- Email: [email protected]
Merogony and gametogony of Eimeria mccrodocki (protozoa—eimeriidae) in the mule deer, Odocoileus h. hemionus
Veterinary Parasitology, 24 (1987) 1--5 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands
1
MEROGONY AND GAMETOGONY OF EIMERIA MCCORDOCKI (PROTOZOA EIMERIIDAE) IN THE MULE DEER, ODOCOILEUS H. HEMIONUS - -
B. A B B A S * , G. P O S T and W.C. M A R Q U A R D T
I
Department of Fishery and WildlifeBiology and ~Department of Zoology, Colorado State University, Fort Collins, CO 80523 (U.S.A.)
ABSTRACT
Abbas, B., Post, G. and Marquardt, W.C., 1987. Merogony and gametogony of Eimeria mccordocki (Protozoa -- Eimeriidae) in the mule deer, Odocoileus h. hemionus. Vet. Parasitol., 24: 1--5.
Eimeria mccordocki and E. madisonensis oocysts were isolated from feces of 21 of 40 captive mule deer in Fort Collins, Colorado. The two species were separated from each other by infecting one mule deer fawn, and the life cycle of E. mccordocki was studied for the first time, Four to six-weeks-old mule deer fawns were inoculated orally with E. mccordocki and killed 9, 13 and 15 days after infection. Asexual and sexual stages of life cycle developed in the ileum of mule deer, only in the surface epithelial cells of the villi. The asexual stages consisted of two generations of meronts.
INTRODUCTION
The literature on coccidia of Cervidae is very scanty (Landrum and Honess, 1955; Levine and Ivens, 1970). Eimeria mccordocki was first isolated from black-tailed deer (Odocoileus h. hemionus) b y Honess (1941). Samuel and Trainer (1971) reported E. rnccordocki from 13% of deer in Texas and observed a higher incidence during winter. Experimental infection with E. mccordocki in black-tailed deer resulted in a severe gastroenteritis and produced necrosis m the intestine (Abbas and Post, 1980). In this paper we describe the life cycle of E. rnccordocki in y o u n g black-tailed deer fawns.
*Present address: Department of Medicine Toxicology and Pharmacology, Faculty of Veterinary Science, University of Khartoum, P.O. Box 32, Khartoum North, Sudan.
0304-4017/87/$03.50
© 1987 Elsevier Science Publishers B.V.
MATERIALS AND METHODS
Source o f parasites Mixed E. mccordocki and E. madisonensis infection was diagnosed in 21 of 40 (52%) black-tailed deer raised in captivity in Fort Collins, Colorado (Abbas, 1979). Oocysts were purified and sporulated according to conventional procedures (Benbrook and Sloss, 1965). E. mccordocki was obtained as a pure isolate from one fawn (No. 97, see below) experimentally infected with the two parasites. Oocytes of E. mccordocki collected from this animal were used throughout this study.
Experimental animals Five black-tailed deer fawns, 2--5 days old, were obtained from different localities in Colorado and Wyoming and were raised in confinement for 4--6 weeks prior to experimentation. The fawns were examined for internal parasites daily for the first week and weekly thereafter. A pen which had been unoccupied for 1 year previous to the experiment was used to house the fawns; the surface layer of material was removed, followed by careful disinfection. No other animals were allowed into the pen. Disposable gloves and boots were worn on entering the pen and were always left within the pen. Contact with people was limited to one investigator. The fawns were given a diet of two parts pasteurized whole bovine milk mixed with one part evaporated milk. Each fawn received 90 ml of the mixture four t i m e s per day.
Experimental infection A design based on results of the pilot infection in Fawn 97 was adopted for the inoculation and necropsy of Fawns 93, 94, 95 and 100 (Table I). TABLE I Experimental infection of deer fawns with Eimeria mccordocki and Eimeria madisonensis and time (days) of performing necropsy Fawn No.
97 95 94 93 100
Age at infection (wk)
T o t a l dose of o o c y s t s E. m c c o r d o c k i
E. m a d i s o n e n s i s
D u r a t i o n of infection (days)
6 4 3 4 5
15 18 16 18 24
75 0 0 0 0
27 7 9 13 15
500 000 800 000 000
Each fawn received the oocysts in the milk diet and were observed daily for clinical signs. Fecal samples were collected every 12 h. Animals were killed by inhalation of CO2 (dry ice) in an air-tight mask and the entire intestines were dissected free from the viscera. Tissue specimens were taken at 30-cm intervals, starting at 4 cm from the pyloric sphincter. Intestinal rings were rinsed in water fixed in 10% neutral saline formalin, dehydrated in ethyl alcohol, e m b e d d e d in paraffin, cut at 5 pm intervals and stained with hematoxylin and eosin. RESULTS AND DISCUSSION Infection in Fawn 97 resulted in severe gastroenteritis, fever, dehydration and weight loss. E. mccordocki had a prepatent period of 19 days and patency for 10 days. A detailed account of the o o c y s t o u t p u t from Fawn 97 was given by Abbas (1979). None of the four experimental animals infected later excreted oocysts in the feces since they were killed during the prepatent period. The clinical signs of coccidiosis were essentially the same in all of the fawns, except Fawn 95, which apparently did n o t become infected. There was anorexia, mild to severe dysentery, fatigue, dehydration and loss of weight.
