Systemic Sarcocystosis in a Wild Turkey from Georgia
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Journal of Wildlife Diseases, 36(4), 2000, pp. 755±760 q Wildlife Disease Association 2000 Systemic Sarcocystosis in a Wild Turkey from Georgia J. P. Dubey,1 C. F. Quist,2,4 and D. L. Fritz31Parasite Biology and Epidemiology Laboratory, Livestock and Poultry Sciences Institute, United States Department of Agriculture, Agricultural Research Service, Beltsville, Maryland 20705-2350, USA; 2 Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602, USA; 3 Pathology Division, U.S. Army Medical Research Institute of Infectious Disease, 1425 Porter Street, Fort Detrick, Maryland 21702-8011, USA; 4 Corresponding author (e-mail: [email protected]). ABSTRACT: Acute sarcocystosis was diagnosed pectoral muscles. Tissues were slightly de- in an adult female wild turkey (Meleagris gal- hydrated and pale, but the carcass was lopavo) that was collected from Early County (Georgia, USA) in February of 1998. Marked slightly autolyzed. A mild peritoneal effu- in¯ammatory lesions were seen in the heart, sion was noted, and the pericardial sac lung, and liver and were associated with pro- contained a moderate amount of serosan- tozoal schizonts and merozoites. The organisms guinous ¯uid. A yellow ¯at 6 mm plaque were identi®ed as Sarcocystis sp. (Acomplexa: was present on the right ventricular wall. Sarcocystidae) based on structure and antige- nicity. Protozoa divided by endopolygeny, mer- The liver was pale, mottled, and had faint ozoites lacked rhoptries, and the organisms did pinpoint to 1 mm dark foci across the cap- not react to anti-S. falcatula antibodies but re- sular surface. acted to anti-S. cruzi antibodies. Specimens of heart, skeletal muscle, Key words: Acute sarcocystosis, case re- lung, liver, spleen, kidney, pancreas, gas- port, Meleagris gallopavo silvestris, myocardi- tis, pneumonia, Sarcocystis sp., schizont, wild trointestinal tract, cerebrum, and cerebel- turkey. lum were ®xed in 10% buffered neutral formalin. Paraf®n embedded sections were Clinical sarcocystosis has been reported stained with hematoxylin and eosin (HE) once in chickens (Mutalib et al., 1995), a and examined microscopically. Selected red lory (Page et al., 1989), a cockatiel (Ja- sections also were tested with anti-Sarco- cobson et al., 1984), and other psittacine cystis cruzi, anti-Toxoplasma gondii, anti- birds (Hillyer et al., 1991; Clubb and Neospora caninum, anti-Sarcocystis falca- Frenkel, 1992) but is rarely observed in tula, and anti-Sarcocystis neurona poly- other avian species. Sarcocystosis has been clonal rabbit antibodies (Dubey et al., reported in an eagle (Dubey et al., 1991b), 1991a, 1998; Hamir et al., 1993; Lindsay a goshawk (Aguilar et al., 1991), and a wild and Dubey, 1989). The peroxidase-anti- turkey (Teglas et al., 1998). We are re- peroxidase reaction was used to reduce porting another case of acute sarcocystosis nonspeci®c reactions associated with per- in an eastern wild turkey (Meleagris gal- oxidases in poultry tissues. Pieces of lung lopavo silvestris) and providing more de- and heart were embedded in methacry- tails of the structure and identifying char- late, and 3 mm were stained with HE or acteristics of the parasite. periodic acid schiff (PAS) reaction. For- An adult female Eastern wild turkey was malin-®xed lung tissue also was processed found dead in a squatted position in a ®re- for transmission electron microscopy as break by foresters in Early County (Geor- described previously (Dubey et al., 1995). gia, USA. 318229N; 848569W) on February A representative specimen of the parasite 9, 1998. The bird was transported to the has been deposited at the U.S. National Southeastern Cooperative Wildlife Dis- Parasite Collection (Beltsville, Maryland, ease Study (Athens, Georgia, USA) where USA; Accession number 89097). it was examined at necropsy 2 days later. Histologically, the right ventricle of the On gross examination, the bird weighed heart (including sections through the 3.4 kg with few subcutaneous or internal grossly visible pale focus) had multiple foci body fat reserves and moderate wasting of of myo®ber degeneration with mild to 755 756 JOURNAL OF WILDLIFE DISEASES, VOL. 36, NO. 4, OCTOBER 2000 moderate interstitial edema and in¯am- Ultrastructurally, the parasite was locat- mation consisting predominantly of lym- ed freely in host cytoplasm and divided by phocytes, plasma cells and macrophages. endopolygeny (Dubey et al., 1989). The Protozoal schizonts were found in associ- nucleus became multilobed and merozo- ation with in¯ammatory foci. Widely scat- ites budded from the surface (Fig. 2). tered foci of myo®ber necrosis, mononu- Merozoites contained organelles found in clear in¯ammation, and clusters of proto- coccidian merozoites except there were no zoal zoites also were seen in the left ven- rhoptries (Fig. 3). tricular wall. Similar multiple small foci of In those Sarcocystis spp. in which the in¯ammation and necrosis containing pro- life