Menu Expand
Equine Infectious Diseases E-Book

Equine Infectious Diseases E-Book

Debra C. Sellon | Maureen Long

(2013)

Additional Information

Book Details

Abstract

Ideal for both practitioners and students, this comprehensive resource covers the diagnosis, treatment, and prevention of infectious disease in horses. Organized by infectious agent — virus, bacterial and rickettsial, protazoal, and fungal — it includes complete coverage of the individual diseases caused by each type of agent. A section on clinical problems examines conditions such as ocular infections, CNS infections, and skin infections. It also addresses the importance of preventing and controlling infectious disease outbreaks with coverage of epidemiology, biosecurity, antimicrobial therapy, and recognizing foreign equine diseases.

  • Full-color photos and illustrations provide clear, accurate representations of the clinical appearance of infectious diseases.
  • Features the most recent information on the global threat of newly emergent diseases such as African Horse Sickness.
  • Includes a comprehensive section on the prevention and control of infectious diseases.
  • More than 60 expert contributors share their knowledge and expertise in equine infectious disease.
  • A companion CD-ROM, packaged with the book, includes complete references linked to PubMed.

Table of Contents

Section Title Page Action Price
Front Cover cover
endsheet 4 IFC4
Equine Infectious Diseases i
Copyright Page iv
Dedication v
Contributors vi
Preface xi
Acknowledgments xi
Table Of Contents xiii
1 Clinical Problems 1
1 Respiratory Infections 1
Equine Respiratory Tract 1
Normal Respiratory Flora 1
Pulmonary Defense Mechanisms 1
Anatomic and Physiologic Considerations 2
Clinical Findings Associated with Infectious Respiratory Disease 3
Diagnostic Approach to Infectious Respiratory Disease 3
Upper Respiratory Tract Infections 4
Diseases of the Upper Respiratory Tract 4
Rhinitis and Sinusitis 4
Lymphoid Pharyngeal Hyperplasia 5
Arytenoid Chondritis 5
Viral Diseases 5
Strangles 6
Therapy of Upper Respiratory Viral Infections 7
Lower Respiratory Tract Infections 7
Etiology and Epidemiology 7
Bacterial Pneumonia 7
Miscellaneous Causes of Pneumonia 7
Pulmonary Abscess 7
Pathogenesis 7
Clinical Findings 7
Diagnosis 8
Therapy 8
Pneumonias 8
Pleuropneumonia 8
Etiology and Epidemiology 8
Clinical Findings 8
Diagnosis 9
Therapy 10
Interstitial Pneumonia 11
Etiology 11
Clinical Findings 12
Diagnosis 12
Therapy 12
Prognosis 13
Parasitic Pneumonia 13
Etiology 13
Clinical Findings 13
Diagnosis 13
Therapy 13
Prognosis 14
Guttural Pouch 14
Anatomy 14
Pathogenesis 14
Clinical Examination 15
Empyema 16
Etiology 16
Clinical Findings 16
Diagnosis 16
Medical Therapy 16
Surgical Therapy 17
Guttural Pouch Mycosis 17
Etiology 17
Clinical Findings 17
Diagnosis 18
Medical Therapy 18
Surgical Therapy 18
Prognosis 19
Temporohyoid Osteoarthropathy 19
Etiology 19
Clinical Findings and Diagnosis 19
Therapy 20
Suggested Readings 20
Guttural Pouch 20
References 21.e1
2 Cardiovascular Infections 21
Infective Endocarditis 21
Etiology and Pathogenesis 21
Clinical Findings 25
Diagnosis 26
Therapy 28
Prognosis 30
Inflammatory Valvulitis 30
Myocarditis 30
Etiology and Pathogenesis 30
Clinical Findings 31
Diagnosis 31
Therapy 31
Prognosis 31
Pericarditis 31
Etiology and Pathogenesis 31
Clinical Findings 34
Diagnosis 34
Echocardiography 34
Electrocardiography, Thoracic Radiography, and Cardiac Catheterization 34
Laboratory Investigations 35
Therapy 36
Prognosis 36
Jugular Thrombophlebitis 36
Etiology and Pathogenesis 36
Clinical Findings 36
Diagnosis 37
Diagnostic Ultrasonography 37
Laboratory Investigations 37
Therapy 37
Prognosis 37
Prevention 37
Caudal Vena Cava Thrombosis Syndrome 39
Arterial Thrombosis, Arteritis, and Aortitis 39
Cardiac Complications in Systemic Inflammatory Response Syndrome and Sepsis 39
Cardiac Dysrhythmias 39
Cardiac Involvement in Multiple Organ Dysfunction 41
References 41.e1
3 Gastrointestinal and Peritoneal Infections 42
Oral Cavity 42
