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Histologic and Ultrastructural Lesions of Mourning Doves (Zenaida macroura) Poisoned by Lead Shot
Histologic and Ultrastructural Lesions of Mourning Doves (Zenaida macroura) Poisoned by Lead Shot RONALD J. KENDALL 1 and PATRICK F. SCANLON Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 HUGO P. VEIT Division of Pathobiology and Public Practice, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (Received for publication October 12, 1982) ABSTRACT Studies were conducted in which mourning doves (Zenaida macroura) were administered lead shot, and their tissues were examined by histology and their kidneys were examined by electron microscopy. Doves that ingested four number 8 lead shot and were sacrificed 4 days later had highly elevated lead concentrations in kidney and had acid-fast intranuclear and acid-fast intracytoplasmic inclusions in the cells of the proximal convoluted tubules. Hemosiderin loading was present in the liver as was elevated concentrations of lead in liver. Doves that ingested either four or eight number 8 lead shot and were sacrificed 9 days later had elevated lead concentrations in liver, and hemosiderin loading was present. Acid-fast intranuclear inclusions were present in the proximal convoluted tubule cells. Kidney lead was highly elevated and cellular degeneration was evident with electron microscopic examination. (Key words: doves, lead poisoning, kidney pathology, intranuclear inclusions, intracytoplasmic inclusions) 1983 Poultry Science 62:952-956 INTRODUCTION Lead poisoning via ingestion of lead shot has been d o c u m e n t e d as a significant m o r t a l i t y factor in US waterfowl p o p u l a t i o n s (Bellrose, 1 9 5 9 ; Bagley et al,, 1967). However, little is k n o w n of t h e e x t e n t of lead poisoning in m o u r n i n g doves or u p l a n d game birds in general. Hunting over managed dove fields will likely increase t h e availability of s p e n t lead s h o t t o doves as well as t h e increased risk of ingestion (Locke and Bagley, 1 9 6 7 ; Lewis and Legler, 1 9 6 8 ; Kendall a n d Scanlon, 1 9 7 9 ) . A confirmed case of lead poisoning in a m o u r n i n g dove was r e p o r t e d b y Locke and Bagley ( 1 9 6 7 ) . T h e bird c o n t a i n e d t w o lead pellets in t h e gizzard, was m o r i b u n d and emaciated, and acid-fast intranuclear inclusion bodies were f o u n d in cells of t h e p r o x i m a l convoluted tubules. Roscoe ( 1 9 7 8 ) found such intranuclear inclusion bodies in t h e p r o x i m a l c o n v o l u t e d t u b u l e cells in mallards (Anas platyrhynchos) t h a t had ingested lead shot. Hemosiderin loading was f o u n d in t h e livers of mallards suffering from lead poisoning.
1 Huxley College of Environmental Studies, Western Washington University, Bellingham, WA 98225.
More information on t h e histopathology of lead shot poisoning in m o u r n i n g doves would be useful in characterizing lead poisoning in this species and would be of diagnostic value. F o r these reasons, an e x p e r i m e n t was c o n d u c t e d in which m o u r n i n g doves were administered lead shot, and their tissues were e x a m i n e d histologically and their kidneys were e x a m i n e d b y electron microscopy. MATERIAL AND METHODS T h r e e m o u r n i n g doves were trapped in O c t o b e r 1 9 7 9 and t r a n s p o r t e d t o t h e l a b o r a t o r y and confined in suspended stainless steel cages ( 2 4 x 1 8 x 1 8 c m ) . Corn diet [ m e a n ± SE, lead c o n c e n t r a t i o n = .16 ± .09 Mg/g. dry weight ( D W ) ] , grit, and water were provided ad libitum. After 4 8 hr in t h e cages, one bird received n o lead shot and t w o birds received 4 lead shot ( # 8 , X = 73 m g / s h o t ) . All were sacrificed b y decapitation at 4 days after lead shot ingestion. Brain, liver, kidney, spleen, proventriculus, gizzard, d u o d e n u m , pectoral muscle, heart, and lungs for all birds were examined b y s t a n d a r d histological techniques ( H u m a s o n , 1 9 7 2 ) . Kidney tissue was e x a m i n e d with electron microscopy (Kendall, 1980).
