Area veterinarians warn that canine heartworm disease has reached epidemic levels in Dallas County and are urging dog owners who have not had their pets tested to take advantage of a free screening being offered this week at three local animal hospitals.

The number of dogs carrying the disease is currently estimated to be in the thousands. If left untreated, the disease is fatal.

“We’re asking that all owners who have never had their dogs checked before to bring them in for a free diagnostic and consultation,” said veterinarian Dr. Donny Buster. “We will check for the presence of heartworms and discuss possible treatment options.”

The heartworm larva are transmitted from dog to dog through mosquito contact.

The parasite enters the dog’s body from the “snout” of the mosquito bearing blood from its previous victim. This small larva goes through the blood to the heart chambers, where it grows up to 8 inches in length and somewhat resembles spaghetti.

An infected dog can carry as many as 40 to 60 full-grown worms in its blood stream, which can completely interfere with normal blood flow.

Dogs that test positive for heartworms should be treated by a veterinarian to avoid heart damage and then placed on a preventative drug.

Prevention has come a long way. Thirty years ago, the only preventative option available required owners to administer one pill a day. New options include a pill that only needs to be given once a month and a shot that is good for up to six months.

Veterinarian Dr. Frances Kendrick estimated that half the dog population of Dallas County is currently not on any heartworm prevention program. “We have just such a tremendous mosquito population in this area that it’s vital that all dogs be placed on some kind of preventative.”

She said the symptoms of heartworms include coughing, coughing up blood, lethargic disposition and abdominal swelling.

Veterinarian Dr. Mike Wells said, “Part of the problem with heartworms is that the dogs look perfectly healthy in the early stages, and owners can’t tell that there’s anything wrong. We can’t even tell it just by looking. But by the time the signs become readily apparent, it can be too late. Then they leave here crying because we had to put their 6-year-old dog to sleep.”

Animal hospitals participating in the free screening are Valley Creek Veterinary Hospital, 3013 Citizens Parkway, 872-7577; Northside Animal Hospital, 2612 Citizens Parkway, 872-2355; and Selma Animal Hospital, 501 Cahaba Road, 875-3700.

The screening will be offered this coming Monday through Friday.