Advances in Parasitology (eBook)

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2011 | 1. Auflage
310 Seiten
Elsevier Science (Verlag)
978-0-08-087900-0 (ISBN)

Infos

First published in 1963, Advances in Parasitology contains comprehensive and up-to-date reviews in all areas of interest in contemporary parasitology.

Advances in Parasitology includes medical studies on parasites of major influence, such as Plasmodium falciparum and trypanosomes. The series also contains reviews of more traditional areas, such as zoology, taxonomy, and life history, which shape current thinking and applications.

Eclectic volumes are supplemented by thematic volumes on various topics including Remote Sensing and Geographical Information Systems in Epidemiology and The Evolution of Parasitism--A phylogenetic persepective.

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First published in 1963, Advances in Parasitology contains comprehensive and up-to-date reviews in all areas of interest in contemporary parasitology. Advances in Parasitology includes medical studies on parasites of major influence, such as Plasmodium falciparum and trypanosomes. The series also contains reviews of more traditional areas, such as zoology, taxonomy, and life history, which shape current thinking and applications. Eclectic volumes are supplemented by thematic volumes on various topics including Remote Sensing and Geographical Information Systems in Epidemiology and The Evolution of Parasitism--A phylogenetic perspective.

Inhalt

Cover 1
Advances in Parasitology 4
Copyright Page 5
TOC$Contents 6
Contributors 8
Preface 10
Obituary 12
CH$Chapter 1: Strain Theory of Malaria: The First 50 Years 18
1. Introduction 19
2. Background 20
3. Clinical Virulence 23
4. Reaction to Anti-malarial Remedies 26
5. Infectivity 29
6. Antigenic Properties 33
7. Latency and Relapse 45
8. Summary and Discussion 50
Acknowledgments 55
References 55
CH$Chapter 2: Advances and Trends in the Molecular Systematics of Anisakid Nematodes, with Implications for their Evolutionary Ecology and Host-Parasite Co-evolutionary Processes 64
1. Introduction 66
2. Molecular Systematics of Anisakid Nematodes 68
3. The Current Taxonomy 72
4. Phylogenetic Systematics of Anisakid Nematodes 108
5. Genetic Differentiation in Anisakids 117
6. Host-Parasite Cophylogeny 125
7. Host Preference, Ecological Niche and Competition 131
8. Anisakids as Biological Indicators 136
9. Conclusions and Identification of Gaps in Our Knowledge of Anisakids to be Filled by Future Research 147
Acknowledgments 154
References 154
CH$Chapter 3: Atopic Disorders and Parasitic Infections 166
1. Introduction 167
2. Atopic Disorders 168
3. Relationship of Parasites to Atopic Disorders 171
4. Laboratory Studies on Atopy Using Selected Parasites and Rodent Models 192
5. Concluding Remarks 199
References 201
CH$Chapter 4: Heartworm Disease in Animals and Humans 210
1. Introduction (Biology and Life Cycle) 212
2. Epidemiology in Domestic and Wild Hosts 216
3. Pathogenesis, Immunology and Wolbachia Endosymbiosis 226
4. Canine Heartworm Disease 239
5. Feline Heartworm Disease 250
6. Heartworm Disease in Ferrets 270
7. Human Dirofilariosis 275
8. Emerging Strategies in Heartworm Treatment and Control 280
Acknowledgments 282
References 282
IDX$Index 304
Contents of Volumes in this Series 312
Colour Plate Section 319

Textauszug

Chapter 2

Advances and Trends in the Molecular Systematics of Anisakid Nematodes, with Implications for their Evolutionary Ecology and Host–Parasite Co-evolutionary Processes

Simonetta Mattiucci*; Giuseppe Nascetti†    * Department of Public Health Sciences, Section of Parasitology, “Sapienza”—University of Rome, P.le Aldo Moro, 5, 00185 Rome, Italy
† Department of Ecology and Sustainable Economic Development—Tuscia University—Via S. Giovanni Decollato, 1, 01100 Viterbo, Italy