952
PATHOLOGY OF LEAD SHOT POISONING
Lead concentrations (jug/g, DW) were determined in the brain, liver, bone, and kidney utilizing atomic absorption spectrophotometry (Scanlon et al., 1980). Six mourning doves were trapped in December 1979, transported to the laboratory, and confined in suspended stainless steel cages. The birds were maintained as previously described for the October 1979 dove collection except a 72-hr holding period was allowed before lead dosing. Three birds received no lead shot, two birds received 4 shot, and one bird received 8 shot (all #8, X = 73 mg/shot), and the doves were sacrificed 9 days after ingestion of the lead pellets. After sacrifice, liver and kidney were examined histologically and kidney tissue by electron microscopy. Lead concentrations (/ig/g, DW) were measured in the brain, liver, bone, and kidney by atomic absorption spectrophotometry.
RESULTS
Doves FD-1 and FD-2, which received 4 lead pellets, had highly elevated lead concentrations in the kidney and liver (Table 1). When sacrificed at 4 days after lead shot ingestion, histological examination revealed acid-fast inclusion bodies in cells of the proximal convoluted tubules. Although there were a few intranuclear inclusions identified, most inclusions were intracytoplasmic. Electron microscopic examination did
953
not reveal intranuclear bodies. Histologically, the liver of FD-1 had moderate hemosiderin loading of the Kupffer cells. All other tissues examined had no lesions. Bird FD-2 had elevated kidney and brain lead of 345.95 and 17.21 jUg/g, respectively. Histologic examination of the liver revealed light hemosiderin-loading of the Kupffer cells. Histologically, only a few intranuclear bodies were found in the proximal convoluted tubule cells, and this suggested that the bird had not absorbed as much lead from the pellets as did dove FD-1. Most inclusions found in the kidney were intracytoplasmic. Electron microscopic examination did not reveal intranuclear inclusion bodies. Histopathological examination indicated that dove FD-3 (not dosed with lead shot) had no remarkable lesions. Electron microscopic examination of the kidney revealed no inclusion bodies in the nuclei of cells of the proximal convoluted tubules. The dove had background concentrations of lead in kidney, liver, and brain (Table 1); however, lead in bone was elevated in this individual (162.72 Mg/g. DW). Birds that were trapped in December 1979 and received no lead pellets had relatively low lead concentrations in tissue (Table 2). Histological examination of bird FD-4 showed that epithelial cells in the proximal convoluted tubules did not have intranuclear inclusion bodies nor was hemosiderin loading detected in the liver. Electron microscopic examination of
TABLE 1. Lead concentrations (vg/g, dry weight) in the kidney, liver, brain, and femur together with histology of kidney and liver and electron microscopic examination of the kidney of 3 mourning doves that were dosed with either four number 8 lead shot or no shot and sacrificed at 4 days after dosing Individual mourning doves Variable Kidney Liver Brain Femur Kidney1 (inclusions PCT) Liver3 (hemosiderin loading) Kidney 4 (EM exam-inclusions PCT)
FD1 4 shot
FD2 4 shot
FD3 0 shot
639.43 214.71 11.93 264.36 (+,D 2 (+,2)
345.95 58.35 17.21 372.75 (+,1) (+,D
12.38 1.60 1.72 162.72
(-)
(-)
(-) (-) (-)
1 Histological examination for acid-fast intranuclear inclusions in cells of the proximal convoluted tubules (PCT). 2
+, Lesions present (3 = high, 2 = moderate, and 1 = light): —, no detectable lesions.
3
Histological examination for hemosiderin loading in the liver.
4
Electron microscopic (EM) examination for intranuclear inclusion bodies in the cells of the PCT.
