Many people mistakenly believe chiggers jump like fleas. However, chiggers do not jump; they are the larval stage of mites and primarily move by crawling. These tiny organisms cause intensely itchy bites, particularly after spending time in outdoor environments. Understanding their behavior, how they attach to hosts, and effective prevention methods can help minimize encounters.
Understanding Chigger Behavior
Chiggers are the larval stage of mites, making them arachnids related to spiders and ticks. These larvae are extremely small, typically 0.15 to 0.3 millimeters, and are often yellowish to light-red. The six-legged larval stage is the only one that feeds on humans and animals. Nymph and adult stages have eight legs and prey on insect eggs and other small arthropods in the soil. Chigger larvae crawl onto vegetation and then onto a host when brushed against.
Chiggers thrive in warm, humid areas such as tall grasses, weeds, brush, and wooded habitats. They are most active when ground temperatures range from 77°F to 86°F. Their activity significantly decreases below 60°F, and they are typically killed below 42°F. Chiggers often occur in patchy distributions within these favorable environments.
How Chiggers Attach to Hosts
Chiggers transfer from vegetation to a host by crawling onto clothing or skin when a person brushes against infested plants. Once on a host, these tiny larvae migrate across the skin in search of a feeding site. They prefer warm, moist areas where clothing fits tightly or where the skin is thin, such as ankles, waistlines, behind the knees, and armpits. Tight clothing, like waistbands or sock lines, can cause chiggers to cluster and begin feeding in those areas.
Chiggers do not burrow into the skin or feed on blood. Instead, they attach to hair follicles or pores by inserting their piercing mouthparts. During feeding, they inject digestive enzymes into the skin, which dissolves tissue cells. The chigger then feeds by sucking up these liquefied tissues through a feeding tube called a stylostome.
Preventing Chigger Encounters
Preventing chigger encounters involves a multi-faceted approach. Wearing protective clothing is a primary defense when venturing into areas where chiggers might be present. Long-sleeved shirts and long pants, preferably made of tightly woven fabrics, create a physical barrier against the mites. Tucking pant legs into socks or boots further prevents chiggers from reaching the skin.
Applying insect repellents also offers protection. Repellents containing DEET are effective on exposed skin, as they make it difficult for chiggers to detect a host. For clothing, products treated with permethrin can be used, but permethrin should not be applied directly to the skin. Permethrin-treated clothing remains effective through several washings and kills chiggers that come into contact with it.
Avoiding or modifying chigger-infested areas also reduces the risk. Regularly mowing lawns and clearing overgrown brush or weeds eliminates the protective cover and humidity chiggers favor. When walking outdoors, staying on established trails and avoiding dense vegetation helps minimize exposure. After outdoor activities, taking a warm, soapy shower or bath within a few hours can dislodge any attached chiggers. Washing exposed clothing in hot water eliminates any remaining mites.