Saving Key deer from a deadly worm takes a new turn

U.S. wildlife officials are taking the rare step of trying to inoculate Key deer against a ghastly screwworm threatening to wipe out the planet’s last remaining herd.

Biologists at the National Key Deer Refuge on Wednesday began feeding a prophylactic drug to deer on Cudjoe and Sugarloaf keys, where no deer have yet been infected — an intervention regularly used on livestock but rarely on wild herds and never before on key deer. The drug works by paralyzing and killing screwworm larvae feeding on the deer’s open wounds.

Sick deer in the early stages of infection will also begin receiving antibiotic shots, said Chris Eggleston, acting manager of the refuge in Big Pine where the outbreak started in August.

“It’s definitely new territory for the Key deer,” he said.

The infection, first confirmed Sept. 30, has spread quickly through the small herd estimated at about 1,000. As of Tuesday, 101 deaths had been tallied, a toll quickly outpacing the number killed annually by motorists generally considered the toy-sized deer’s most imminent threat.

The severe infestation is also testing the limits of the herd’s management, which focused on keeping the animals as wild as possible by limiting human contact. Feeding is prohibited, although the deer can often be founding rooting through gardens or trash, or begging for food from motorists.

No screwworm infestation has ever been documented in the herd, so biologists and vets say they are having to learn as they go when it comes to treatment. They initially focused on wiping out the screwworms by releasing sterile male screwworms that mate with wild flies. The Florida Department of Agriculture has also issued a quarantine that stretches from the south border of Key Largo to Key West and has set up highway checkpoints to inspect all animals coming and going from the chain of islands.

But eliminating the flies could take up to six months and with the rapid rise in deaths, wildlife managers this week initiated the more aggressive measures.

On Wednesday, staff started trying to work out a strategy to deal with a herd that includes some tame deer and some hidden deep in the refuge. For those that will cooperate, they plan to hand feed medicine mixed with feed and mark them with paint. For more skittish deer, the mix will be thrown near them and if they eat, a paint-filled squirt bottle used to mark them. It’s less disturbing to the wary deer than aerosol paint.

“We tried things under pressure that made a hissing sound and the deer definitely didn’t like that,” Eggleston said.

For the hardest to reach deer, staff will try mixing the medicine in a molasses, edible brick.

Deer treated Wednesday, which included several on Big Pine and No Name keys, were painted blue. Each day, the paint colors will change. The more reclusive deer will obviously go unmarked, Egglestone said, “but that doesn’t mean they’re not treated.”

The U.S. Fish and Wildlife Service is also assembling a team of biologists, law enforcement and volunteer coordinators, who began arriving Wednesday, to deal with the unprecedented outbreak. Biologists also want to make sure the infestation doesn’t spread to other endangered animals, including the Key Largo woodrat, Eggleston said.

Since the outbreak, Eggleston said the refuge has been flooded with calls from people wanting to help. But he warned that no one should try to treat the deer and said it remains unlawful to feed them.

“We’re still pushing that because it could really throw off our efforts right now,” he said. “This is an always changing situation. We’re in the process of trying to act as quickly as we can.”

This story was originally published October 20, 2016 at 6:52 AM with the headline "Saving Key deer from a deadly worm takes a new turn."