Field Guide to Venomous and Medically Important Invertebrates ...

should receive antivenom if available. The success of antivenom therapy depends on the
conditions of the antivenom application (dose, route and time of injection after envenomation,
etc.) and/or on the quality of antivenom. Serotherapy is more efficient when given as soon as
possible after envenomation and with adequate quantities of antivenom. Surgical excision of the
sting site may prevent harmful or fatal consequences in some patients.
Because the range of severity of envenomation is so variable among scorpions, the relative threat
for a particular region should be assessed prior to deployment to that location to determine the
requirement for obtaining appropriate antivenoms.
Chiggers or harvest mites
Mites
Chiggers are larval mites belonging to the family Trombiculidae. They are obligate ectoparasites
on mammalian host before molting to the nymph and adult stages. Adults and nymphs are free-
living and eat small invertebrates and their eggs, and organic matter. The microscopic larval
stage cannot be seen without magnification, but the bright red, eight-legged adult, or harvest
mite, is readily visible with the unaided eye. Chiggers occur in overgrown brush or grassy areas,
especially where small rodents are abundant. Females lay eggs on the ground in groups of
several hundred, and the resulting clumps of larval mites that hatch from these eggs can result in
severe infestations of their hosts. Chiggers produce one generation each year, and they are most
abundant during late summer and early autumn.