Histopathological and molecular evidence of systemic Sarcocystis spp. infection in a free-living Guira Cuckoo (Guira guira)

Abstract

Background: Sarcocystis species are protozoans that require intermediate and definitive hosts to complete their life cycle. Several species of Sarcocystis can infect birds and cause severe lesions. This study aimed to report the anatomopathological and molecular findings compatible with Sarcocystis spp. in guira cuckoos (Guira guira). Case Description: Two guira cuckoos were found dead and submitted for necropsy. Tissues were collected, fixed in 10% buffered formalin, and processed according to routine procedures. The sections were stained with hematoxylin and eosin. Nested polymerase chain reaction (PCR) targeting the 18s ribosomal ribonucleico acid region was performed to detect Sarcocystis spp., followed by digestion with restriction enzymes. Macroscopically, the lungs were edematous and dark red. One animal had partially digested cockroaches in the gizzard. Microscopically, diffuse pulmonary hemorrhage was associated with schizonts compatible with Sarcocystis. Schizonts associated with lymphocytic infiltrates were detected in the liver, skeletal muscle, and muscle tissues of the proventriculus. Encephalitis and gliosis were observed in the brain of one animal. Deoxyribonucleic acid amplification detected products compatible with Sarcocysts spp. in the tongue, heart, liver, pectoral muscle, brain, and esophagus. Conclusion: Together, the histopathological and molecular findings confirm systemic sarcocystosis in guira cuckoos and support their involvement in the local transmission cycle, with the presence of cockroaches suggesting a potential epidemiological link in parasite dissemination.