Prevalence of heartworm infection in the feral cat population of Grand Cayman

Objectives The aim of this study was to determine the presence and prevalence of heartworm infection in the feral cat population of Grand Cayman. Methods During the study period, feral cats were routinely trapped and euthanized for population control by the municipal animal shelter. Cats older than 6 months of age were obtained for post-mortem examination shortly after euthanasia. The heart, lungs, pulmonary vasculature, thoracic and abdominal cavities were examined for the presence, location and number of mature heartworms. Sections of caudal lung were evaluated histologically and serologic tests were performed to screen for additional evidence of heartworm exposure. Results Mature heartworms were identified in the pulmonary vasculature of 4/36 cats (11.1%). An additional nine cats showed histopathologic changes in the lungs consistent with heartworm exposure, and one cat had a positive antibody test. Conclusions and relevance The results indicate a minimum heartworm prevalence of 11.1% within this population of feral cats, consistent with published necropsy reports from other endemic localities. Considering the histopathologic changes observed in this group, the true prevalence is likely higher and underscores the importance of heartworm prevention for the companion cat population of the island