Wednesday, June 17, 2009

Chigger Redux

Sure, we get all sorts of nasty bugs down in Australia. And, sure, we don't have window screens (a.k.a. "fly screens") on our house in Brisbane, thus making it that much easier for various antipodean insects to come bother us in our pajamas. But, none of those bugs are as irritating as chiggers in Arkansas! Amazingly, I mentioned this in a blog entry during our last family visit to Hot Springs two years ago, and here I am again scratching away as I write this.

Chiggers our particularly bothersome because you never see them. They lie in wait in the grass, in bushes, or benches, ready to leap onto your body undetected. They then lay larvae on your body, which crawl around until they find a cozy place to take hold. This description from an Ohio State website says it best:
The preferred feeding locations on people are parts of the body where clothing fits tightly over the skin such as around the belt line, waistline, under girdles and under socks, or where the flesh is thin, tender or wrinkled such as the ankles, in the armpits, back of the knees, in front of the elbow, or in the groin.

ChiggerChigger larvae do not burrow into the skin, nor suck blood. They pierce the skin and inject into the host a salivary secretion containing powerful, digestive enzymes that break down skin cells that are ingested (tissues become liquefied and sucked up). Also, this digestive fluid causes surrounding tissues to harden, forming a straw-like feeding tube of hardened flesh (stylostome) from which further, partially-digested skin cells may be sucked out. After a larva is fully fed in four days, it drops from the host, leaving a red welt with a white, hard central area on the skin that itches severely and may later develop into dermatitis. Any welts, swelling, itching, or fever will usually develop three to six hours after exposure and may continue a week or longer. If nothing is done to relieve itching, symptoms may continue a week or more.

I'm scratching in all sorts of difficult-to-reach places. Won't I have a fun time on our long plane ride back to Oz on Thursday night?

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