Ask any veterinarian and they will recommend you keep your dog on heartworm prevention year-round, but as the weather gets warmer and mosquitoes begin hatching in large numbers, the risks for your dog increase substantially.

When a dog is bitten by an infected mosquito, heartworm larvae is transmitted through the mosquito’s saliva into the dog’s bloodstream. For the next six or seven months or more, the larvae transform into mature heartworms and migrate to the heart, lungs and blood vessels, often growing up to a foot long. As many as 250 worms can infect a single dog, with worms living five to seven years.

At first there won’t be any symptoms at all, but as the heartworms grow and multiply in the lungs, your dog may develop a cough and seem to have less energy than usual. Over time these symptoms will typically get worse and your dog will have trouble breathing. Eventually, without treatment, blood flow to the heart, lungs, and brain will be blocked, causing death.

Heartworms have been diagnosed in all 50 states, but according to Veterinary Practice News, Alabama sees the largest number of heartworm cases in the U.S.

Part of that is due to the climate and the large number of mosquitoes, but much of the blame can be placed on owners who do not have their dogs tested annually and do not use heartworm preventatives.

Traditionally, those preventatives are monthly oral or topical medications, but newer, longer lasting medications have also been introduced, including an injection that lasts six months. It is important your dog be tested for heartworms before starting a prevention program as giving the preventative medication to a dog with heartworms can cause severe reactions.

If your dog does test positive for heartworms, it is not necessarily a death sentence, but it can be a long and expensive course of treatment. Preventing heartworms is far less expensive than treating them, particularly if you purchase medication in three-month or six-month supplies.

Ask your veterinarian if there are discounts for purchasing multipacks or purchasing at certain times of the year and whether the manufacturer offers rebates. And since many heartworm preventatives also prevent other parasites, the monthly investment into your pet’s health will be worth it. Be sure to discuss heartworms and your dog’s risks at its annual visit.

To adopt a dog or cat, visit us at 1701 U.S. 72 (behind Limestone Veterinary Clinic,) visit our Facebook page, or call us at 256-771-7889.

Email your questions or story ideas to me at PetsAndPeople@charter.net; and I’ll check with the experts (veterinarians, animal behaviorists, etc.) and get back to you in a future column.