INVASIVE ENTAMOEBAE IN PRONGHORN (ANTILOCAPRA AMERICANA) FROM WYOMING Author(s): Newton Kingston, Elizabeth S. Williams, and E. Tom Thome Source: Journal of Wildlife Diseases, 26(1):50-54. Published By: Wildlife Disease Association DOI: http://dx.doi.org/10.7589/0090-3558-26.1.50 URL: http://www.bioone.org/doi/full/10.7589/0090-3558-26.1.50
BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder.
BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research.
of Wildlife
Journal
INVASIVE
ENTAMOEBAE
(ANTILOCAPRA FROM
Diseases, 26(1). © Wildlife Disease
1990,
pp.
Association
50-54 1990
IN PRONGHORN
AMERICANA)
WYOMING
Newton
Kingston,
Elizabeth
S. Williams,’
and E. Tom
ThomV
Department of Veterinary Sciences, College of Agriculture, University of Wyoming, Laramie, Wyoming 82070, USA 2Wyoming Game and Fish Department Research Laboratory, Box 3312 University Station, Laramie, Wyoming 82071, USA Trophozoites and cysts of an amoeba resembling Entamoeba bovis were recovered from soft stools of captive pronghorn fawns (Antilocapra americana). Chronic or intermittent diarrhea was observed in most individuals in two groups of hand-raised 1- to 8-mo-old pronghorns. Ileocecal lymph nodes were mildly to moderately enlarged. Microscopic lesions were characterized by lymphoid hyperplasia, focal necrosis and pyogranulomatous inflammation in lymph nodes and focal necrosis and diffuse nonsuppurative enteritis in ileum and cecum. In 12 of 17 fawns, trophic stages of amoebae were observed in the submucosa of the cecum and/or the cortex of the ileocecal lymph node. This is the first report of E. bovis-like organisms invading and causing pathological changes in the tissues of their host. Key words: Pronghorn fawns, Antilocapra americana, Entamoeba sp., case report, diffuse nonsuppurative enteritis, ileum and cecum. ABSTRACT:
INTRODUCTION
With
a few
exceptions,
(Antilocapra amoebae
in the
genus Entamoeba are parasitic organisms found inhabiting various sites in the alimentary tracts of vertebrate hosts. Entamoeba spp. are commonly separated into four groups based on structure of trophozoites and cysts with emphasis placed on nuclear and endosomal structure and the number veloped
of nuclei cyst: four
of the
histolytica-group;
found nuclei
in the
cysts
of the coli-group; cysts are not known for the gingivalis-group; amoebae with uninucleated cysts are placed in the bovisgroup of Entamoebae. Many species with uninucleated cysts from cattle, goats, sheep, swine, deer, antelope, pronghorn and other hosts have been described although morphological differentiation of species from these hosts often is not possible (Noble and species distinct,
Noble, 1952; Levine, have been described the primary criterion
vine,
ginianus)
(1953) from
reported an three captive
necropsied
zoites
of E. coli
to 25 tim; to 19 tm. white-tailed
species have (Le-
amoeba pronghorns
aban-
at
the
Southeastern
live captive white-tailed deer at that institution. On morphological grounds, Kingston and Stabler (1978) identified these amoebae as E. coli and E. bovis. Trophomeasured
re-
(Kingston, Pratt 50
17 to 32
by
15
octonucleate cysts measured 12 Trophozoites of E. bovis from deer measured 6 to 15 by 6
to 12 tim; uninucleate 11 .tm. Macroscopic were not associated
1973).
