jigger \jig"ger\ ji^g"g~er, n. a corrupt. of chigre.
   1. zool. a species of flea tunga penetrans, or
      sarcopsylla penetrans, or pulex penetrans, which
      burrows beneath the skin; called also jigger flea. see
      chigoe.
      1913 webster

   2. zool. any one of several species of small red mites
      esp. tetranychus irritans and tetranychus americanus
      of the family trombiculidae, which, in the larval or
      leptus stage, burrow beneath the skin of man and various
      animals, causing great annoyance. also called chigger.
      southern u. s.
      webster 1913 suppl. +pjc
see also:
tunga penetrans sarcopsylla penetrans pulex penetrans jigger flea chigoe tetranychus irritans 
tetranychus americanus trombiculidae chigger