CARBONDALE, Colorado – One doctor thought the bleeding, strange bumps on Aaron Dallas' head might have been a gnat bite. A specialist thought it was shingles, though both doctors held out the possibility that it was something far more disturbing.
Then the bumps started moving.
A doctor found five active bot fly larvae living on Dallas' head, near the top of his skull, a few weeks after a mosquito apparently placed them there.
"I'd put my hand back there and feel them moving. I thought it was blood coursing through my head," said Dallas, of Carbondale.
"I could hear them. I actually thought I was going crazy."
Dallas said he likely received the larval infestation while on a trip to Belize this summer. Adult bot flies are hairy and look like bees, without bristles. One type, dermatobia hominis, attacks livestock, deer, and humans.
Mosquitoes, stable flies, and other insects are used by female bot flies to carry their eggs to the host, where in this case it was Dallas.
"It was weird and traumatic," said Dallas. "I would get this pain that would drop me to my knees."
After a specialist told him he may have shingles, Dallas tried different creams and salves. But the pain got worse, so Dallas returned to Dr. Kimball Spence.
"When I saw him again, it was pretty obvious something else was going on," said Spence, who could see the spots moving on Dallas' head. "There's an open pit. You see a little activity, not necessarily the larvae, but a fluctuation of the fluid in the pit," Spence said.
The parasites, which were living in a pit 2- to 3- millimeters wide, were removed Thursday. His wife teases him about it now.
"It's much funnier to everyone else," Dallas said. "It makes my stomach turn over. It was cruel."
Spence said bot fly infections are fairly routine in parts of Central and South America.