954
KENDALL ET AL
kidney tissue of bird FD-4 did not identify any remarkable lesions. Doves that ingested lead pellets and were sacrificed 9 days later showed highly elevated •lead concentrations in tissue (Table 2). Histological examination of the kidney indicated acid-fast intranuclear inclusion bodies in a high number of the epithelial cells of the proximal convoluted tubules. These birds had concentrations of lead in kidney in excess of 1000 jug/g, DW. Moderate hemosiderin loading of the Kupffer cells was detected in the liver and lead concentrations were greater than 150/zg/g, DW in all cases. Electron microscopic examination of kidney tissue of birds ingesting 4 or 8 number 8 lead shot revealed intranuclear inclusion bodies in cells of the proximal convoluted tubules. Intracellular lesions observed included reduction and elongation of mitochondria and swelling in many cells (Fig. 1).
of the pellets (4 days), and suggests that transport of lead in the epithelial cells of the proximal convoluted tubules first occurs in large amounts intracytoplasmically before deposition in the nucleus. Hemosiderin loading was seen in the liver of mourning doves that had elevated concentrations of lead in liver. Hemosiderin loading in the liver was light in the lead-poisotied mourning doves, which were sacrificed after 4 days. However, mourning doves sacrificed 9 days after ingestion of shot had a greater degree of hemosiderosis. These findings suggest that hemosiderin deposits in Kupffer cells are directly related to the intravascular and levels of lead in liver. Roscoe (1978) has shown characteristic lesions of lead poisoning in kidneys and livers of mallard ducks. Birds that were lead poisoned had acid-fast intranuclear inclusion bodies in the epithelial cells of the proximal convoluted tubules and hemosiderin loading in the liver. Mourning doves in the present report that were lead poisoned corroborate data reported by Roscoe (1978). Locke and Bagley (1967) reported a case of a mourning dove dying of lead poisoning. The liver and the tibia of that bird contained 72 /ug/g, wet weight (WW) (approximately 288 Hg/g, DW) and 187 jxg/g lead WW, respectively. The tissue lead concentrations of mourning doves experimentally dosed with lead shot
DISCUSSION Acid-fast intranuclear inclusions were detected in proximal convoluted tubule cells in mourning doves that were dosed with lead shot and sacrificed 9 days later. Mourning doves that were dosed with lead shot and sacrificed at 4 days had primarily intracytoplasmic inclusions rather than intranuclear inclusions. This probably was related to the short time after ingestion
TABLE 2. Lead concentrations iug/g, dry weight) in the kidney, liver, brain, and femur together with histology of the kidney and liver and electron microscopic examination of the kidney in 6 mourning doves (December 1979) that were dosed with four or eight number 8 lead shot and sacrificed at 9 days
Tissue Brain lead Kidney lead Liver lead Femur lead Kidney2 (inclusions PCT) Liver5 (hemosiderin loading) Kidney6 (EM exam -inclusions PCT)
FD4
FD5
FD6
0 shot
0 shot
0 shot
FD7 1 4 shot
.92
.13
13.24
42.22
3.02
10.84 1,900.99 267.29 403.84
NS4 NS NS
NS NS NS
NS NS NS
.59
.59
3.13
2.88
(-) 3 (-) (-)
.26 .49 .34
FD8
FD9
4 shot
8 shot
12.16 1,297.57 178.81 528.00 (+,3) (+,3)
10.59 1,181.54 150.00 472.93 (+,2) (+,2)
(+)
(+)
' Bird died at 7 days after ingestion of lead shot. Histological examination for acid-fast intranuclear inclusions in cells of the proximal convoluted tubules (PCT). 3 +, Lesions present (3 = high, 2 = moderate, and 1 = light); —, no detectable lesion. "NS, Histology not studied. 5 Histological examination for hemosiderin loading in the liver. 6 Electron microscopic (EM) examination of intranuclear inclusion bodies. 2
PATHOLOGY OF LEAD SHOT POISONING
955
FIG. 1. Electron microscopic examination (2600 X) of intranuclear inclusion bodies in cells of a proximal convoluted tubule in a captive mourning dove that has experienced lead poisoning. The tubule has a brush border indicated by A, a swollen nucleus indicated by B, and a nucleus with an intranuclear inclusion indicated byC.
