Biology and Identification of the Coccidia (Apicomplexa) of Turtles of the World (eBook)

Donald W. Duszynski, Johnica J. Morrow (Autoren)

eBook Download: PDF | EPUB

2014 | 1. Auflage
222 Seiten
Elsevier Science (Verlag)
978-0-12-801455-4 (ISBN)

Infos

The Biology and Identification of the Coccidia (Apicomplexa) of Turtles of the World is an invaluable resource for researchers in protozoology, coccidia, and parasitology, veterinary sciences, animal sciences, zoology, and biology. This first-of-its-kind work offers a taxonomic guide to apicomplexan parasites of turtles that enables easy parasite identification, with a summary of virtually everything known about the biology of each known parasite species. It is an important documentation of this specific area, useful to a broad base of readers, including researchers in biology, parasitology, animal husbandry, diseases of wild and domestic animals, veterinary medicine, and faculty members in universities with graduate programs in these areas. There are about 330 turtle species on Earth; many are endangered, a growing number of species are kept as pets, and some are still used as food by humans. Turtles, like other vertebrate animals have many different kinds of parasites (viruses, bacteria, protozoa, worms, arthropods, and others). Coccidiosis in turtles has prevented large-scale turtle breeding, and represents a serious problem in need of control. This succinct and highly focused book will aid in that effort. - Offers line drawings and photomicrographs of each parasite from each hosts species - Provides methods of identification and treatment - Presents a complete historical rendition of all known publications on coccidia (and their closest relatives) from all turtle species on Earth, and evaluates the scientific and scholarly merit of each - Provides a complete species analysis of the known biology of every coccidian described from turtles - Reviews the most current taxonomy of turtles and their phylogenetic relationships needed to help assess host-specificity and evaluate what little cross-transmission work is available

Dr. Duszynski, is Professor Emeritus Biology and past Chair of the Department of Biology, The University of New Mexico (UNM). He spent 33 years in academia, publishing numerous articles, monographs, and books, secured private, state and federal grants exceeding $8 million, and mentored > 25 masters and doctoral students and numerous undergraduates in his laboratory, before spending 8 years in administration. During his 41 year tenure at UNM, he taught many courses including parasitology, tropical biology and marine invertebrate biology, and took >1000 students to the neotropics (Belize, Jamaica, Mexico). Don has been a Visiting Research Associate Professor, Department of Physiology & Biochemistry, University of Texas Health Science Center, Houston, a Visiting Associate Professor, Department of Microbiology, University of Texas Medical Branch, Galveston, and Visiting Research Scholar, Kyoto University, Japan. Among the honors received are the Distinguished Service Award and the Clark P. Read Mentor Award from the American Society of Parasitologists (ASP), and the Distinguished Alumnus Award from the Department of Biology, Colorado State University.

