Interesting Facts
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Interesting Facts

Although its just another parasitic organism, Dirofilaria immitis grabs our attention more than any other parasite, especially those of us who have pets.  We see signs in pet stores and watcher commercials on T.V. that tell us the dangers of dog heartworm and what we should do to prevent it.  Through this website my goal is not only to present an in depth analysis of Dirofilaria immitis, but also to give those of you who own dogs or other pets information on how to prevent or treat your four legged family member.  Listed below are things that you should know about prevention or treatment of Dirofilaria immitis and some interesting facts about the parasitic organism. 


Dog: petcenter.com


Prevention (According to the American Heartworm Society)


  • Giving your pet chewables or tablets on a monthly basis
  • Applying topical medication to your pets back
  • Knowing the right time to give your pet these preventative medications ( A good rule of thumb is if there are mosquitoes present in the environment, your pet needs to be protected)


Heartguard: petcenter.com


Clinical Signs (According to the American Heartworm Society)


Clinical Signs Associated with Canine Heartworm Disease
Early Infection No abnormal clinical signs observed
Mild Disease Cough
Moderate Disease Cough, exercise intolerance, abnormal lung sounds
Severe Disease Cough, exercise intolerance, dyspnea (difficulty breathing), abnormal lung sounds, hepatomegaly (enlargement of the liver), syncope (temporary loss of consciousness due to poor blood flow to the brain), ascites (fluid accumulation in the abdominal cavity), abnormal heart sounds, death

 Table above taken from the American Heartworm Society.


Diagnosis (According to Casiraghi 2006)


Here are a few ways in which Dirofilaria immitis is diagnosed:


  • Morphological observation of circulating microfilariae (mf)
  • Detection of circulating antigens
  • Histochemical or immuno-histochemical staining of circulating (mf)
  • Molecular approaches


Dog injection: petcenter.com


Treatment (According to the American Heartworm Society)


The good news is that most of the time treatment of dog heartworm is successful.  The goal of the treatment is to kill the adult worms and all microfilariae.  The only drug on the market approved by the FDA to safely eliminate Dirofilaria immitis is Melarsomine dihydrochloride.  Other treatments are being worked on and tested.


Medicine: petcenter.com



Here are some interesting facts from the American Heartworm Society:


  • Old female heartworms can measure up to 31 cm in length
  • Evidence suggests that adult heartworms have a relatively short lifespan in a cat compared to a dog
  • The normal habitat of the adult heartworm is the right ventricle and adjacent blood supply of the dog
  • Heartworms have also been found in the liver, trachea, esophagus, stomach, feces, eye, brain, spinal cord, and vomit in dogs
  • Heartworms have been known to occur in the cat for more than half a century
  • The first published description of heartworm in a dog appeared in the October 1847 issue of “The Western Journal of Medicine and Surgery”
  • Heartworms are considered Ovoviviparous


   Mosquito: AHS