Flower Mound is warning pet owners that some wild foxes are carrying distemper.
Animal Services said four foxes have tested positive for the canine strain of distemper. Previously, it had identified six raccoons with the disease.
"Most of the signs you see is discharge in the eyes, discharge in the nose; you know, they're not moving around very well. [They are] dehydrated. They're starting to lose weight," said Trae Malone, Animal Services supervisor.
He also said that infected animals often will simply look sick and exhibit a "gum-chewing" behavior -- in which the animal opens and closes its mouth repeatedly.
The city is most concerned about the disease spreading to dogs. Officials are keeping a close eye on new arrivals to the animal shelter in case it spreads.
"We keep them in isolation for four or five days before we put them with the general population," manager Christine Hastings said.
She said the shelter is also checking cats, even though the feline form of the disease has not shown up in the area.
Animal Services recommends that all dog owners in Flower Mound and North Texas take special caution this year to keep their dogs safe. The easiest ways are to vaccinate dogs against the illness, avoid feeding them outdoors and not allowing animals roam close to wooded areas without supervision.
Distemper is a cyclical disease that tends to show up in certain animals every few years during the wintertime. Symptoms in dogs can include breathing issues, intestinal problems, muscular twitching and seizures. It can sometimes lead to death.