Parasitology Pages. Screw-worm Myiasis. A Case in a Dog Canis familiaris

Screw-worm larvae, Cochliomyia hominivorax.  At ca 10 mm  long, these were about to pupate.

As an ecologist, I am meant to view all animals with an objective eye and, usually, with a positive sense of wonder, not unusually accompanied by feelings of joy.  Admittedly, the joy usually only comes when seeing a mammal, snake or bird of prey.  Otherwise I just get a sense of wonder.  However, even I, a naturalist to the core, do occasionally have reason to draw the line.. There are even times when I give myself permission to feel revulsion at certain members of the natural world.  One of these is Tiger Leeches (Haemadipsa picta), which I removed from various selected parts of my anatomy more times than I care to mention when in Danum Valley, Malsysia, in 1997.

The other is the Screw-worm larva, several specimens of which can been seen in the photo above.

A short-haired pointer (a breed of dog) was brought into the clinic today.  Physical examnation revealed a swelling on the distal left thoracic limb.  The dog was taken to the infirmary and the area cleaned.  A blood sample was taken for blood work.  I gently inserted rat-toothed forceps into the hole in the swelling and removed the larvae one at a time.  Each time they came out wriggling.  The dog was being restrained all the time in right lateral decubitus (on its right side) by a veterianry nurse whilst I removed the maggots. They are the larvae of the familar blue-bottle fly, which lays its eggs on the margins of wounds in domestic animals.  

I had dealt with this parasitic infection before, but in wild species.  Once in the right wing of a Blue-and-Yellow Macaw Ara ararauna and Silvery Marmoset Callithrix argentata.