Generally speaking, chiggers are NOT contagious.
More Info: Though theoretically it may be possible for a chigger to pass from one human to another, it is highly improbable. Liken the situation to that of a tick. Once the tick finds a host, it generally does not randomly jump to another host.
Chigger Feeding Habits Make It Unlikely to Leave
The larvae stage of the chigger lifecycle is the only stage that feeds on humans. Not overly discriminate, the larvae will feed on a variety of living creatures including mammals, birds, or reptiles. Once the tiny, six-legged chigger larvae locate a host it will settle in to feed.
Once Engorged the Chigger Moves On
Unlike other parasitic organisms such as mosquitoes and ticks, the chigger larvae do not feed on blood, but skin cells. They sit on the top of the skin and insert their mouthparts into a hair follicle. Once attached, they secrete a digestive enzyme through their saliva that break down skin cells that they then ingest.
The chigger will only feed until encouraged, which can take one to several days, at which time it will fall off and develop into the nymph stage. Nymph and adults do not feed on humans, so once the larvae have had their fill the threat will have passed.
“Chiggers, HYG-2100-98.” Ohioline. N.p., n.d. Web. 25 June 2012. <http://ohioline.osu.edu/hyg-fact/2000/2100.html>.
“Chiggers .” KidsHealth – the Web’s most visited site about children’s health. N.p., n.d. Web. 25 June 2012. <http://kidshealth.org/parent/infections