956
KENDALL ET AL
corroborated toxic concentrations reported for a lead-poisoned mourning dove found in the wild (Locke and Bagley, 1967). Hepatic hemosiderosis in the liver and acid-fast intranuclear inclusion bodies in epithelial cells of the proximal convoluted tubules were found in this bird. Zook et al. (1972) have used the presence of acid-fast intranuclear inclusion bodies as being diagnostic of lead poisoning. Eleven species of birds that died of lead poisoning in a zoo had intranuclear inclusion bodies in epithelial cells of the proximal convoluted tubules as well as elevated liver lead concentrations. Kendall and Scanlon (1983) reported that ringed turtle doves (Streptopelia risoria) that ingested lead shot had inclusions in epithelial cells of the proximal convoluted tubules as did mourning doves. Ringed turtle doves that received a chronic exposure to lead (100 /ug lead/ml H 2 0 ) had severe nephropathy associated with large intranuclear inclusion bodies, swelling of many cell nuclei, and a reduction in mitochondria present in epithelial cells of the proximal convoluted tubules (Kendall and Scanlon, 1982). It appears that intracytoplasmic inclusions could be an important criterion in diagnosing avian species that have been collected within several days after ingestion of spent lead shot. After lead shot ingestion, there is apparently a time delay of several days before the lead is deposited in the nuclei of proximal convoluted tubule cells as intranuclear inclusion bodies. It appears that, as a function of time, intracytoplasmic inclusions serve as an intermediate phase between lead first entering these cells and finally being sequestered into nuclei of epithelial proximal convoluted tubule cells. ACKNOWLEDGMENTS
This project was supported by the Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, and constitutes a part of a
dissertation submitted by the senior author. The National Rifle Association provided a grant-in-aid to help defray publication costs, and the National Wildlife Federation awarded the senior author an Environmental Conservation Fellowship.
REFERENCES Bagley, G. E., L. N. Locke, and G. T. Nightingale, 1967. Lead poisoning in Canada geese. Avian Dis. 11:601-608. Bellrose, F. C , 1959. Lead poisoning as a mortality factor in waterfowl populations. Illinois Natl. Hist. Surv. Bull. 27:235-288. Humason, G. L., 1972. Animal Tissue Techniques. 3rd ed. W. F. Freeman and Company, San Francisco, CA. Kendall, R. J., 1980. The toxicology of lead shot and environmental lead ingestion in avian species with emphasis on the biological significance in mourning dove populations. Ph.D. diss., Virginia Polytechnic Inst. State Univ., Blacksburg, VA. Kendall, R. J., and P. F. Scanlon, 1979. Lead concentrations in mourning doves collected from middle Atlantic game management areas. Proc. Southeastern Assoc. Fish Wildl. Agencies 33:165—172. Kendall, R. J„ and P. F. Scanlon, 1982. Chronic lead ingestion and nephropathy in ringed turtle doves. Poultry Sci. 60:2028-2032. Kendall, R. J., and P. F. Scanlon, 1983. Histology and ultrastructure of kidney tissue from ringed turtle doves that ingested lead shot. J. Environ. Pathol. Toxicol. (In press). Lewis, J. C , and E. Legler, Jr., 1968. L e ad shot ingestion by mourning doves. J. Wildl. Manage. 32:476-482. Locke, L. N., and G. E. Bagley, 1967. Lead poisoning in a sample of Maryland mourning doves. J. Wildl. Manage. 31:515-518. Roscoe, D. E., 1978. Pathology of plumbism in waterfowl and development of a simple diagnostic blood test. Ph.D. diss., Univ. Connecticut, Storrs, CT. Scanlon, P. F., V. D. Stotts, R. G. Oderwald, T. J. Dietrick, and R. J. Kendall, 1980. Lead concentrations in livers of Maryland waterfowl with and without ingested lead shot present in gizzards. Bull. Environ. Contam. Toxicol. 26:855-860. Zook, B. C , R. M. Sauer, and F. M. Garner, 1972. Lead poisoning in captive wild animals. J. Wildl. Dis. 8:264-272.
