Michelle Wagner, age 8, Jefferson, S.D., for her question:

HOW DO CHIGGERS BITE?

A chigger, also correctly called a jigger, is the common name of two pests: the chigoe flea and the larva of a harvest mite. Only the harvest mite larva lives in North America.

The harvest mite is a small red creature that creeps into the skin pores and hair follicles of man to feed and create a rash. He bites with needlelike fangs in his mouth. He is merely a nuisance since his bite only causes itching, but in Oriental countries and on many of the Pacific islands he carries a typhuslike disease called Japanese river fever. The parasitic larvae of the harvest mite usually get the disease from infected rodents. The mite keeps the disease during its nymphal and adult stages and gives it to the larvae of the next generation, which pass it on to men.

Harvest mites are most common in the Middle West and South.