Extra-intestinal coccidiosis in the kiwi (Apteryx spp.)

Figures & data

Table 1.  Details of all cases of extra-intestinal coccidiosis in kiwi (Apteryx spp.) diagnosed at Massey University (1991 to 2011) using histological methods.

Huia case ID	Species	Age	Habitat	Primary cause of death	Renal coccidia: PM/RE	Gross renal pathology	Renal oocysts and/or gametocyte per field of view	Hepatic coccidia: PM/RE	Gross hepatic pathology	Other coccidia: pulmonary / splenic / enteric
1432	Brown	8 wk	Wild	Predation, stoat	+/ +	None	96.2	−/ +	None	−/ − / +
1570	Brown	26 wk	Cap	Anaesthetic death	+/ +	None	22.2	−/ −	None	U/ − / +
1581	Brown	Ch	Wild	Trauma, head	+/ +	None	Autolysed	−/ −	None	−/ − /−
1913	Brown	Sub	Wild	Coccidiosis, enteric	−/ −	None	0.0	−/ +	None	−/ − / +
1932	Brown	23 wk	Wild	Predation, stoat	−/ +	None	9.3	−/ −	None	−/ − /U
1936	Brown	13 wk	Cre	Myocarditis	+/ +	None	8.7	−/ −	Rounded liver edges	−/ − / +
1976	Brown	3 wk	Cap	Coccidiosis, enteric	−/ +	Renal pallor, slightly swollen	367	−/ −	None	−/U/ +
2197	Brown	17 wk	Cap	Nephritis	+/ +	Renal pallor	22.9	+/ +	Three pinpoint white lesions	−/ − / +
2202	Brown	28 wk	Cap	Myocardial degeneration	+/ +	Renal pallor	33.7	−/ +	None	−/ − / +
2219	Brown	Juv	Wild	Bronchopneumonia, airsacculitis	+/ +	None	16.8	−/ −	None	−/U/U
2520	Brown	13 wk	Cap	Renal coccidiosis	+/ +	Swollen, miliary white serosal streaks	235.2	−/ −	None	−/ − / +
2586	Brown	9 wk	Cap	Renal coccidiosis	+/ +	Mild uric acid serosal accumulations	271	+/NE	Miliary small (<1 mm) “necrotic” foci	−/ − / +
2589	Brown	17 wk	Cap	Hepatic coccidiosis	+/ +	None	46.1	+/ +	Diffuse miliary pinpoint white spots	−/ + /+
2598	Brown	Juv	Cre	Cardiomyopathy	−/ +	Kidneys dark, enlarged	3.7	−/ −	Hepatomegaly	−/ − /U
3090	Brown	6 wk	Cap	Euthanasia (bilateral limb deformity)	+/ +	None	10.7	−/ −	None	−/ − / +
3101	Brown	26 wk	Wild	Neural larval migrans, gastric nematodiasis	U/ +	None	1.9	−/NE	None	−/U/ −
3275	Brown	3 wk	Cap	Cryptosporidia	+/ −	Renal pallor, slightly swollen	−	−/NE	Hepatic pallor, friable	−/ − /U
3298	Brown	18 mth	Cap	Hepatic, enteric coccidiosis	−/ −	Renal congestion	−	+/ +	Hepatic congestion	−/U/ +
4444	Brown	Ad	Cap	Cholecystitis	−/NE	Dark red	−	+/ +	None	−/ − /U
4467	Tokoeka	Juv	Cap	Renal coccidiosis	+/NE	Congested, streaks and foci of white material	421	−/ −	None	−/ − / +
4479	Brown	Ad	Cap	Proventricular impaction	−/NE	None	−	+/ +	Miliary white foci	−/ − /U
4846	Gsk	13 wk	Cap	Chlamydosis	+/NE	None	−	−/NE	Hepatomegaly, pale ochre w pale red mottling	−/ − /−
4929	Brown	7 wk	Cap	Septicaemia, bacterial	−/NE	Pallor, renomegaly, mottled red colour	−	−/NE	None	−/ + /U
5133	Brown	Juv	Cap	Coccidiosis, enteric	−/NE	None	−	+/NE	None	+/ − / +
6076	Gsk	22 wk	Wild	Emaciation	+/NE	None	−	−/NE	None	−/ − /U
ad, adult (>18 months old); cap, captive; ch, chick (<25 days old); cre, crèche; Gsk, great spotted kiwi; hab, habitat; juv, juvenile (26 days to 18 months old); mth, month; NE, not evaluated; PM, diagnosis post-mortem; RE, diagnosis on re-examination; sub, sub-adult ; U, unknown; wk, weeks; +, positive; −, negative.

