January 27, 2012

Heartworms in Dogs: The Hidden Threat

Filed under: Dog Deworming — Tags: — 1st Pet Naturals @ 11:34 pm

Heartworms in DogsMosquito Season – A Dangerous Time for Your Dog and Cat.

Humans are often warned to remain vigilant during mosquito season, as mosquitoes are known to transmit the dangerous viral infection West Nile Virus. However, pets are just as susceptible to illnesses carried by mosquitoes. The most common mosquito bite induced illness is the heartworm. A heartworm infestation is serious and potentially fatal condition caused by parasitic worms that live in the heart and the blood vessels that supply blood to the lungs of the infected animals. Heartworms are spread through mosquitoes: a mosquito bites an infected animal where it contracts the heartworms, thereby injecting the immature worms through the saliva into the tissue of the next animal which is bitten. While the a typical host is often the dog, heartworms can also affect cats, wolves, coyotes, foxes, ferrets and sea lions.

Once inside the dog, the worms migrate to the lungs, and potentially the right side of the heart, where they mature into adults and begin to reproduce. These worms grow up to 15-30 centimeters long, and in severe cases, a dog may be infected with hundreds of worms. Mature worms produce thousands of larvae that are spread to other dogs or cats by mosquitoes. The infection results in damage to the heart, lungs and liver. The pet may dies as a result of severe damage to internal organs. In Canada, Ontario has the most heartworm cases (in 2010, 564 dogs tested positive for heartworm, 432 of those dogs were located in Ontario). In the United States, infection is most common on the Atlantic Coast – from Texas to New Jersey and along the Mississippi River. What’s concerning is that the majority of cases were found to not be on heartworm preventative medication. Alternatively, they may have been receiving heartworm medication, but the pet owner may not have administered the medication correctly.

Symptoms and Tests

If your dog has an early heartworm infection, few worms may be present, and your dog may fail to display symptoms of heartworms. However, typical heartworm signs include your pet tiring easily, exercise intolerance, and a soft, deep cough. If the disease progresses, the symptoms will become more severe, the dog will lose weight and have difficulties breathing.

There are several tests available to test for worms. The most accurate is the heartwormatigen test, which tests for an antigen produced by the adult female heartworm are identified. Microfilarial concentration tests take a sample of blood and place them under the microscope to identify the parasites. Keep in mind with the microfilarial test, a negative diagnosis does not rule out the infection as approximately 10 to 25 percent of dogs do not show microfilariae circulating in their blood. The third option is to use a chest X-ray, and this option is the best way for determining the severity of the infection, particularly if you think the infection is severe. With an X-ray image, you can enlarge the right ventricle and/or pulmonary arteries to view how infected they are. An ECG may show worms in the right ventricular and pulmonary artery. If the worms are blocking the superior vena cava, the worms may be seen in the vena cava. Blood and urine samples are obtained to check for anemia and assess kidney and liver function.


The most effective way to avoid heartworms in dogs is to use a preventive. Preventives kill the heartworm larvae before they have a chance to grow and mature into adult heartworms. Some preventatives contain other ingredients that will control other parasites, such as the roundworm or hookworm. Remember that mosquitoes can get indoors, so it is important to administer a heartworm preventative pill even if they stay inside. Preventative medications should be administered monthly.

The best preventative medication is all natural pet care, as it won’t have any negative side effects on your animal. To prevent other worms in dogs, such as hookworms, tapeworms, roundworms and whip-worms, try the Rhizo D-Wormer for Dog Worms.

Disclaimer: 1st Pet Naturals is an education resource, and all information herein is strictly for educational purposes. It is not intended to diagnose, treat, prevent, or cure disease, nor is it meant to replace the (prescribed) treatment or recommendations of your veterinarian or healthcare provider. Always inform your veterinarian or healthcare provider of any products that your pet is taking, including herbal remedies and supplements.