Disseminated coccidiosis in short-beaked echidnas (Tachyglossus ...

Brief communications 483
Figure 5. Bear liver reacted with Sarcocystis cruzi antisera. A. Overview showing wide distribution of positively stained organisms
(arrows). 30 x . B. Discrete and intensely stained organisms (arrows). 150 x .
2. Dubey JP, Duncan DE, Speer CA, Brown C: 1992, Congenital
sarcocystosis in a two-day-old dog. J Vet Diagn Invest 4:89-93.
3. Dubey JP, Speer CA: 1991, Sarcocystis canis n. sp. (Apicomplexa:
Sarcocystidae), the etiologic agent of generalized coccidiosis
in dogs. J Parasitol 77:522-527.
4. Dubey JP, Speer CA, Fayer R: 1989, Sarcocystosis of animals
and man. CRC Press, Boca Raton, FL.
5. Lindsay DS, Dubey JP: 1989, Immunohistochemical diagnosis
J Vet Diagn Invest 5:483-488 (1993)
of Neospora caninum in tissue sections. Am J Vet Res 50: 198 l-
1983.
6. Mense MG, Dubey JP, Homer BL: 1992, Acute hepatic necrosis
associated with a Sarcocystis-like protozoa in a sea lion
(Zalophus californianus). J Vet Diagn Invest 4:486490.
7. Rakich PM, Dubey JP: 1992, Acute hepatic sarcocystosis in a
chinchilla. J Vet Diagn Invest 4:484-486.
Disseminated coccidiosis in short-beaked echidnas
(Tachyglossus aculeatus) from Australia
The short-beaked echidna (Tachyglossus aculeatus) is a
spiny-coated egg-laying mammal belonging to the order
J. P. Dubey, W. J. Hartley
Monotremata and is naturally found only in Australia and
New Guinea. It feeds almost entirely on ants and termites.
Little is known of the diseases of echidnas, but intestinal
coccidiosis is considered common. 1,5
The echidna case materials were from the native fauna
From the Zoonotic Diseases Laboratory, Livestock and Poultry
Sciences Institute, BARC-East, ARS, USDA, Beltsville, MD 20705-
2350 (Dubey), and the Taronga Zoo, PO Box 20, Mosman, New pathology register maintained at the Taronga Zoo in Sydney,
South Wales 2088, Australia (Hartley).
Australia. Case nos. 1, 3, and 5 came from the Melbourne
Received for publication October 28, 1992. Zoo, and case nos. 2 and 4 were from the Sydney Zoo col-

484
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Table 1. Summary of examination of tissues* from echidnas with protozoal lesions.

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Figures 6-10. Sections of the liver of naturally infected echidnas. HE, 750 x .6. Echidna no. 1. Focus of hepatic necrosis and mononuclear
cell infiltration and a schizont with a residual body (arrow). 7. Echidna no. 1. Three merozoites in a vacuole. Note the size and shape of
merozoites is distinct from the schizont in Fig. 6. The hepatocytes are vacuolated. 8. Echidna no. 5. A collection of 5 protozoan bodies
with nuclei (arrowheads) separated by septa. Whether these protozoa are developing microgamont or schizont could not be determined.
9. Echidna no. 5. A microgamont (arrow) with slender microgametes (arrowheads). 10. Echidna no. 5. A granuloma with an oocyst in the
center of the lesion. Note the oocyst wall (arrowheads) and the central nucleus (arrow).
lections (Table 1). Only paraffin-embedded 5-6-µm-thick Neospora caninum, and Sarcocystis cruzi using the techhistologic
sections were available for this study. Sections were niques and reagents described previously. 4
initially examined after staining with hematoxylin and eosin Lesions were most severe in echidna no. 1 and were present
(HE). Selected sections were stained with periodic acid-Schiff in the lung, liver, kidneys, heart, and spleen. Pneumonia was
hematoxylin (PASH) or with antisera to Toxoplasma gondii, characterized by diffuse mixed mononuclear cell interstitial
Figures 1-5. Sections of lungs of naturally infected echidnas. HE. 1. Echidna no. 1. Longitudinally cut artery with strands of fibrin and
blood elements. Two schizonts (arrowheads) are visible in the endothelium. 150 x . 2. Higher magnification of the artery in Fig. 1 showing
2 immature schizonts (arrows) in the endothelium and several free merozoites (arrowheads) in the lumen. 750 x . 3. Echidna no. 1. Two
groups of merozoites (arrowheads) in the interstitium. 1,500 x . 4. Echidna no. 1. A schizont in the alveolar interstitium showing a central
residual body (arrow) and slender merozoites (arrowheads). Compare the structure of the merozoites that of merozoites in Fig. 2. 1,500 x .
5. Echidna no. 2. An oocyst with central nucleus (arrow) in the alveolus. 750 x.

