Preface xiii
1 Animal associations 1
1.1 Introduction 1
1.2 Animal associations 1
1.2.1 Symbiosis 2
1.2.2 Commensalism 5
1.2.3 Phoresis 5
1.2.4 Mutualism 6
1.2.5 Parasitism 7
1.2.6 Intra-specific parasites 8
1.2.7 Parasitoids 9
1.2.8 The concept of harm 10
1.3 Parasite hosts 11
1.3.1 Protozoa and helminths as hosts 11
1.3.2 Classes of hosts for parasites 12
1.4 The co-evolution of parasites and their hosts 13
1.4.1 Evolutionary relationships between host and parasite 14
1.4.2 Parasites and the evolution of sexual reproduction 15
1.5 Parasitism as a ‘lifestyle’: advantages and limitations 16
1.5.1 Main advantages of a parasitic lifestyle 17
1.5.2 Main limitations of a parasitic life style 17
1.6 The economic cost of parasitic diseases 18
1.6.1 Economic consequences of parasitic diseases of humans 18
1.6.2 Economic consequences of parasitic diseases of domestic animals 19
1.6.3 Estimating the costs of morbidity due to disease 19
1.6.4 Economic consequences of parasitic diseases of wildlife 20
1.7 Why parasitic diseases remain a problem 21
1.8 Taxonomy 24
1.8.1 The binomen system 25
Questions 27
2 Parasitic protozoa, fungi and plants 28
2.1 Introduction 28
2.2 Parasitic protozoa 28
2.2.1 Kingdom Protista 28
2.3 Phylum Rhizopoda 29
2.3.1 Genus Entamoeba 29
2.3.2 Other species of pathogenic amoebae 33
2.4 Phylum Metamonada 34
2.4.1 Order Diplomonadida 34
2.4.2 Order Trichomonadida 37
2.5 Phylum Apicomplexa 40
2.5.1 Genus Plasmodium 42
2.5.2 Plasmodium life cycle 43
2.5.3 Genus Theileria 45
2.5.4 Genus Babesia 46
2.6 Subclass Coccidiasina 50
2.6.1 Suborder Eimeriorina 50
2.6.2 Isospora group 51
2.6.3 Genus Cyclospora 52
2.6.4 Family Sarcocystidae 53
2.6.5 Genus Toxoplasma 54
2.6.6 Genus Neospora 58
2.6.7 Family Cryptosporidiidae 60
2.7 Phylum Kinetoplastida 62
2.7.1 Genus Leishmania 63
2.7.2 Leishmania life cycle 66
2.7.3 Genus Trypanosoma 70
2.8 Phylum Chlorophyta 81
2.8.1 Genus Prototheca 82
2.9 Kingdom fungi 83
2.9.1 Microsporidia 83
2.10 Kingdom plantae 85
Questions 85
3 Helminth parasites 86
3.1 Introduction: invertebrate taxonomy 86
3.2 Phylum Platyhelminthes 87
3.3 Class Trematoda 87
3.3.1 Family Fasciolidae 89
3.3.2 Family Cathaemasiidae: Genus Ribeiroia 93
3.3.3 Family Dicrocoeliidae 95
3.3.4 Family Opisthorchiformes 96
3.3.5 Family Paragonomidae 98
3.3.6 Family Schistosomatidae 99
3.4 Class Cestoda 103
3.4.1 Order Pseudophyllidea/Diphyllobothriidea 103
3.4.2 Order Cyclophyllidea 104
3.4.3 Family Taeniidae 105
3.4.4 Family Anoplocephalidae 110
3.5 Phylum Acanthocephala 112
3.6 Phylum Nematoda (Nemata) 114
3.6.1 Class Enoplea 117
3.6.2 Class Rhabdita 121
3.6.3 Family Onchocercidae 129
3.6.4 Family Dracunculidae 132
Questions 135
4 Arthropod parasites 137
4.1 Introduction 137
4.2 Phylum Chelicerata 138
4.2.1 Family Demodicidae 139
4.2.2 Family Sarcoptidae 140
4.2.3 Family Psoroptidae 143
4.2.4 Suborder Ixodida 144
4.2.5 Family Argasidae 145
4.2.6 Family Ixodidae 146
4.2.7 Tick paralysis 147
4.3 Phylum Crustacea 148
4.3.1 Subclass Copepoda 148
4.3.2 Infra-Class Cirripedia 150
4.3.3 Subclass Branchiura 150
