Larue County Animal Clinic

121 Shepherdsville Rd
Hodgenville, KY 42748



Posted March 12, 2010

In some areas of Kentucky (as close as Bowling Green) and other parts of the nation, veterinarians are starting to diagnose positive cases of 


heartworms in dogs that have been on monthly preventative year-around. At the present time we do not know why this is happening but it is occurring with all of the oral monthly preventatives. Speculation is that there could be a new strain of mosquito that could have resulted from the after effects of hurricane Katrina or there could be other reasons.  


Update posted February 17, 2011

Although research is still going on and new things being discovered about this problem, there is a new finding. According to an article in February 2011 "Clinicians Update", it is being found that a single treatment of heartworm preventative, even though highly effective, might not be 100% effective as once thought. Repeated treatments are likely to maximize efficacy, so year-round preventative is essential for the most reliable heartworm control.

The macrocyclic lactones (used in the oral forms of heartworm preventatives) revolutionized heartworm control when they first became available over 20 years ago and continue to be the foundation of heartworm prevention. However, information published in the Journal of Veterinary Internal Medicine seems to suggest that it is more important than ever that 

1. Owners  practice good compliance,

2. That products be administered year-round and

3. That testing of animals on prevention be perforned annually without fail.

We are recommending annual testing now and are requiring it every 2 years as a minimum standard for dogs on year-round preventatives.

If your dog needs to be tested or if you have questions concerning this, be sure and call us at 358-4474.