1 Huxley College of Environmental Studies, Western Washington University, Bellingham, WA 98225.
More information on t h e histopathology of lead shot poisoning in m o u r n i n g doves would be useful in characterizing lead poisoning in this species and would be of diagnostic value. F o r these reasons, an e x p e r i m e n t was c o n d u c t e d in which m o u r n i n g doves were administered lead shot, and their tissues were e x a m i n e d histologically and their kidneys were e x a m i n e d b y electron microscopy. MATERIAL AND METHODS T h r e e m o u r n i n g doves were trapped in O c t o b e r 1 9 7 9 and t r a n s p o r t e d t o t h e l a b o r a t o r y and confined in suspended stainless steel cages ( 2 4 x 1 8 x 1 8 c m ) . Corn diet [ m e a n ± SE, lead c o n c e n t r a t i o n = .16 ± .09 Mg/g. dry weight ( D W ) ] , grit, and water were provided ad libitum. After 4 8 hr in t h e cages, one bird received n o lead shot and t w o birds received 4 lead shot ( # 8 , X = 73 m g / s h o t ) . All were sacrificed b y decapitation at 4 days after lead shot ingestion. Brain, liver, kidney, spleen, proventriculus, gizzard, d u o d e n u m , pectoral muscle, heart, and lungs for all birds were examined b y s t a n d a r d histological techniques ( H u m a s o n , 1 9 7 2 ) . Kidney tissue was e x a m i n e d with electron microscopy (Kendall, 1980).
952
PATHOLOGY OF LEAD SHOT POISONING
Lead concentrations (jug/g, DW) were determined in the brain, liver, bone, and kidney utilizing atomic absorption spectrophotometry (Scanlon et al., 1980). Six mourning doves were trapped in December 1979, transported to the laboratory, and confined in suspended stainless steel cages. The birds were maintained as previously described for the October 1979 dove collection except a 72-hr holding period was allowed before lead dosing. Three birds received no lead shot, two birds received 4 shot, and one bird received 8 shot (all #8, X = 73 mg/shot), and the doves were sacrificed 9 days after ingestion of the lead pellets. After sacrifice, liver and kidney were examined histologically and kidney tissue by electron microscopy. Lead concentrations (/ig/g, DW) were measured in the brain, liver, bone, and kidney by atomic absorption spectrophotometry.
RESULTS
Doves FD-1 and FD-2, which received 4 lead pellets, had highly elevated lead concentrations in the kidney and liver (Table 1). When sacrificed at 4 days after lead shot ingestion, histological examination revealed acid-fast inclusion bodies in cells of the proximal convoluted tubules. Although there were a few intranuclear inclusions identified, most inclusions were intracytoplasmic. Electron microscopic examination did
953
not reveal intranuclear bodies. Histologically, the liver of FD-1 had moderate hemosiderin loading of the Kupffer cells. All other tissues examined had no lesions. Bird FD-2 had elevated kidney and brain lead of 345.95 and 17.21 jUg/g, respectively. Histologic examination of the liver revealed light hemosiderin-loading of the Kupffer cells. Histologically, only a few intranuclear bodies were found in the proximal convoluted tubule cells, and this suggested that the bird had not absorbed as much lead from the pellets as did dove FD-1. Most inclusions found in the kidney were intracytoplasmic. Electron microscopic examination did not reveal intranuclear inclusion bodies. Histopathological examination indicated that dove FD-3 (not dosed with lead shot) had no remarkable lesions. Electron microscopic examination of the kidney revealed no inclusion bodies in the nuclei of cells of the proximal convoluted tubules. The dove had background concentrations of lead in kidney, liver, and brain (Table 1); however, lead in bone was elevated in this individual (162.72 Mg/g. DW). Birds that were trapped in December 1979 and received no lead pellets had relatively low lead concentrations in tissue (Table 2). Histological examination of bird FD-4 showed that epithelial cells in the proximal convoluted tubules did not have intranuclear inclusion bodies nor was hemosiderin loading detected in the liver. Electron microscopic examination of
TABLE 1. Lead concentrations (vg/g, dry weight) in the kidney, liver, brain, and femur together with histology of kidney and liver and electron microscopic examination of the kidney of 3 mourning doves that were dosed with either four number 8 lead shot or no shot and sacrificed at 4 days after dosing Individual mourning doves Variable Kidney Liver Brain Femur Kidney1 (inclusions PCT) Liver3 (hemosiderin loading) Kidney 4 (EM exam-inclusions PCT)
FD1 4 shot
FD2 4 shot
FD3 0 shot
639.43 214.71 11.93 264.36 (+,D 2 (+,2)
345.95 58.35 17.21 372.75 (+,1) (+,D
12.38 1.60 1.72 162.72
(-)
(-)
(-) (-) (-)
1 Histological examination for acid-fast intranuclear inclusions in cells of the proximal convoluted tubules (PCT). 2
+, Lesions present (3 = high, 2 = moderate, and 1 = light): —, no detectable lesions.
