Flesh-eating screwworm appears outside Florida Keys in stray dog

For the first time in more than three decades, New World screwworm has been found on Florida’s mainland.

A stray dog was found in Homestead with the flesh-eating parasite last week and the worms in its body were confirmed as screwworm. The dog has been treated and is in good health.

It wasn’t known if someone from the Keys abandoned the dog or if it got infested in another way.

Jenn Meale, communications director for the state Department of Agriculture and Consumer Services, said surveillance efforts between the department and the U.S. Department of Agriculture have increased in the Homestead area.

State and federal officials are trapping and monitoring flies in the region and keeping in touch with veterinarians, animal shelters and rescue groups, but there have been no other reports of screwworm.

The spread of screwworm on the mainland could be devastating to Florida’s livestock, which is why Meale said efforts to lock down any presence of screwworm have increased. There is no sign as to where the screwworm came from, Meale said.

Fertile screwworm flies are still around in the Lower Keys. A Key deer was found Saturday on Little Palm Island with an infestation in its head, after which it had to be euthanized, said Refuge Manager Dan Clark.

The worms were sent to the U.S. Department of Agriculture’s National Veterinarian Services Laboratory in Iowa to determine whether they were screwworms.

“It certainly looked like a pretty bad infestation,” said Clark, who has seen his fair share of the larvae that dig down into living tissue.

Screwworm flies lay their eggs in the wounds of injured animals. The larvae hatches and then feeds on the wound, basically eating the deer live.

Should the larvae be confirmed as screwworms, the death of the Little Palm Island Key deer will be the 135th caused by the parasitic larvae since July. Some have had to be euthanized and others have died from their screwworm-inflicted conditions.

On Jan. 3, a deceased deer was found on Big Munson Island, to the southwest of Little Palm Island. USDA lab results confirmed it died from screwworm. The last time a Key deer had to be euthanized prior to Saturday was Dec. 11. The deer was also found on Big Munson Island, Clark said.

Both Little Palm and Big Munson islands are private and not part of the National Key Deer Refuge, he added. To the east is Cook Island, also private. In all three places, Clark said refuge officers and volunteers are boosting up the doses of antiparasitic medicine doramectin given to deer.

Clark said a total 11,416 doses have been given to deer, 7,609 doses of which were obtained at 16 medication stations placed throughout the Lower Keys. The deer access food and are medicated by rubbing up against rollers soaked in the medicine.

USDA officials have also increased their monitoring of the islands for both sterile and fertile screwworm flies.

Nearly 80 million sterile New World screwworm flies have been released by the USDA in the Lower Keys and Marathon since October. The sterile flies mate with wild flies, driving down the number of wild flies that create parasitic larvae in the deer because the offspring of sterile flies can’t hatch.

The herd is now estimated in the upper 700s, Clark said, adding 93 deer have been found dead since July from being hit by cars or, rarely, from natural causes.

“People are often surprised by that number. It seems like a lot, but it’s not horribly atypical for this time of year,” he said.

Thousands of pet owners traveling out of the islands have been stopping at a roadside checkpoint in Key Largo where federal officials examine their pets for New World screwworm. So far, no cases have been found in the 10,202 inspected animals leaving the Keys since the 24-hour northbound checkpoint opened in early October.

Katie Atkins: 305-440-3219

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