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Heartworm Causes

Heartworm Causes

What Causes Heartworms in Dogs?

In short, heartworm disease is caused by the Dirofilaria immitis parasite which spreads through mosquito bites.  Only infected mosquitos carry the disease. This means that an infected dog cannot infect another dog.  An infected dog is not one of the heartworm causes.  Once an infected mosquito bites a dog, it takes around six to seven months for the larvae to mature to adult heartworms.

So, you can say that mosquitos with the D. immitis worm are the main heartworm causes. The adult worms then start reproducing in the lungs, heart, blood vessels and other vital organs. Adult heartworms are about 12 inches long and can stay in the body of the dog for almost seven years. An infected dog can have more than 300 worms in its system. Eventually, they cause death in pets.

Heartworm was first discovered in 1947 in the southern part of the United States.  Recently, heartworms have spread to nearly in nearly all directions, to multiple locations inside infected mosquitos.  The highly infected regions are 150 miles coast of New Jersey, Texas and along River Mississippi. Other affected areas are Middle East, Southeast Asia, Korea, Japan and Australia.

You should educate yourself so that you are in a position to see the heartworm red flags, and take your dog to screening.  This can help save your dog’s life.

Important things to remember about heartworms:

• Only infected mosquitos can transmit the disease.
Mature heartworms in dogs are more than 26 cm.
Heartworm prevention is better than and less costly than heartworm treatment.
• Even though dogs survive the infection, heartworms can still leave some permanent damage.

Tips to help prevent heartworms:

• Ensure the dog gets heartworms vaccine shots.
• Be on the lookout for heartworm symptoms.
• The overall health of the dog should be monitored by undergoing microfilariae screening once in a while.

Heartworm symptoms include:

• Fatigue;
• Swelling of the abdomen;
• Weight loss;
• Coughing;
• Diarrhea;
• Loss of appetite.


(The image above is a derivative of Cu Faoil (text), Anka Friedrich,; CC BY-SA.)

Dog with Heartworms