ContentsXV190-219Chapter11:TrematodesorFlukesClassificationoftrematodes190>Fasciolopsisspecies210Generalcharacteristicsoftrematodes191>Gastrodiscoidesspecies213Bloodflukes193>Watsoniusspecies 213>Schistosoma species194,201,202>Heterophyes species214Liverfluke202>Metagonimus species214>Fasciola species202,206214>Echinostomaspecies>Clonorchisspecies206>Lungfluke215>Opisthorchis species208,210>Paragonimus species215Intestinal fluke 210220-247Chapter12:Nematodes-|(lntestinalNematodes)>Enterobiusvermicularis 227General properties ofnematodes220230Classification 220Small intestinal nematodesGeneral description 221>Hookworm230Large intestinal nematodes224>Strongyloides species237,2421224>Trichuristrichiura>Ascarisspecies242,246248-261Chapter13:Nematodes-l Nematodes of LowerAnimalsthat Rarelyinfect ManClassification:248Capillaria species255,256,257Larva migrans248Trichostrongylus species 257Toxocariasis 250Dioctophymerenale258Angiostrongylusspecies252Oesophagostomumspecies259aBaylisascaris procyonis253Ternidensdeminutus2591260Lagochilascarisminor 253Mammomonogamuslaryngeus.Anisakiasis 253260Thelaziaspecies-254Gnathostomaspecies.262-289Chapter14:Nematodes-Ill(SomaticNematodes)>Onchocercavolvulus277Classification 262Filarial nematode262>Mansonellaspecies280,281Lymphaticfilarialnematodes265>Dirofilariaspecies282>Wuchereriabancrofti265OtherSomatic nematodes282>Brugiaspeices274,275S282>Dracunculus medinensisOtherfilarial nematodes276>Trichinellaspiralis 285>Loaloa 276
Chapter 14: Nematodes—III (Somatic Nematodes) 262–289 Chapter 13: Nematodes—II Nematodes of Lower Animals 248–261 that Rarely infect Man Chapter 12: Nematodes—I (Intestinal Nematodes) 220–247 Chapter 11: Trematodes or Flukes 190–219 • Classification of trematodes 190 • General characteristics of trematodes 191 • Blood flukes 193 h Schistosoma species 194, 201, 202 • Liver fluke 202 h Fasciola species 202, 206 h Clonorchis species 206 h Opisthorchis species 208, 210 • Intestinal fluke 210 h Fasciolopsis species 210 h Gastrodiscoides species 213 h Watsonius species 213 h Heterophyes species 214 h Metagonimus species 214 h Echinostoma species 214 h Lung fluke 215 h Paragonimus species 215 • General properties of nematodes 220 • Classification 220 • General description 221 • Large intestinal nematodes 224 h Trichuris trichiura 224 h Enterobius vermicularis 227 • Small intestinal nematodes 230 h Hookworm 230 h Strongyloides species 237, 242 h Ascaris species 242, 246 • Classification 262 • Filarial nematode 262 • Lymphatic filarial nematodes 265 h Wuchereria bancrofti 265 h Brugia speices 274, 275 • Other filarial nematodes 276 h Loa loa 276 h Onchocerca volvulus 277 h Mansonella species 280, 281 h Dirofilaria species 282 • Other Somatic nematodes 282 h Dracunculus medinensis 282 h Trichinella spiralis 285 • Classification 248 • Larva migrans 248 • Toxocariasis 250 • Angiostrongylus species 252 • Baylisascaris procyonis 253 • Lagochilascaris minor 253 • Anisakiasis 253 • Gnathostoma species 254 • Capillaria species 255, 256, 257 • Trichostrongylus species 257 • Dioctophyme renale 258 • Oesophagostomum species 259 • Ternidens deminutus 259 • Mammomonogamus laryngeus 260 • Thelazia species 260 Contents xv
xviEssentialsofMedical ParasitologySection4:Miscellaneous293-313Chapter15:LaboratoryDiagnosis of Parasitic Diseases293310IntroductionIntradermalskintests293311MorphologicalidentificationtechniquesXenodiagnostictechniques311Culture techniques in parasitology303AnimalinoculationmethodsImmunodiagnosticmethods307Imagingtechniques3116309Molecular methods314-321Chapter16:Medical EntomologyMedical entomology314Class arachnida319Vector314320.Classcrustacea314320Class insectaControlofArthropods325-333AppendicesAppendixIAppendixVClinical syndromes in parasitology325Biomedical waste management inAppendixIIparasitology330AppendixVICommontropical parasiticdiseases327Morphological forms ofparasites seen intheAppendix III331fecalsampleRomanowsky stains, composition and stainingprocedures 327Appendix IV329Laboratory-acquiredparasiticinfectionsIndex335-341
Section 4: Miscellaneous Chapter 15: Laboratory Diagnosis of Parasitic Diseases 293–313 • Introduction 293 • Morphological identification techniques 293 • Culture techniques in parasitology 303 • Immunodiagnostic methods 307 • Molecular methods 309 • Intradermal skin tests 310 • Xenodiagnostic techniques 311 • Animal inoculation methods 311 • Imaging techniques 311 Chapter 16: Medical Entomology 314–321 Appendices 325–333 • Medical entomology 314 • Vector 314 • Class insecta 314 • Class arachnida 319 • Class crustacea 320 • Control of Arthropods 320 • Appendix I Clinical syndromes in parasitology 325 • Appendix II Common tropical parasitic diseases 327 • Appendix III Romanowsky stains, composition and staining procedures 327 • Appendix IV Laboratory-acquired parasitic infections 329 • Appendix V Biomedical waste management in parasitology 330 • Appendix VI Morphological forms of parasites seen in the fecal sample 331 Index 335–341 xvi Essentials of Medical Parasitology