Inhalt

Front Cover 1
The Biology and Identification of the Coccidia (Apicomplexa) of Turtles of the World 4
Copyright Page 5
Dedication 6
Table of Contents 8
Preface and Acknowledgments 12
1 Introduction 14
Turtles Are Food, Pets, Lab Animals, and Majestic Creatures 14
Coccidia in Turtles: Perpetrators, Symptoms, and Disease 16
2 Suborder Cryptodira, Hidden-Necked Turtles 20
Family Chelydridae, Snapping Turtles, 2 Genera, 4 Species 20
Genus Chelydra Schweigger, 1812 (3 Species) 20
Eimeria chelydrae Ernst, Stewart, Sampson, & Fincher, 1969
Eimeria filamentifera Wacha & Christiansen, 1979a
Eimeria serpentina McAllister, Upton, & Trauth, 1990b
Isospora chelydrae McAllister, Upton, & Trauth, 1990b
Genus Macrochelys Gray, 1856 (Monospecific) 27
Eimeria harlani Upton, McAllister, & Trauth, 1992
Superfamily Testudinoidea 29
Family Emydidae, Pond, Box, Water Turtles, 11 Genera, 50 Species 29
Genus Chrysemys Gray, 1844 (Monospecific) 29
Eimeria chrysemydis Deeds & Jahn, 1939
Eimeria marginata (Deeds & Jahn, 1939) Pellérdy, 1974
Eimeria tetradacrutata Wacha & Christiansen, 1976
Genus Clemmys Ritgen, 1828 (Monospecific) 35
Genus Deirochelys Latreille, 1801 (Monospecific) 35
Genus Emydoidea Holbrook, 1838 (Monospecific) 35
Genus Emys Duméril,1805 (3 Species) 35
Eimeria delagei (Labbé, 1893) Reichenow, 1921 35
Eimeria emydis Segade, Crespo, Ayres, Cordero, Arias, García–Estévez, Iglesias, & Blanco, 2006
Eimeria gallaeciaensis Segade, Crespo, Ayres, Cordero, Arias, García–Estévez, Iglesias, & Blanco, 2006
Genus Glyptemys Agassiz, 1857 (2 Species) 40
Eimeria lecontei Upton, McAllister, & Garrett, 1995
Eimeria megalostiedae Wacha & Christiansen, 1974
Genus Graptemys Agassiz, 1857 (13 Species) 44
Eimeria graptemydos Wacha & Christiansen, 1976
Eimeria juniataensis Pluto & Rothenbacher, 1976
Eimeria pseudogeographica Wacha & Christiansen, 1976
Genus Malaclemys Gray, 1844 (Monospecific) 50
Genus Pseudemys Gray, 1856 (8 Species) 50
Eimeria cooteri McAllister & Upton, 1989
Eimeria somervellensis McAllister & Upton, 1992
Eimeria texana McAllister & Upton, 1989b
Genus Terrapene Merrem, 1820 (4 Species) 56
Eimeria carri Ernst & Forrester, 1973
Eimeria ornata McAllister & Upton, 1989a
Genus Trachemys Agassiz, 1857 (15 Species) 60
Eimeria pseudemydis Lainson, 1968 60
Eimeria scriptae Sampson & Ernst, 1969
Eimeria stylosa McAllister & Upton, 1989b
Eimeria trachemydis McAllister & Upton, 1988
Family Testudinidae, Tortoises, 15 Genera, 57 Species 68
Genus Aldabrachelys Loveridge and Williams, 1957 (3 Species) 68
Genus Astrochelys Gray, 1873 (2 Species) 68
Genus Chelonoidis Fitzgerald, 1835 (13 Species) 69
Eimeria amazonensis Lainson, Da Silva, Franco, & De Souza, 2008
Eimeria carajasensis Lainson, Da Silva, Franco, & De Souza, 2008
Eimeria carbonaria Lainson, Da Silva, Franco, & De Souza, 2008
