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PARASITIC MITES OF HUMANS
M ichael F. Potter, Extension Entomologist M ites are very small arthropods which are closely Persons walking in chigger-infested areas can be related to ticks. M ite larvae have six legs whereas the protected by treating clothing (cuffs, socks, waistline, nymphal and adult stages have eight. M ost species of sleeves) or exposed skin with tick repellents. Some mites are pests of agricultural crops. However, certain repellents should only be used on clothing; and it is types of mites are parasitic on humans. important to follow label directions. People who suspectthey may have been attacked by chiggers should take a ! Chiggers
soapy bath immediately and apply antiseptic to anywelts. A local anesthetic will provide temporary relief Chiggers are the larvae of a family of mites that aresometimes called red bugs.
Regular mowing and removal of weeds and brush make The adults are large, red mites areas less suitable for chiggers and their wild hosts.
often seen running over M owing also enhances penetration and performance of miticides, should they be required. Chigger populations Chiggers are extremely small can be further reduced by treating infested areas with (0.5 mm) and are difficult to residual miticides. Applications should be thorough but see without magnification. The restricted to areas frequented and suspected of being six-legged larvae are hairy ! Human Scabies
encountered outdoors in low, damp places wherevegetation is rank and grass and weeds are overgrown.
Some species also infest drier areas, however, making it Sarcoptes scabei, infest the skin difficult to predict where an infestation will occur. of a variety of animals including humans. The types of Sarcoptes Chiggers overwinter as adults in the soil, becoming inhabiting the skin of mammals active in the spring. Eggs are laid on the soil. After are all considered forms of hatching, the larvae crawl about until they locate and Sarcoptes scab ei a n d can attach to a suitable host. The larvae do not burrow into exchange hosts to some degree.
the skin, but inject a salivary fluid which produces a (For example, Canine scabies can hardened, raised area around them. Body fluids from the be temporarily transferred from host are withdrawn through a feeding tube. Larvae feed dogs to humans, causing itching for about 4 days and then drop off and molt to and lesions on the waist, chest nonparasitic nymphs and adults. Chiggers feed on a variety of wild and domestic animals, as well as humans.
The life cycle (from egg to egg) is completed in about 50 Human scabies mites are very small and are rarely seen.
They commonly attack the thin skin between the fingers,the bend of the elbow and knee, the penis, breasts, and M ost people react to chigger bites by developing reddish the shoulder blades. The mites burrow into the skin, welts within 24 hours. Intense itching accompanies the making tunnels up to 3 mm (0.1 inch) long. W hen they welts, which may persist for a week or longer if not first burrow into the skin, the mites cause little irritation, treated. Bites commonly occur around the ankles, but after about a month, sensitization begins. A rash waistline, armpits, or other areas where clothing fits appears in the area of the burrows and intense itching is tightly against the skin. Besides causing intense itching, chigger bites that are scratched may result in infection and sometimes fever. Chiggers in North America are not Scabies mites are transmitted by close personal contact, known to transmit disease. usually from sleeping in the same bed. Bedridden individuals in institutions (e.g., nursing homes) may also source. Their bites cause moderate to intense itching and pass the mites from caregiver to patient. The adult irritation. Rodent and bird mites are very tiny, but fertilized female mite is usually the infective life stage.
usually can be seen with the naked eye. They are about She adheres to the skin using suckers on her legs and the size of the period at the end of this sentence. burrows into the skin where she lays her oval eggs. In 3to 5 days these eggs hatch into larvae and move freely The first step in controlling bird or rodent mites is to over the skin. Soon they transform into nym phs and eliminate the host animals and remove their nesting reach maturity 10 to 14 days after hatching. sites. Often, the nests will be found in the attic, aroundthe eaves and rafters, or in the gutters or chimney.
A scabies infestation should be handled as a medical Gloves should be used when handling dead animals. A problem and is readily diagnosed and treated by most respirator should also be worn when removing nest physicians. (Confirmation requires isolating the mites in materials to avoid inhaling fungal spores and other a skin scraping.) The first step to control a scabies potential disease-producing organisms associated with infestation usually involves softening the skin with soap and water to make sure the pesticide treatments canpenetrate well. An evening bath followed by overnight After nests are removed, the areas adjacent to the nest treatment works best. A total body (neck- down) should be sprayed or dusted with a residual insecticide application of topical pesticide medication should such as those products labeled for flea control. Space or remain for 8-12 hours before showering in the morning.
ULV treatments with non-residual materials (e.g., Commonly used products include lindane (Kwell (tm)), synergized pyrethrins) can be used in conjunction with permethrin (Elimite (tm)) and crotamiton (Eurax (tm )).
residual sprays. Space treatm ents are especially useful Follow directions on the product package carefully. when the mite infestation has dispersed widely from thenesting site. In this case, more extensive treatment with Because the sym ptoms of scabies mite infestations are residual and non-residual insecticides may also be delayed by about a month, other members of the necessary in other areas of the structure where mites are household besides those showing symptoms may be observed. A vacuum cleaner or cloth moistened with harboring the mites. It is important that everyone in the alcohol can be used to eliminate mites crawling on open infected family or living group go through the treatment regime. A second treatment may be necessary toeliminate an infestation of scabies m ites, but patientsshould avoid overzealous pesticide treatment since itching may persist for a week or more after treatmentand does not necessarily indicate treatment failure. Scabies mites cannot live off of a human host for morethan 24 hours. Therefore, insecticide treatment ofpremises is not warranted. It is recommended, however,that coincident with treatment, the clothing and beddingfrom infested individuals be washed in hot water or drycleaned. ! Bird and Rodent Mites
Parasitic mites that occasionally infest buildings areusually associated with wild or domestic birds orrodents. Bird and rodent mitesnormally live on the host or intheir nests, but migrate to otherareas of the structure when theanimal dies or abandons thenest. Rodent mites often becomea nuisance after an infestationof mice or rats has beenelim inated. People usuallybecome aware of the problemwhen they are attacked by mitessearching for an alternate food

Source: https://entomology.ca.uky.edu/files/efpdf3/ef637.pdf