|D. hominis larva|
As you probably already know, flies are animals belonging in phylum Arthropoda under the class Insecta. All flies belong to the order Diptera, meaning "two-wing"; this is in reference to the fact that these insects have only one pair of wings as opposed to two pairs like most other insects. The second pair of wings in most flies have been reduced to vestigial structures called "halteres". These structures now function mostly as balancing organs and have a knob-like appearance. This order houses about 120,000 species representing 140 families. The family that contains bot flies is the family Oestridae. This family is split into four subfamilies: Cuterebrinae (skin bot flies), Oestrinae (head maggots), Hypodermatinae (cattle grubs, ox warbles, and heel flies), and Gasterophilinae (stomach bots flies infecting horses and their relatives, elephants, and rhinos). Our D. hominis is found in subfamily Cuterebrinae and is common from Southeast Mexico down through the South American continent, extending to Argentina and Chile. Though we call it the "human skin bot", it will actually develop beneath the skin of just about any warm-blooded animal...mammals or even birds.
|Adult human skin bot fly|
The life cycle of this fly is similar to other flies in that it involves the laying of an egg what will hatch into a larva, which will go on to form a pupa from which an adult fly will eventually emerge. Unlike most flies that infect their hosts (a condition known as "myiasis" which we will discuss in a moment), this fly does not lay eggs directly onto their hosts' bodies. Nope, these guys are much more devious. An adult female fly will catch another parasitic insect, like maybe a mosquito, and glue her eggs onto the insect's body with the opercula (little flaps that open to release the eggs' contents) of the eggs facing downward. It is unknown how many different types of insect carries are used by D. hominis, but there are at least 48 different types of flies and on tick species that have been known to be carriers. Once one of these carriers lands on warm skin, the opercula open releasing the larvae onto their new hosts. The larvae then burrow into unbroken skin and make a home in the dermal layers of the skin, where they stay for about 6 weeks before burrowing out of the skin and falling into the soil where they form a pupa and undergo metamorphosis, emerging as adult flies ready to mate and restart the cycle.
|Bot fly larva being removed from a leg|
|Human skin bot fly larva|
No matter how awesome it is that these guys make antibacterials from their spit, they are not fun to have burrowing into your dermis. The best way to remove a bot fly larva from yourself is to suffocate the little guy and then pull him out by squeezing or using tweezers. There are several ways to suffocate the larva. One way is to put tape over the wound, but this is not recommended as it can actually rip the larva causing problems with total removal. Another, less damaging way is to apply several coats of nail polish to the wound, but this can be problematic when removing the nail polish and is easily applied incorrectly due to the nature of skin. The best, most effective way with the easiest cleanup is to apply a generous coating of petroleum jelly to the wound. Which ever method you use, leave the applied substance on the wound for about a day or more, then you can remove the substance and subsequently remove the fly. Some sources say that a venom extractor (found in snake-bite first aid kits) can be very effective at removing these larvae.
Moral of the Story
|I think if you get a bot fly, |
someone should buy you this shirt.