2 Viral Diseases 132
12 Laboratory Diagnosis of Viral Infections 132
Introduction 132
Detection of Virus or Viral Components 133
Isolation of Live Virus 133
Cell Culture, Egg Culture, and Animal Inoculation 133
Detection of Viral Nucleic Acids 134
Polymerase Chain Reaction, Real-Time Polymerase Chain Reaction, and Nested Polymerase Chain Reaction 134
Viral Characterization 135
In Situ Methods: Detection of Virus in Tissue Sections 136
Histopathology 136
Immunofluorescence and Immunohistochemistry 136
Microarray Detection of Viruses 137
In Situ Hybridization 138
Detection of Virus in Clinical Samples 138
Enzyme-Linked Immunosorbent Assay (Indirect ELISA) 138
Electron Microscopy 138
Detection of the Serologic Response 138
Virus Neutralization 139
Enzyme-Linked Immunosorbent Assay 139
Agar Gel Immunodiffusion 139
Hemagglutination Inhibition Assay 139
Serologic Interpretation 140
References 140.e1
13 Equine Influenza Infection 141
Etiology 141
Epidemiology 142
Pathogenesis 143
Clinical Findings 144
Immunity 144
Diagnosis 145
Antigen Detection 145
Virus Isolation 145
Immunoassays 146
Immunofluorescence 146
Reverse Transcriptase–Polymerase Chain Reaction 146
Antibody Detection 147
Hemagglutination Inhibition 147
Single Radial Hemolysis 147
ELISA-Based Assays 148
Pathologic Findings 148
Therapy 149
Medical Therapy 149
Antiviral Therapy 149
Prevention 150
Vaccination 150
Husbandry 150
Public Health Considerations 151
References 151.e1
14 Equine Herpesviruses 151
Etiology 152
Virology Overview 152
Viral Genomes 152
Viral Replication 152
Lytic and Latent Infection Cycles 153
Viral Proteins 155
Glycoproteins 155
Epidemiology 155
Spread of Infection 155
Latency 156
Reactivation from Latency 156
Pathogenesis and Pathologic Findings 157
Respiratory Tract 157
Viremia 157
Uterus 157
Central Nervous System 157
Virulence 157
Immunology 158
Immune Evasion 159
Clinical Findings 159
Respiratory Disease 159
Abortion 160
Other Reproductive Syndromes 160
Neonatal Foals 160
Stallions 160
Neurologic Disease 161
Diagnosis 161
History and Clinical Signs 161
Case Selection 161
Direct Demonstration of Infection 161
Immunofluorescence 161
Polymerase Chain Reaction 162
Virus Isolation 163
Histopathology 163
Indirect Evidence of Infection 163
Hematology 163
Serology 163
Cerebrospinal Fluid Analysis 164
Diagnosis of Latent Infection 164
Treatment 165
Respiratory Disease 165
Abortion 165
Ocular Disease 165
Equine Herpesvirus Myeloencephalopathy 165
Vaccination 166
Control 167
References 168.e1
15 Equine Viral Arteritis 169
Etiology 169
Molecular Properties of Equine Arteritis Virus 169
Resistance to Physical and Chemical Agents 170
Epidemiology 170
Outbreaks 170
Seroprevalence and Breed Predilection 171
Transmission 171
Carrier State and Molecular Epidemiology 171
Pathogenesis 173
Clinical Findings 174
Diagnosis 176
Virus Isolation 176
Histopathologic Examination and Viral Antigen Detection 177
Viral Nucleic Acid Detection 177
Serologic Diagnosis 177
Pathology 177
Therapy 178
Prevention 178
Immunity 178
Vaccination 179
Husbandry and Control Programs 179
Public Health Considerations 181
Acknowledgments 181
References 181.e1
16 African Horse Sickness 181
Etiology 182
Epidemiology 182
Pathogenesis 183
Clinical Findings 183
“Dunkop” or “Pulmonary” Form 184
“Dikkop” or “Cardiac” Form 184
“Mixed” Form 184
Horsesickness Fever 185
Diagnosis 185
Pathologic Findings 186
Macroscopic Pathology 186
“Dunkop” or “Pulmonary” Form 186
“Dikkop” or “Cardiac” Form 186
“Mixed” Form 186
Microscopic Pathology 186
Therapy 188
Prevention 188
Public Health Considerations 188
References 188.e1
17 Adeno, Hendra, and Equine Rhinitis Viral Respiratory Diseases 189
Equine Adenoviruses 189
Etiology 189
Epidemiology 189
Pathogenesis 189
Immunity 190
Clinical Findings 190
Diagnosis 191
Clinical Laboratory 191
Virus Isolation 191
Serology 191
Pathologic Findings 192
Therapy and Prevention 192
Public Health Considerations 192
Hendra Virus: a Henipavirus 192
Etiology 192
Epidemiology 192
Pathogenesis and Pathology 193
Clinical Findings 194
Diagnosis 194
