Screwworm infestation called a ‘grave threat’ to deer population

An infestation of New World screwworm “poses a grave threat to the last subspecies of Key deer we all know and love,” Florida’s top agricultural official said Monday.

“This is not one to be taken lightly,” Florida Commissioner of Agriculture Adam H. Putnam said at a gathering of local, state and federal officials in Key Largo. The three-foot-high deer are found only in the Florida Keys.

The screwworms have caused the euthanization of more than 50 of the 1,000 endangered Key deer, their heads and body parts eaten away by larvae. Screwworms feed on the live tissue of any warm-blooded mammal.

Dan Clark, manager of the National Key Deer Refuge, said samples from dead Key deer came back positive for screwworrm fly from federal labs on Sept. 30.

GRAPHIC PHOTO: Screwworm-inflected dead in “gory condition”

From early September to this week, 30 Key deer have either been euthanized or found dead from screwworm on Big Pine Key and No Name Key. But wildlife officials theorize the infestation has been going on since at least July, so the number of confirmed dead Key deer is closer to 60.

The carcasses are being incinerated at the refuge.

Monroe County Commissioner Sylvia Murphy remembers the last screwworm outbreak decades ago. Her German shepherd was infected. She noticed a sore about the size of a quarter.

“Trust me, you don’t want to have to” to deal with it, Murphy said. “It’s yucky, but it can be treated.”

Since chemicals and pesticides have proven not to be effective in the past when eradicating the screwworm fly, U.S. Department of Agriculture officials will begin releasing sterile male flies to mate with female flies this week.

A plane carrying sterile male flies is set to arrive at Florida Keys Marathon International Airport on Tuesday and twice a week for what could be the next six months, said Dr. Cristopher A. Young, assistant district director for the USDA’s Animal and Plant Health Inspection Service.

The flies have been sterilized using radiation and are supplied by the USDA’s breeding location in Panama, Putnam said. Female screwworm flies mate only once in their lifetime, storing male sperm to fertilize eggs in the future, so if it mates with a sterile male the life cycle is broken.

Putnam urged pet owners who notice anything out of the ordinary, like sores that aren’t healing, to immediately contact their veterinarians so the animals can be tested for screwworm fly. It can be successfully treated, especially if caught early.

Federal and state officials continue to operate a 24-hour northbound checkpoint in Key Largo at mile marker 106, which was set up on Oct. 3 to inspect all animals leaving Monroe County for signs of the parasitic fly larvae. Putnam encouraged pet owners to pull over and have their pets inspected for screwworm.

So far, state Department of Agriculture and Consumer Services law enforcement officers have inspected about 200 vehicles heading out of the Keys with pets and found no instances of the screwworm fly, Putnam said.

This story was originally published October 10, 2016 at 4:29 PM with the headline "Screwworm infestation called a ‘grave threat’ to deer population."