15Chapter1General Introduction:ParasitologyContd..IvermectinUsedforlymphaticflariasis in AfricaKills by interfering with nervoussystemandmusclefunction,inDOCforonchocerciasisparticularby enhancing inhibitoryAlternative drug for Loa loaandMansonellainfectionsneurotransmissionDoxycyclineTargetsthe intracellularWolbachiaAlternativedrugforlymphaticfilariasispresentinsidetheMicrofilariaAbbreviations: DNA, deoxyribonucleic acid; DOC, drug ofchoice; RNA, ribonucleic acid; PFOR,pyruvateferredoxin oxido-reductaseenzyme; ATP,adenosinetriphosphate; NADH, nicotinamide adenine dinucleotideEXPECTEDQUESTIONSI.Write short notes on:(b)Trichomonasvaginalis(a)Paratenichost(c)Trypanosomabrucei(b)Reservoirhost(d)Ascaris(c)Indirect/complex life cycle3.Cholangiocarcinomaisassociated(d)Immuneevasionmechanisms ofthewithchronicinfectionof:parasites(a)Paragonimuswestermani(e)Antiparasitic drugs(b)FasciolahepaticaIl.Differentiatebetween:(c)Clonorchissinensis(a)Definitivehostandintermediatehost(d)Schistosomahaematobium(b)Directandindirect lifecycle4. Which of thefollowingparasiteisIll.Multiplechoicequestions(McQs):transmitted by dog:1. A host harboring adult or sexual(a)Taenia saginatastage of a parasite is called:(b)Hymenolepisnana(a)Definitive host(c)Echinococcusgranulosus(b)Intermediatehost(d)Diphyllobothriumlatum(c) Reservoir host5.Blood-suckingvectormaytransmit:(d)Noneof theabove(a)Ascaris lumbricoides2.Parasitewhichmaybetransmitted(b)Ancylostomaduodenaleby sexual contact is:(c)Strongyloides stercoralis(a)TrypanosomacruziPlasmodium(d)Answers1. (a)2. (b)3. (c)4. (c)5. (d)
Chapter 1 General Introduction: Parasitology 15 Ivermectin Kills by interfering with nervous system and muscle function, in particular by enhancing inhibitory neurotransmission Used for lymphatic fi lariasis in Africa DOC for onchocerciasis Alternative drug for Loa loa and Mansonella infections Doxycycline Targets the intracellular Wolbachia present inside the Microfi laria Alternative drug for lymphatic fi lariasis Abbreviations: DNA, deoxyribonucleic acid; DOC, drug of choice; RNA, ribonucleic acid; PFOR, pyruvate ferredoxin oxidoreductase enzyme; ATP, adenosine triphosphate; NADH, nicotinamide adenine dinucleotide. Contd. EXPECTED QUESTIONS I. Write short notes on: (a) Paratenic host (b) Reservoir host (c) Indirect/complex life cycle (d) Immune evasion mechanisms of the parasites (e) Antiparasitic drugs II. Differentiate between: (a) Defi nitive host and intermediate host (b) Direct and indirect life cycle III. Multiple choice questions (MCQs): 1. A host harboring adult or sexual stage of a parasite is called: (a) Defi nitive host (b) Intermediate host (c) Reservoir host (d) None of the above 2. Parasite which may be transmitted by sexual contact is : (a) Trypanosoma cruzi (b) Trichomonas vaginalis (c) Trypanosoma brucei (d) Ascaris 3. Cholangiocarcinoma is associated with chronic infection of : (a) Paragonimus westermani (b) Fasciola hepatica (c) Clonorchis sinensis (d) Schistosoma haematobium 4. Which of the following parasite is transmitted by dog : (a) Taenia saginata (b) Hymenolepis nana (c) Echinococcus granulosus (d) Diphyllobothrium latum 5. Blood-sucking vector may transmit: (a) Ascaris lumbricoides (b) Ancylostoma duodenale (c) Strongyloides stercoralis (d) Plasmodium Answers 1. (a) 2. (b) 3. (c) 4. (c) 5. (d) Chapter-01.indd 15 5/17/2014 5:48:11 PM
2SectionProtozoologyChapter2IntroductiontoProtozoaChapter3AmoebaChapter4Flagellates-l(IntestinalandGenitalChapter5Flagellates-ll(HemoflagellatesChapter6Sporozoa-l(MalariaParasiteandBabesia)Chapter7Sporozoa-ll(OpportunisticCoccidianParasitesChapter8Miscellaneous Protozoa
Section 2 Chapter 2 Introduction to Protozoa Chapter 3 Amoeba Chapter 4 Flagellates—I (Intestinal and Genital) Chapter 5 Flagellates—II (Hemoflagellates) Chapter 6 Sporozoa—I (Malaria Parasite and Babesia) Chapter 7 Sporozoa—II (Opportunistic Coccidian Parasites) Chapter 8 Miscellaneous Protozoa Protozoology Chapter 02.indd 17 5/17/2014 5:47:37 PM
