Case Report — A Case Report of Avian Malaria (Plasmodium spp.) in Pen-Reared Pigeons (Columbia livia)

SUMMARY. One dead 6-week-old, male racing pigeon ( Columbia livia ) was submitted for postmortem evaluation after presenting with weight loss, anorexia, dry shanks, dehydration and lethargy. The bird belonged to a confined flock with 12 other pigeons raised by a hobbyist. Two pigeons in the flock reportedly had died with a history of similar clinical signs. On gross examination, the liver and the spleen were diffusely dark brown to black. Histopathology revealed moderate to large amounts of anisotropic, intracytoplasmic black pigment, compatible with hemozoin, in the spleen, liver, lung and kidneys, with small amounts in the heart and meninges of the brain. Marked plasmacytic infiltrates were observed in liver, lungs, heart and kidneys. Blood smears from a clinically affected concomitant pigeon from the flock revealed numerous light-blue, round to oval, intraerythrocytic trophozoites and meronts suggestive of Plasmodium spp. PCR and sequencing tests were performed from spleen and ceca using fragments of the 18S ribosomal RNA and the mitochondrial cytochrome B (cytB) genes. Sequencing results confirmed the presence of Plasmodium in the affected pigeon. Although an exact genetic match could not be determined, the most similar species to the isolate from this study are P. relictum , P. matutinum, P. lutzi and P. homocircumflexum .