Virus Isolation 194
Quantitative Real-Time Polymerase Chain Reaction 194
Serology 194
Antigen Detection 194
Therapy 194
Prevention 194
Vaccination 194
Other Methods 195
Public Health Considerations 195
Equine Rhinitis a Virus and Equine Rhinitis B Viruses 195
Etiology 195
Epidemiology 196
Pathogenesis 196
Clinical Findings 196
Diagnosis 197
Clinical Laboratory and Virus Isolation 197
Serology 197
Virus Detection 197
Pathologic Findings 197
Therapy 197
Prevention 197
Public Health Considerations 197
References 197.e1
18 Viral Diarrhea 198
Equine Rotavirus 198
Etiology 198
Epidemiology 198
Pathogenesis 199
Clinical Findings 199
Diagnosis 199
Field Testing Procedures 199
Other Diagnostic Options 200
Pathologic Findings 200
Therapy 200
Prevention 201
Vaccination 201
Husbandry/Infection Control 201
Public Health Considerations 201
Equine Coronavirus 201
Etiology 201
Epidemiology and Clinical Findings 202
Coronavirus in Adult Horses 202
Diagnosis 203
Husbandry/Infection Control 203
Equine Torovirus 203
Etiology 203
Epidemiology 203
Clinical Findings 203
References 203.e1
19 Rabies 203
Etiology 204
Epidemiology 204
Pathogenesis 205
Clinical Findings 205
Diagnosis 205
Pathologic Findings (Figs. 19-5 through 19-13) 206
Therapy 208
Prevention 208
Public Health Considerations 209
Acknowledgments 209
References 209.e1
20 Equine Alphaviruses 210
Eastern Equine Encephalitis 210
Etiology 210
Epidemiology 211
Pathogenesis 211
Clinical Findings 212
Diagnosis 212
Pathologic Findings 213
Therapy 213
Prevention 213
Public Health Considerations 214
Western Equine Encephalitis 214
Etiology 214
Epidemiology 214
Pathogenesis 215
Clinical Signs 215
Diagnosis 215
Pathology 215
Treatment 215
Prevention 215
Venezuelan Equine Encephalitis 215
Etiology 215
Epidemiology 216
Pathogenesis 217
Clinical Findings, Diagnosis, and Pathologic Findings 217
Prevention 217
References 217.e1
21 Flavivirus Encephalitides 217
Etiology 218
Epidemiology 220
Life Cycle and Transmission 220
Vectors 220
Hosts and Reservoirs 221
Geographic and Seasonal Distribution 221
Intrinsic Risk Factors 221
Pathogenesis 222
Immune Responses 223
Neuronal Injury 223
Clinical Findings 223
Diagnosis 224
West Nile Virus 224
Japanese Encephalitis 225
Pathologic Findings 225
Therapy 225
Prevention 226
Public Health Considerations 226
References 226.e1
22 Borna Disease 226
Etiology 227
Epidemiology 227
Pathogenesis 228
Clinical Findings 229
Diagnosis 230
Antemortem Diagnosis 230
Postmortem Diagnosis 231
Pathologic Findings 231
Therapy 232
Prevention 232
Public Health Considerations 232
References 232.e1
23 Equine Infectious Anemia 232
Etiology 233
Epidemiology 233
Prevalence 233
Transmission 234
Pathogenesis 235
Thrombocytopenia 235
Anemia 235
Immune Control 235
Clinical Findings 236
Diagnosis 237
Pathologic Findings 237
Therapy 238
Prevention 238
Public Health Considerations 238
References 238.e1
24 Vesicular Stomatitis 239
Etiology 239
Epidemiology 239
Disease in United States 239
Transmission 240
Arthropod Vector Transmission 240
Other Forms of Transmission 240
Risk Factors 240
Pathogenesis 241
Clinical Findings 241
Diagnosis 242
Therapy 243
Prevention 243
Public Health Considerations 243
References 244.e1
25 Papillomavirus Infections 244
Equine Warts 244
Etiology 244
Epidemiology 244
Pathogenesis 244
Clinical Findings 245
Diagnosis 245
Pathologic Findings 245
Therapy 245
Prevention 246
Public Health Considerations 246
Aural Plaques 246
Etiology and Pathogenesis 246
Clinical Findings 246
Diagnosis 246
Treatment and Prevention 246
Sarcoids 246
Etiology 246
Epidemiology 247
Pathogenesis 247
Clinical Findings 247
Diagnosis 248
Pathologic Findings 249
Therapy 249
Surgical Resection 249
Cryotherapy 249
Carbon Dioxide Laser Therapy 249
Hyperthermia 249
Irradiation 250
Photodynamic Therapy 250
Immunotherapy 250
Chemotherapy 250
Prevention 251
Public Health Considerations 251
References 251.e1
26 Miscellaneous Viral Diseases 251
Miscellaneous Orbivirus Infections 251
Equine Encephalosis 251
Etiology and Epidemiology 251
Clinical Findings 252
Diagnosis 252
