The term chigger (or jigger) can refer to either of two distinct parasitic arthropods with similar behaviors.

Chigoe flea

The term originated as a corruption of the name of the chigoe flea (Sarcopsylla penetrans or Pulex penetrans), a tropical flea common in South America and the West Indies. The breeding females of this insect burrow into exposed skin and lay eggs, causing strong irritation and itching. If left inside the skin this may lead to infection or other dangerous complications.

Trombiculid mite

Trombiculid mites (also known as Red Bugs, Harvest Mites or Scrub-Itch Mites) are one-half a millimeter wide chrome-orange mites in the family Trombiculidae that live in berry patches, tall grass and weeds, woodland edges, pine straw, leaves, and treebark. These relatives of spiders are nearly microscopic measuring 0.4mm (1/100 of an inch). The chigger's six-legged parasitic larva will crawl onto humans, rabbits, toads, box turtles , quail, and even some insects, and bite the host. They inject digestive enzymes into the skin that break down skin cells. They then feed on liquefied skin until engorged or drop off. Severe itching occurs for up to a week after they drop off. After they drop off their hosts, the larvae mature into adults, which have 8 legs and do not harm humans. The females lay 3-8 eggs in a litter, usually on a leaf or under the roots of a plant, and die by autumn.

This usage, especially common in the United States, likely originated as a misidentification of the mites as chigoes, due to their similar burrowing behavior. However, it has become widespread enough that it is now generally considered a correct usage of the term.

Comfort and avoidance

After being outdoors, a hot bath or shower and immediate laundering of clothing may eliminate the chiggers before they will attach to skin. Repellents generally contain one of the following active ingredients: DEET, Catnip oil extract - Nepetalactone, Citronella or eucalyptus oil extract. Scratching is discouraged in order to avoid breaking the skin and causing a secondary infection. A covering to reduce air exposure over the itchy area, such as fingernail polish , calamine lotion, petroleum jelly, or baby oil, will help reduce itching. It is a myth that the larva burrow into the skin and a covering such as fingernail polish kills the chigger. The severe itching is accompanied with red pimple-like bumps (papules) or hives and skin rash or lesion on a sun-exposed area. For humans, itching usually occurs after the larvae detach from the skin.

Bibliography

• Tideland Treasure: The Naturalist's Guide to the Beaches and Salt Marshes of Hilton Head Island and the Southeastern Coast, Revised Edition, by Todd Ballantine

External links

• Ohio State University Extension Fact Sheet, Entomology, Chiggers, HYG-2100-98
• Iowa State University Department of Entomology Insect Information Note
• NIH Medline Plus