Table 2.  Clinical signs reported in kiwi (Apteryx spp.) associated with various forms of extra-intestinal coccidiosis.

Huia case ID	Coccidiosis	Clinical signs (duration prior to death)
1936	Renal, enteric	Weight loss (7 days); moribund, dehydrated, increased respiratory effort and lung sounds, sticky oral mucus (immediately pre-mortem)
1976	Renal, enteric	Weight loss (5 days)
2202	Renal, hepatic, enteric	Chronic unresponsive dermatitis (weeks); dyspnoea, bloody tracheal mucus (immediately pre-mortem)
2586	Renal, hepatic, enteric	Reduced voluntary food intake (12 to 24 h)
2589	Renal, hepatic, enteric, splenic	Reduced voluntary food intake (6 days); haematochezia (1 day)
3275	Renal	Inappetant (5 days)
3298	Hepatic, enteric	Inappetant (4 days); poor body condition, depressed, explosive malodorous diarrhoea and haematochezia, dehydrated (immediately pre-mortem)
4444	Hepatic	No clinical signs
4846	Renal	Inappetant (7 days); tachycardia, lymphocytosis (6 days)
4929	Splenic	Reduced voluntary food intake, weight loss (2 days)
5133	Hepatic, enteric, pulmonary	Lethargy, inappetance, progression to lateral recumbency (12 h)

Figure 1.  1a: Partially eviscerated juvenile brown kiwi (A. mantelli; Case 1976) with kidneys in situ demonstrating renal pallor and renomegally associated with a heavy burden of coccidia. BW, body wall; CaL, caudal pole left kidney; CaR, caudal pole right kidney; CrL, cranial pole left kidney; CrR, cranial pole right kidney; R, transected rectum. 1b: Low-power view illustrating coccidial organisms (arrow) within collecting ducts of the medullary cone in the kidney of a juvenile brown kiwi (H&E stain). Scale bar = 200 µm. 1c: Coccidial oocysts causing dilation and obstruction of a collecting duct in the kidney of a juvenile brown kiwi (H&E stain). Scale bar = 20 µm. 1d: Renal collecting ducts of a juvenile brown kiwi demonstrating gametocytes within epithelial cells (H&E stain). Scale bar = 20 µm. 1e: Immature meronts causing tubular dilation within collecting duct epithelial cells in the kidney of a juvenile brown kiwi (H&E stain). Scale bar = 20 µm. 1f: Mature meronts with radially projecting merozoites within a renal collecting duct of a juvenile brown kiwi (H&E stain). Scale bar = 20 µm.

Figure 2.  2a: Pinpoint white serosal foci associated with coccidiosis in the liver of a brown kiwi chick (Case 2586). Scale bar = 20 mm. 2b: Focal areas of necrosis within the liver of a juvenile brown kiwi associated with coccidial meronts (H&E stain). Scale bar = 500 µm. 2c: An immature macromeront within the liver of a juvenile brown kiwi (H&E stain). Scale bar = 200 µm. 2d: An alternative form of macromeront surrounded by a thick eosinophilic capsule within the liver of a brown kiwi chick (H&E stain). Scale bar = 200 µm.

Table 3.  Morphometrics of various extra-intestinal coccidial stages identified in this study.

Extra-intestinal site	Coccidial stage (n)	Mean length (µm)	Length range (µm)	Mean width (µm)	Width range (µm)
Renal	Oocyst (399)	17.2	11.9 to 22.9	12.4	5.7 to 16.2
Renal	Macrogametocyte (120)	13.2	8.8 to 18.4	10.1	7.7 to 14.7
Renal	Microgametocyte (77)	14.5	7.0 to 20.7	10.9	5.2 to 16.5
Renal	Immature meront (18)	7.9	5.3 to 10.0	6.8	4.7 to 7.3
Renal	Merozoite (30)	7.9	6.4 to 9.3	1.6	1.2 to 2.0
Hepatic	Macromeront (9)	309.0	89.0 to 468.0	227.0	76.0 to 417.0
Hepatic	Mature macromeront type II (1)	399.0		237.0
Splenic	Meronts (20)	8.4	6.5 to 16.8	6.7	4.8 to 9.2
Pulmonary	Meronts (20)	9.6	7.1 to 14.2	7.1	5.4 to 10.2

Figure 3.  A macromeront within the spleen of a juvenile brown kiwi (H&E stain). Scale bar = 100 µm.

Figure 4.  Pulmonary histopathology of a juvenile brown kiwi illustrating coccidial meronts (H&E stain). Scale bar = 100 µm.