Pathologic Findings 252
Public Health Considerations 252
Peruvian Horse Sickness Virus 252
Miscellaneous Alphavirus Infections 252
Getah Virus 252
Etiology and Epidemiology 252
3 Bacterial and Rickettsial Diseases 257
27 Laboratory Diagnosis of Bacterial Infections 257
Direct Microscopic Examination 257
Sampling for Bacterial Culture 258
Indications 258
Samples Most Appropriate for Culture 258
Methods for Collection 258
Suspected Anaerobic Infection 259
Blood Culture 259
Joint Culture 260
Wounds 260
Sampling for Enteric Infections 260
Clostridial Enteritis 260
Ocular Infections 261
Botulism and Tetanus 261
Sample Transport 261
Submission 261
Interpretation of Isolation and Identification Results 261
Molecular Methods for Detecting Bacterial Pathogens 262
Polymerase Chain Reaction 262
Toxin Gene Detection 263
Molecular Epidemiology 263
Antimicrobial Susceptibility Testing 263
Indications 263
Methods 263
Interpretation 264
Serologic Diagnosis of Bacterial Diseases 264
References 265.e1
28 Streptococcal Infections 265
Overview 265
Streptococcus equi Subsp. equi 265
Etiology 265
Epidemiology 267
Transmission 267
Inapparent Carrier Horses 267
Environmental Persistence of S. equi 268
Pathogenesis 268
Clinical Findings 269
Manifestations Associated with Severe Lymph Node Enlargement 269
Complications Associated with Metastatic Spread of Infection 269
Internal Infection 269
Immune-Mediated Complications 271
Purpura Hemorrhagica 271
Myositis 271
Glomerulonephritis and Myocarditis 272
Agalactia 272
Diagnosis 272
Culture 272
Polymerase Chain Reaction 272
Serology 272
Therapy 272
Horses with Early Clinical Signs 272
Horses with Lymph Node Abscessation 273
Horses with Complications 273
Drugs of Choice for Therapy 273
Prevention 273
Vaccination 273
Quarantine and Bacteriologic Screening 274
Control of Outbreaks 274
Outbreak Investigations 274
Carriers with S. equi Infection of Guttural Pouches 275
Detection 275
Treatment 275
Hygiene Measures 276
Public Health Considerations 276
Streptococcus equi Subsp. zooepidemicus 276
Etiology, Epidemiology, and Pathogenesis 276
Clinical Findings 277
Therapy 277
Prevention 277
4 Fungal Diseases 393
46 Laboratory Diagnosis of Fungal Diseases 393
Introduction to Fungi 393
Host Susceptibility 394
Sources of Fungal Pathogens 394
Laboratory Safety 394
Specimen Collection and Transport 394
Skin 394
Eye 394
Blood 394
Fluids 395
Tissue 395
Direct Examination 395
Potassium Hydroxide Treatment 395
India Ink 395
Gram Stain 395
Other Stains 396
Culture and Identification 396
Dermatophyte Culture 396
Culture of Fluid or Tissue 397
Identification of Fungal Species 397
Pneumocystis carinii (P. jirovecii) 397
Interpretation of Culture Results 398
Molecular Diagnosis of Fungal Infections 398
Fungal Antigen Detection 398
Antifungal Susceptibility Testing 398
Serology 399
References 399.e1
47 Coccidioidomycosis 399
Etiology 400
Epidemiology and Epizootiology 401
Pathogenesis 402
Clinical Findings 402
Diagnosis and Pathologic Findings 404
Therapy 405
Prevention and Public Health Considerations 405
Acknowledgments 406
References 406.e1
48 Sporotrichosis 406
Etiology 406
Epidemiology and Pathogenesis 406
Clinical Findings 407
Diagnosis 407
Therapy, Prognosis, and Prevention 408
Public Health Considerations 408
References 408.e1
49 Candidiasis 408
Etiology 408
Epidemiology 408
Pathogenesis 409
Clinical Findings 409
Thrush 409
Systemic Candidiasis 409
Diagnosis 410
Therapy 410
Antifungal Therapy 410
Polyenes 410
Azoles 410
Topical Therapy 411
Supportive Therapy 411
References 411.e1
50 Dermatophytosis 411
Etiology 411
Epidemiology 411
Pathogenesis 412
Virulence Factors 412
Host Factors and Immune Response 412
Environmental Factors 412
Clinical Findings 412
Diagnosis 413
Wood’s Lamp 413
Direct Examination of Hair 413
Culture 413
Pathology 414
Therapy 414
Topical Therapy 414
Systemic Therapy 414
Environmental Control 414
Prevention 414
Vaccine 414
Public Health Considerations 414
References 414.e1
51 Pythiosis and Zygomycosis 415
Pythiosis 415
Etiology and Epidemiology 415
Clinical Findings 415
