Dirofilaria immitis in Panama City: first molecular detection with public health implications

This report details a fatal case of canine dirofilariasis with concomitant Ehrlichia canis infection, emphasizing the role of molecular diagnostics and highlighting diagnostic and epidemiological gaps in Panama, particularly regarding stray dogs as key foci of infection. An 8-year-old mixed-breed dog presented with severe clinical signs, including adult nematode expectoration, lymphocytosis, eosinopenia, anemia, and thrombocytopenia. Rapid immunochromatographic tests confirmed co-infection with Dirofilaria immitis and Ehrlichia canis, with abundant microfilariae on blood smear. Echocardiography revealed severe right ventricular dilation, tricuspid regurgitation, and D. immitis adults in the heart and pulmonary artery. Necropsy confirmed severe right atrial rupture with hemopericardium and extensive parasitic burden, identified as D. immitis by molecular analysis (453 bp 16S rRNA product). This case underscores the advanced pathology of dirofilariasis and the aggravating role of co-infection, highlighting Panama's significant epidemiological challenges, including vector prevalence, stray-dog reservoirs, and limited access to therapy. These findings highlight the need for molecular diagnostics, comprehensive control strategies, and robust surveillance programs, especially for stray dog populations, to mitigate impacts on animal and public health.