Eimeria geochelona Couch, Stone, Duszynski, Snell, & Snell, 1996
Eimeria iversoni McAllister, Duszynski, & Roberts, 2014
Eimeria jaboti (Carini, 1942) 79
Eimeria lainsoni (Lainson et al., 1990) Hurková, Modrý, Koudela, & Šlapeta, 2000
Eimeria motelo Hurková, Modrý, Koudela, & Šlapeta, 2000
Eimeria welcomei Lainson, Da Silva, Franco, & De Souza, 2008
Isospora rodriguesae Lainson, Da Silva, Franco, & De Souza, 2008
Genus Chersina Schweigger, 1812 (Monospecific) 88
Genus Geochelone Fitzinger, 1835 (3 Species) 88
Genus Gopherus Rafinesque, 1832 (5 Species) 89
Eimeria paynei Ernst, Fincher, & Stewart, 1971
Genus Homopus Walbaum, 1782 (5 Species) 90
Genus Indotestudo Schlegel & Müller, 1844 (3 Species)
Genus Kinixys Schweigger, 1812 (8 Species) 91
Genus Malacochersus Siebenrock, 1903 (Monospecific) 91
Genus Manouria Schlegel & Müller, 1844 (2 Species)
Genus Psammobates Linnaeus, 1758 (3 Species) 91
Genus Pyxis Bell, 1827 (2 Species) 91
Genus Stigmochelys Gray, 1873 (Monospecific) 91
Genus Testudo Linnaeus, 1758 (5 Species) 92
Eimeria brodeni Cerruti, 1930 92
Isospora testudae Davronov, 1985 93
Family Geoemydidae (Bataguridae) Asian River, Leaf & Roofed, &
Genus Batagur Gray, 1856 (6 Species) 95
Eimeria zbatagura Široky & Modrý, 2010
Genus Cuora Gray, 1856 (13 Species) 96
Eimeria hynekprokopi Široky & Modrý, 2010
Genus Cyclemys Bell, 1834 (7 Species) 98
Eimeria palawanensis Široky & Modrý, 2010
Eimeria petrasi Široky & Modrý, 2010
Genus Geoclemys Gray, 1831 (Monospecific) 101
Genus Geoemyda Gmelin, 1789 (2 Species) 101
Genus Hardella Gray, 1831 (Monospecific) 101
Genus Heosemys Gray, 1831 (4 Species) 101
Eimeria arakanensis Široky & Modrý, 2006
Genus Leucocephalon McCord, Iverson, & Boeadi, 1995 (Monospecific)
Genus Malayemys Lindholm, 1931 (2 Species) 103
Eimeria surinensis Široky & Modrý, 2010
Genus Mauremys Gray, 1869 (9 Species) 105
Eimeria mitraria (Laveran & Mesnil, 1902) Doflein, 1909
Genus Melanochelys Gray, 1834 (2 Species) 109
Eimeria patta Široky & Modrý, 2005
Genus Morenia Duméril & Bibron, 1835 (2 Species)
Genus Notochelys Gray, 1834 (Monospecific) 111
Genus Orlitia Gray, 1873 (Monospecific) 111
Genus Pangshura Gray, 1831 (4 Species) 111
Eimeria pangshurae Široky & Modrý, 2010
Eimeria kachua Široky & Modrý, 2005
Genus Rhinoclemmys Fitzinger, 1835 (9 Species) 115
Genus Sacalia Gray, 1870 (2 Species) 115
Genus Siebenrockiella Lindholm, 1929 (2 Species) 115
Genus Vijayachelys Henderson, 1912 (Monospecific) 115
Family Platysternidae, Big-Headed Turtles, 1 Genus, Monotypic 115
Genus Platysternon Gray, 1831 (Monospecific) 115
Superfamily Trionychoidea 115
Family Carettochelyidae, Pignose Turtles, 1 Genus, Monotypic 115
Genus Carettochelys Ramsay, 1886 (Monospecific) 115
Family Trionychidae, Softshell Turtles, 13 Genera, 30 Species 116
Genus Amyda Saint-Hilaire, 1809 (Monospecific) 116
Genus Apalone Rafinesque, 1832 (3 Species) 116