Diagnosis 416
Cytology 416
Culture 417
Serology 417
Molecular Assays 417
Immunohistochemistry 417
Pathologic Findings 417
Therapy 418
Surgery 418
Immunotherapy 418
Medical Therapy 418
Zygomycosis 419
Etiology and Epidemiology 419
Clinical Findings 419
Basidiobolomycosis 419
Conidiobolomycosis 419
Mucormycosis 420
Pathologic Findings 420
Diagnosis 420
Therapy 420
References 421.e1
52 Aspergillosis 421
Etiology 421
Virulence Factors 422
Epidemiology 422
Mycotic Keratitis (Keratomycosis) 422
Endometritis and Placentitis 423
Aflatoxicosis 423
Pathogenesis 423
Keratomycosis 423
Endometritis and Placentitis 424
Aflatoxicosis 424
Clinical Findings 424
Mycotic Keratitis 424
Pulmonary Aspergillosis 425
Nasal or Sinus Aspergillosis 425
Central Nervous System Aspergillosis 425
Endometritis and Placentitis 425
Aflatoxicosis 425
Diagnosis 425
Serology 425
Real-Time Quantitative Polymerase Chain Reaction 425
Culture 425
Susceptibility Testing 425
Biopsy 426
Immunohistochemical Techniques 426
Mycotic Keratitis 426
Cytologic Examination 426
Culture 426
Corneal Biopsy and Staining 427
Pulmonary Aspergillosis 427
Nasal and Sinus Aspergillosis 427
Central Nervous System Aspergillosis 427
Endometritis and Placentitis 427
Aflatoxicosis 427
Therapy 428
Polyene Antifungal Drugs 428
Azole Antifungal Drugs 428
Chitin Synthesis Inhibitors 430
Mycotic Keratitis 430
Polyene Antifungal Drugs 430
Azole Antifungal Drugs 431
Silver Sulfadiazine 431
Povidone-Iodine Solution 431
Thiabendazole 431
Choice of Antifungal Medication 431
Duration of Therapy 432
Surgical Treatment 432
Other Treatments 432
Corticosteroid Treatment Contraindicated 432
Prognosis 432
Pulmonary Aspergillosis 432
Nasal and Sinus Aspergillosis 432
Endometritis and Placentitis 433
Aflatoxicosis 433
References 433.e1
53 Miscellaneous Fungal Diseases 433
Blastomycosis 433
Etiology 433
Virulence Factors 433
Epidemiology 433
Pathogenesis 434
Clinical Findings 434
Diagnosis 434
Cytology 434
Ancillary Diagnostic Testing 434
Culture 435
Molecular Identification of Yeasts 435
Serology 435
Antibody Detection 435
Antigen Detection 436
Therapy 436
Prevention 436
Cryptococcosis 436
Etiology 436
Virulence Factors 436
Capsule 436
Melanin 436
Thermotolerance 436
Epidemiology 437
Pathogenesis 437
Clinical Findings 437
Diagnosis 438
Clinical Diagnostic Testing 438
Radiography and Computed Tomography 438
Ancillary Diagnostic Testing 438
Biopsy 438
Culture 438
Serology 439
Assays for Cryptococcal Antigens 439
Antibody Detection 439
Pathologic Findings 439
Upper Respiratory Tract 440
Lower Respiratory Tract 440
Central Nervous System 440
Gastrointestinal Tract 440
Reproductive Tract 440
Subcutaneous Tissue 440
Therapy 440
Histoplasmosis 440
Etiology 440
Virulence 440
Epidemiology 441
Pathogenesis 441
Clinical Signs 442
Mycotic Keratitis 442
Diagnosis 442
Clinical Diagnostic Testing 442
Cytology 442
Ancillary Diagnostic Testing 442
Culture 442
Histopathology 442
Serology 442
Antigen Detection 442
Molecular Identification 443
Intradermal Testing 443
Pathology 443
Mycotic Keratitis 443
Therapy 444
Mycotic Keratitis 444
Histoplasma capsulatum var. farciminosum 444
Etiology 444
Epidemiology 444
Pathogenesis 444
Clinical Signs 444
Diagnosis 445
Cytology 445
Culture 445
Pathology and Histology 445
Serologic Tests 445
Animal Inoculation 445
Intradermal Testing 445
Therapy 445
Prevention 446
Pneumocystis Infections 446
Etiology 446
Epidemiology 446
Pathogenesis 446
Clinical Findings 447
Diagnosis 447
Pathologic Findings 448
Therapy 448
Prevention 448
Public Health Considerations 448
References 448.e1
5 Parasitic Diseases 449
54 Laboratory Diagnosis of Parasitic Diseases 449
Helminth Diagnosis 449
Protozoan Diagnosis 449
Laboratory Procedures 449
Gross Fecal Examination 449
Fecal Flotation 449
Fecal Cultures 453
Fecal Sedimentation 453
Direct Fecal Smear 454
Baermann Procedure 454
Cellophane (Scotch) Tape Test 454
McMaster’s Procedure 454
Impression Smears 455
Skin Biopsy Examination 455
Blood Smears 455
Isolated Worms Recovered from Necropsy or Passed in Feces 455