The life cycle o f E. mccordocki The development of the parasitic stages of E. mccordocki was confined to the last 90--140 cm of the small intestine. Few parasitized cells were observed near the ileocecal valve. No organisms were seen in the large intestine. Different stages and overlapping generations of meronts were found in specimens from Fawns 93, 94 and 100. No evidence of parasitism was found in Fawn 95 which was killed 7 days after inoculation. The parasites developed in the villar epithelial cells (Fig. 1); parasites were n o t seen in the crypts, muscularis mucosa, lacteals or in connective tissue cells. The meronts were of two morphological types. The smaller meronts developing early in the infection will be referred to as 'first generation meronts'. The larger meronts developing later will be referred to as 'second generation meronts'. Mature meronts were seen at 9 days and contained a small residual body (Fig. 2). The nuclei were at the periphery of meronts. Meronts were 8.75 X 11.60 u m (8.75--12.8 X 7.75--10.5 Urn, n = 100) and had 15.7 (8--22) merozoites. First generation merozoites were 5.8 X 1.7 ~m (5.5--6.5 × 1.5--2.0 urn), banana.shaped (Fig. 3) and contained one refractile granule at each end and a conspicuous centrally located nucleus. Second generation meronts were f o u n d in all three fawns. They were more numerous in Fawn 93, which was killed 13 days after inoculation. Mature meronts were more numerous than immature meronts in this animal. They
Fig. 1. Surface epithelial cells in the ileum containing 2--5 meronts of E. mccordocki (H&E, X 100).
Fig. 2. Second generation meronts and merozoites -- 13 days after infection, Fawn 93 (H&E, x 280).
Fig. 3. First generation merozoites - - 9 days after infection, Fawn 94 (H&E, x 280).
did n o t differ greatly in shape from first generation meronts but had a smaller residual body. Second generation meronts were 12.5 × 10.7 pm (9.8--14.4 × 9.5--11.5 pro, n = 100) and contained 13--28 merozoites. Most second generation meronts observed in Fawn 94 were immature, but the number of mature meronts increased consistently in Fawns 93 and 100. Second generation merozoites were 7.4 × 2.1 #m (6.7--7.5 × 2.0--2.3/~m) and were longer than first generation meronts. Macrogamonts and microgametocytes were first seen at Day 13 of infection, but mature gamonts (Fig. 4) were n o t seen until 15 days post-infection. Micro- and macrogamonts and mature second generation meronts were seen 15 days postinfection. The gamonts and meronts were located in the same part of the host cell and both developed in the same portions of the intestine. Macrogamonts varied from 3.5 to 25.0 #m in diameter. Microgamonts were 9.5--11.5 /~m in diameter. Fertilization was not observed and fully formed oocysts were n o t seen.
Fig. 4. Macrogamonts -- 15 days after infection, F a w n 100 (H&E, × 280).
REFERENCES Abbas, B., 1979. The life cycle of Eimeria mccordocki in the mule deer. M.Sc. Thesis, Colorado State University, F o r t Collins, CO, 76 pp. Ahbas, B. and Post, G., 1980. Experimental coccidiosis in mule deer fawns. J. Wildl. Dis., 16: 565--570. Benbrook, E.A. and Sloss, M.W., 1965. Veterinary Clinical Parasitology, Iowa State University Press, Ames, IA, p. 248. Honess, R.F., 1941. A new coccidium, Eimeria mccordocki n. sp. from the black-tailed deer. J. Colo. Wyo. Acad. Sci., 3 : 48. Landrum, J.F. and Honess, R.F., 1955. Some internal parasites of the mule deer Odocoileus h. heminus in Wyoming. Wyo. Game and Fish Comm. Bull., 8: 413--422. Levine, N.D. and Ivens, V., 1970. The Coccidian Parasites (Protozoa, Sporozoa) of Ruminants. Illinois Biological Monograph No. 44. University of Illinois Press. p. 148. Samuel, W.M. and Trainer, D.O., 1971. Some ecologic factors influencing Eimeria mccordocki (Honess, 1941) in white-tailed deer, Odocoileus virginianus. J. Protozool., 18: 306--308.
