Bots - Internal Parasites

Stomach bots are the larvae of the horse bot flies. There are more than one species and they differ primarily in the location on the horse, where the eggs are laid, and in the way in which the eggs hatch.

How your horse becomes infected:
During the summer and early fall, eggs are deposited by the bot fly on the hair of the forelegs, shoulders, lips, and muzzle of the horse. The eggs hatch as they are licked by the horse and enter the mouth via the tongue.The minute larvae burrow into the tongue, remain there for approximately one month and then migrate to the stomach.

Health effects:
They attach themselves to the mucous membrane living in the stomach, causing damage to the stomach wall and sometimes producing a fatal colic when they block the valve located at the juncture of the stomach and small intestine. The larvae remain in the stomach for 8—10 months until they have completed their development. They detach themselves from the wall and are passed out in the manure.

The larvae pupate outside the host and the mature fly emerges in about one month. The flies mate and reproduce, thus completing the life cycle, The female fly darts at the horse very quickly and repeatedly, attaching an egg to a hair each time. While the flies do not bite, they do annoy the horses, causing them to run or exhibit a restless condition.