Black fly bites concern pet owners, though vets say they're mostly harmless

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As spring turns the corner into summer and bugs start to emerge once again in Minnesota, there's one particular insect that experts say is causing an increasing number of problems for local pet owners and veterinarians.

Calls have been flooding into local animal clinics from concerned people reporting flat, red lesions caused by black flies, sometimes known as a buffalo fly or a buffalo gnat, on their pets. 

"Most of the time we will see maybe five or six red spots on the dog’s belly where there’s not any fur," said Dr. Teresa Hershey from Westgate Pet Clinic. "But this year we’re seeing them all over the dog, and some dogs have multiples, 20, 30 bites.

Dr. Amanda Maijer of Banfield Pet Hospital also confirms the uptick in calls from concerned owners, reporting 86 phone calls over the bites this week alone. 

“Over the last two years it’s really become more prominent and what we end up seeing is this bullseye type lesion," she said. “It's worse than in past years."

The bright lesions were enough to scare the Johnson family after their pair of Chihuahuas came home with the big, red spots typical of black fly bites. They thought it was ringworm at first, but soon discovered the source. 

"We freaked and were like, 'Don’t touch the dogs!’ and quick called the vet," said Sarah Johnson. "They assured us it was just bites."

The insects typically sit in grass and therefore have prime access to many pets, feeding on the blood of other animals as they pass. The flies also don't discriminate between city and country pets.

Despite their scary appearance, experts say there's no itching sensation or long-term damage caused by black fly bites. As a result, there's often no treatment necessary for spots which usually go away on their own in a week or so--a welcome relief for pet owners like the Johnsons, who said even the sight of those bites made them want to give their dogs a little extra love.

"They're a part of the family," Johnson said.

If your dog has spots that don’t go away after a week, however, or if your pet is continually biting or scratching that’s a good sign you need to see a vet. Otherwise you can always call or send in a photo to make sure what your’e dealing with is grass gnats and not something more serious.