486 Brief communications
Figures 11-15. Sections of tissues of naturally infected echidnas. HE. 11. Heart of echidna no. 1, showing an inflammatory focus and
a schizont (arrow) in a capillary. 150 x . 12. Higher magnification of the capillary with schizont in Fig. 11. Perivascular infiltration of
mononuclear cells and a schizont (arrow). 750 x . 13. Kidney of echidna no. 1, with glomerulonephritis in cortex and a necrotic focus on
the left. 150 x. 14, 15. Spleen of echidna no. 5, showing 2 schizonts (arrows) with structurally distinct merozoites. 1,500 x.
inflammation, associated with protozoa, Protozoa were seen
in the venules, capillaries, large blood vessels, and the interstitium
(Figs. 1-4). Protozoa divided by schizogony. Immature
and mature schizonts and free merozoites were seen
in the endothelium of large blood vessels and in unidentified
cells in the vascular lumina (Fig. 2). Schizonts were up to 20
x 15 µm and contained up to 16 merozoites, sometimes
around a central residual body (Fig. 4). Merozoites in some
schizonts were slender (< 1 µm thick), whereas others were
up to 2 µm thick (Figs. 3, 4). Schizonts and merozoites were
PAS negative. Similar but milder lesions with fewer parasites
were seen in the lungs of echidna nos. 2 and 3. In echidna
no. 2, 3 unsporulated oocysts were seen in separate alveoli
(Fig. 5).
Hepatitis was seen in echidna nos. 1, 3, and 5. In echidna
no. 1, the hepatic lesions consisted of generalized portal tract
mixed mononuclear cell infiltration extending into hepatic
cords. Other changes were bile ductule proliferation, mild
bile stasis, and mild recent fibrinous perihepatitis (Fig. 6).
Relatively few schizonts were seen (Figs. 6, 7). Similar but
milder lesions were seen in echidna nos. 3 and 5. In addition
to the type of lesions in echidna no. 1, granulomas were
scattered throughout the liver in echidna no. 5. Schizonts,
zoites, gamonts and oocysts were associated with these granulomas
(Figs. 8-10). Schizonts were up to 15 µm in diameter
and contained slender merozoites. There were also collections
of 1 or 2 zoites with thickness up to 3 µm; these zoites
contained PASH-positive granules. One mature 33- x 32pm
male (micro) gamont with slender microgametes is shown
in Fig. 9. There were several unsporulated oocysts up to 25

Brief communications 487
Figures 16-20. Sections of intestines of echidnas naturally infected with coccidia. HE. 16. Echidna no. 5. Gamonts in epithelial cells
lining the glands of Lieberkiihn and the surface epithelium. Arrow points to an infected gland near the muscularis mucosae. 75 x. 17.
Echidna no. 2. A schizont in the lamina propria with numerous tiny merozoites (arrow). Note several developing macrogametes (arrowheads)
in the surface epithelial cells. 750 x . 18. Echidna no. 2. A mature microgamont with a central residual body (arrow) and microgametes in
surface epithelium. Two macrogametes (arrowheads) are also present. 19. Echidna no. 4. Two oocysts (arrows) in surface epithelial cells.
20. Echidna no. 5. Two oocysts (arrow) in the surface epithelial cells. 750 x .
µm in diameter. One oocyst with a nucleus and oocyst walls cell interstitial inflammation (Fig. 13). Many glomeruli apis
shown in Fig. 10. There were other oocyst-size empty peared enlarged and hypercellular. Some had adhesions bespaces,
suggesting the destruction of oocysts by granuloma- tween the visceral and parietal layers of Bowman’s capsule.
tous host response. There were also immature microgamont- A few had erythrocytes in Bowman’s capsule, and others
like unidentified structures. contained a few to many granulocytes. Many cortical tubules
Myocarditis was seen only in echidna no. 1 and was char- were distended with granulocytes and contained erythroacterized
by a moderately severe mixed mononuclear cell cytes, hemoglobin, and/or other blood pigments. Some medgranulocytic
interstitial inflammation. One large focus of ullary collecting tubules contained erythrocytes and blood
subendocardial myonecrosis with surrounding inflammatory pigments. Numerous glomerular capillary tufts contained 1
response is shown in Fig. 11. Schizonts were seen associated and occasionally 2 schizonts. Schizonts were occasionally
with lesions (Fig. 12). seen in extraglomerular tissue.
Renal lesions were seen in echidna nos. 1 and 3 and con- Splenitis was seen in echidna no. 1 and consisted of a
sisted of moderate, focal disseminated mixed mononuclear massive, almost complete multifocal recent noninflamma-

