Amphibian Coccidia: Taxonomy, Host
Specificity, Ecology, and Phylogeny.
Matthew G. Bolek, Donald W. Duszynski, and
Steve J. Upton
Department of Biology,
University of Nebraska at Kearney
Department of Biology, University of New Mexico, and Division
of Biological Sciences, Kansas State University
6,009 Extent Species of Amphibia
(Frost, 2007)
Anura
Caudata
Gymnophiona
Amphibian Coccidia
• Coccidia of frogs and toads, salamanders
and newts, and caecilians are the least
known of all the tetrapod vertebrate
classes.
Generalized Life Cycle of a Coccidian
2
3
1
Generalized Life Cycle of a Coccidian
1
Generalized Life Cycle of a Coccidian
2
Generalized Life Cycle of a Coccidian
3
The Frogs and Toads
(Anurans)
Anurans
• 5,453 extant species of frogs and toads in
395 genera and 45 families.
Anurans
• Of the 5,453 anuran species, only 1.2%
(67/5,453) of species in 7.6% (30/395) of
the genera and 31.1% (14/45) of the
families have ever been examined for
coccidia.
Anurans
• 18 species of Eimeria, 2 species of
Goussia, 1 species of Hyaloklossia and 9
species of Isospora have been described.
4X2
4X2
2X4
2X4
Anuran Coccidia World Distribution
8
7
7
4
3
*
Eimeria spp. of Anurans
Ovoidal
Irregular
Spherical
Variation in Oocyst Morphology
Stieda body
Oocyst Residium
Micropile Cap
Micropile
Variation in Endogenous Development
Extranuclear
Intranuclear
Bolek unpublished; Jirků and Modrý 2005
Variation in Sporulation
Exogenous
Endogenous
Bolek unpublished; Duszynski et al., 2007
Morphotypes of Anuran Eimeria
OR
MT 1
6
+
MT 2
4
-
MT 3
1
-
MT 4
2
-
SB
++
+
+
-
MC
-
-
+
-
Development
En
In
In
En
Sporulation
Ex
Ex
Ex
En
No. spp.
Caudatans
• 560 extant species of salamanders and
newts in 64 genera and 9 families.
Caudatans
• Of the 560 caudatan species, only 8.0%
(45/560) of species in 28.1% (18/64) of the
genera and 67% (6/9) of the families have
ever been examined for coccidia.
Caudatans
• 19 Eimeria and 2 Isospora species have
been described from the 560 described
caudatan species.
Caudatan Coccidia World Distribution
12
6
3
19 Eimeria spp. of Caudata
Elliptical
Spherical-Subspherical
Morphotypes of Caudata Eimeria
OR
MT 1
4
+
MT 2
6
-
MT 3
2
+/-
MT 4
2
-
SB
+
+
+
-
MC
-
-
+
-
Development
En
En
In
?
Sporulation
Ex
Ex
Ex
Ex
No. spp.
Gymnophionans
• 121 extant species of caecilians in 14
genera and 3 families.
Gymnophionans
• Only 1 Eimeria species has been described
from caecilians.
Eimeria dermophis Asmundsson, Campbell
and Duszynski, 2000
Host Specificity and Ecology of
Amphibian Coccidia
Host Specificity and Ecology
• Few studies exist on host specificity of coccidian
parasites of amphibians.
• Lavier (1941) was unable to infect the common
European toad with I. brumpti recovered from
the green toad.
• Anuran coccidia are genus specific; whereas
some caudatan coccidia can infect numerous
genera of salamanders in the same family.
• How do amphibians become infected with these
coccidia species?
• Examination of field collected tadpoles of western chorus frogs
indicated that they shed oocysts of Eimeria streckeri, Isospora
cogginsi and Isospora delicatus.
Prevalence of Eimeria streckeri in Adults, Tadpoles,
and Metamorphosed Western Chorus Frogs
N = 102
N = 44
N = 47 N = 45
Prevalence of Isospora cogginsi in Adults, Tadpoles,
and Metamorphosed Western Chorus Frogs
N = 102
N = 44
N = 47
N = 45
Prevalence of Isospora delicatus in Adults, Tadpoles,
and Metamorphosed Western Chorus Frogs
N = 102
N = 44
N = 47 N = 45
We collected western chorus frog eggs, brought
them into the laboratory, and reared tadpoles.
Experimental Infections
We exposed these tadpoles to coccidia
oocysts.
90% (18/20) of experimentally exposed tadpoles of western chorus
frogs shed oocysts of Isospora delicatus.
Tadpoles shed oocysts 9-10 days post exposure, and
continued shedding oocysts for 7 days, and did not
retain the infection before metamorphosis.
Sporulation: Exogenous.
Tadpole and metamorphosed frog digestive system.
Other Anuran Coccidia
• Goussia spp. only infect tadpoles and are
lost during metamorphosis, but
sporulated oocysts are found in the liver
sinuses of metamorphosed anurans.
• Hyaloklossia sp. infects tadpole and
metamorphosed anuran kidneys and
survives metamorphosis.
Salamander larvae feed on live prey in the open
water column and therefore few should be infected
with coccidia
N = 20
N = 19
N = 20
N = 14
100% (9/9) of metamorphosed tiger salamanders shed
oocysts of Eimeria ambystomae.
Conclusion
• 5,896 of the 6,009 (98%) of the amphibian species
have not been examined for coccidia parasites.
• Field data suggests that coccidia of anurans are
genus specific; whereas coccidia of caudatans are
genus or family specific.
• Goussia spp. exhibit stadial host specificity in
tadpoles, whereas Eimeria, Hyaloklossia and
Isospora species can infect larval and adult
amphibians.
• No phylogeny exist for amphibian coccidia.
Acknowledgments
• Miloslav Jirků (University of Vet & Pharm
Scie, Czech Republic)
• Dr. Armando Irizarry-Rovira (Eli Lilly and
Co.)
• Cedar Point Biological Station
• UNL School of Biological Sciences Special
Funds, Initiative for Ecological and
Evolutionary Analysis UNL, Center for Great
Plains Studies