Eimeria amydae Roudabush, 1937 116
Eimeria apalone McAllister, Upton, & McCaskill, 1990a
Eimeria dericksoni Roudabush, 1937 120
Eimeria mascoutini Wacha & Christiansen, 1976
Eimeria pallidus McAllister, Upton, & McCaskill, 1990a
Eimeria spinifera McAllister, Upton, & McCaskill, 1990a
Eimeria vesticostieda Wacha & Christiansen, 1977
Genus Chitra Gray, 1831 (3 Species) 129
Genus Cyclanorbis Gray, 1854 (2 Species) 129
Genus Cycloderma Peters, 1854 (2 Species) 129
Genus Dogania Gray, 1844 (Monospecific) 129
Genus Lissemys (Gray, 1831) Smith, 1931 (2 Species) 130
Eimeria innominata Kar, 1944 130
Eimeria irregularis Kar, 1944 131
Eimeria koormae Das Gupta, 1938a, b 132
Eimeria légeri (Simond, 1901) Reichenow, 1921 134
Genus Nilssonia Gray, 1831 (5 Species) 135
Eimeria triangularis Chakravarty & Kar, 1943
Eimeria trionyxae Chakravarty & Kar, 1943
Genus Palea Meylan, 1987 (Monospecific) 139
Genus Pelochelys Gray, 1864 (3 Species) 139
Genus Pelodiscus Fitzinger, 1835 (4 Species) 139
Genus Rafetus Daudin, 1802 (2 Species) 139
Genus Trionyx Saint-Hilaire, 1809 (Monospecific) 139
Superfamily Kinosternoidea 139
Family Dermatemydidae, River Turtles, 1 Genus, Monotypic 139
Genus Dermatemys Gray, 1847 (Monospecific) 139
Family Kinosternidae, Mud & Musk Turtles, 4 Genera, 25 Species
Genus Claudius Cope, 1865 (Monospecific) 140
Genus Kinosternon Spix, 1824 (18 Species) 140
Eimeria lutotestudinis Wacha & Christiansen, 1976
Genus Staurotypus Wagler, 1830 (2 Species) 142
Genus Sternotherus Gray, 1825 (4 Species) 142
Superfamily Chelonioidea 142
Family Cheloniidae, Sea Turtles, 5 Genera, 6 Species 142
Genus Caretta Rafinesque, 1814 (Monospecific) 142
Eimeria caretta Upton, Odell, & Walsh, 1990
Genus Chelonia Brongniart, 1800 (Monospecific) 144
Caryospora cheloniae Leibovitz, Rebell, & Boucher, 1978
Genus Eretmochelys Linnaeus, 1766 (Monospecific) 149
Genus Lepidochelys Fitzinger, 1843 (2 Species) 149
Genus Natator McCulloch, 1908 (Monospecific) 149
Family Dermochelyidae, Leatherback Turtles, 1 Genus, Monotypic 149
Genus Dermochelys Blainville, 1816 (Monospecific) 149
Discussion and Summary 149
Coccidia and Coccidiosis in Cryptodira 150
Endogenous Development 152
Treatment and Prevention 153
Host Specificity in Cryptodira Coccidia 153
Prevalence of Eimerians in Cryptodira 154
Archiving Biological Specimens for Future Study 155
3 Suborder Pleurodira, Side-Necked Turtles 158
Family Chelidae, Austro-American Sideneck Turtles, 14 genera, 52 species 158
Genus Acanthochelys Gray, 1873 (4 Species) 158
Genus Chelodina Fitzinger, 1826 (12 Species) 158
Genus Chelus Schneider, 1783 (Monospecific) 159
Genus Elseya Gray, 1867 (5 Species) 159
Genus Elusor Cann & Legler, 1994 (Monospecific)
Genus Emydura Bonaparte, 1836 (4 Species) 159
Genus Hydromedusa Wagler, 1830 (2 Species) 159
Genus Mesoclemmys Gray, 1873 (10 Species) 159