4.3.4 Subclass Pentastomida – tongue worms 151
4.4 Sub-phylum Hexapoda 153
4.4.1 Order Phthiraptera (lice) 155
4.4.2 Order Siphonaptera (fleas) 159
4.4.3 Order Diptera (true flies) 162
4.4.4 Suborder Nematocera 162
4.4.5 Suborder Brachycera 163
4.4.6 Family Calliphoridae 166
4.4.7 Genus Chrysomya 168
4.4.8 Genus Cochliomyia 168
4.4.9 Genus Auchmeromyia 169
4.4.10 Genus Cordylobia 170
4.4.11 Family Sarcophagidae 170
4.4.12 Family Oestridae 171
4.4.13 Subfamily Gasterophilinae 173
4.4.14 Subfamily Hypodermatinae 174
4.4.15 Subfamily Cuterebrinae 176
4.4.16 Family Streblidae 177
4.4.17 Family Nycteribiidae 178
Questions 178
5 Parasite transmission 180
5.1 Introduction 180
5.2 Contaminative transmission 181
5.3 Transmission associated with reproduction 184
5.3.1 Sexual transmission 184
5.3.2 Transmission within the gametes 187
5.3.3 Congenital transmission 188
5.4 Autoinfection 189
5.5 Nosocomial transmission 190
5.6 Active parasite transmission 191
5.7 Hosts and vectors 192
5.7.1 Paratenic hosts 192
5.7.2 Intermediate hosts 193
5.7.3 Vectors 194
5.8 Host factors 196
5.8.1 Host identification 196
5.8.2 The influence of host behaviour on parasite transmission 197
5.9 Co-transmission and interactions between infectious agents 199
5.10 How religion can influence parasite transmission 202
5.11 The influence of war on parasite transmission 204
5.12 The influence of parasites on host behaviour 205
5.13 Environmental factors 207
5.13.1 Natural environmental variables 207
5.13.2 Pollution 207
5.13.3 Global warming 209
Questions 211
6 Immune reactions to parasitic infections 212
6.1 Introduction 212
6.2 Invertebrate immunity 213
6.3 Vertebrate immunity 215
6.3.1 Innate immunity 215
6.3.2 Adaptive immunity 218
6.3.3 Cell-mediated immunity 220
6.4 Innate immunity to parasitic infection 221
6.4.1 Physical factors 221
6.4.2 Chemical and microbial factors 222
6.4.3 The acute inflammatory response 223
6.4.4 Cell-mediated immunity 225
6.5 Adaptive immunity 226
6.5.1 Avoiding the host immune response 227
6.5.2 Depression of the immune system 232
6.6 Immunity to malaria 233
6.7 Schistosoma mansoni and Hepatitis C virus interactions 237
6.8 HIV-AIDS and parasitic disease 238
6.8.1 Parasites and the transmission of HIV 239
6.8.2 Parasite-HIV co-infections 240
6.8.3 Leishmania-HIV co-infections 240
6.8.4 Malaria–HIV co-infections 242
6.8.5 Toxoplasma–HIV co-infections 243
6.8.6 Microsporidia–HIV co-infections 243
Questions 243
7 Pathology 245
7.1 Introduction 245
7.2 Factors that influence pathogenesis 245
7.2.1 Host factors that influence pathogenesis 245
7.2.2 Parasite factors that influence pathogenesis 246
7.3 Mechanisms by which parasites induce pathology 247
7.3.1 Direct damage 248
7.3.2 Indirect damage 249
7.4 Types of pathology 250
7.4.1 Abortion and obstetric pathology 250
7.4.2 Anaemia 251
7.4.3 Anorexia 253
7.4.4 Apoptosis 253
7.4.5 Calcification 254
7.4.6 Cancer 255
7.4.7 Castration 257
7.4.8 Delusional parasitosis 258
7.4.9 Diarrhoea 258
7.4.10 Elephantiasis 260
7.4.11 Fever 261
7.4.12 Granulation and fibrosis 262
7.4.13 Hyperplasia 264
7.4.14 Hypertrophy 265
