03212-A: Wolbachia-targeting qPCR for Detection of Heartworm Infection in Dogs

Abstract

Canine Heartworm Disease (CHD) caused by Dirofilaria immitis continues to be the most important parasitic disease of dogs in the United States with more than 100,000 positive cases each year. CHD may produce severe clinical signs in infected dogs and approximately $75 million are spent annually for the treatment and prevention of heartworm.

The key to the management and treatment of CHD is accurate diagnosis. Several tests are available including commercial antigen detection tests, or microscopical or molecular microfilariae detection tests. Although these tests showed promising sensitivities, often discrepancies occur between different tests. Additionally, there is no test available for early diagnosis of CHD before the maturation of female worms and the appearance of microfilariae in circulation. To address these gaps, novel diagnostics are needed to reduce the occurrence of false-negative and -positive results which will be clinically informative for veterinary decisions on the implementation of the heartworm adulticidal protocol.

In this project, the researchers will establish and validate a qPCR that targets Wolbachia, an obligate symbiont of filarial worm, for the detection of D. immitis. A probe-based qPCR will be designed based on targeting the ftsZ gene of Wolbachia and validated using a well-characterized dog blood and serum sample repository tested for D. immitis using different methods. Considering the high population of Wolbachia in adults (both males and females) and in developing stages of heartworm and their possible release into circulation, the team anticipates that detection of this endosymbiont will outperform tests detecting the heartworm. Improving the current protocols for  heartworm diagnosis will greatly impact the management and treatment of CHD and dog health.

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