By Penn State News

A Penn State entomologist is asking Pennsylvania deer hunters for help with research on biting flies that are active in the fall, which may be vectors of dangerous disease.

Michael Skvarla, associate professor of entomology and biology in the College of Agricultural Sciences, wants to document the locations and prevalence of these “keds” in an effort to determine whether they pose risks to human health.

Research has suggested that the insects, an introduced species of biting fly originally found in Europe, Siberia and northern China, may be carriers of diseases normally associated with ticks.

Deer keds frequently are mistaken by hunters as ticks, Skvarla noted. Keds may superficially resemble ticks, but the former are typically larger, ranging from 1/8 to 3/16 inches long.

Keds are also highly mobile and found on the deer belly, while ticks are attached to the skin, do not move around much, and are usually found around the head and neck.

“We’re asking hunters to record the number of keds that land on them along with temperature and weather conditions, so we can try to determine the factors that drive ked abundance and where in the state hunters may be most at risk for ked bites,” he said.

Skvarla’s research indicates that keds may harbor anaplasma, the bacteria that cause anaplasmosis; and bartonella, the bacteria associated with bartonellosis.

Anaplasmosis is on the rise in Pennsylvania, he pointed out. “We’re not trying to scare hunters, but we want to let them know that these insects are around, and they might carry pathogens,” he said.

In nature, the deer ked is a parasite on white-tailed deer, elk, horses, cattle and humans in North America, according to Skvarla. Under laboratory conditions, keds also will feed on dogs, house mice, moles, monkeys, pigeons and domestic fowl.

“On humans, the deer ked will engorge on blood in 15 to 25 minutes — but the bite is barely noticeable and leaves little trace at first,” he said. “Within three days the site develops into a hard, reddened welt. The accompanying itch is intense and may last 14 to 20 days. This reaction is probably the result of the body's reaction to the fly saliva.”

Skvarla noted that he is hoping to receive ked samples from hunters, especially winged keds, which are flying in search of hosts September through October — and sometimes as late as December, according to Penn State Extension — and haven’t yet consumed their first blood meal.

Keds shed their wings as soon as they land on a host and begin to feed, he explained. If a winged ked is found with pathogens, it would indicate they could be transmitted to people.

To participate in keds research this fall, visit this website.

To learn more about keds, visit this Penn State Extension page.

(Reprinted from Penn State News.)

[Posted: October 20, 2022]

10/24/2022