They're tiny brown parasites, jumping bugs that bite. San Antonio seems to have more fleas than ever this year, and ordinary medications just don't seem to work against these blood-suckers.

Dr. Michael Woolley of Family Pet Hospital in Stone Oak, said that we saw an increase in fleas this year.

"We had a really really wet summer, so it was good for them," he said. "We really have only had one or two good freezes, and that's just not enough."

It is enough to keep Dr. Woolley busy, prescribing flea treatments all day. But these determined fleas are not always responding to topical drugs anymore.

"In recent years, we certainly have seen dogs become more resistant to many of the flea medications," Dr. Woolley said.

Robin Howell saw fleas on his dog, Perseus, for the very first time this year. And they didn't just get a hold of Percy.

"You feel something biting on you, and sometimes you see them jumping!" Howell said.

Dr. Woolley says that much of the flea life cycle goes on in the environment.

"They have a pupae stage, a larvae stage, and they have lots of eggs," he said.

That's why it's important to continue treating your home and pet, because the eggs of those unwanted guests can hang around for weeks to come.