Suggested Readings 456
55 Equine Protozoal Myeloencephalitis 456
Etiology 456
Epidemiology 457
Pathogenesis 459
Clinical Findings 461
Diagnosis 462
Pathologic Findings 464
Therapy 465
Antiprotozoal Drugs 465
Ponazuril 465
Diclazuril 466
Folate Inhibitors 466
Supportive Therapy 466
Prevention 467
Public Health Considerations 467
References 467.e1
56 Piroplasmosis 467
Etiology 468
Life Cycles 469
Babesia caballi 469
Theileria equi 469
Epidemiology 470
Pathogenesis and Immunity 471
Clinical Findings 472
Acute Equine Piroplasmosis 472
Chronic Equine Piroplasmosis 472
Inapparent Carrier 472
Pathology 472
Diagnosis 473
Microscopy 473
Serology 473
Other Diagnostic Methods 474
Therapy 474
Prevention 475
Public Health Considerations 475
References 475.e1
57 Nematodes 475
Gastrointestinal Nematodes 475
Strongylosis 475
Strongylinae (Large Strongyles, Strongylins) 475
Etiology 475
Epidemiology 476
Pathogenesis 476
Clinical Findings 477
Diagnosis 477
Pathologic Findings 478
Therapy 478
Prevention 478
Public Health Considerations 478
Cyathostominae (Cyathostomes, Cyathostomins, Small Strongyles, Trichonemes) 478
Etiology 478
Epidemiology 479
Pathogenesis 479
Clinical Findings 479
Diagnosis 479
Pathologic Findings 479
Therapy 479
Prevention 480
Public Health Considerations 481
Parascarosis 481
Etiology and Epidemiology 481
Pathogenesis 481
Clinical Findings 482
Diagnosis 482
Pathologic Findings 482
Therapy 482
Prevention 483
Public Health Considerations 483
Strongyloidosis 483
Etiology and Epidemiology 483
6 Prevention and Control of Infectious Diseases 515
61 Epidemiology of Equine Infectious Disease 515
Basics 515
Definition 515
Epidemiologic Approach 515
Disease Ecology 515
Disease Agent 515
Host 516
Environment 516
Individual 516
Population 516
Disease Causation 517
Identifying Causal Factors 517
Measuring Disease 517
Population-at-Risk 518
Types of Data 518
Using Interval Data 518
Using Categorical Data 518
Ratios, Proportions, and Rates 518
Ratios 518
Proportions 518
Rates 518
Epidemiologic Measures of Disease Frequency 519
Prevalence 519
Cumulative Incidence 519
Incidence Rate 520
Relationship between Prevalence and Incidence 520
Temporal Patterns of Disease 520
Comparing Groups 522
Using Measurement Data 522
Is the Difference Real? 522
Using Categorical Data 523
Comparing Cumulative Incidence: Attributable Risk and Attributable Fraction 523
Comparing Cumulative Incidence: Relative Risk 523
Comparing Prevalences: Odds Ratio 523
Outbreak Investigations: Attack Risk Table 523
Is the Difference Real? 525
Properties of Diagnostic Tests 525
Types of Measurement 525
Test Accuracy 526
Estimation of Sensitivity and Specificity 526
Interpretation of Test Results: Predictive Values 527
Using Tests in Combination 528
Other Diagnostic Test Characteristics 528
Strategies for Prevention of Infectious Disease 528
Managing an Outbreak of Infectious Disease 529
References 529.e1
62 Biosecurity and Control of Infectious Disease Outbreaks 530
Ethics of Infection Control 530
Veterinarian’s Role in Biosecurity 531
Level of Biosecurity 531
Importance of Biosecurity 531
Protect Patients 531
Protect Personnel 531
Protect Hospital/Practice 532
Judicious Antimicrobial Use 532
Biosecurity Program Development 532
Hazard Analysis/Identification 532
Critical Control Point Identification 533
Critical Limits for Preventive Measures 533
Critical Control Point Monitoring 533
Corrective Action Plan 533
Evaluation of the Biosecurity Program 533
Preventive Measures 533
Transmission Routes 534
Daily Attire 534
Hand Hygiene 534
Barrier Nursing Precautions 534
Gowns 535
Gloves 535
Facial Protection 535
Footwear Hygiene 535
Movement Restriction and Traffic Flow Management (Personnel, Patients, Visitors) 535
Separation and Isolation 535
Separation 536
Isolation 536
Footbaths/Footmats 536
Enhancing Biosecurity Protocol Compliance 537
Environmental Infection Control 537
Cleaning 537
Disinfection 537
Waste Management and Disposal 537
Wildlife Reservoirs 538
Monitoring Biosecurity Protocol Effectiveness 539
Patient Monitoring 539