Introductionto2ProtozoaChapterOutlineGeneralfeaturesofprotozoaExpectedquestionsClassification of protozoa>On other hand, the protozoa are un-GENERALFEATURESOFdoubtedlylowereukaryotesastheypos-PROTOZOAsesscellular organelles and have similarTheprotozoa areunicellular eukaryotic cellsmetabolicpathways.thatperformall thephysiologicalfunction.·MorethantwolakhsprotozoaarenamedCLASSIFICATIONOFPROTOZOAbut only about 70 species belonging toTheTraditional1980s Classificationnearly30 genera infect human beingsBasedontherecommendationof the:Many of theseprotozoa are relativelycommittee on SystematicsandEvolution ofharmlessbutfewmaycausesomeofthethe Societyof Protozoologists conducted byimportantdiseasesoftropicalcountrieslikeLevine et al (1980), the protozoan parasitesmalaria, kala azar, sleeping sickness andwere classified (Table2.1)Chaga'sdisease,etcwhichtogetherthreatenThoughit satisfiedtherequirements oftheonequarterofthepopulationof theWorldprotozoologists but couldn'tmeet some oftheWiththeadventof HIV/AIDS,someofrequirementsofmedical parasitologists.them are increasinglybeingrecognized asopportunisticpathogensliketoxoplasmosis,Corliss'sInterim User Friendlycryptosporidiosis,etcClassification (1994)Ingeneral,protozoa areplaced betweenCorliss proposeda user-friendlyclassificationprokaryotesand highereukaryotestrying to meet the requirements of both>Like bacteria, they are small, singleprotozoologists and medical parasitologists.celled,1-150μm size,shortgenerationHe divided the living creatures into sixtime, higher reproduction rates andkingdoms.Unicellularparasites (generallyhaveatendencytoinduceimmunitytoacceptedasprotozoa)arecategorizedintotworeinfection in thosewho survivephylumArchezoa and Protozoa
2 Introduction to Protozoa GEnERAL FEAtuREs oF pRotoZoA Th e protozoa are unicellular eukaryotic cells that perform all the physiological function. z More than two lakhs protozoa are named but only about 70 species belonging to nearly 30 genera infect human beings z Many of these protozoa are relatively harmless but few may cause some of the important diseases of tropical countries like malaria, kala azar, sleeping sickness and Chaga’s disease, etc which together threaten one quarter of the population of the World z With the advent of HIV/AIDS, some of them are increasingly being recognized as opportunistic pathogens like toxoplasmosis, cryptosporidiosis, etc z In general, protozoa are placed between prokaryotes and higher eukaryotes h Like bacteria, they are small, single celled, 1–150 µm size, short generation time, higher reproduction rates and have a tendency to induce immunity to reinfection in those who survive h On other hand, the protozoa are undoub tedly lower eukaryotes as they possess cellular organelles and have similar metabolic pathways. CLAssiFiCAtion oF pRotoZoA the traditional 1980s Classifi cation Based on the recommendation of the committee on Systematics and Evolution of the Society of Protozoologists conducted by Levine et al (1980), the protozoan parasites were classifi ed (Table 2.1) Th ough it satisfi ed the requirements of the protozoologists but couldn’t meet some of the requirements of medical parasitologists. Corliss’s interim user Friendly Classifi cation (1994) Corliss proposed a userfriendly classifi cation trying to meet the requirements of both protozoologists and medical parasitologists. He divided the living creatures into six kingdoms. Unicellular parasites (generally accepted as protozoa) are categorized into two phylum—Archezoa and Protozoa. Chapter Outline • General features of protozoa • Classifi cation of protozoa • Expected questions Chapter 02.indd 19 5/17/2014 5:47:37 PM
20ProtozoologySection2soaoooioaoooanosoonooeeiaoiaoroooroaaeooDasonDIPIDIisaiisuaoooapoinsneeeierooosedoepiaoaooeseosoponsrarodoonsooaoesoqonaeooooswnkydqnseeeao(ooos)eawnjkyd
20 section 2 Protozoology table 2 .1: The traditional 1980s classifi cation of protozoa (Levine et al., 1980) Phylum Subphylum Super class Class Subclass Order Suborder Genus Sarcomastigophora (Amoeba and fl agellates) Mastigophora Zoomastigophorea Kinetoplastida Trypanosomatina Leishmania Trypanosoma Retortamonadida Retortamonas Chilomastix Diplomonadida Diplomonadina Giardia Enteromonadina Enteromonas Trichomonadida Trichomonas Pentatrichomonas Dientamoeba Sarcodina Rhizopoda Lobosea Gymnamoebia Amoebida Tubulina Entamoeba Endolimax Iodamoeba Acanthopodina Acanthamoeba Schizopyrenida Naegleria Apicomplexa (sporozoans) Sporozoea Coccidia Eucoccidiida Eimeriina Eimeria Toxoplasma Cryptosporidium Cyclospora Isospora Sarcocystis Haemosporina Plasmodium Piroplasmia Piroplasmida Babesia Microspora Microsporea Microsporida Apansporoblastina Enterocytozoon Encephalitozoon Pleistophora Trachipleistophora Brachiola Nosema Vittaforma Microsporum Ciliophora Kinetofragminophorea Vestibuliferia Trichostomatida Trichostomatina Balantidium Adapted from: Topley and Wilson’s Microbiology and Microbial Infections (Parasitology volume), 10th edition. Chapter 02.indd 20 5/17/2014 5:47:39 PM
