The past few years we have seen a rise is this terrible disease in our area. Last year our clinic identified 9 new cases, and so far this year we have already diagnosed 5. This is significant when you consider that 10 years ago we might find a case each year or every other year, and mainly in animals that traveled outside the area. Now it is happening with patients that have lived here their entire lives. 2 of the patients that were diagnosed so far this year have been on prevention during this year; but missed some months.
Unfortunately a high percentage of dogs and cats remain unprotected, or receive preventatives inconsistently. Many people do not realize how serious heartworm can be, and that their dog or cat can die from it. Others are not aware that it comes from contact with mosquitoes; and that even animals who live primarily indoors can still be exposed. They are also not aware that there is no treatment for cats, and that the treatment for dogs involves using a form of arsenic and can be both risky and expensive ($1000-3000 depending on the size of the dog). And that the disease is very advanced by the time any symptoms are apparent.
An animal can contract Heartworm if he or she is bitten by an infected mosquito. The mosquito injects an early stage of the disease into the body. This early stages matures as it migrates into the skin and through the blood stream. As it matures, it eventually travels to the right side of the heart. At this location, the adult worms can reproduce. This process takes about 6-8 months. The worms also can migrate to other organs such as liver and lungs and cause damage to these tissues. As the number of worms increase, symptoms of illness begin to occur. Coughing, exhaustion with exercise, shortness of breath, weight loss, lethargy, and vomiting are the most common signs. Unfortunately, sudden death is also a common symptom.
It is easy to start your companion on heartworm prevention. For patients that are under 8 months old, no labwork is needed. For patients that are older, a blood test for heartworm should be done. If this test is negative, prevention should be given every 30 days. The prevention kills an early stage of Heartworm called the microfilaria. The manufactures of preventatives recommend annual screening to identify breakthrough infection. Preventatives are not perfect, and often are not given every 30 days. Most manufactures will guarantee protections if preventatives are purchased through a veterinarian, and will pay for treatment if there is a problem.
If your cat tests positive, there is no treatment. If your dog tests positive, additional screening tests such as blood work and x-rays will be done to stage the level of the infection. The American heartworm society recommends that all canines receive treatment in stages to make it safer for your companion. Immiticide, the drug that kills the adult Heartworm is a form of arsenic. Currently this medication is not being manufactured in the USA, and is being shipped from other countries on a limited basis. Prior to this therapy, a dog is placed on antibiotics and preventatives to kill the early stage of this illness. 30 days later treatment can begin. A canine is hospitalized during treatment with the initial injection, and then is strictly crate confined with no running, jumping, or playing for 30 days. Then the second and third injection can be given a day apart, and again the patient is confined with no running, jumping, or playing for 30 days. As the Immiticide kills the adult Heartworm, the dead worms create clots in the body. If the patient is too active, these clots can move and create blockages in other areas of the body. This can be deadly depending on the location of the clot. The more Heartworms that are present, the higher the risk for complications. Follow up testing is done to insure that a dog is now free from disease.
Our clinic carries both Heartguard and Trifexis for dogs. These medications are both given by mouth, and also help to prevent some internal parasites as well. Trifexis also protects against fleas. For felines we offer Advantage multi. This topical medication also protects against fleas, some internal parasites, and ear mites. We have recently changed to annual testing because of the increase in the prevalence of this life threatening illness. Routine testing is not expensive, and a monthly dose of Heartworm prevention is about the price of a latte at Starbucks for a small dog. Heartguard offers rebates if a year of product is purchased through your veterinarian. Use caution with where you purchase preventatives. Many on line pharmacies will sell non-USA manufactured preventatives or expired products. Also keep in mind that manufactures will typically only guarantee medications that are purchased through your veterinarian.
Please protect your cherished canines and felines from this deadly malady.