Eimeria jirkamoraveci Široký et al. (2006a) 159
Genus Myuchelys Thomson & Georges, 2009 (5 Species)
Genus Phrynops Wagler, 1830 (4 Species) 161
Genus Platemys Schneider, 1792 (Monospecific) 161
Genus Pseudemydura Siebenrock, 1901 (Monospecific) 161
Genus Rheodytes Legler & Cann, 1980 (Monospecific)
Genus Rhinemys Wagler, 1830 (Monospecific) 161
Superfamily Pelomedusoidea 161
Family Pelomedusidae, Afro-American Sideneck Turtles, 2 Genera, 19 Species 161
Genus Pelomedusa Lacépède, 1788 (Monospecific) 161
Eimeria lokuma Široký et al. (2006b) 161
Genus Pelusios Wagler, 1830 (18 Species) 163
Family Podocnemididae, Madagascan Big Headed, and American Sideneck River Turtles, 3 Genera, 8 Species 163
Genus Erymnochelys Grandidier, 1867 (Monospecific) 163
Genus Peltocephalus Duméril & Bibron, 1835 (Monospecific)
Eimeria peltocephali Lainson & Naiff (1998)
Genus Podocnemis Wagler, 1830 (6 Species) 165
Eimeria lagunculata Lainson et al. (1990) 165
Eimeria mammiformis Lainson et al. (1990) 168
Eimeria podocnemis Lainson et al. (1990) 170
Discussion and Summary 171
4 Cryptosporidium, Sarcocystis, Toxoplasma in Turtles 174
Cryptosporidium in Turtles 174
Sarcocystis in Turtles 176
Sarcocystis kinosterni Lainson & Shaw, 1972
Toxoplasma in Turtles 177
5 Species Inquirendae in Turtles 180
Species Inquirendae (28) 180
Coccidium sp. of Jacobson et al., 1994 180
Coccidium sp. of Garner et al., 1998 180
Coccidium sp. of Garner et al., 2006 181
Coccidium sp. of Innis et al., 2007 182
Caryospora sp. of Greiner, 2003 182
Cryptosporidium sp. of Bourdeau, 1988, 1989 183
Cryptosporidium sp. of Funk, 1987 183
Cryptosporidium sp. 1 of Graczyk & Cranfield, 1998
Cryptosporidium sp. 2 of Graczyk & Cranfield, 1998
Cryptosporidium sp. of Graczyk et al., 1997 184
Cryptosporidium sp. of Graczyk et al., 1998 184
Cryptosporidium sp. of Häfeli & Zwart, 2000
Cryptosporidium sp. of Heuschele et al., 1986 185
Cryptosporidium sp. of Xiao et al., 2004 185
Eimeria sp. of Bone, 1975 vide Wacha & Christiansen, 1976
Eimeria sp. of McAllister et al., 1994 186
Eimeria sp. of Wacha & Christiansen, 1976
Eimeria sp. 1 of Wacha & Christiansen, 1980
Eimeria sp. 2 of Wacha & Christiansen, 1980
Mantonella hammondi Wacha & Christiansen, 1974b
Sarcocystis sp. of Keymer, 1978a 188
Sarcocystis sp. of Keymer, 1978b 188
Sarcocystis spp. of Meshkov, 1975 189
Sarcocystis sp. 1 of Weishaar et al., 1988 189
Sarcocystis sp. 2 of Weishaar et al., 1988 189
Sarcocystis sp. 3 of Weishaar et al., 1988 189
Sarcocystis sp. 4 of Weishaar et al., 1988 190
Sarcocystis sp. 5 of Weishaar et al., 1988 190
6 Discussion and Summary 192
Biodiversity 192
Variety of Oocyst Structures and Shape 193
Host Specificity 195
Pathology 196
Epidemiology 197
Treatment and Control 198
Archiving Biological Specimens 199
Closing Remarks 200
Tables 202
Literature Cited 216