3
Histological examination for hemosiderin loading in the liver.
4
Electron microscopic (EM) examination for intranuclear inclusion bodies in the cells of the PCT.
954
KENDALL ET AL
kidney tissue of bird FD-4 did not identify any remarkable lesions. Doves that ingested lead pellets and were sacrificed 9 days later showed highly elevated •lead concentrations in tissue (Table 2). Histological examination of the kidney indicated acid-fast intranuclear inclusion bodies in a high number of the epithelial cells of the proximal convoluted tubules. These birds had concentrations of lead in kidney in excess of 1000 jug/g, DW. Moderate hemosiderin loading of the Kupffer cells was detected in the liver and lead concentrations were greater than 150/zg/g, DW in all cases. Electron microscopic examination of kidney tissue of birds ingesting 4 or 8 number 8 lead shot revealed intranuclear inclusion bodies in cells of the proximal convoluted tubules. Intracellular lesions observed included reduction and elongation of mitochondria and swelling in many cells (Fig. 1).
of the pellets (4 days), and suggests that transport of lead in the epithelial cells of the proximal convoluted tubules first occurs in large amounts intracytoplasmically before deposition in the nucleus. Hemosiderin loading was seen in the liver of mourning doves that had elevated concentrations of lead in liver. Hemosiderin loading in the liver was light in the lead-poisotied mourning doves, which were sacrificed after 4 days. However, mourning doves sacrificed 9 days after ingestion of shot had a greater degree of hemosiderosis. These findings suggest that hemosiderin deposits in Kupffer cells are directly related to the intravascular and levels of lead in liver. Roscoe (1978) has shown characteristic lesions of lead poisoning in kidneys and livers of mallard ducks. Birds that were lead poisoned had acid-fast intranuclear inclusion bodies in the epithelial cells of the proximal convoluted tubules and hemosiderin loading in the liver. Mourning doves in the present report that were lead poisoned corroborate data reported by Roscoe (1978). Locke and Bagley (1967) reported a case of a mourning dove dying of lead poisoning. The liver and the tibia of that bird contained 72 /ug/g, wet weight (WW) (approximately 288 Hg/g, DW) and 187 jxg/g lead WW, respectively. The tissue lead concentrations of mourning doves experimentally dosed with lead shot
DISCUSSION Acid-fast intranuclear inclusions were detected in proximal convoluted tubule cells in mourning doves that were dosed with lead shot and sacrificed 9 days later. Mourning doves that were dosed with lead shot and sacrificed at 4 days had primarily intracytoplasmic inclusions rather than intranuclear inclusions. This probably was related to the short time after ingestion
TABLE 2. Lead concentrations iug/g, dry weight) in the kidney, liver, brain, and femur together with histology of the kidney and liver and electron microscopic examination of the kidney in 6 mourning doves (December 1979) that were dosed with four or eight number 8 lead shot and sacrificed at 9 days
Tissue Brain lead Kidney lead Liver lead Femur lead Kidney2 (inclusions PCT) Liver5 (hemosiderin loading) Kidney6 (EM exam -inclusions PCT)
FD4
FD5
FD6
0 shot
0 shot
0 shot
FD7 1 4 shot
.92
.13
13.24
42.22
3.02
10.84 1,900.99 267.29 403.84
NS4 NS NS
NS NS NS
NS NS NS
.59
.59
3.13
2.88
(-) 3 (-) (-)
.26 .49 .34
FD8
FD9
4 shot
8 shot
12.16 1,297.57 178.81 528.00 (+,3) (+,3)
10.59 1,181.54 150.00 472.93 (+,2) (+,2)
(+)
(+)
' Bird died at 7 days after ingestion of lead shot. Histological examination for acid-fast intranuclear inclusions in cells of the proximal convoluted tubules (PCT). 3 +, Lesions present (3 = high, 2 = moderate, and 1 = light); —, no detectable lesion. "NS, Histology not studied. 5 Histological examination for hemosiderin loading in the liver. 6 Electron microscopic (EM) examination of intranuclear inclusion bodies. 2
PATHOLOGY OF LEAD SHOT POISONING
955
FIG. 1. Electron microscopic examination (2600 X) of intranuclear inclusion bodies in cells of a proximal convoluted tubule in a captive mourning dove that has experienced lead poisoning. The tubule has a brush border indicated by A, a swollen nucleus indicated by B, and a nucleus with an intranuclear inclusion indicated byC.
