Canine Heartworm Tests

If you have suspicions that your dog has heartworm disease and you take him to your veterinarian, the vet will take a detailed history of the animal to build up a complete picture. He will give an examination and canine heartworm tests and x-rays done.

Of the canine heartworm tests available, an antigen test is usually the definitive proof, one way or the other.

This comprises the testing of a blood sample for the presence of a very specific protein that is only present in blood when a female worm gives birth to the live L1 larvae or microfilaria.

The protein is passed into the dog’s blood by the female worm during the process and the antigen test can pick up this protein if more than two adult worms are present in your dog.

microfilaria in bloodThere is also a test which can detect the presence of these microfilaria in the dog’s bloodstream. This test is called a Knotts test.

A blood sample from your dog is specially treated so that when the blood is spun in a special machine, the sediment in the bottom of the test tube can be examined under a high-power microscope to see if larvae are present. Continue reading

Dog Heartworm Symptoms

Dog heartworm symptoms will almost certainly be completely absent in the early stages of the disease. However, when adult heartworms are present, there are two factors which cause the appearance of tell-tale signs of the disease.

The first factor is that the quantity of worms present cause the obstruction of blood flow to a greater or lesser extent, blood flow is also restricted due to the inflammation within the blood vessels themselves caused by the presence of a large number of worms. The second factor is the damage caused to the pulmonary arteries, these are the arteries within the lungs themselves.

dog heartworm symptomsSymptoms of heartworm disease first start to manifest when the L5 larvae (please see article on the lifecycle of heartworms for more information on the larval stages), migrate into the right ventricle of the heart and the arteries around this part of the heart. Unfortunately, damage to the arteries is caused very quickly, within a few days inflammation is caused as the body tries to repair the damage being caused by the worms but sadly, the body cannot keep up with the rate at which the damage is being inflicted and this results in arteries becoming dilated and aneurysms are common as are blood clots and sometimes smaller blood vessels become completely blocked.

This sort of damage is visible on X rays. The body tries hard to compensate for all this damage but as fluid starts to build up round these blood vessels inside of the lungs, there is not sufficient lung area to enable enough oxygen to pass into the circulating blood. So, the dog’s body becomes starved of oxygen resulting in an inability and unwillingness to exercise, shortness of breath and a cough caused by the fluid in the lungs, even a type of pneumonia may also occur. Continue reading

Heartworm For Dogs, Four Stages Of Disease

Heartworm for dogs can be very severe, even fatal. If it has been diagnosed in your dog, it goes without saying that it is a very worrying time.

Your veterinary surgeon will assess your pet to decide which of the four categories (or stages) of the disease he is in before deciding on the best course of heartworm treatment for dogs available.

Many factors are taken into consideration during assessment of of the problem in dogs. The most basic being the size, age and weight of the dog, pre-existing health problems and the severity of the infection with adult worms.

Some vets now have access to computerised aids to diagnosis into which all these factors can be fed and a result will be produced for the vet to act upon.

Heart worm is classified as follows in dogs:-

Heartworm for dogsClass 1
A dog categorised as class one is at the lowest risk. Usually this will be a younger dog who is normally healthy, has normal blood test results and is not exhibiting any symptoms of the disease although minimal disease presence has been seen on x-ray plates. A dog in class one will probably only cough very rarely, if at all and may only show minor signs of fatigue even after quite strenuous exercise. Continue reading

Heartworm Preventative Medicines

There are different types of heartworm preventative medicines. For dogs, you have a choice of three different types, either heartworm pills for dogs, chewables (a flavoured chew containing the medicine) or medicine that can be spotted on to your dog’s skin (spot ons).

Pills or chewables taken orally are the most usually prescribed preventative treatments. Chewable tablets are very popular with owners as it is pretty easy to get a dog to take this as a delicious treat with none of the concerns of trying to get him to take a pill. However, some dogs are allergic to ingredients in the chewables so a pill may be the best option.

heartworm preventativeAn allergy could be resolved as simply as changing from one brand of chewable to another as it could be just the fact that some meds contain beef whilst others use pork. For example, if your dog is allergic to beef, Interceptor may be prescribed as it uses pork and if your dog is allergic to pork, heartgard may be prescribed as it uses beef.

One thing to bear in mind is that you should NEVER give any heartworm preventative medication intended for a dog to a cat as some ingredients that are safe for dogs can be dangerous to cats. Continue reading