Environmental Monitoring 539
Use of Outdoor Exercise Areas at Equine Hospitals 540
Specific Aspects of Biosecurity 540
Summary of Biosecurity in Equine Veterinary Hospitals 540
Biosecurity in Equine Ambulatory Practice 540
Protection of Resident Horses and Control of Infectious Diseases at Equine Events 541
Equine Owners 542
Protection of Resident Horses 542
Protection of Traveling Horses 543
Conclusions 543
References 543.e1
63 Infectious Diseases and International Movement of Horses 544
Growth of Horse Industries Worldwide 544
Basis for International Movements and Trade in Equine Germplasm 545
Economic Impact 545
Changing Trends 545
Factors Influencing Global Distribution of Equine Diseases 546
International Trade in Equids, Semen, and Embryos 546
Multinational Trade Agreements 547
Emergent Diseases 548
New Variants of Established Pathogens 548
Climate Disturbance Effects 548
Availability of New Vectors 548
Migration of Amplifying/Reservoir Hosts or Vectors of Specific Pathogens 549
Reliability of Preexport Testing 549
Disease Spread from Feral Equids 549
Agroterrorism 549
Reducing the Risk of International Spread of Equine Diseases 549
Preexport Requirements 550
Postimport Requirements 550
Monitoring Surveillance and Reporting of Diseases 550
Industry Initiatives 550
References 551.e1
64 Immunoprophylaxis 551
Active Immunization 551
Basic Principles 551
Types of Vaccines 552
Inactivated Vaccines 552
Protein or Subunit Vaccines 552
DNA Vaccines 552
Modified Live Vaccines 553
Recombinant Vaccines 553
Vaccine Augmentation 553
Marker Vaccines 553
Vaccine Adjuvants 553
Regulatory Aspects of Vaccination 554
Licensing and Safety of Vaccines 554
Adverse Events 555
Safety of Vaccines in Broodmares 555
Passive Immunization 556
Use of Exogenous Antibodies 556
Passive Transfer of Maternal Immunity 556
Vaccination of Foals and Influence of Maternal Antibodies on Vaccine Responses 557
Concept of Core and Noncore Vaccines 558
Vaccination Recommendations for Specific Diseases 558
Tetanus 558
Equine Encephalomyelitis 559
West Nile Virus 559
Equine Influenza 560
Vaccination Protocols for Influenza 562
Primary Vaccination of Adult Horses 562
Routine Revaccination 562
Vaccination of Pregnant Mares 562
Vaccination of Foals 562
Vaccination in an Outbreak 563
Future Influenza Vaccines 563
Equine Herpesvirus (Rhinopneumonitis) 564
Future Vaccination Strategies to Prevent Herpesvirus Infection 565
Streptococcus equi subsp. equi Infection (Strangles) 566
Rabies 567
Equine neorickettsiosis (Potomac Horse Fever) 567
Botulism 568
Equine Viral Arteritis 569
Rotaviral Diarrhea 569
Anthrax 570
Equine Rhinitis A Virus 570
Miscellaneous Infections 570
References 570.e1
65 Antimicrobial Therapy 571
Principles of Therapy 571
Microbial Susceptibility 571
Streptococcus and Pasteurella 571
Actinobacillus 571
Staphylococcus 571
Anaerobic Bacteria 572
Pseudomonas, Enterobacter, Klebsiella, and Escherichia coli 572
Fungi 572
Bacterial Susceptibility Testing 572
Agar Disk Diffusion Test 572
Minimum Inhibitory Concentration Determination 572
Pharmacokinetic-Pharmacodynamic Optimization of Doses 573
Aminoglycosides 573
Fluoroquinolones 573
β-Lactam Antibiotics 574
Bacteriostatic Drugs 574
Tissue Penetration of Drugs 574
Impaired Diffusion into Tissues 575
Intracellular Drug Penetration 575
Local Factors That Affect Antibiotic Effectiveness 575
Absorption of Antimicrobials in Horses 576
Injectable Drugs 576
Oral Absorption 576
Local Drug Administration 576
Considerations for Antimicrobials in Foals 576
Adverse Drug Reactions in Horses 577
Alternative Uses of Antimicrobials in the Horse 578
Update on Antibiotics Used in Horses 578
Fluoroquinolone Antimicrobials 578
Macrolides and Derivatives 579
β-Lactam Antibiotics 579
Aminoglycosides 580
Trimethoprim-Sulfonamides 580
Tetracyclines 581
Chloramphenicol 581
Metronidazole 581
Miscellaneous Antibiotics 581
Rifampin 581
Aztreonam 581
Fosfomycin 582
Antifungal Drugs 582
Azoles 582
Imidazoles 582
Triazoles 582
Polyenes 582
Griseofulvin 582
Terbinafine 582
Antiviral Drugs 583