Noble covered
now
Cooperative Wildlife Disease Study (Athens, Georgia, USA) and similar amoebae were subsequently found in soft stools from
1973). When and named as has been a
presumed host specificity. All of the in the bovis-group of Entamoebae been considered to be non-pathogenic
at the
of cattle, E. ovis of sheep, E. polecki of goats or E. suis of swine. Two species of amoebae were recovered from the rectal contents of a diarrheic white-tailed deer fawn (Odocoileus vir-
in the fully deare found in cysts eight
americana)
doned Jackson Hole Wildlife Park near Moran, Wyoming (USA). Primarily based on the host, he designated the form from pronghorn as a new species and named it Entamoeba antilocaprae although he conceded the fact that the new species could not be distinguished readily from E. bovis
et
1981). a!. (1979)
cysts measured 6 to or microscopic lesions with these amoebae described
amoebae
KINGSTON
morphologically identical with E. bovis from the ceca of 13 of 14 captive elk (Cervus elaphus nelsoni) from the Sybille Wildlife Research Unit (Wyoming Game and Fish Department, ming, USA). Trophozoites sured
5 to
sured
2
14 by to
measured measured
Wheatland, from
4 to
5
10 /Lm;
zm.
were
Amoebae rheic feces
nuclei
mea-
Uninucleate
6 to 10 tm; 2 to 3 m.
to amoebae
Wyomea-
elk
nuclei Lesions
not
cysts
in these cysts attributable
seen
in these
elk.
were recovered from the diarof a moose (Alces alces) at the
Sybille Wildlife were considered
Research conspecific
Unit
in 1977 and with E. bovis.
Uninucleate cysts measured diameter and nuclei measured The moose died some time recovering from the chronic
5 to 11 tm in 2 to 5 m. later without diarrhea, and
amoebae were present in the feces time of death. There was no evidence the amoeba infection was involved diarrheic episodes and examination sues from in parenteral host record
the
moose revealed no amoebae sites. Moose constitute a new for E. bovis.
Intermittent horn
diarrhea
fawns
used
of leptospirosis bille Wildlife 1982.
was
in
Herein,
the
seen
recovery
and
at the Sy1981 and description
from these pronghorns changes associated
parasites
are
and with
fawns
were
IN PRONGHORN
housed
51
in contact
and the in isolation.
with
remaining fawns The presence of
amoebae in pronghorn was not correlated with experimental group; in the remainder of this report animals are discussed without reference to the leptospirosis study. Feces were examined in saline or iodine wetmount preparations by light and phase contrast microscopy. Permanent preparations were wetfixed
in
with
hot
Schaudinn’s
Gomori’s
solution
trichrome
or
and
iron
stained
hematoxylin.
Photomicrographs were made at 450 and 1,000 x magnifications of fresh and fixed specimens and measurements were made using a calibrated filar micrometer. Fawns were necropsied as soon as possible following death or euthanasia at approximately 12,
14,
15,
31
fawns
were
of
because
age
rhea; of
and
G
vision,
ileum, buffered and
in
Depending brain,
colon
(CSF),
bacteria
(Carter,
lymph
techniques
neu-
cut
of gross
bile
were
solution, and
presence
fluid standard
eye
in 10%
sections
mesenteric
by
and
Zenker’s
lung,
cultured
gland, lymph
fixed
tissue
Six
of brain,
pituitary
hematoxylin
the
and Di-
Sections
or
with
treated
USA).
10017,
animals,
paraffin,
in one
been
mesenteric
spiral
upon
liver,
occurred
gland,
formalin
stained
wk
diar-
Agricultural
kidney,
most
two
G Benzathine
killed.
cecum,
from
1981, 14
had
York
adrenal heart,
collected
m,
not
In persistent
Pfizer, New
were
liver,
nodes,
animals
(Penicillin
gland,
lung,
also
York,
pronghorn thyroid
circling
Procaine,
New
age. and
These
antibiotics
Penicillin
of
approximately
weakness
and
animals.
with
wk at
of
blindness the
33
euthanized
cerebrospinal
the these
ENTAMOEBAE
inoculated animals were maintained
embedded
studies
1985) Unit in
AL-INVASIVE
additional
tral
in prong-
experimental
(Hoffman, Research
of amoebae pathologic
at the that in the of tis-
E
or
feces,
at
5
eosin.
lesions, nodes, were
for pathogenic
1984).
documented. RESULTS
MATERIALS
The cow’s
pronghorn milk
at
found wk
as of
and
with
fresh
smooth
eight and sp.)
ta),
and
mix
and
dried and
fresh
other
water. in
11 fawns
the
were
ra interrogans
serovar
of
leptospira
BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder.
BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research.
of Wildlife
Journal
INVASIVE
ENTAMOEBAE
(ANTILOCAPRA FROM
Diseases, 26(1). © Wildlife Disease
1990,
pp.
Association
50-54 1990
IN PRONGHORN
AMERICANA)
WYOMING
Newton
Kingston,
Elizabeth
S. Williams,’
and E. Tom
ThomV
Department of Veterinary Sciences, College of Agriculture, University of Wyoming, Laramie, Wyoming 82070, USA 2Wyoming Game and Fish Department Research Laboratory, Box 3312 University Station, Laramie, Wyoming 82071, USA Trophozoites and cysts of an amoeba resembling Entamoeba bovis were recovered from soft stools of captive pronghorn fawns (Antilocapra americana). Chronic or intermittent diarrhea was observed in most individuals in two groups of hand-raised 1- to 8-mo-old pronghorns. Ileocecal lymph nodes were mildly to moderately enlarged. Microscopic lesions were characterized by lymphoid hyperplasia, focal necrosis and pyogranulomatous inflammation in lymph nodes and focal necrosis and diffuse nonsuppurative enteritis in ileum and cecum. In 12 of 17 fawns, trophic stages of amoebae were observed in the submucosa of the cecum and/or the cortex of the ileocecal lymph node. This is the first report of E. bovis-like organisms invading and causing pathological changes in the tissues of their host. Key words: Pronghorn fawns, Antilocapra americana, Entamoeba sp., case report, diffuse nonsuppurative enteritis, ileum and cecum. ABSTRACT:
INTRODUCTION
With
a few
exceptions,
(Antilocapra amoebae
in the
genus Entamoeba are parasitic organisms found inhabiting various sites in the alimentary tracts of vertebrate hosts. Entamoeba spp. are commonly separated into four groups based on structure of trophozoites and cysts with emphasis placed on nuclear and endosomal structure and the number veloped
of nuclei cyst: four
of the
histolytica-group;
found nuclei
in the
cysts
of the coli-group; cysts are not known for the gingivalis-group; amoebae with uninucleated cysts are placed in the bovisgroup of Entamoebae. Many species with uninucleated cysts from cattle, goats, sheep, swine, deer, antelope, pronghorn and other hosts have been described although morphological differentiation of species from these hosts often is not possible (Noble and species distinct,
Noble, 1952; Levine, have been described the primary criterion
vine,
ginianus)
(1953) from
reported an three captive
necropsied
zoites
of E. coli
to 25 tim; to 19 tm. white-tailed
species have (Le-
amoeba pronghorns
aban-
at
the
Southeastern
live captive white-tailed deer at that institution. On morphological grounds, Kingston and Stabler (1978) identified these amoebae as E. coli and E. bovis. Trophomeasured
re-
(Kingston, Pratt 50
17 to 32
by
15
octonucleate cysts measured 12 Trophozoites of E. bovis from deer measured 6 to 15 by 6
to 12 tim; uninucleate 11 .tm. Macroscopic were not associated
1973).
Noble covered
now
Cooperative Wildlife Disease Study (Athens, Georgia, USA) and similar amoebae were subsequently found in soft stools from
1973). When and named as has been a
presumed host specificity. All of the in the bovis-group of Entamoebae been considered to be non-pathogenic
at the
of cattle, E. ovis of sheep, E. polecki of goats or E. suis of swine. Two species of amoebae were recovered from the rectal contents of a diarrheic white-tailed deer fawn (Odocoileus vir-
in the fully deare found in cysts eight
americana)
doned Jackson Hole Wildlife Park near Moran, Wyoming (USA). Primarily based on the host, he designated the form from pronghorn as a new species and named it Entamoeba antilocaprae although he conceded the fact that the new species could not be distinguished readily from E. bovis
et
1981). a!. (1979)
cysts measured 6 to or microscopic lesions with these amoebae described
amoebae
KINGSTON
morphologically identical with E. bovis from the ceca of 13 of 14 captive elk (Cervus elaphus nelsoni) from the Sybille Wildlife Research Unit (Wyoming Game and Fish Department, ming, USA). Trophozoites sured
5 to
sured
2
14 by to
measured measured
Wheatland, from
4 to
5
10 /Lm;
zm.