Textauszug

Chapter 1

Introduction

This chapter notes the importance of turtles in the lives of humans (food, lab animals, and pets) and the majestic nature of these slow moving creatures as denizens of our earthly environment. It briefly discusses the physical features of turtles, their habitats, and how to distinguish between the two major groups (suborders) of extant turtles. We mention various ways in which humans have used and continue to use turtles and note that at least 50% of all turtle taxa may be nearing the brink of extinction. We identify and discuss the three protist families and five of their genera that are found most commonly in turtles; these include: Eimeriidae (Eimeria, Isospora, Caryospora spp.), Sarcocystidae (Sarcocystis spp.), and Cryptosporididae (Cryptosporidium sp.). The general biology, life cycles, and morphology of the stages used in identification of these groups are discussed. Finally, we mention that the order Testudines (turtles) consists of 2 suborders, 14 families with 92 genera that comprise 328 species. Coccidia have been described from 10 of the 14 (71%) families, 32 of the 92 (35%) genera, and only 64 of the 328 (19.5%) turtle species.

Keywords

Turtles; food; pets; lab animals; coccidia; species; taxonomy; systematics; epidemiology of disease; Eimeria; Isospora; Caryospora; Sarcocystis; Cryptosporidium

This treatise on coccidia species known from turtles has several predecessors including, The Coccidia of Snakes of the World (Duszynski & Upton, 2009) and The Biology and Identification of the Coccidia of Rabbits of the World (Duszynski & Couch, 2013). Like the others, it is intended to be the most comprehensive discourse, to date, describing the structural and biological knowledge of all coccidian parasites that infect turtles. These protists (Phylum Apicomplexa) seem relatively common in turtles and are represented by about 71 species that fit taxonomically into five genera in three families that include Cryptosporidiidae Léger, 1911 (Cryptosporidium), Eimeriidae Minchin, 1903 (Caryospora, Eimeria, Isospora), and Sarcocystidae Poche, 1913 (Sarcocystis). An overview of the general biology, taxonomy, life cycles, and numbers of species of eimeriid and cryptosporid coccidia from wild mammals was published a decade ago (Duszynski & Upton, 2001), and monographic works on the coccidia of certain selected vertebrate groups also are available including: Amphibia (Duszynski et al., 2007); Chiroptera (Duszynski, 2002); Insectivora (Duszynski & Upton, 2000); Marmotine squirrels (Rodentia) (Wilber et al., 1998); and Primates and Scandentia (Duszynski et al., 1999). No such review exists for the coccidia of turtles. Here we strive to resolve that void because turtles have a long and important history shared with humans and many (>50%) of their extant species are threatened with extinction as human populations continue to increase on Earth.

Turtles are Food, Pets, Lab Animals, and Majestic Creatures

Almost everyone can recognize turtles because of their shells. These are remarkable and distinguishing structures that enclose the body of the entire animal in a bony case that only opens at the front and the rear. The shell, of course, helps to protect them from natural enemies, but it also has limited their morphological diversity; there are terrestrial and aquatic turtles, but no turtles can climb (arboreal) or fly.

The habits of turtles often may be deduced by the appearance of their shells. Terrestrial turtles (e.g., tortoises and box turtles) generally have high, domed shells and stout limbs, whereas aquatic turtles usually have relatively flat shells (for less resistance in water) and webbed feet. However, some aquatic forms (e.g., mud and musk turtles) spend more time walking on the bottom than they do swimming, and these may have more distinct dome-shaped shells than those that swim quickly to capture prey and avoid predation. Other aquatic turtles have even more specialized soft shells that lack a bony layer, while still others have greatly reduced dermal bones and the stiff dermal scales, which have been replaced by a flexible covering of skin (Pough et al., 2004).

Sometimes the term Testudines is used by biologists to encompass all turtles, including both their extinct ancestors and the two major groups of living (extant) turtles (Cryptodira and Pleurodira) and their descendants. The term Chelonia is widely used for the extant clades only. All extant turtles belong to one of these two groups (clades) that are taxonomically referred to as suborders. The Cryptodira and the Pleurodira are distinguished from each other by the way they retract their necks. Turtles placed into the Cryptodira retract their neck in a vertical plane, whereas members of the Pleurodira (side-necked turtles) retract their necks in a horizontal or sideway plane. Nonetheless, because of the many unique structural features (shell, skeleton, skull bones, others), the monophyly of turtles has never been in serious question by herpetologists (Pough et al., 2004).