21Chapter2 Introduction to ProtozoaSubkingdom NeozoaMolecularClassification(2000)The hierarchical system can be accuratelyUnicellular eukaryotic organisms typicallyrepresented by the ribonucleic acid (RNA)possessingmitochondria and otherorganelles.and protein sequences of the organisms.Phylum Amoebozoa: Unicellular euka-With advance of molecular techniques, theryotic organisms with pseudopodia usedribosomal RNA and protein sequences areforlocomotionandfeedingstudied, and a new classification has been>Class Amoebaea: free living amoebadevised.withandmitochondriaCavalierandSmith'ssixkingdomsclassifi>ClassEntamoebidea:Obligateamoebacation-molecularclassificationisbasedwith secondarylossofmitochondriaonthesixkingdomtheoryproposedbyPhylum Percolozoa: Unicellular organ-CavalierandSmith(1998).Theyarebacteria,isms having1-4temporaryflagella andprotozoa,animalia,fungi,plantaeandmitochondria but lacking Golgi bodieschromistaPhylum Euglenozoa: Unicellular organTheunicellularprotozoanparasitesconsti-ismshaving1-4flagella,mitochondria andtute thirteen phyla of which the humanGolgibodiesparasites belong to seven phyla which arePhylum Sporozoa:Unicellulareukaryoticdistributed in three kingdoms-Protozoa,organismspossessingapicalcomplexmadeFungiandChromista(Table2.2)up of polar rings,rhoptries,micronemesThedescription in this book will beaccor-and conoiddingtothis classification.PhylumCiliophora:Unicellularorganismshavingcilia as locomotororganand twoKingdomProtozoanucleiof different size and ploidy-(1)Unicellular eukaryotic,phagotrophic, non-macronucleusand (2)micronucleusphotosynthetic organism withouta cellwall.SubkingdomArchezoaKingdomFungiUnicellular eukaryotic organisms exhibitingEukaryotic heterotrophic organisms lackingvarious prokaryotic features in ribosomesplastids but possessing cell wall containingand transfer ribonucleic acid (tRNA)andchitin and β-glucan.lackingmitochondriaand otherorganelles..Phylum Metamonada:Unicellular intes-KingdomChromistatinalflagellates(2-8numbers)Unicellular eukaryotic,photosynthetic fila-.PhylumParabasalia:Unicellularflagellatesmentous or colonial, organisms (in partwith one or more nuclei and numerous"algae");somewith secondaryloss ofplastids.flagella and parabasal body
Chapter 2 Introduction to Protozoa 21 Molecular Classification (2000) The hierarchical system can be accurately represented by the ribonucleic acid (RNA) and protein sequences of the organisms. With advance of molecular techniques, the ribosomal RNA and protein sequences are studied, and a new classification has been devised. z Cavalier and Smith’s six kingdoms classification—molecular classification is based on the six kingdom theory proposed by Cavalier and Smith (1998). They are bacteria, protozoa, animalia, fungi, plantae and chromista z The unicellular protozoan parasites constitute thirteen phyla of which the human parasites belong to seven phyla which are distributed in three kingdoms—Protozoa, Fungi and Chromista (Table 2.2) z The description in this book will be according to this classification. Kingdom Protozoa Unicellular eukaryotic, phagotrophic, nonphotosynthetic organism without a cell wall. Subkingdom Archezoa Unicellular eukaryotic organisms exhibiting various prokaryotic features in ribosomes and transfer ribonucleic acid (tRNA) and lacking mitochondria and other organelles. z Phylum Metamonada: Unicellular intestinal flagellates (2–8 numbers) z Phylum Parabasalia:Unicellular flagellates with one or more nuclei and numerous flagella and parabasal body. Subkingdom Neozoa Unicellular eukaryotic organisms typically possessing mitochondria and other organelles. z Phylum Amoebozoa: Unicellular eukaryotic organisms with pseudopodia used for locomotion and feeding h Class Amoebaea: free living amoeba with and mitochondria h Class Entamoebidea:Obligate amoeba with secondary loss of mitochondria z Phylum Percolozoa: Unicellular organisms having 1–4 temporary flagella and mitochondria but lacking Golgi bodies z Phylum Euglenozoa: Unicellular organisms having 1–4 flagella, mitochondria and Golgi bodies z Phylum Sporozoa: Unicellular eukaryotic organisms possessing apical complex made up of polar rings, rhoptries, micronemes and conoid z Phylum Ciliophora:Unicellular organisms having cilia as loco motor organ and two nuclei of different size and ploidy—(1) macronucleus and (2) micronucleus. Kingdom Fungi Eukaryotic heterotrophic organisms lacking plastids but possessing cell wall containing chitin and b-glucan. Kingdom Chromista Unicellular eukaryotic, photosynthetic filamentous or colonial, organisms (in part “algae”); some with secondary loss of plastids. Chapter 02.indd 21 5/17/2014 5:47:39 PM