An early spring and plenty of standing water this year provided plenty of breeding areas for mosquitoes. These bloodsuckers don't just bite. They carry many diseases, including heartworms.

You may not fret much about heartworms. But if dogs and cats could worry about them, they would.

"Heartworms are the No. 1 killer of dogs besides cars," said Dr. Jim Strickland, a veterinarian with the University of Georgia Extension Service. "And it's almost completely preventable."

Heartworms kill thousands of dogs and some cats every year. In the Southeast, where mosquitoes thrive nearly year-round, animals can become infected during any season.

Strickland said the heartworm goes through a year-long life cycle. The parasite relies on mosquitoes to carry it from one animal to another.

"Once the larva is transmitted into an animal, it stays in the bloodstream and moves into the heart, where it becomes an adult," Strickland said.

The adult heartworms take up space in the heart, preventing it from working efficiently. They eventually cause death by congestive heart failure. Your vet can treat pets for adult heartworms, but the procedure is costly and risky.

The best way to treat animals, Strickland said, is to prevent the heartworms from becoming adults. Preventive medicines use tiny doses of insecticides to kill the larvae in the animal.

A preventive for cats has recently been released to veterinarians for prescription. "Only about 10 percent of cats will become infected," Strickland said. "But it's a much more serious condition in cats, with poor treatment options."

He recommends, though, that pet owners get their pets tested for these and other parasites every two to three years. Although the preventives are effective, some larvae may survive and grow to adults.

"Almost every dog, if it lives long enough, will get heartworms," Strickland said. "Truly, an ounce of prevention is worth many pounds of cure."

Extension entomologist Maxcy Nolan said mosquitoes are plentiful this year. "Some years the mosquito population is up, and some years it's down," he said. "This year it's definitely up."

Nolan said weather patterns this year have been favorable for mosquitoes. The relatively warm winter didn't kill mosquito eggs as bitter cold does. And frequent rain leaves lots of puddles where mosquitoes breed.

"The smaller the area of water, whether in a puddle, a bucket or even a tree hole, the more concentrated the number of mosquito larvae," Nolan said.

In spite of popular belief, ponds and small lakes aren't mosquito nurseries. These larger water areas usually have wind blowing across them that drown mosquito larvae. And they contain fish that eat the developing insects.

Nolan said getting rid of small water areas is the best way to control mosquitoes around your home.

"Mosquitoes probably don't move more than a few hundred feet from where they were bred and developed." Preventing their development is the most effective way to reduce their number.

Repellent sprays, Nolan said, work on your pets as well as they work on you. Contact your county agent to learn more about controlling mosquitoes around your home.