[JuneBugs Momma]

Here is another study done by the Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University. This is a pretty long article/study but worth the read.

Most of the inefficiency is in the area extending along the Mississippi River from Tennessee through Louisiana, there are many practitioners who contend that the heartworm preventives they have been using are no longer protecting dogs from infection. On the other hand, it has been reported that a very high percentage of these product failures are occurring in pets where compliance has not been as good as initially perceived by the claimant. This speaks to the continuing problem of trying to identify resistance in the field, where treatment failures may or may not accurately reflect an underlying issue of resistance. However, other knowledge has come to light in the past 18 months that suggests that the veterinary community should be concerned about the threat of heartworm resistance.

This study also includes comparisons of Heartguart, Trifexis, etc.
Areas north of the Mississippi/Tennessee Valley have not seen such lack of efficacies.


Parasites & Vectors | Full text | Heartworms, macrocyclic lactones, and the specter of resistance to prevention in the United States