Monday, September 13, 2010

Case of the Week 130

OK, usually I stick with human parasites, but I recently came upon some rodents with the most remarkable parasites! We were conducting a catch and release study of small rodents to determine what diseases they were carrying. In the particular area that we were trapping, a large percentage of mice had the following parasites:

One with a parasite in its chest region


Here is a video showing how the parasite was slightly moving (although it's hard to make out since the mouse's heart is also beating):


Another mouse with double parasites in its posterior


We were able to remove one of these for further examination. Here is the video of its removal:


Here is the object we removed:


Finally, here is the mouse after we removed the parasite, showing the pocket that was left behind:



Identification?

15 comments:

Anonymous said...

Botfly larva??

neuro_nurse said...

Where in the world - Africa?
Cordylobia anthropophaga - tumbu fly.

Anonymous said...

Botfly larva. One of the Cuterebra species?

Parasite Gal said...

Actually, it's in the midwestern United States!

neuro_nurse said...

Wohlfahrtia vigil?

neuro_nurse said...

Wohlfahrtia vigil?

Bill said...

Bot Fly larva.
I tried to rear two of the larvae to adults but they did not pupate.
Identification to species would have been easier. Probably _Cuterebra sp._ These larva drop off the host and pupate in the ground then emerge as adults. See _Dermatobia hominis_ for human bot fly information and images in Wallace Peters' "A Colour Atlas of Arthropods in Clinical Medicine"

SGH said...

Since it's so old, not sure if anyone will see this, but I have a question regarding the parasite in question. I recently in southern florida came across a mouse with three of these larvae visible from the rear. My dog actually pounced and snatched the mouse in his mouth, and when the mouse didn't scurry off when I made Wookie drop it, I inspected further. Man these buggers give me the hebeejebees! They aren't transmissible, are they?

Parasite Gal said...

Hi SGH,
No, thankfully, they aren't transmissible. They're just part of the lifecycle of a fly that is parasitic during it's larval stage. Once they mature, they fall our of the host (mouse) and pupate in the ground. Eventually, an adult fly will emerge from the pupa stage.

I should mention that there are some flies outside of the US that do use humans as their host - South America and Africa are 2 locations where you are at risk. So you may want to find out more about these areas, should you ever decide to take a trip to an endemic area.

Pam Scape said...

While looking for things to write about related to my mouse trap blog, I've seen this kinda of parasite, but never a double exit, so to speak, and then reading the comment about the triple exit, eek, poor little guys.

Anonymous said...

Thank you for your pictures and information. I live in Minnesota, and found a dead mouse on the stairway to the basement with one of these wiggling "pods" next to it. Upon closer examination, there was a vacant space under the tail. I thought at first the mouse had been stepped on, forcing the uterus out of the body, but no pics of mouse anatomy matched what I was seeing. It greatly disturbed me, as I was wondering if humans or dogs could be host for this parasite. I am greatly relieved to know that this is rodent specific.

Anonymous said...

So far no one has given this parasite a name. I found one today in the trap. I'd like to know more but can't find the name. Anyone?

Parasite Gal said...

Hi Anon,
This is actually the rodent bot fly, Cuterebra species. Here is an entry on this organism at BugGuide.net - a great reference for bugs!

http://bugguide.net/node/view/690009

JACOB WOOTON said...

does the mouse survive the life cycle of the parasite? I just found one of these yesterday and the mouse looked in really bad shape. It looked like it was being tortured. not sure what to do I dropped the mouse into a pond thinking it would either drown the mouse or cause the parasite to exit the wound. The mouse swam with some trouble, but my attempt seemed to do no good for anyone. Would it have died anyway?

Parasite Gal said...

Jacob, the Mose does survive, although it doesn't always do as well as a non-infected mouse!