If either a blood test or the onset of symptoms betray the presence of heartworms, treatment is indicated. NOTE, before treatment begins, it is recommended that the dog have a 2 week course of antibiotics to treat a parasite that the heartworms often carry called Wolbachia. This reduces complications during the treatment.

Treatment is highly efficacious if the disease is diagnosed early in the disease process. Before the worms can be treated, however, the dog must be evaluated for good heart, liver, and kidney function to ensure the animal can survive the treatment. Any insufficiencies in these organs must be dealt with first, before treatment, as the eradication process can be taxing on organ function. Usually the adult worms are killed with an arsenic-based compound. The currently recommended compound, melarsomine dihydrochloride, is marketed under the brand name Immiticide. It has a greater efficacy and fewer side effects than previous formulation ( thiacetarsamide sodium, sold as Caparsolate) which makes it a safer alternative for dogs with late-stage infestations.

Traditionally, the first dose of the medication has been given in 2 injections administered 24 hours apart. Then the second dose comes a month later with a single injection. The last dose is an oral medication one month later. A more conservative approach is to make the first dose a single injection, wait a month, then do the second dose as the 2 injections 24 hours apart, and the last dose a month later with the oral medication. The next month, the dog begins its monthly preventative medication.

When the treatment first starts, a week or two of Prednisone can reduce the dog's level of discomfort. While this does slow down the eradication of the heartworms, the heartworms will be destroyed and the increased comfort for the dog it very important! Your vet can advise on how much to use and for how long.

During the 2 months of treatment, the dog must rest (restricted exercise) so as to give its body sufficient time to absorb the dead worms without ill effect. Otherwise, when the dog is under exertion, dead worms may break loose and travel to the lungs, potentially causing respiratory failure and death. By rest, we mean no activity. They should stay in a crate most of the time with trips outside to potty while on a leash. They can sit quietly in your lap or walk across the floor, but no running, no playing with toys, no rough housing with other dogs, no jumping, no fast walking even! According to the American Heartworm Society, use of aspirin in dogs infected with heartworms is no longer recommended due to a lack of evidence of clinical benefit, and may be contraindicated. It had previously been recommended for its effects on platelet adhesion and reduction of vascular damage caused by the heartworms.

Once heartworm tests come back negative, the treatment is considered a success. This does not always happen as soon as the course of treatment is completed. There can be a positive test for as long as 6 months to a year after treatment. This is normal and does not mean that the dog still is truly heartworm positive, it usually means that the non producing stage of the heartworms are still present and dying off.

Surgical removal of the adult heartworms is also a treatment that may be indicated, especially in advanced cases with substantial heart involvement. This is rarely done.

Long term monthly administration of ivermectin (but apparently not moxidectin, milbemycin or selamectin) year round for at least three years at the dose normally used for heartworm prevention (see " Prevention") also removes most adult heartworms from most dogs. However, this is not the treatment of choice for removal of adult heartworms for two reasons. First, not all dogs are completely cleared of heartworms by this treatment. More importantly, adult heartworms do not begin to die until some 18 months of treatment have elapsed, which is not acceptable under most circumstances. The heartworms are causing damage during this time, damage that can be irreversible. This treatment is normally reserved for dogs that are not likely to tolerate treatment with the harsher (older, sicker dogs).

From time to time various " homeopathic," "natural" or " organic" products are touted as cures or preventives for heartworm disease. However, such products have never been proven effective by rigorous scientific methods, and the claims should be viewed with a great deal of skepticism.
Prevention – Just Do It!

Prevention of heartworm infection can be obtained through a number of veterinary drugs. Most popular are ivermectin (sold under the brand name Heartgard), milbemycin (Interceptor) and moxidectin (ProHeart) administered as pills or chewable tablets. These drugs are given monthly during the local mosquito season. Moxidectin is also available in a six-month sustained release injection, Proheart 6, administered by veterinarians, but the injectable form of moxidectin was taken off the market in the United States due to safety concerns. ProHeart 6 remains on the market in many other countries including Canada and Japan and is used with great success. Its sister product, ProHeart SR-12 is used extensively in Australia and Asia as a 12 month injectable preventative. Selamectin ( Revolution), on the other hand, is a topical preventive that is likewise administered monthly. This drug is not as effective in preventing heartworms as the other preventatives as it can wash off and the amount administered is hard to gage on the dog. Some of these drugs also kill other parasites, including intestinal worms. In addition, selamectin controls fleas, ticks, and mites.

Preventative drugs are highly effective, and when regularly administered will protect more than 99 percent of dogs from infection. Most failures of protection result from irregular and infrequent administration of the drug. However, the monthly preventives all have a reasonable margin for error in their administration such that if a single month's dose is accidentally missed, adequate protection is usually provided so long as the next two monthly doses are administered on schedule.

Cats may be treated with ivermectin (Heartgard for Cats), milbemycin ( Interceptor), or the topical selamectin (Revolution for Cats).

Monthly heartworm prevention should be administered beginning within a month of the onset of the local mosquito season and continued for a month after the cessation of local mosquito activity. In warm climates, such as the warm temperate climate along the immediate Gulf coast of the United States and in tropical and subtropical regions, heartworm prevention must be administered year round. Some authorities recommend year round administration even in colder climates on the theory that mosquito activity may occur during the occasional unseasonable warm spell, but others argue that computer models indicate heartworm transmission is highly unlikely under such circumstances.
Human health considerations

The dog heartworm is a negligible public health risk, because it is unusual for humans to become infected. Additionally, human infections usually are of little or no consequence, although rarely an infected human may show signs of respiratory disease. In most cases, however, the heartworm dies shortly after arriving in the human lung, and a nodule, known as a granuloma, forms around the dead worm as it is being killed and absorbed. If an infected person happens to have a chest X-ray at that time, the granuloma may resemble lung cancer on the X-ray and require a biopsy to rule out the life threatening condition. This may well be the most significant medical consequence of human infection by the dog heartworm.

At one time it was thought that the dog heartworm infected the human eye, with most cases reported from the southeastern United States. However, these cases are now known to be caused by a closely-related parasite of raccoons, Dirofilaria tenuis . Several hundred cases of subcutaneous (under the skin) infections in humans have been reported in Europe, but these are almost always caused by another closely-related parasite, Dirofilaria repens, rather than the dog heartworm.
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Donna Farmer
tomatoe98@gmail.com
205-266-4625

Keller Williams Realty, Homewood Sales Center

Birmingham Boston Terrier Rescue
www.bhambtr.org