1SectionIntroductionChapter1General Introduction:Parasitology
Section 1 Chapter 1 General Introduction: Parasitology Introduction Chapter-01.indd 1 5/17/2014 5:48:03 PM
GeneralIntroduction:1ParasitologyChapterOutlineTaxonomyofparasitesPathogenesis ofparasiticdiseasesParasiteImmunologyofparasiticdiseasesHostLaboratory diagnosisof parasitic diseasesHost-parasite relationshipTreatmentofparasiticdiseasesTransmission of parasitesExpectedquestionsLifecycleof theparasitesMedical Parasitologydeals with the studyofspecies name with an initial small letter,animalparasites,whichinfectandproducee.g,Entamoebahistolyticadiseases inhuman beings.PARASITETAXONOMYOFPARASITESParasite is a living organism, which lives inAccording to the binomial nomenclatureasoruponanotherorganism(host)andderivessuggestedbyLinnaeus,eachparasitehastwonutrients directly from it, without giving anynames:agenus and aspeciesname.benefitto the host.These names are either derived from:Protozoaandhelminths(animalparasites)names of their discoverers, Greek or Latinare studied in Medical Parasitologywords of the geographical area where theyParasites may be classified as:arefound,habitat of theparasite,or hostsEctoparasite: They inhabit the surface ofinwhichparasitesarefoundand its sizeandshape.the body of the host without penetratingAll parasites are classified under theintothetissues.Theyareimportantvectorsfollowing taxonomicunits-the kingdom,transmittingthepathogenic microbes.Thesubkingdom,phylum,subphylum,superinfection bytheseparasites is called asclass, class, subclass, order, suborder, superinfestation, e.g.,fleas or ticksfamily,family,genus and species.Endoparasite:They livewithinthebodyofThe generic name of the parasite alwaysthe host (e.g., Leishmania).Invasion bythebegins with an initial capital letter andendoparasiteiscalledasinfection
Medical Parasitology deals with the study of animal parasites, which infect and produce diseases in human beings. TAXONOMY OF PARASITES According to the binomial nomenclature as suggested by Linnaeus, each parasite has two names: a genus and a species name. Th ese names are either derived from: names of their discoverers, Greek or Latin words of the geographical area where they are found, habitat of the parasite, or hosts in which parasites are found and its size and shape. All parasites are classifi ed under the following taxonomic units—the kingdom, subkingdom, phylum, subphylum, super class, class, subclass, order, suborder, super family, family, genus and species. Th e generic name of the parasite always begins with an initial capital letter and species name with an initial small letter, e.g., Entamoeba histolytica. PARASITE Parasite is a living organism, which lives in or upon another organism (host) and derives nutrients directly from it, without giving any benefi t to the host. Protozoa and helminths (animal parasites) are studied in Medical Parasitology. Parasites may be classifi ed as: z Ectoparasite: Th ey inhabit the surface of the body of the host without penetrating into the tissues. Th ey are important vectors transmitting the pathogenic microbes. Th e infection by these parasites is called as infestation, e.g ., fl eas or ticks z Endoparasite: Th ey live within the body of the host (e.g., Leishmania). Invasion by the endoparasite is called as infection. 1 General Introduction: Parasitology Chapter Outline • Taxonomy of parasites • Parasite • Host • Host-parasite relationship • Transmission of parasites • Life cycle of the parasites • Pathogenesis of parasitic diseases • Immunology of parasitic diseases • Laboratory diagnosis of parasitic diseases • Treatment of parasitic diseases • Expected questions Chapter-01.indd 3 5/17/2014 5:48:04 PM
4Section1IntroductionThe endoparasites are offollowingtypes:source of infection toother susceptibleObligate parasite:They cannot existhosts. (e.g., dog is the reservoir host forwithout a parasitic life in the host (e.g.,cysticechinococcosis)Plasmodiumspecies)Paratenichost:Itis thehost,inwhich.Facultative parasite: They can live athe parasite lives but it cannot developparasitic life or free-living life, when thefurther and not essentialfor its life cycle isopportunityarises(e.g.,Acanthamoeba)known as paratenic host (e.g., fresh water.Accidentalparasite:Theyinfectan unusualprawn for Angiostrongylus cantonensis,host (e.g.,Echinococcus granulosus infectbig suitablefishforplerocercoid larva ofhumansaccidentally)DiphvllobothriumlatumandfreshwaterAberrantparasite or wanderingparasite:fishes for Gnathostoma spinigerum).ItTheyinfectahostwheretheycannotliveorfunctions as a transport or carrier hostdevelop further (e.g., Toxocara in humans).Amplifier host: It is the host, in which theparasitelives and multiplies exponentially.HOSTHOST-PARASITERELATIONSHIPHostisdefinedasanorganism,whichharborsthe parasite and provides nourishment andTherelationship between the parasite and theshelter.host, maybedivided intothefollowingtypes:Hosts maybe of the