re: My lab with "heartworms"

People tend to think all heartworm infections are the same. There are many different classes of heartworms. You can even have heartworms and have a negative test. The test only comes back positive if you have adult females. An all male infection will produce a negative test. People compare heartworm treatments but you have to compare stage of disease. If your dog was on heartworm prevention and came up positive its likely had 1or 2 worms. In these cases ivermectin can often times kill the worms at higher doses. Ivermectin can also be toxic to dogs at high doses. The problem is ivermectin has been used so extensively over the last 30 years concerns are arising that there may be resistance like bacteria to antibiotics. Glad your dog was one of the lucky ones. A lot aren't so lucky.