Heartworms (Again)

Heartworm disease is a series but preventable condition. (Image Source)

While we briefly touched on heartworm disease last week, it is such an important topic I thought we would look a little more closely at it again. Heartworm disease is preventable. This is so important to remember. You dramatically decrease the risk of your pet contracting heartworm if you keep them on a monthly heartworm preventative. The added bonus of some of these preventatives is that they will help protect your pet against some of the intestinal parasites we focused on last week. We have reached a point where it is recommended to keep pets on the prevention year round. It used to be customary to stop in the winter months (except in the southern states) as we saw less mosquitoes at those times. However we are seeing mosquitoes later in the year and they seem to come back sooner each year too.  It is much easier to remember to give it monthly than to take a break. Also it is MUCH cheaper and safer to keep your pet on heartworm prevention then to treat heartworm disease.

 

This incident map is from 2010 but you can begin to see that cases are become more frequent in northern states. (Image Source) 

As we mentioned before heartworms are transmitted by mosquitoes. The baby worms are deposited into the blood supply then travel to the lungs where they mature into adults and start to cause the clinical signs associated with this condition. This includes coughing, exercise intolerance and sometimes decrease appetite/ weight. Cats can also be affected by heartworm but many times will not show symptoms at all. If they do show symptoms, they can be similar to that of dogs, or it could be much more dramatic including seizures and difficulty walking. The good news is, there are preventatives available for cats too!

 

An example of a 'snap test' that is frequently used to diagnose heartworm disease. (Image Source)

To identify if your dog has heartworms there is a blood test that is performed. Many times veterinarians will initially use the ‘snap’ test. If that is positive it is a good idea to verify the presence of the larvae (or baby heartworms) in the blood stream. This is done by looking at a small amount of blood under the microscope. Testing for heartworm disease should be done prior to starting any heartworm preventatives. Heartworm disease in cats is much more difficult to diagnosis and may require advanced imaging such as an ultrasound of the heart.

 

An example of the typical heartworm life cycle. (Image Source)

If your pet is positive, the good news is there are treatment options. The bad news is that many of the treatments can be very expensive and not without risks. The typical treatment includes a series of three injections administered deep into the muscles along the spinal column. This can be painful and most patients will be started on anti-inflammatory medication to help control their discomfort. During this time the worms will be killed off and can start to flood the blood supply. If the pet is too active, this could lead to an increase in circulation and the worms can actually flood the respiratory system and lead to death. Many times the hardest part of treatment can be keeping your pet EXTREMELY quiet. After treatment is completed a recheck blood test should be performed at 6 months. During this time the pet should be kept on monthly preventatives as directed by your veterinarian.

 

An example of 'baby heartworms' found in the blood supply. These are typically identified under the microscope. (Image Source)

Again, this is a very brief overview of what can be a complicated and drawn out condition. For more information on heartworm disease you can visit the following website here. You can also ask your veterinarian about their recommendations.