Wednesday, June 11, 2008

It's Chigger Time Again!

There was a faint hope in my heart that, after 6 years away from Kansas, my body's extreme over-reaction to chiggers would have faded. So each warm day that went by without my finding any chigger bites after a walk-about was cause for hope. Alas, that hope is gone. Yesterday, June 10th, was official "Beginning of Chigger Season" day on our homestead this year.

On the plus side, my body's reaction to the bite(s) I received appear to be a little muted. So far.

So, in my normal attempt to find something good (or at least interesting) in a seemingly negative animal or situation, I did some web research on chiggers today.

The first article I came across, a fact sheet (HYG-2100-98) from Ohio State University's Extension system, started out with a statement that I loved. It encapsulates so much! "Probably no creature on earth can cause as much torment for its size than the tiny chigger."

Okay, I certainly can't disagree with that. But I was looking for some fun, interesting or positive facts. Here's what I came up with....

The chiggers that we know and "love" are the newly hatched larval stage of a tiny mite from the genus Trombicula. Mites are closely related to ticks. The adult chigger mite, actually called a harvest mite, is small (about 1/20 of an inch long); the newly hatched larva is microscopic (1/150 - 1/120 of an inch). This newly hatched larva is the ONLY stage of this animal's lifespan that is parasitic.

In fact, the older nymphs and the adults eat tiny insects and the eggs of arthropods, including mosquito eggs. That could actually qualify them as beneficial to humans, in one of nature's ironic twists.

Another interesting piece of information that I learned is that we are rather accidental hosts for chiggers. In fact, our allergic reaction occurs precisely for this reason! Actually, chiggers are primarily on the prowl for reptiles, such as snakes and turtles, and birds. These animals do not respond with allergic reactions to chigger bites.

So, now that we're on the topic of actual chigger bites, I learned a little bit about the actual "bite" process itself. Chiggers do not burrow into our skin. They do not suck our blood. What a chigger does is insert its mouthparts into a skin pore or hair follicle, especially in an area of thin skin or tight clothing. The next step is to inject salivary juices containing potent digestive enzymes into our skin, literally liquefying some of our skin cells. Finally the chigger sucks up the liquid that results. Surrounding tissues harden in an attempt to block off the intrusion, and a straw-like structure is formed through which the chigger continues to alternately inject digestive enzymes and suck out liquified skin cell contents.

It is our body's reaction to the digestive enzymes and the hardened "straw" (called a stylostome) that creates the inflammation response and itchiness. In our country, there is no known disease transmitted by chigger bites. However, secondary infections due to wounds created by scratching are not infrequent.

It takes about 4 days for a chigger to fully feed. Once done, it falls off and changes into the next life stage, the nymph. As mentioned earlier, no other stage in the chigger's life feeds on us or on any other vertebrate.

The chigger stays on the skin's surface the entire time that it feeds and, thus, it is unlikely to complete its meal before being removed because it's been scratched off or scrubbed off in a bath or shower. If it hasn't completed its big first meal, the chigger that is removed from the skin dies. It is unable to reattach or to go on to it's next life stage.

Although it seems like chiggers prefer "biting" women and children to men, the actual difference in bites is due to the thinner skin that women and children have in comparison to men.

And one last piece of information that I find amazing.... In Missouri Department of Conservation's article "Chiggers!", they have calculated a chigger's journey to locate a suitable eating site by comparing it to a human journey:

"The chiggers that annoy people have long legs and can move rapidly. They are capable of getting all over a person's body in just a few minutes. The long trek from a victim's shoe to the belt line (a favorite point of attack) is a climb that take about 15 minutes but is more than 5000 times the chiggers's tiny length. That's about the same as a human scaling a large mountain-and on an empty stomach."

I don't know about you, but I have to have some respect for an animal that's willing to make that kind of journey just to eat a little take-out.

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