pittsburgh, head lice affects children more than other types of lice, while body lice and pubic lice commonly impact the adult population. Scabies also brings severe itching with a rash of small pimples and scaly crusty skin mostly on the hands. "Color Atlas and Synopsis of Clinical Dermatology" says that bedbugs, after their long trek to find a human meal, bite exposed areas such as the face, neck, arms and legs; they notoriously bite three times in a row. The bites turn red and form pustules. The flea bites in numbers. After forming fluid filled vesicles, the bites burst and crust over.
Prevention
Cleanliness goes a long way toward warding off parasitic infections. School-age children should regularly bath and wash their hair and refrain from sharing grooming with other children. Keeping fleas at bay by treating the first trace of them and giving pets flea preventative and frequent baths is helpful as well. A well-vacuumed house can keep the flea numbers down. A clean house can also prevent scabies and bedbugs.
Treatment
For all infestations, oral antihistamines to ease the discomfort of itchiness is prescribed. Washiing everyone's bed linens on the hottest washer setting is also essential. If economically feasible, replacing all throw pillows and bed pillows with new ones is advised. Placing them in sealed plastic bags for a week after washing is an alternative for replacement. For lice, using an OTC anti-lice preparations not only for the infected child but for every member of the household will help control the problem. Using a fine tooth flea comb, methodically combing out the eggs from the hair strands of the infected person will reduce the number of lice. For scabies, prescription creams such as lindane are often prescribed.
References
- "Color Atlas and Synopsis of Clinical Dermatology"; Thomas B. Fitzpatrick, M.D., PhD., D.Sc. et al; 1997
- Dorland's Illustrated Medical Dictionary, 31st ed.; Sanders Elsevier, publisher; 2007
- Children's Hospital of Pittsburgh: Lice; 2008
- Children's Hospital of Pittsburgh: Scabies; 2008