488 Brief communications
tory parenchymal necrosis and lysis associated with groups
of bacteria (probably secondary infection), with focal hemorrhages.
Structurally distinct types of schizonts with slender
merozoites (Fig. 14) or short stubby merozoites (Fig. 15) were
seen.
Intestinal coccidiosis was seen in echidna nos. 2, 4, and 5
(Figs. 16-20). Lesions were more severe in the small intestines
of echidna nos. 2 and 5 and consisted of desquamation
of epithelial cells of glands of Lieberkiihn and surface epithelium,
hypertrophy of villous epithelium, and mononucle-
ar cell infiltration in lamina propria. Gamonts and oocysts
were seen in all 3 echidnas.
Oocysts were approximately 25 x 20 µm and were unsporulated
(Figs. 18-20). Few schizonts were seen only in 1.
echidna no. 2. A 45- x 25-µm schizont with numerous tiny
merozoites in the lamina propria of the small intestine is
shown in Fig. 17.
Protozoa in the lung and liver of echidna no. 1 did not 2.
react to T. gondii, N, caninum, or S. cruzi antisera.
Protozoa in extraintestinal tissues of echidnas were un- 3 =
J Vet Diagn Invest 5:488-494 (1993)
The intravascular schizonts in the lungs of the echidnas
were structurally similar to schizonts of Sarcocystis, particularly
of the Sarcocystis species in cattle, sheep, and goats. 3
Some of the schizonts in the liver, lungs, and spleen were
difficult to distinguish from tachyzoites of T. gondii. 2 However,
T. gondii tachyzoites always divide into 2 by endodyogeny,
whereas the extraintestinal protozoa of the echidnas
divided into many organisms by schizogony. 2
Acknowledgements. We thank the staff of the Veterinary
Research Institute in Melbourne who made 3 of the cases
available for examination.
References
identified. Protozoa in the intestines of echidnas in the pres-
4.
ent study appeared to be structurally similar to the intestinal
coccidia of the echidnas. 1 Barker IK, Beveridge I, Munday BL: 1985, Coccidia (Eimeria
tachyglossi) n. sp., E. echidnae n. sp., and Octosporella hystrix n.
sp.) in the echidna, TachygZossus aculeatus (Monotremata: Tachyglossidae).
J Protozool 32:523-525.
Dubey JP, Beattie CP: 1988, Toxoplasmosis ofanimals and man.
CRC Press, Boca Raton, FL.
Dubey JP, Speer CA, Fayer R: 1989, Sarcocystosis of animals
and man. CRC Press, Boca Raton, FL.
Lindsay DS, Dubey JP: 1989, Immunohistochemical diagnosis
of Neospora caninum in tissue section of dogs. Am J Vet Res 50:
Gamonts and oocysts in the liver 1981-1983.
of echidna no. 5 and in the lungs of echidna no. 2 were 5 Whittington RJ: 1988, The monotremes in health and disease
structurally similar to intestinal gamonts and oocysts. How-
l in Australian wildlife. Proc Postgrad Comm Vet Sci Univ Sydney,
ever, it was not possible to link these extraintestinal stages pp. 727-787.
because not all tissues were available from each echidna.
Cycad (Zamia puertoriquensis) toxicosis in a group of
dairy heifers in Puerto Rico
Rachel Y. Reams, Evan B. Janovitz, Farrel R. Robinson,
John M. Sullivan, Carlos Rivera Casanova, Edwin Más
Cycads are a group of palm-like plants in the family
Cycadaceae 19 found in tropical and subtropical areas
throughout the world. Cycads have been used for centuries
for food and for decorative and medicinal purposes. Cycad
toxicosis has been associated with ingestion of raw leaves
and nuts and inadequately washed flour. 5,10,12-19 Clinical signs
in humans are usually related to disturbances of the gastrointestinal
tract, such as vomiting, diarrhea, and colic 5,12 but
coma and paralysis have also been reported. 19 Cycad toxicosis
has been suspected as a cause of amyotrophic lateral
sclerosis-parkinsonism dementia (ALS-PD) in the western
From the Indiana Animal Disease Diagnostic Laboratory and the
Department of Veterinary Pathobiology, Purdue University, West
Lafayette, IN 47907 (Reams, Janovitz, Robinson, Sullivan), the Manati
Veterinary Clinic, Manati, PR 00701 (Rivera Casanova), and
the Department of Pasture Management, University of Mayaguez,
Mayaguez, PR 00680 (Mas). Current address (Sullivan): Marion-
Merrell Dow, PO Box 68740, Indianapolis, IN 46268-0470.
Received for publication November 3, 1992.
Pacific region, 18,19 although this association has been disputed.
2-4
Cycad toxicosis has been reported in livestock, primarily
ruminants. 5,6,10,11,15,16 Two distinct syndromes, neurologic and
hepatic-gastrointestinal, 15 have been described in ruminants.
Ruminants with the hepatic-gastrointestinal syndrome of
cycad toxicosis were depressed and anorectic 10,16 and lost
weight. 16 Necropsy findings included cirrhosis, ascites, and
hemorrhage and necrosis of the mucosa of the small intestine
and abomasum. 10,15 Microscopically, hepatocellular megalocytosis,
periacinar necrosis, fibrosis around central veins,
cholestasis, and biliary duct hyperplasia were present. 10,15
The neurologic syndrome of cycad toxicosis in cattle- has
been called Zamia staggers. That syndrome is characterized
clinically by weight loss followed by lateral swaying of the
hind quarters, with weakness, ataxia and proprioceptive defects
in the rear limbs. 6,11 Demyelination and axonal degeneration
were present in the brain, spinal cord, and dorsal-root
ganglia. 11 Surviving cattle remained ataxic and-had secondary
atrophy of the musculature of the hind quarters. 6,11,15