By CELESTE BAUMGARTNER
Ohio Correspondent

PARIS, Ky. — Most people try to keep flies out of the barn, but not Dr. David Harris: In a specially prepared area of his barn, the veterinarian keeps flies to produce maggots for wound therapy. The maggots are primarily used in equine podiatry.

Harris admits that his business has a certain “yuck” factor.

During the Civil War it was discovered that when wounded soldiers who had been left in the field finally received medical attention, they often benefited from the maggots that entered their wounds, Harris said. The critters ate away at the dead and necrotic tissue and many of these patients survived, where others did not.

Surgeons began introducing maggots into certain types of wounds. With antibiotics and new surgical procedures use of maggots fell by the wayside, Harris said. They have made a comeback primarily because they are effective against Staphylococcus aureus (MRSA), a staph that’s become resistant to antibiotics.

What Harris is doing is a bit different. At his facility, Haltere Laboratory, he produces a medical-grade maggot – green blow fly larva – for wound therapy in the veterinary industry, mostly to treat horses with foot problems. To relieve an abscess, often much sole material must be pared away, and this undermines the sole. Maggots can be introduced into a smaller hole.

Harris delivers the maggots in a vial to veterinarians or vet clinics (they can be overnighted anywhere in the United States). The vet concentrates them on a piece of gauze which is placed on the wound and bandaged over.
When maggots exit the wound – the recommendation is to wash them out – the bandage materials are enclosed in a plastic bag and disposed of so the maggots cannot pupate and become flies.

One horse hit a post while racing at Churchill Downs. It had an injury to the stifle area. There was a lot of tissue damage, and a large wound opened.
“It came to the clinic for surgery after 30 days of treatment and no results,” Harris said. “The surgeon was going to cut away the dead tissue; that is hard to do without destroying healthy tissue. In this case he used a couple of treatments of maggots and sent the horse back to the track. Everything went fine.

 “The maggots excrete a substance that kills bacteria, as well as they liquefy the dead tissue and either digest it or allow it to run out of the wound,” he explained. “They tend to stimulate granulation tissue and new vessels to allow better blood flow and (allow) more oxygen to get to the soft tissues.”

Harris began raising maggots after he retired from Claiborne Farm. He converted a space in his barn to a humidity-controlled “fly room.” He stimulates the caged flies to lay eggs, which are cleaned and sterilized. After the eggs hatch (in 12 hours) he collects the larvae and puts them into three-ounce vials. They are stored at 50 degrees and can be held that way for a week.

Harris and an entomologist from UK are applying for research grants to investigate some “interesting things,” he said. One is a possibility of making the larvae fluoresce under black light so they would be easier to find; another is having the larvae produce a protein that would attach to the opiate receptors in the wound to block sensation. Yet a third is to raise a wingless fly so they won’t survive if they do happen to pupate.

“There’s no book on how to rear blow flies.” Harris said. “It has been trial and error. It’s been interesting, a lot of fun. I really enjoy it.”
For more information online, visit www.halterelab.com