A Laboratory Test for Detecting Drug Resistance in Canine Heartworm Disease

United States Australian Shepherd Foundation

Dirofilaria immitis is the nematode parasite that causes heartworm disease in the United States. Heartworm infection causes severe pathology and suffering in dogs and cats. Until recently, heartworm infection was a preventable disease due to the availability of effective monthly preventative treatments.

A recent development shows drug-resistant heartworms have emerged in the United States. The scope of the resistance issue has not yet been characterized because there is a critical need to develop a test that can discriminate drug-susceptible and drug-resistant parasites. Recent research assessed computer-aided motility studies of the parasite in the presence of drugs, however, there are no motility differences among parasite isolates in these assays.

The investigators have developed biochemical stains and measurements that can quantify parasite killing in the presence of anti-parasitic drugs. In this study, the investigators will evaluate various metabolic assays and staining procedures to compare drug-susceptible and drug-resistant heartworm isolates in an effort to identify the best assay for detecting heartworm killing, and thereby creating a tool to rapidly identify resistant infections in dogs.


Matt Brewer, DVM, PhD
Iowa State University

Progress Report

Final:  Grant-02458-A-Laboratory-Test-Detecting-Drug-Resistance-Heartworm-Disease-Final