956
KENDALL ET AL
corroborated toxic concentrations reported for a lead-poisoned mourning dove found in the wild (Locke and Bagley, 1967). Hepatic hemosiderosis in the liver and acid-fast intranuclear inclusion bodies in epithelial cells of the proximal convoluted tubules were found in this bird. Zook et al. (1972) have used the presence of acid-fast intranuclear inclusion bodies as being diagnostic of lead poisoning. Eleven species of birds that died of lead poisoning in a zoo had intranuclear inclusion bodies in epithelial cells of the proximal convoluted tubules as well as elevated liver lead concentrations. Kendall and Scanlon (1983) reported that ringed turtle doves (Streptopelia risoria) that ingested lead shot had inclusions in epithelial cells of the proximal convoluted tubules as did mourning doves. Ringed turtle doves that received a chronic exposure to lead (100 /ug lead/ml H 2 0 ) had severe nephropathy associated with large intranuclear inclusion bodies, swelling of many cell nuclei, and a reduction in mitochondria present in epithelial cells of the proximal convoluted tubules (Kendall and Scanlon, 1982). It appears that intracytoplasmic inclusions could be an important criterion in diagnosing avian species that have been collected within several days after ingestion of spent lead shot. After lead shot ingestion, there is apparently a time delay of several days before the lead is deposited in the nuclei of proximal convoluted tubule cells as intranuclear inclusion bodies. It appears that, as a function of time, intracytoplasmic inclusions serve as an intermediate phase between lead first entering these cells and finally being sequestered into nuclei of epithelial proximal convoluted tubule cells. ACKNOWLEDGMENTS
This project was supported by the Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, and constitutes a part of a
dissertation submitted by the senior author. The National Rifle Association provided a grant-in-aid to help defray publication costs, and the National Wildlife Federation awarded the senior author an Environmental Conservation Fellowship.
REFERENCES Bagley, G. E., L. N. Locke, and G. T. Nightingale, 1967. Lead poisoning in Canada geese. Avian Dis. 11:601-608. Bellrose, F. C , 1959. Lead poisoning as a mortality factor in waterfowl populations. Illinois Natl. Hist. Surv. Bull. 27:235-288. Humason, G. L., 1972. Animal Tissue Techniques. 3rd ed. W. F. Freeman and Company, San Francisco, CA. Kendall, R. J., 1980. The toxicology of lead shot and environmental lead ingestion in avian species with emphasis on the biological significance in mourning dove populations. Ph.D. diss., Virginia Polytechnic Inst. State Univ., Blacksburg, VA. Kendall, R. J., and P. F. Scanlon, 1979. Lead concentrations in mourning doves collected from middle Atlantic game management areas. Proc. Southeastern Assoc. Fish Wildl. Agencies 33:165—172. Kendall, R. J„ and P. F. Scanlon, 1982. Chronic lead ingestion and nephropathy in ringed turtle doves. Poultry Sci. 60:2028-2032. Kendall, R. J., and P. F. Scanlon, 1983. Histology and ultrastructure of kidney tissue from ringed turtle doves that ingested lead shot. J. Environ. Pathol. Toxicol. (In press). Lewis, J. C , and E. Legler, Jr., 1968. L e ad shot ingestion by mourning doves. J. Wildl. Manage. 32:476-482. Locke, L. N., and G. E. Bagley, 1967. Lead poisoning in a sample of Maryland mourning doves. J. Wildl. Manage. 31:515-518. Roscoe, D. E., 1978. Pathology of plumbism in waterfowl and development of a simple diagnostic blood test. Ph.D. diss., Univ. Connecticut, Storrs, CT. Scanlon, P. F., V. D. Stotts, R. G. Oderwald, T. J. Dietrick, and R. J. Kendall, 1980. Lead concentrations in livers of Maryland waterfowl with and without ingested lead shot present in gizzards. Bull. Environ. Contam. Toxicol. 26:855-860. Zook, B. C , R. M. Sauer, and F. M. Garner, 1972. Lead poisoning in captive wild animals. J. Wildl. Dis. 8:264-272.