1
MEROGONY AND GAMETOGONY OF EIMERIA MCCORDOCKI (PROTOZOA EIMERIIDAE) IN THE MULE DEER, ODOCOILEUS H. HEMIONUS - -
B. A B B A S * , G. P O S T and W.C. M A R Q U A R D T
I
Department of Fishery and WildlifeBiology and ~Department of Zoology, Colorado State University, Fort Collins, CO 80523 (U.S.A.)
ABSTRACT
Abbas, B., Post, G. and Marquardt, W.C., 1987. Merogony and gametogony of Eimeria mccordocki (Protozoa -- Eimeriidae) in the mule deer, Odocoileus h. hemionus. Vet. Parasitol., 24: 1--5.
Eimeria mccordocki and E. madisonensis oocysts were isolated from feces of 21 of 40 captive mule deer in Fort Collins, Colorado. The two species were separated from each other by infecting one mule deer fawn, and the life cycle of E. mccordocki was studied for the first time, Four to six-weeks-old mule deer fawns were inoculated orally with E. mccordocki and killed 9, 13 and 15 days after infection. Asexual and sexual stages of life cycle developed in the ileum of mule deer, only in the surface epithelial cells of the villi. The asexual stages consisted of two generations of meronts.
INTRODUCTION
The literature on coccidia of Cervidae is very scanty (Landrum and Honess, 1955; Levine and Ivens, 1970). Eimeria mccordocki was first isolated from black-tailed deer (Odocoileus h. hemionus) b y Honess (1941). Samuel and Trainer (1971) reported E. rnccordocki from 13% of deer in Texas and observed a higher incidence during winter. Experimental infection with E. mccordocki in black-tailed deer resulted in a severe gastroenteritis and produced necrosis m the intestine (Abbas and Post, 1980). In this paper we describe the life cycle of E. rnccordocki in y o u n g black-tailed deer fawns.
*Present address: Department of Medicine Toxicology and Pharmacology, Faculty of Veterinary Science, University of Khartoum, P.O. Box 32, Khartoum North, Sudan.
0304-4017/87/$03.50
© 1987 Elsevier Science Publishers B.V.
MATERIALS AND METHODS
Source o f parasites Mixed E. mccordocki and E. madisonensis infection was diagnosed in 21 of 40 (52%) black-tailed deer raised in captivity in Fort Collins, Colorado (Abbas, 1979). Oocysts were purified and sporulated according to conventional procedures (Benbrook and Sloss, 1965). E. mccordocki was obtained as a pure isolate from one fawn (No. 97, see below) experimentally infected with the two parasites. Oocytes of E. mccordocki collected from this animal were used throughout this study.
Experimental animals Five black-tailed deer fawns, 2--5 days old, were obtained from different localities in Colorado and Wyoming and were raised in confinement for 4--6 weeks prior to experimentation. The fawns were examined for internal parasites daily for the first week and weekly thereafter. A pen which had been unoccupied for 1 year previous to the experiment was used to house the fawns; the surface layer of material was removed, followed by careful disinfection. No other animals were allowed into the pen. Disposable gloves and boots were worn on entering the pen and were always left within the pen. Contact with people was limited to one investigator. The fawns were given a diet of two parts pasteurized whole bovine milk mixed with one part evaporated milk. Each fawn received 90 ml of the mixture four t i m e s per day.
Experimental infection A design based on results of the pilot infection in Fawn 97 was adopted for the inoculation and necropsy of Fawns 93, 94, 95 and 100 (Table I). TABLE I Experimental infection of deer fawns with Eimeria mccordocki and Eimeria madisonensis and time (days) of performing necropsy Fawn No.
97 95 94 93 100
Age at infection (wk)
T o t a l dose of o o c y s t s E. m c c o r d o c k i
E. m a d i s o n e n s i s
D u r a t i o n of infection (days)
6 4 3 4 5
15 18 16 18 24
75 0 0 0 0
27 7 9 13 15
500 000 800 000 000
Each fawn received the oocysts in the milk diet and were observed daily for clinical signs. Fecal samples were collected every 12 h. Animals were killed by inhalation of CO2 (dry ice) in an air-tight mask and the entire intestines were dissected free from the viscera. Tissue specimens were taken at 30-cm intervals, starting at 4 cm from the pyloric sphincter. Intestinal rings were rinsed in water fixed in 10% neutral saline formalin, dehydrated in ethyl alcohol, e m b e d d e d in paraffin, cut at 5 pm intervals and stained with hematoxylin and eosin. RESULTS AND DISCUSSION Infection in Fawn 97 resulted in severe gastroenteritis, fever, dehydration and weight loss. E. mccordocki had a prepatent period of 19 days and patency for 10 days. A detailed account of the o o c y s t o u t p u t from Fawn 97 was given by Abbas (1979). None of the four experimental animals infected later excreted oocysts in the feces since they were killed during the prepatent period. The clinical signs of coccidiosis were essentially the same in all of the fawns, except Fawn 95, which apparently did n o t become infected. There was anorexia, mild to severe dysentery, fatigue, dehydration and loss of weight.