7.4.15 Inflammation and ulceration 265
7.4.16 Jaundice 267
7.4.17 Metaplasia 267
7.4.18 Pressure atrophy 267
7.4.19 Psychological disturbance 268
7.5 Damage to specific organs 269
7.5.1 The bladder 269
7.5.2 The brain 270
7.5.3 The digestive system 273
7.5.4 The genitalia 276
7.5.5 The kidney 277
7.5.6 The liver 279
7.5.7 The lungs 281
7.5.8 The skin 284
7.5.9 The spleen 288
7.6 Co-infections and pathogenesis 289
Questions 290
8 The useful parasite 292
8.1 Introduction: the goodness of parasites? 292
8.2 The importance of parasites for the maintenance of a healthy immune system 293
8.2.1 The hygiene hypothesis 293
8.2.2 Type 1 diabetes mellitus 294
8.2.3 Irritable bowel syndrome (IBS) 296
8.2.4 Inflammatory bowel disease 297
8.3 The use of parasites to treat medical conditions 297
8.3.1 Helminth therapy 298
8.3.2 Larval therapy 302
8.3.3 Leech therapy 304
8.3.4 Malaria therapy (malariotherapy) 305
8.4 Parasites as sources of novel pharmaceutically-active compounds 308
8.5 Parasites as biological control agents 309
8.5.1 Life cycle of the entomopathogenic nematodes Heterorhabditis and Steinernema 310
8.6 Parasites as forensic indicators 312
Questions 314
9 Identification of protozoan and helminth parasites 316
9.1 Introduction 316
9.2 The importance of correct identification 316
9.3 Properties of an ideal diagnostic test 318
9.4 Isolation of parasites 320
9.5 Identification from gross morphology 323
9.5.1 Morphological identification of Entamoeba 325
9.5.2 Morphological identification of Plasmodium and Babesia 326
9.5.3 Morphological identification of Taenia tapeworms 327
9.5.4 Morphological identification of filarial nematode infections 327
9.6 Biochemical techniques 329
9.7 Immunological techniques 329
9.8 Molecular techniques 331
9.9 Rapid diagnostic tests (RDTs) 334
9.9.1 Rapid diagnostic tests for malaria 335
9.9.2 Rapid diagnostic test for filariasis 337
9.10 MALDI-TOF MS 337
Questions 338
10 Parasite treatment and control 339
10.1 Introduction 339
10.2 Importance of understanding parasite life cycles for effective treatment and control 339
10.3 Treatment of parasitic diseases 341
10.3.1 The ideal antiparasitic drug 341
10.3.2 Pharmaceutical drugs 345
10.3.3 DNA/RNA technology 347
10.3.4 Molecular chaperones (heat shock proteins) 349
10.3.5 Nanotechnology 350
10.3.6 Quantum dots 352
10.3.7 Natural remedies 353
10.3.8 Homeopathy 355
10.4 Vaccines against parasitic diseases 356
10.4.1 Attenuated vaccines 358
10.4.2 Killed vaccines 359
10.4.3 Recombinant vaccines 359
10.4.4 Toxoid vaccines 360
10.4.5 DNA vaccines 361
10.4.6 Vaccine administration 362
10.5 Control of parasitic diseases 362
10.5.1 Eradication, elimination and control of parasitic diseases 362
10.5.2 Education 364
10.5.3 Environmental modification and cultural control 365
10.5.4 Remote Sensing (RS) and GIS technology 368
10.5.5 Treating the individual or the population 369
10.5.6 Piggy-backing control programmes 370
10.5.7 Disruptions to control programmes 371
10.5.8 Role of governments, foundations, and aid organisations 371
Questions 373
References 375
Index 431
