Fatal Sarcocystis calchasi-associated meningoencephalitis in 2 captive vulturine guineafowl

Abstract

Two captive vulturine guineafowl (Acryllium vulturinum) were presented with lethargy, hyporexia, weight loss, and progressive neurologic signs. One of the guineafowl was seropositive for Sarcocystis falcatula (1:50 dilution). Both guineafowl died within 5 d of presentation. Histologic examination revealed nonsuppurative meningoencephalitis with gliosis, associated with occasional schizonts in the neuropil. Using fresh-frozen brain tissue, PCR was performed to amplify the ITS1 RNA region and portions of the 18S ribosomal RNA gene (18S gene) and the 28S ribosomal RNA gene (28S gene). Analysis of nucleic acid sequences from the resulting amplicons indicated that Sarcocystis calchasi was the likely cause of disease. To our knowledge, S. calchasi-associated disease has not been reported previously in the order Galliformes.

Keywords: Galliformes; Sarcocystis calchasi; aviary; guineafowl; meningoencephalitis.

Figure 1.

Fatal Sarcocystis calchasi–associated meningoencephalitis in captive vulturine guineafowl, case 2. A. Severe lymphocytic meningitis (M) and zone of mild gliosis and cuffing in the underlying neuropil of the midbrain. H&E. Bar = 560 µm. B. Severe perivascular lymphoid cuffs (arrow) in white matter of the midbrain. H&E. Bar = 560 µm. C. Microglial nodule (arrow) in white matter of the cerebellum. H&E. Bar = 140 µm. D. Schizont (arrow) within the neuropil of the white matter of the cerebellum. H&E. Bar = 60 µm. Inset: higher magnification of schizont showing the merozoites in concentric arrangement around a central residual body (arrow), which is partially out of the plane of section. H&E. Bar = 15 µm.