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Necrotizing meningoencephalitis caused by Sarcocystis falcatula in bare-faced ibis (Phimosus infuscatus)
Guilherme Konradt1, Matheus Viezzer Bianchi2, Ronaldo Viana Leite-Filho2
1Departamento de Patologia Clínica Veterinária, Setor de Patologia Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9090, Prédio 42505, Porto Alegre, RS, 91540-000, Brazil. guikonradt@yahoo.com.br.
Abstract:
The infection by S. falcatula is commonly associated with respiratory disease in captive psittacine birds, with a few case reports of this protozoan causing encephalitis in wild birds. We describe the clinical, pathological, and molecular aspects of an infection by S. falcatula in a bare-faced ibis (Phimosus infuscatus). Clinically, wing paralysis and mild motor incoordination were observed. At necropsy, the telencephalic cortex showed multifocal to coalescing yellowish soft areas. Histologically, multifocal to coalescent nonsuppurative necrotizing meningoencephalitis of telencephalic cortex, cerebellum, and brainstem was observed. Necrotic areas showed multiple protozoan organism characteristics of Sarcocystis sp. schizonts in the cytoplasm of endothelial cells or lying free in the neuropil. Partial genetic sequences of the gene encoding cytochrome b (CYTB), the gene encoding the beta subunit of RNA polymerase (RPOB) and the first internal transcribed spacer (ITS-1) from Sarcocystis sp. schizonts revealed that the parasite had ITS-1 sequences that were 100% identical to the homologous alleles from Sarcocystis sp. shed by Didelphis albiventris in Brazil. RPOB and CYTB sequences were 100% identical to homologous of S. falcatula available in Genbank. Thus, this is the first report of necrotizing meningoencephalitis caused by S. falcatula in bare-faced ibis (P. infuscatus).
Insights
This study details the first reported case of Sarcocystis falcatula causing necrotizing meningoencephalitis in a bare-faced ibis. The protozoan parasite led to neurological symptoms and brain lesions in the wild bird.
Area of Science:
- Veterinary Neurology
- Avian Pathology
- Parasitology
Background:
- Sarcocystis falcatula commonly causes respiratory disease in captive psittacine birds.
- Encephalitis due to Sarcocystis falcatula has been rarely reported in wild birds.
Observation:
- A bare-faced ibis (Phimosus infuscatus) presented with wing paralysis and motor incoordination.
- Necropsy revealed multifocal yellowish soft areas in the telencephalic cortex.
- Histopathology showed nonsuppurative necrotizing meningoencephalitis with Sarcocystis sp. schizonts.
Findings:
- Molecular analysis identified the parasite as Sarcocystis falcatula.
- ITS-1 sequences were identical to Sarcocystis sp. from opossums in Brazil.
- RPOB and CYTB gene sequences matched S. falcatula in GenBank.
Implications:
- This is the first report of Sarcocystis falcatula causing necrotizing meningoencephalitis in bare-faced ibis.
- Highlights the potential for S. falcatula to cause severe neurological disease in diverse wild bird species.
- Emphasizes the importance of considering Sarcocystis infections in wild birds with neurological signs.
