What to do when the Heartworm test is positive

When your young, healthy dog has a positive heartworm test,  

I recommend that we watch closely for these things: 

  • a soft cough, especially when exercising or excited.
  • a general slowing down, with intolerance to exercise. 
  • a pot belly, indicating fluid in the abdomen. 
  • a loss of weight over the back but a gain in the belly (fluid).

I like to xray the chest and do a  proBNP blood test  to see if there is any heart damage going on right now.  If so, then heart meds will be needed.

If we don’t see any signs that the heart is in trouble,  then    

I recommend the “slow kill ” /  “soft kill” method of treatment: 

  • go on monthly Heartgard  preventive or monthly oral ivermectin.  Do not use Interceptor or Sentinal brands for positive dogs.  
  • plus a prescription of Doxycycline 100mg daily for one month, then stop for two months, then give daily for one month, then stop for two months, for a total of one year. 

The slow kill method works because the life expectancy of a heartworm is 18 to 24 months. So if you put your dog back on monthly ivermectin preventive, he will not catch any new ones, and the old ones that are there will die off one at a time.  Gently. Within 18-24 months, the heartworm antigen ELISA test will revert to negative.  

But if heart disease symptoms appear (as above) then we need to reevaluate this program.  Click here for more on heart disease signs.

The “slow kill” method of treatment is much easier on the dog than the traditional arsenic injections.  (Immiticide) With arsenic treatment the worms all die at once. Then for months, there will be a decaying knot of spaghetti-sized worms clogging up the circulation. This definitely creates clots and pneumonia.  After Immiticide, dogs must be confined for weeks or months. These side effects plus the risks plus the expense add up to a bad deal for you and for your dog.  

Some vets think the slow kill is voodoo.  I don’t. The American Heartworm Society is usually very conservative, but their latest findings support the slow kill method as an alternate therapy.  I agree. I haven’t done the arsenic method in more than 10 years. 

Read more about heartworms.  To get a good simple summary, click on this American Heartworm Society link.  Veterinarians get their technical information from these specialists.  

Another good reference is the LSU Vet School site: click here.   

To read the most technical and up-to-date information meant for vets,  Click here.   

Whatever you do, don’t go by what your neighbor says about heartworms.  A lot has changed in the past few years. We have come a long way in detecting early and treating intelligently.  Heartworms used to be considered a fatal disease. Now we have options.    

Read about it all and email me with any questions.  catdrnan@gmail.com