Insect bites and infestation

[markchambers]

I recently traveled to Bali, whilst there I found a fly drinking blood from what I thought was a scratch on my ankle. Since then it has itched non stop and appears to be a single punture wound. Is there a fly that lays eggs in people. I expected mosquitos and the usual spiders etc. I do not want to go to a doctors and waste his time.

Sorry if this is a silly question

Mark

[Philip Parks, MD]

Dear Mark:

This is not a silly question and I apologize for the delay in the response.

Can you tell me when you were in Bali and how long ago you found the fly "drinking blood" from the apparent scratch on your ankle?

How does the wound on your ankle look now? Pain? Swelling? Redness? Itchy?

The comments regarding flies laying eggs in people may get graphic quickly. Flies can lay eggs in people and animals. Flies lay eggs in dead tissue and maggots are the larval stage of the flies.

There are flies that can lay eggs in living tissue and maggots will then emerge from the  site. The eggs usually remain at the site where the fly had access to open tissue and the maggots will slowly grow and emerge.

Treatment is simple--hot compresses and removal of the larva from the site followed by disinfection/washing of the site.

I hope this is helpful to you.

~•~ Dr. Parks

This answer is not intended as and does not substitute for medical advice. The information presented in this posting is for patients’ education only. As always, I encourage you to see your personal physician for further evaluation of your individual case.

[swampcritter]

Swampy loves insect critters, but is not a doctor. Having said that:

Fly larvae vastly prefer dead tissue, so if you have a wound a fly will not lay eggs unless there is sufficient dead tissue for the maggots to feed.

There is one exception to this rule -- that is the screwworm fly. However, you would have known soon after had this fly been a screwworm, you would have seen the larvae by now and the wound would be a lot larger. Plus, screwworm flies, as far as Swampy knows, don't live in Bali.

Chances are, the fly you saw was a tabanid having a blood meal prior to laying eggs. The eggs would be laid in water, possibly a coastal marsh, but not in you. The reason, incidentally, that the fly needs the blood is that it uses the protein to construct the eggs. Normally, the adult flies eat sugar from plants.

A good example of a fly that needs a blood meal and whose larvae live in salt marshes is the greenhead fly, Tabanus nigrovittatus, which lives near the east coast of the US. If you visit the Jersey shore and get bitten, chances are, you have made the acquaintance of the female greenhead.