Maggots leave endangered mini deer in ‘gory’ condition

In what looks like a scene from a horror movie, photos of small endangered Key deer in Florida with heads half-gone show the deadly effects of New World screwworm.

More than 40 of the nearly 1,000 endangered Key deer living at the National Key Deer Refuge on Big Pine Key in the Florida Keys have been euthanized due to the presence of screwworm, said Dan Clark, manager of the National Key Deer Refuge. At least eight of the deer were euthanized Sunday and Monday.

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service confirmed Tuesday the presence of screwworm at the refuge.

Screwworm flies lay their eggs in the wounds of injured animals. When the larvae hatch, they feed on the wound as it becomes larger.

“They’re in as gory of a condition as you can imagine,” Clark said of the infected deer. Staff members started seeing more deer with open sores and lesions infested with fly larvae in September. “That made us ask a lot of questions.”

This is the first local infestation of screwworm in the United States in more than 30 years, according to the USDA. The USDA and Florida Commissioner of Agriculture Adam H. Putnam declated Monroe County an “agricultural state of emergency” Monday.

Many of the deer are infected beyond rehabilitation, at which point they are put down with a bolt gun, a modified pistol with a spring-loaded steel rod that causes mortality quickly after being discharged into the head of the deer, Clark said.

Clark’s staff members from the National Wildlife Refuges Complex and others from the Florida Fish and Wildlife Conservation Commission and Monroe County Sheriff’s Office have been performing the euthanizations, Clark said.

The screwworm fly lays eggs only in the wounds of living animals. Carcasses are be deposited in a safe spot away from the public where “nature can take its course,” he said.

Staff members from the Big Pine complex aren’t actively chasing deer, but may encounter an infected deer while performing population surveys or receive a call from someone who sees an injured deer. After the deer is put down, the maggots are removed from the carcass.

Humans can be infected the same way the flies infect animals, according to Clark and area veterinarians. How the fly arrived on Big Pine Key has yet to be determined by the USDA and other agencies.

The screwworm fly is not widely present in the United States, but it is found in most South American countries and in five countries in the Caribbean.

The presence of screwworm can be an agricultural nightmare for farmers, Clark said, and would be much more difficult to eradicate had it been discovered in a place such as Texas.

“Thankfully, we have the ability to isolate it here,” he said.

Federal and state officials will remain at a 24-hour northbound checkpoint in Key Largo at mile marker 106, which was set up on Monday to inspect all animals leaving Monroe County for signs of the parasitic fly larvae. They are not pulling all cars over but hope those transporting animals will voluntarily stop to get their animals checked.

This story was originally published October 6, 2016 at 11:34 AM with the headline "Maggots leave endangered mini deer in ‘gory’ condition."