Cyclic Amines 583
Nucleoside Analogs 583
Neuraminidase Inhibitors 583
Antiprotozoal Drugs 583
Treatment of Equine Protozoal Myeloencephalitis 583
Folate Synthesis Inhibitors 583
Triazine Derivatives 583
Treatment of Other Protozoal Diseases 584
References 584.e1
66 Immunotherapy 584
Immunostimulants 584
Induction of Nonspecific Immune Responses 584
Bacterial Particles 586
Propionibacterium acnes 586
Bacille Calmette-Guérin Vaccine and Mycobacterium Cell Wall Extracts 587
Unmethylated Cytosine-Phosphate-Guanosine Motifs 588
Exogenous Cytokines 589
Interferon-α 589
Other Cytokines: Present and Future 590
Other Immunomodulators 590
Parapoxvirus ovis 590
Levamisole Phosphate 591
Caprine Serum Fraction 591
Acemannan 591
Imiquimod 591
Echinacea angustifolia 591
Ginseng 591
Vaccination 591
Types of Vaccines 591
Vaccine Adjuvants 591
Neonatal Vaccination 593
Molecular Vaccines 593
Cancer Vaccines 593
Immunotherapy for Hyposensitization 593
Passive Immunity 594
Transfer of Nonspecific Antibodies 594
Transfer of Antigen-Specific Antibodies 594
Rhodococcus equi 594
West Nile Virus 595
Endotoxemia 595
Clostridium botulinum 595
Clostridium tetani 595
Snake Venoms 595
Transfusion-Induced Immunomodulation 595
Immunosuppressants 596
Inhibitors of Gene Expression or Transcription 596
Glucocorticoids 596
Phosphatase and Kinase Inhibitors 596
Cyclosporine 596
Tacrolimus 596
Rapamycin (or Sirolimus) 597
Mycophenolate Mofetil 597
Leflunomide 597
Inhibitors of Nucleotide Synthesis 597
Azathioprine 597
Alkylating Agents 597
Cyclophosphamide and Chlorambucil 597
Vinca Alkaloids 597
Vincristine 597
Monoclonal Antibodies 597
References 597.e1
Appendices 598
Appendix A Infectious Disease Rule-Outs for Medical Problems* 598
Respiratory Problems 598
Cough 598
Nasal Discharge 598
Respiratory Noise 598
Rhinitis, Sinusitis 598
Pleural Effusion 598
Dyspnea 598
Gastrointestinal Problems 599
Diarrhea in Adult Horses 599
Diarrhea in Foals 599
Abdominal Pain 599
Dysphagia 599
Icterus 599
Oral Ulcerations or Vesicles 599
Hepatomegaly, Hepatic Inflammation 599
Abdominal Mass 599
Abdominal Effusion 599
Central Nervous System Problems 600
Cortical Signs 600
Brainstem Signs 600
Spinal Cord or Peripheral Nerve Signs 600
Urinary Tract Problems 600
Dysuria, Stranguria, Pollakiuria 600
Incontinence 600
Hematuria 600
Renal Failure 600
Musculoskeletal Problems 600
Myositis, Increased Muscle Enzyme Activity 600
Lameness, Stiffness, Arthritis 600
Muscle Fasciculations 601
Cardiovascular Problems 601
Cardiomyopathy, Myocarditis, Endocarditis 601
Reproductive Problems 601
Abortion, Infertility, Early Embryonic Loss, Birth of Weak Foals 601
Scrotal/Preputial Enlargement 601
Hemolymphatic Problems 601
Enlarged Lymph Nodes 601
Lymphangitis 601
Anemia 601
Petechial Hemorrhages 601
Ventral Abdominal or Limb Edema 601
Hypoalbuminemia 602
Thrombocytopenia 602
Ocular Problems 602
Uveitis 602
Keratitis 602
Conjunctivitis 602
Corneal Edema 602
Blindness 602
Skin Problems 602
Hair Loss 602
Pruritus 602
Crusting, Scaling 603
Ulcers, Fistulas, Granulomatous Lesions 603
Papulonodular Lesions 603
Large Nodular Dermatoses or Abscesses 603
Sudden Death 603
Collapse and Sudden Death 603
Appendix B Laboratory Testing for Infectious Diseases 604
Understanding Older and Newer Formats for Detection of Infection 604
Proper Procedures: Collection, Transport, Storage 604
Standardization 604
International Standards 605
North American Standards 606
Private Laboratories 606
Interpretation of Polymerase Chain Reaction Results 606
Status of Molecular Testing for Particular Diseases 606
Vesicular Diseases 606
Diarrheal Diseases 611
Respiratory Diseases 612
Central Nervous System Pathogens 612
Miscellaneous Polymerase Chain Reaction–Based Assays of Diagnostic Utility 613
Cyathostomin Infection 613
Conclusion 613
References 613.e1
Appendix C Diagnostic Test Kits 614
Appendix D Antimicrobial Drug Formulary 615
Index 618
A 618
B 620
C 622
D 625
E 626
F 629
G 630
H 631
I 632
J 634
K 634
L 634
M 636
N 638
O 639
P 640
Q 642
R 642
S 644
T 647
U 648
V 648
W 650
X 650
Y 650
Z 650