followingtypes:Definitive host:Thehost in which theSymbiosis:It is theclose associationadult parasites replicate sexually (e.g.,between thehostand theparasite.Bothareanopheles species), is called as definitiveinterdependentupon each other that onecannot live without the help of the otherhost.The definitive hosts maybe human orNone of them suffer any harm from eachnonhuman livingthingsother.Intermediate host: The host in which theCommensalism:It is an association in whichparasite undergoes asexual multiplicationtheparasite onlyderives the benefit withoutis called as intermediate host. (e.g., incausingany injurytothehost.Acommensalmalaria parasite lifecycle,humans are theiscapableof livinganindependent lifeintermediatehosts)Parasitism: It is an association in which the>Intermediatehostsareessentialfortheparasite derives benefit from the host andcompletionofthelifecycleforsomealways causes some injury to the host.Theparasiteshost getsno benefit in return.Some parasites require two inter-mediate hosts to complete their diffe-Disease:Thedisease is the clinicalrentlarvalstages.Theseareknownasmanifestationoftheinfection,which showsthefirstandsecondintermediatehoststhe active presence,and replication of therespectively(e.g.,Amphibian snails areparasite causing damage to the host. It maythefirstintermediatehostandaquaticbe mild, severe and fulminant and in someplants arethe secondintermediatehostcases may even cause death of the host.forFasciolahepatica)Carrier: The person who is infected withHosts can also be:the parasite without any clinical or subReservoirhost: It is a host, which harboursclinical disease is referred to as a carrier.Hethe parasites and serves as an importantcan transmittheparasites to others
4 Section 1 Introduction Th e endoparasites are of following types: z Obligate parasite: They cannot exist without a parasitic life in the host (e.g., Plasmodium species) z Facultative parasite: They can live a parasitic life or free-living life, when the opportunity arises (e.g., Acanthamoeba) z Accidental parasite: Th ey infect an unusual host (e.g., Echinococcus granulosus infect humans accidentally) z Aberrant parasite or wandering parasite: Th ey infect a host where they cannot live or develop further (e.g., Toxocara in humans). HOST Host is defi ned as an organism, which harbors the parasite and provides nourishment and shelter. Hosts may be of the following types: z Definitive host: The host in which the adult parasites replicate sexually (e.g., anopheles species), is called as defi nitive host. Th e defi nitive hosts may be human or nonhuman living things z Intermediate host: Th e host in which the parasite under goes asexual multiplication is called as intermediate host. (e.g., in malaria parasite life cycle, humans are the intermediate hosts) h Intermediate hosts are essential for the completion of the life cycle for some parasites h Some parasites require two intermediate hosts to complete their diff erent larval stages. Th ese are known as the fi rst and second interme diate hosts respectively (e.g., Amphibian snails are the fi rst intermediate host and aquatic plants are the second inter mediate host for Fasciola hepatica) Hosts can also be: z Reservoir host: It is a host, which harbours the parasites and serves as an important source of infection to other susceptible hosts. (e.g., dog is the reservoir host for cystic echinococcosis) z Paratenic host: It is the host, in which the parasite lives but it cannot develop further and not essential for its life cycle is known as paratenic host (e.g., fresh water prawn for Angiostrongylus cantonensis, big suitable fi sh for plerocercoid larva of Diphyllobothrium latum and freshwater fishes for Gnathostoma spinigerum). It functions as a transport or carrier host z Amplifi er host: It is the host, in which the parasite lives and multiplies exponentially. HOST-PARASITE RELATIONSHIP Th e relationship between the parasite and the host, may be divided into the following types: z Symbiosis: It is the close association bet ween the host and the parasite. Both are interdependent upon each other that one cannot live without the help of the other. None of them suff er any harm from each other z Commensalism: It is an association in which the parasite only derives the benefi t without causing any injury to the host. A commensal is capable of living an independent life z Parasitism: It is an association in which the parasite derives benefi t from the host and always causes some injury to the host. The host gets no benefi t in return. Disease: Th e disease is the clinical manifestation of the infection, which shows the active presence, and repli cation of the parasite causing damage to the host. It may be mild, severe and fulminant and in some cases may even cause death of the host. Carrier: Th e person who is infected with the parasite without any clinical or sub clinical disease is referred to as a carrier. He can transmit the parasites to others. Chapter-01.indd 4 5/17/2014 5:48:04 PM