cycle is known, the intermediate host, tozoa were present in the lungs, liver, and often a herbivore, becomes infected with spleen. Mild perivascular lymphocytic cuff- Sarcocystis sp. by ingesting sporocysts ing was noted in sections of cerebrum and from feces of the de®nitive host, which is cerebellum with mild vacuolar degenera- usually a carnivore. Sporocysts release the tion of white matter and rare gliosis, but sporozoites initiating an asexual cycle con- no organisms could be identi®ed on rou- sisting of schizonts, which are usually tine sections. found in vascular endothelium, and sar- Protozoa were more commonly found in cocysts, which are found in muscle. It is the heart and lungs than in other tissues. the invasion of the endothelium by the Organisms were not found in vascular en- schizonts that generally results in the path- dothelium. The host cell parasitized could ogenic effects associated with sarcocystosis not be determined with certainty but ap- (Dubey et al., 1989). peared to be a myocyte or macrophage. The life cycle of S. falcatula is unusual Only asexual stages were seen and con- in that the asexual life cycle occurs in birds sisted of immature and mature schizonts and the sexual life cycle occurs in opos- and individual merozoites (Fig. 1B±G). sums (Didelphis virginiana) (Box et al., Schizonts divided by multiple nuclear di- 1984). After ingestion by a susceptible vision (Fig. 1D). A parasitophorous vacu- bird, the schizonts of S. falcatula can per- ole was not seen, except around individual sist up to 5 mo and can be highly patho- merozoites (Fig. 1C). Schizonts were elon- genic to some species of birds (Smith et gated in the heart and were seen following al., 1987a, b, 1989). Sarcocystis falcatula the long axis of the myo®bers (Fig. 1D, E) has been shown to be infective to canaries, whereas they were small in lungs. A resid- ®nches, budgerigars, and pigeons but not ual body was seen occasionally in schizonts to gallinaceous birds (Box and Smith, in lungs (Fig. 1G). Schizonts in heart were 1982). Food contamination with S. falca- slender and up to 50 mm long (Fig. 1E). tula sporocysts from opossum feces or In regular HE stained sections, merozoites from cockroaches that have ingested opos- were dif®cult to identify. In plastic embed- sum feces is thought to be the source of ded sections stained with HE, merozoites the infection in several outbreaks in psit- were 3±4 mm long and up to 1 mm wide tacine birds (Hillyer et al., 1991; Clubb (n 5 10). Individual merozoites contained and Frenkel, 1992). a centrally-located nucleus. Schizonts and Organisms in the present turkey from merozoites were negative with periodic southwest Georgia were structurally simi- acid Schiff reaction. In the lungs, organ- lar to those found in the previously re- isms were located in alveolar septa, and ported wild turkey from West Virginia some schizonts were present in alveoli (Teglas et al., 1998). As in that case, or- (Fig. 1G). Schizonts and merozoites ganisms were not found in endothelial stained with anti-S. cruzi serum but not cells, which contrasts reports of infections with anti-S. neurona, anti-S. falcatula, with S. falcatula in psittacine birds (Teglas anti-T. gondii, and anti-N. caninum sera. et al., 1998). Organisms were found in SHORT COMMUNICATIONS 757 FIGURE 1. Lesions and Sarcocystis sp. in sections of heart (Fig. 1A±E) and lungs (Fig. 1F, G) of the wild turkey from Georgia, USA. Bar in A is 200 mm, Bars in B to G 5 10 mm. H&E stain. A. Focus of necrosis and in¯ammation. Note degeneration of myo®bers and in¯ammatory exudate. B. Zoite (double arrows) with central nucleus. C. Merozoite differentiating into uninucleate meront with centrally located nucleus. There appears to be a space around the zoite. D. Elongate schizont with multilobed nucleus (arrows) E. Mature elongated tortuous schizont with merozoites. One merozoite is cut longitudinally (arrowheads). F. Two mul- tinucleated schizonts (arrows). G. Schizont (arrow) with a residual body (arrowhead). neural tissues in the previous wild turkey. antibody. Ultrastructurally and antigenical- In the present case, in¯ammation was pre- ly, the parasite is a species of Sarcocystis sent in the brain. While no organisms but the species has yet to be identi®ed. could be found, infection of neural tissues Whether wild or domestic turkeys are ab- may have been the cause of this in¯am- normal or normal hosts for this parasite mation. remains to be determined. The parasite in the present turkey was This work was conducted through the not S. falcatula because schizonts were not sponsorship from the ®sh and wildlife found in endothelial cells and because the agencies of Alabama, Arkansas, Florida, organisms did not react to anti-S. falcatula Georgia, Kentucky, Louisiana, Maryland, 758 JOURNAL OF WILDLIFE DISEASES, VOL. 36, NO. 4, OCTOBER 2000 FIGURE 2. Transmission electron micrograph of an immature schizont of Sarcocystis sp. from a wild turkey with multilobed nucleus (N) and merozoite analagen (arrows).