Prevalence of Infection With Dirofilaria Immitis in Cats in Townsville, Australia

Abstract

Objective Dirofilaria immitis commonly infects Australian dogs. Studies on the prevalence of infection by this parasitic helminth in Australia cats are rare and relatively old. Data obtained from other countries would suggest a likely prevalence of 4.7–16%. The current study aimed to determine the prevalence of D. immitis in an endemic region of Australia by antigen, antibody and PCR testing. Methods 172 healthy cats over 6 months of age from the Townsville region of Australia were tested for D. immitis specific antibodies and antigen using a commercially available kit. 50 samples were subsequently retested using a second commercially available antibody kit. 48 of these samples were checked for D. immitis DNA using PCR. Results No cat tested positive on any test. The Ausvet Epitools epidemiology calculator was used to calculate prevalences. Maximum antigen (1.27%), antibody (2.1%) and PCR (2.1%) prevalences were calculated. Conclusion Our results suggest that the prevalence of heartworm infection in pet cats in this region of Australia is lower than expected based on data from other areas around the world.