Most of the common worms associated with dogs are found in the gastrointestinal tract: roundworms, hookworms, whipworms, and tapeworms. Although these worms are pesky and they can cause diarrhea, anemia, and other symptoms if left untreated, they can be easily treated and eliminated from your dog. If you suspect the presence of any of these worms your vet can do a simple exam to confirm their presence and treat your dog for them relatively inexpensively. Some owners worm their dogs a couple of times per year as a preventive measure.


Heartworms are different from these intestinal worms. Heartworms are spread by mosquitoes. The mosquito first bites an animal that is already infected with heartworms. This animal has tiny microfilariae – small, thread-like worms — in its bloodstream which the mosquito can transmit to another animal, such as your dog. Once these larvae are in your dog’s bloodstream they start to migrate toward the dog’s heart and lungs. When they are in the heart and lungs they become established and begin to grow. Adult heartworms can reach over a foot in length and live for years. A dog can host up to about 250 heartworms.

It takes several months from the time the dog is first infected for the heartworms to reach the lungs and heart and for them to be detected in a test by your veterinarian.

Where are heartworms found

In recent decades heartworms infections in dogs have been found in dogs in all 50 states. Heartworms have been found in dogs as young as a year old. Areas with higher mosquito populations are more likely to have heartworm-infected dogs, but any dog can get heartworms.


The symptoms may be barely noticeable at first, especially if the dog does not get a great deal of exercise. The heart and lungs are the organs more often affected but the liver and kidneys can also be affected. The first symptom is often a cough that becomes chronic, followed by exercise intolerance and abnormal lung sounds. When the disease is severe the dog may have difficulty breathing, enlargement of the liver, temporary loss of consciousness because of poor blood flow to the brain, fluid accumulation in the abdominal cavity, abnormal heart sounds, and death.

Diagnosis and treatment

Your veterinarian can diagnose heartworms. There are several tests available. Most dogs can be successfully treated for the illness, especially if it is caught early. Treatment usually costs several hundred dollars depending on the method chosen and where you live. Complications can sometimes occur with heartworm treatment, especially if the dog has many adult heartworms present.

Heartworm prevention

By far the best, easiest, and least expensive way to keep your dog safe from heartworms is by keeping him on monthly heartworm prevention. Heartworm preventives work by killing any microfilariae which have been transmitted to your dog by mosquitoes each month – before they can do any harm. There are several different drugs used in various heartworm preventives for this purpose but they all act in the same way. Products include daily and monthly chewables as well as topical preventives that are applied to the skin. Some of these products are combined with products to kill other worms or with flea and tick medications. You should talk to your veterinarian to decide which heartworm preventive would be best for your dog.

Heartworm disease is a serious condition that affects dogs and other animals.  It is spread by mosquitoes and it occurs in all fifty states in the U.S.  Left untreated, it can be deadly.


The heartworm life cycle

Heartworms have a life cycle that depends on the mosquito and a host body.  The cycle begins when an adult female heartworm releases her young into the bloodstream of a host body, such as a dog.  Then a mosquito must bite the dog, taking in blood and microfilariae (the immature heartworms).  It takes about two weeks for the microfilariae to mature to a larval stage where they can infect another animal.  When the mosquito bites another animal, such as a dog, the larvae enter the bloodstream and the dog becomes infected.  Over the course of about six months, the larvae will work their way to the dog’s lungs and heart and become adult worms.  They can live for up to seven years and grow to be up to 10-12 inches long.  A dog can have as many as 250 heartworms in his heart and longs.


Symptoms of heartworm disease

Symptoms of heartworm disease aren’t usually noticeable until the dog is well past the early stages of infection.  Once a dog is heavily infested with heartworms he can have a mild but regular cough, be reluctant to exercise, tire easily, have a loss of appetite, and lose weight.


The heartworm test

Dogs should be tested for heartworms annually.  The test is a simple blood test that detects an antigen that indicates heartworms are present or the microfilariae in the bloodstream.



Luckily, there are a number of good heartworm preventives available today.  Heartgard Plus, Tri-Heat Plus, and Iverhart Max all contain ivermectin and will kill microfilariae in a dog’s bloodstream, thus preventing heartworms from developing.  However, ivermectin products should not be used by collie-type dogs such as Collies, Shelties, and Border Collies.  Some people suggest that ivermectin should not be used on any herding dogs.  Some of these breeds have a mutation in the MDR1 gene which causes ivermectin to be toxic to them.


You can also use Interceptor or Sentinel to prevent heartworm.  These medications contain milbemycin oxime.  Revolution contains selamectin.  Advantage contains moxidectin.  All of these preventives will keep heartworms from developing in your dog after a mosquito has bitten him.  There are no preventives which can guarantee that your dog will not be bitten or receive heartworm larvae into his bloodstream.  Preventives work by killing off the larvae that is in your dog’s bloodstream each month before it can go to your dog’s heart and lungs.


Products for heartworm prevention must be obtained by prescription.



If your dog does develop heartworms there are treatments but they can be difficult for your dog and they are costly.  It is much easier to prevent heartworms than it is to treat them later.



Heartworm disease is a serious and often deadly condition in dogs.  Talk to your veterinarian about which method of heartworm prevention is best for your dog so you can protect him.


Article by Nancy Cope, owner of the popular online dog boutique, where you will find a wide range of products to pamper your pooch.  Select from gourmet treats, gift baskets, designer apparel, toys and more.

Tips For Treating Heartworm In Dogs

If you are like most pet owners, your pet is most likely a beloved companion, friend, and family member. When your pet gets sick, you may react with both panic and great concern. A common problem that many dogs have is heartworm. If you are looking for some tips for treating heartworm in dogs, this article can help.

This disease is caused by a parasite that infects your dog and resides in its heart. When it becomes an issue, it can cause the valves in your dog’s heart to become blocked and the arteries may also become clogged. This will make it hard for your dog to breathe and can lead to death.

In order to treat this problem, you first need to be able to recognize it. If your dog has this parasite, he or she may find it hard to breathe and may have a chronic cough. Your dog may also become very tired and weak.

Since this parasite can remain in your dog for many years before it is noticed, you should be sure to take your dog to the vet regularly. A vet can notice the issue before it starts and can also provide you with medication that prevents the parasite from remaining within your dog’s system.

As soon as you think that your dog may have this problem, you should take action. Take your dog to the vet and have the appropriate blood tests performed. If a positive test results, your dog may have to have its health assessed to find out if it is healthy enough to be treated.

When treating heartworm in dogs, medication is normally used. The drugs will be injected by the vet as soon as the issue is confirmed and you will most likely have to provide your dog with regular medications and administer a second injection after a period of time has passed. After your dog has been medicated, you should force your dog to rest for at least a week and constantly monitor its health. More treatments may be needed in some cases.

Article by Nancy Cope, owner of 4 rescue dogs and the popular online dog boutique