were
Amoebae rheic feces
nuclei
mea-
Uninucleate
6 to 10 tm; 2 to 3 m.
to amoebae
Wyomea-
elk
nuclei Lesions
not
cysts
in these cysts attributable
seen
in these
elk.
were recovered from the diarof a moose (Alces alces) at the
Sybille Wildlife were considered
Research conspecific
Unit
in 1977 and with E. bovis.
Uninucleate cysts measured diameter and nuclei measured The moose died some time recovering from the chronic
5 to 11 tm in 2 to 5 m. later without diarrhea, and
amoebae were present in the feces time of death. There was no evidence the amoeba infection was involved diarrheic episodes and examination sues from in parenteral host record
the
moose revealed no amoebae sites. Moose constitute a new for E. bovis.
Intermittent horn
diarrhea
fawns
used
of leptospirosis bille Wildlife 1982.
was
in
Herein,
the
seen
recovery
and
at the Sy1981 and description
from these pronghorns changes associated
parasites
are
and with
fawns
were
IN PRONGHORN
housed
51
in contact
and the in isolation.
with
remaining fawns The presence of
amoebae in pronghorn was not correlated with experimental group; in the remainder of this report animals are discussed without reference to the leptospirosis study. Feces were examined in saline or iodine wetmount preparations by light and phase contrast microscopy. Permanent preparations were wetfixed
in
with
hot
Schaudinn’s
Gomori’s
solution
trichrome
or
and
iron
stained
hematoxylin.
Photomicrographs were made at 450 and 1,000 x magnifications of fresh and fixed specimens and measurements were made using a calibrated filar micrometer. Fawns were necropsied as soon as possible following death or euthanasia at approximately 12,
14,
15,
31
fawns
were
of
because
age
rhea; of
and
G
vision,
ileum, buffered and
in
Depending brain,
colon
(CSF),
bacteria
(Carter,
lymph
techniques
neu-
cut
of gross
bile
were
solution, and
presence
fluid standard
eye
in 10%
sections
mesenteric
by
and
Zenker’s
lung,
cultured
gland, lymph
fixed
tissue
Six
of brain,
pituitary
hematoxylin
the
and Di-
Sections
or
with
treated
USA).
10017,
animals,
paraffin,
in one
been
mesenteric
spiral
upon
liver,
occurred
gland,
formalin
stained
wk
diar-
Agricultural
kidney,
most
two
G Benzathine
killed.
cecum,
from
1981, 14
had
York
adrenal heart,
collected
m,
not
In persistent
Pfizer, New
were
liver,
nodes,
animals
(Penicillin
gland,
lung,
also
York,
pronghorn thyroid
circling
Procaine,
New
age. and
These
antibiotics
Penicillin
of
approximately
weakness
and
animals.
with
wk at
of
blindness the
33
euthanized
cerebrospinal
the these
ENTAMOEBAE
inoculated animals were maintained
embedded
studies
1985) Unit in
AL-INVASIVE
additional
tral
in prong-
experimental
(Hoffman, Research
of amoebae pathologic
at the that in the of tis-
E
or
feces,
at
5
eosin.
lesions, nodes, were
for pathogenic
1984).
documented. RESULTS
MATERIALS
The cow’s
pronghorn milk
at
found wk
as of
and
with
fresh
smooth
eight and sp.)
ta),
and
mix
and
dried and
fresh
other
water. in
11 fawns
the
were
ra interrogans
serovar
of
leptospira