Abstract

The application of molecular systematics to the anisakid nematodes of the genera Anisakis, Pseudoterranova and Contracaecum, parasites of aquatic organisms, over the last two decades, has advanced the understanding of their systematics, taxonomy, ecology and phylogeny substantially. Here the results of this effort on this group of species from the early genetic works to the current status of their revised taxonomy, ecology and evolutionary aspects are reviewed for each of three parasitic groups. It has been shown that many anisakid morphospecies of Anisakis, Contracaecum and Pseudoterranova include a certain number of sibling species. Molecular genetic markers provided a rapid, precise means to screen and identify several species that serve as definitive and intermediate and or/paratenic hosts of the so far genetically characterized species. Patterns of differential distribution of anisakid nematodes in various definitive and intermediate hosts are presented. Differences in the life history of related species can be due both to differential host–parasite co-adaptation and co-evolution, and/or to interspecific competition, that can reduce the range of potential hosts in sympatric conditions. Phylogenetic hypotheses attempted for anisakid nematodes and the possible evolutionary scenarios that have been proposed inferred from molecular data, also with respect to the phylogeny of their hosts are presented for the parasite–host associations Anisakis-cetaceans and Contracaecum-pinnipeds, showing that codivergence and host-switching events could have accompanied the evolution of these groups of parasites.

Finally, examples in which anisakid nematodes recognized genetically at the species level in definitive and intermediate/paratenic hosts from various geographical areas of the Boreal and Austral regions and their infection levels have been used as biological indicators of fish stocks and food-web integrity in areas at high versus low levels of habitat disturbance (pollution, overfishing, by-catch) are presented.

1 Introduction

Adult nematodes of the genera of most species of the anisakid nematodes Anisakis, Dujardin, 1845, Pseudoterranova Krabbe, 1878 and Contracaecum Railliet and Henry, 1913 are parasites of the alimentary tract of aquatic vertebrates. They display indirect life cycles in aquatic ecosystems and involve various hosts at different levels in food webs. Marine mammals (cetaceans and pinnipeds) and fish-eating birds serve as definitive hosts; fish, squids and other invertebrates serve as intermediate or paratenic hosts; and crustaceans serve as first intermediate hosts. In humans, several larval anisakid nematodes cause the zoonotic disease, presently known as ‘anisakidosis’ or ‘anisakiosis’, when consumed in raw or undercooked fish. Anisakis is considered as the most important anisakid genus with regard to human infection (Audicana et al., 2002, and references therein), but some species of Pseudoterranova also have been implicated in human infections (Adams et al., 1997; Oshima, 1987), and a few species of Contracaecum are potentially infective (Vidal-Martinez et al., 1994). This zoonosis has a history starting from the first report (Van Thiel, 1960) of a larval nematode from herring in the gastro-intestinal tract of humans in the Netherlands. Some aspects of human anisakidosis have recently been reviewed by Audicana et al. (2002). Because of the existence of several excellent reviews by others authors on the history and clinical aspect of the anisakidosis (Audicana et al., 2002; Chai et al., 2005; Umehara et al., 2007), this introduction will not summarize the major events that mark the history of anisakid nematodes as causative agents of anisakidosis, but instead will highlight major landmarks involved in our understanding of their taxonomic status and ecology based on genetic markers. This field has had a major impact during the last 20 years on our knowledge of these parasites, including their host-specificity, geographical range and the possible identification of human cases of anisakidosis.