The life cycle o f E. mccordocki The development of the parasitic stages of E. mccordocki was confined to the last 90--140 cm of the small intestine. Few parasitized cells were observed near the ileocecal valve. No organisms were seen in the large intestine. Different stages and overlapping generations of meronts were found in specimens from Fawns 93, 94 and 100. No evidence of parasitism was found in Fawn 95 which was killed 7 days after inoculation. The parasites developed in the villar epithelial cells (Fig. 1); parasites were n o t seen in the crypts, muscularis mucosa, lacteals or in connective tissue cells. The meronts were of two morphological types. The smaller meronts developing early in the infection will be referred to as 'first generation meronts'. The larger meronts developing later will be referred to as 'second generation meronts'. Mature meronts were seen at 9 days and contained a small residual body (Fig. 2). The nuclei were at the periphery of meronts. Meronts were 8.75 X 11.60 u m (8.75--12.8 X 7.75--10.5 Urn, n = 100) and had 15.7 (8--22) merozoites. First generation merozoites were 5.8 X 1.7 ~m (5.5--6.5 × 1.5--2.0 urn), banana.shaped (Fig. 3) and contained one refractile granule at each end and a conspicuous centrally located nucleus. Second generation meronts were f o u n d in all three fawns. They were more numerous in Fawn 93, which was killed 13 days after inoculation. Mature meronts were more numerous than immature meronts in this animal. They
Fig. 1. Surface epithelial cells in the ileum containing 2--5 meronts of E. mccordocki (H&E, X 100).
Fig. 2. Second generation meronts and merozoites -- 13 days after infection, Fawn 93 (H&E, x 280).
Fig. 3. First generation merozoites - - 9 days after infection, Fawn 94 (H&E, x 280).
did n o t differ greatly in shape from first generation meronts but had a smaller residual body. Second generation meronts were 12.5 × 10.7 pm (9.8--14.4 × 9.5--11.5 pro, n = 100) and contained 13--28 merozoites. Most second generation meronts observed in Fawn 94 were immature, but the number of mature meronts increased consistently in Fawns 93 and 100. Second generation merozoites were 7.4 × 2.1 #m (6.7--7.5 × 2.0--2.3/~m) and were longer than first generation meronts. Macrogamonts and microgametocytes were first seen at Day 13 of infection, but mature gamonts (Fig. 4) were n o t seen until 15 days post-infection. Micro- and macrogamonts and mature second generation meronts were seen 15 days postinfection. The gamonts and meronts were located in the same part of the host cell and both developed in the same portions of the intestine. Macrogamonts varied from 3.5 to 25.0 #m in diameter. Microgamonts were 9.5--11.5 /~m in diameter. Fertilization was not observed and fully formed oocysts were n o t seen.
Fig. 4. Macrogamonts -- 15 days after infection, F a w n 100 (H&E, × 280).
REFERENCES Abbas, B., 1979. The life cycle of Eimeria mccordocki in the mule deer. M.Sc. Thesis, Colorado State University, F o r t Collins, CO, 76 pp. Ahbas, B. and Post, G., 1980. Experimental coccidiosis in mule deer fawns. J. Wildl. Dis., 16: 565--570. Benbrook, E.A. and Sloss, M.W., 1965. Veterinary Clinical Parasitology, Iowa State University Press, Ames, IA, p. 248. Honess, R.F., 1941. A new coccidium, Eimeria mccordocki n. sp. from the black-tailed deer. J. Colo. Wyo. Acad. Sci., 3 : 48. Landrum, J.F. and Honess, R.F., 1955. Some internal parasites of the mule deer Odocoileus h. heminus in Wyoming. Wyo. Game and Fish Comm. Bull., 8: 413--422. Levine, N.D. and Ivens, V., 1970. The Coccidian Parasites (Protozoa, Sporozoa) of Ruminants. Illinois Biological Monograph No. 44. University of Illinois Press. p. 148. Samuel, W.M. and Trainer, D.O., 1971. Some ecologic factors influencing Eimeria mccordocki (Honess, 1941) in white-tailed deer, Odocoileus virginianus. J. Protozool., 18: 306--308.