The weather’s warmer, you’re able to spend more time outside with your dog, and all is good with the world. You’re in the backyard ready to enjoy an evening kicking back and then you hear that all-too-familiar high-pitched buzzing sound. Yes, they’re back – mosquitoes! For some people, mosquitoes are merely an irritation with bites leaving itchy welts on the skin, but many others fear the health issues that these tiny insects can bring in the form of malaria, West Nile or the Zika virus. Although many of us think about the effects of mosquitoes on humans, we sometimes overlook the harm they can do to pets in the form of heartworm.
Heartworm causes serious disease in dogs affecting the heart, the lungs, and the blood vessels of the dog and ultimately it results in death. Heartworm is a parasitic roundworm that is spread to a dog if he is bitten by a mosquito. It is the only way that dogs can get heartworm – it cannot be caught from another infected dog. When a dog is bitten by an infected mosquito, the larvae migrate from the bite site to the heart, lungs, and blood vessels and this takes approximately 6-7 months. During this 6-7 months, the larvae develop into adult heartworms. These adults then make their homes in these organs and blood vessels and start to reproduce. Adult heartworms can grow up to 12 inches long and can live for 7 years. A dog can have as many as 250 worms in his system. If a dog has been bitten by an infected mosquito, it is likely that there will no symptoms for 7 months.
After 7 months, you may start to see symptoms suggesting that your dog may have heartworm. Symptoms may include the following:
Soft dry cough
This is from the heartworm multiplying in the lungs. The dog may cough more after exercise and may even faint. Exercise does not need to be strenuous for this to occur.
Your dog becomes very lethargic
If your once active dog is suddenly not wanting to be active and preferring to sleep or rest rather going for a walk. This may be a sign of heartworms.
Because your dog is so lethargic, even activities like eating can be too much effort. As a result, the dog may choose to rest in preference to eating. If a dog doesn’t eat normally, weight loss will likely result.
If your dog is experiencing difficulties in breathing, it may be due to heartworm. If the lungs have heartworms living there, it can make breathing difficult and fluid can build up in the lungs and surrounding blood vessels.
Protruding ribs and bulging chest
The dog may look this way because of weight loss and because of fluid on the lungs.
Your dog may appear to be asthmatic or even allergic. This is because of the build-up of fluid and heartworm inhabiting the lungs.
When there are large numbers of heartworm it can cause a blockage in the heart resulting in the collapse and ultimately the death of the dog.
The last four symptoms occur when heartworms end up in other parts of the body other than the heart, lungs, and blood vessels.
As with many illnesses, the above symptoms can indicate other health issues, so vets have other ways of detecting heartworms. Blood tests are a good way to determine whether there are heartworms by checking the presence of certain proteins (antigens) in the blood produced by heartworms. The earliest this can be detected is at around 5 months after the dog has been bitten by the mosquito. X-rays, ECG, and echocardiography can also help to determine what is going on in the heart and lungs of the dog.
Treatment is achieved by initially stabilizing the dog’s condition prior to the actual treatment beginning. The veterinarian may start by giving the dog antibiotics (to eliminate the bacteria that the heartworm give out when they die), preventative treatments (to stop heartworm reaching adulthood by eliminating the larvae), and steroids (to stop inflammation). The actual treatment can then begin and may be in the form of a series of injections to eliminate adult heartworm from the dog. Your dog will need to be hospitalized for this process. Pre-treatment stabilization and treatment can take several months to achieve. Following this, the younger heartworm and larvae are eliminated. In certain situations, surgical removal may be required.
Following treatment, the dog will need to rest far more than usual. Physical exercise increases the rate at which the heartworm will cause damage to a dog’s heart or lungs. A very active dog with only a few heartworms can be more at risk than a very inactive dog with lots of heartworms. Your veterinarian will advise when exercise can be resumed and this will need to be introduced slowly and gradually. Six months after the treatment you will need to have your dog tested for heartworms again. This is because the veterinarian needs to check that all heartworms were eliminated during the treatment process. The longer the time that heartworms are present, the more damage they can do.
The best approach to managing heartworms is to prevent them in the first place. There are many products on the market that are designed to prevent a whole variety of problems ranging from heartworm to fleas in one single application. These can be provided in the form of a pill or spot treatments applied to the skin. These monthly treatments do not prevent heartworms but eliminate any larvae that have been acquired by the dog during that month.
It is always advisable to discuss heartworm concerns with your veterinarian. He or she can advise you on the best preventative measures to protect your dog from this parasite.
Information given in this article is not a substitute for advice from a qualified medical professional. Please consult a veterinarian for advice specific to your dog.