Starting from the knowledge summarized in the exhaustive revision by Smith and Wootten (1978), this review treats the explosion in the literature that has accompanied research activities on these nematodes and resulted in a series of discoveries over the last 25 years on the systematics and ecology of anisakid nematodes using molecular genetic tools applied to their taxonomy. Indeed, based on the advances in our understanding of the basic biology of Anisakis, reviewed by Smith and Wootten (1978), this introduction starts from their concluding remarks highlighting knowledge gaps and perspectives for investigations over the next 30 years. One major gap concerned the identification of species. Indeed, in the case of the species belonging to the genus Anisakis, they wrote: ‘…despite Davey's revision (1971), there are still taxonomic problems, including the distinction between A. simplex and A. typica … …The generic diagnosis of Anisakis should be re-examined …. Anisakis larva (I) from North Atlantic waters has been cultured in vitro and shown to develop into A. simplex: There is need to culture the other “larval types” in order to confirm that they do, in fact, represent Anisakis and, if so, to determine which species they represent ….’. In 1978, Smith and Wootten underlined the major gap in our knowledge of nematode biology at that date, as represented by the genus Anisakis but also relevant to other anisakid species, that is, the identification of biological species. Indeed, species identification, based on morphological characters only, is difficult for adults, but even more difficult for larval stages.

The need for species identification was especially important for larval stages of Anisakis because they have been implicated as causative agents of human anisakidosis. Indeed, Smith and Wootten (1978) concluded their review as follows: ‘…in these circumstances there is need for reliable methods of differential diagnosis. There is much scope for future investigation’. Thus, this ‘future investigation’ started with the application of molecular genetic methodologies in an attempt to address the systematics of these anisakids. The prospect of assessing anisakid nematode biodiversity based on molecular genetic markers as the preferred diagnostic tools seemed promising because the unambiguous identification of specimens causing human disease (anisakidosis) is essential for a proper epidemiological survey.

The power of resolution of molecular genetic methodologies in detecting anisakid species revolutionized the taxonomy of these species during the following 25 years. Most descriptions of parasite species conformed with what can be regarded as the ‘morphological or typological, species concept’. Because genetic speciation is not always accompanied by corresponding morphological change, the actual number of biological species is likely to be greater than the current tally of nominal species, most of which are delineated based on morphological grounds.

Detecting biological species of anisakid nematodes challenged parasitologists via an expected genetic variation and heterogeneity within the nominal species and has led to the definition of anisakid species according to the Mayr's (Mayr, 1963) ‘biological species concept’ (BSC).

The aim of this review is to gather together the many and varied aspects concerning the biology and evolutionary ecology of those anisakid species detected genetically and recognized as members of Anisakis, Pseudoterranova and Contracaecum, including (a) species presently accepted as senior synonyms based on the application of different molecular genetic markers; (b) current molecular genetic approaches to identify anisakid species; (c) ecological evidence relating to the geographical distribution of detected species, their host preferences and life cycles; (d) the use of anisakid nematodes as biological tags for fish stock identification in a multidisciplinary approach; (e) correlation between the values of genetic variability and the levels of parasitic infection in definitive and intermediate/paratenic hosts as indicators of the integrity of marine food webs; (f) estimates of genetic divergence at intraspecific and interspecific levels; and (g) estimates of their genetic relationships based on different clustering approaches inferred from different molecular genetic data sets and their use to infer phylogenetic hypothesis...

Produkt-Details

• Erscheint lt. Verlag: 2.9.2011
• Mitarbeit: Herausgeber (Serie): S.I. Hay, David Rollinson
• Sprache: englisch
• Themenwelt: Sachbuch/Ratgeber
• Themenwelt: Medizin / Pharmazie ► Allgemeines / Lexika
• Themenwelt: Medizin / Pharmazie ► Gesundheitsfachberufe
• Themenwelt: Medizin / Pharmazie ► Medizinische Fachgebiete ► Mikrobiologie / Infektologie / Reisemedizin
• Themenwelt: Studium ► Querschnittsbereiche ► Epidemiologie / Med. Biometrie
• Themenwelt: Naturwissenschaften ► Biologie ► Mikrobiologie / Immunologie
• Themenwelt: Technik
• ISBN-10: 0-08-087900-4 / 0080879004
• ISBN-13: 978-0-08-087900-0 / 9780080879000