Turtles and humans share a long association, with the former being used as gourmet food, as subjects in both oriental and traditional medicine and contemporary medical research, their fat as a base for cosmetics, their shells as jewelry and, of course, millions of humans have them as pets. There are currently 328 distinct turtle species recognized by herpetologists. However, the number of turtle taxa becomes more complex because 56 of those species are polytypic (have more than one immediately subordinate taxon), which introduces 124 additional recognized subspecies (Rhodin et al., 2010). Thus, herpetologists now recognize 452 taxa of modern tortoises and turtles, of which 10 taxa (8 species, 2 subspecies) are now considered extinct. In their 2010 update on turtles of the world, Rhodin et al. (2010) listed 156 of the 328 species (48%) as Threatened, with 90 (27%) as Critically Endangered or Endangered on the International Union for the Conservations of Nature (IUCN) Red List. When they included Extinct-in-the-Wild and Extinct species, their data suggested that at least 50% of all modern turtle and tortoise species either are already extinct or threatened with extinction. In other words, turtles are threatened with extinction at a much higher risk than almost all other vertebrate species. The threats that turtles face include, but are not limited to, long-term unsustainable exploitation, habitat destruction, overharvesting for consumption, and the international pet trade.

Coccidia in Turtles: Perpetrators, Symptoms, and Disease

This review primarily is concerned with the eimeriid coccidia found in turtles, but mention also will be made of genera and species in two other protist families, Sarcocystidae (Sarcocystis, Toxoplasma spp.) and Cryptosporididae (Cryptosporidium sp.). All species in these genera are single-celled, intracellular, eukaryotic parasites (Protozoa: Apicomplexa) that pass a highly resistant propagule, the oocyst, in the feces of their definitive host. Most of these parasites develop in the epithelial cells of the gastrointestinal tract, but a few develop in other tissues and organs. Their life cycles are complex and include both asexual reproduction (merogony), which can produce extremely high numbers of individuals, and sexual reproduction (gamogony) that allows genetic recombination. After fertilization takes place and oocyst wall formation and development is completed, the oocyst leaves the host epithelial cell, destroying it, and usually (but not always) needs a period of time outside the host to undergo its final developmental process, sporogony. After sporogony, the oocyst becomes infective to the next host that may encounter this stage and ingest it.

The majority of the species summarized in our review are in the Eimeriidae (Eimeria, Isospora, Caryospora spp.). As best we know, all of these parasites are homoxenous in their development; that is, they have a single host, direct (host-to-host) life cycle. Cryptosporidium species also have direct life cycles, but Sarcocystis species are heteroxenous in that they require two hosts, a definitive host that discharges the oocysts, and an intermediate host that contains infective tissue stages/cysts that must be eaten by the definitive host to complete the life cycle. Toxoplasma species can be either homoxenous (only in felids) or heteroxenous in their development. Even though their intracellular development kills their hosts’ epithelial or endothelial cells, most coccidia are considered nonpathogenic; however, as we will learn in the following chapters, we know so little about the complete development and life cycles of the majority of known species, that we really don’t know what levels of pathogenicity may exist in turtle coccidia. Still, there are exceptions to these gaps in our understanding, as noted in later chapters.

The most distinguishing feature of the coccidian life cycle that allows diagnosis, for example, by a veterinarian, is the structure of the sporulated oocyst; oocysts of most coccidians (e.g., Caryospora, Eimeria, Isospora, Toxoplasma spp.) leave their host unsporulated and need molecular oxygen and usually a temperature different than the body temperature of their host to undergo sporulation. A few, however, like the Cryptosporidium and Sarcocystis species, have completely sporulated oocysts and/or sporocysts that leave their host in its feces. In the...

Produkt-Details

• Erscheint lt. Verlag: 4.8.2014
• Sprache: englisch
• Themenwelt: Medizin / Pharmazie
• Themenwelt: Naturwissenschaften ► Biologie ► Mikrobiologie / Immunologie
• Themenwelt: Naturwissenschaften ► Biologie ► Zoologie
• Themenwelt: Veterinärmedizin ► Klinische Fächer ► Parasitologie
• Themenwelt: Weitere Fachgebiete ► Land- / Forstwirtschaft / Fischerei
• ISBN-10: 0-12-801455-5 / 0128014555
• ISBN-13: 978-0-12-801455-4 / 9780128014554