Introduction to Parasitology and Protozoa .ppt
- 3. Introduction to Parasitology • Each animal is a host of many parasites; thus, there are far more parasitic organisms on earth than there are nonparasitic organisms.
- 4. Introduction to Parasitology • Each animal is a host of many parasites; thus, there are far more parasitic organisms on earth than there are nonparasitic organisms. • It has been estimated that more than 50% of all living plants and animals are parasitic at some stage during their life cycle.
- 5. Why do we study parasites? • Parasites provide unique examples of biological phenomena not found in free- living organisms.
- 6. Why do we study parasites? • Parasites provide unique examples of biological phenomena not found in free- living organisms. • Medical Importance
- 7. Why do we study parasites? • Parasites provide unique examples of biological phenomena not found in free- living organisms. • Medical Importance • Veterinary Importance
- 8. Why do we study parasites? • Parasites provide unique examples of biological phenomena not found in free- living organisms. • Medical Importance • Veterinary Importance • Economic Importance
- 9. Medical Importance of Parasites • Humans are hosts to many species of parasites.
- 10. Medical Importance of Parasites • Humans are hosts to many species of parasites. • Many of these parasites are causative agents of major public health problems of the world.
- 11. Ascaris 1.3 billion Hookworms 1.3 billion Whipworms 1 billion Filarial worms 657 million Malaria 500 million Schistosomes 270 million Amebiasis 50 million Taeniad tapeworms 50 million Clonorchis 20 million Chagas’ Disease 15 million These parasites cause untold suffering and death in the world today. Recent estimates of the number of people infected with parasites in the world are:
- 12. Examples of Medical Importance in the World
- 13. Examples of Medical Importance in the World • The life expectancy of an Egyptian is in the mid-40's due to Schistosomes.
- 14. Examples of Medical Importance in the World • The life expectancy of an Egyptian is in the mid-40's due to Schistosomes. • 15 million children in the world will die this year from a combination of malnutrition and parasites.
- 15. Examples of Medical Importance in the World • The life expectancy of an Egyptian is in the mid-40's due to Schistosomes. • 15 million children in the world will die this year from a combination of malnutrition and parasites. • Over 1 million African children will die this year from the effects of malaria.
- 16. Examples of Medical Importance in the World • The life expectancy of an Egyptian is in the mid-40's due to Schistosomes. • 15 million children in the world will die this year from a combination of malnutrition and parasites. • Over 1 million African children will die this year from the effects of malaria. • Many cases of plague, transmitted by fleas, still occur throughout the world.
- 17. Human parasitology • Human parasitology is the study of those organisms which parasitize humans. • According to the very broad definition of parasitology – parasites should include the viruses, bacteria, fungi, protozoa and metazoa (multi-celled organisms) – which infect their host species – However, for historical reasons the first three have been incorporated into the discipline of Microbiology.
- 18. Symbiosis • Symbiosis – Two different organisms, live together and interact • In this association – one partner lives in or on another one’s body • 3 types – Mutualism – Commensalism – Parasitism.
- 19. • Mutualism – – is a permanent association between two different organisms that life apart is impossible – two partners benefit each other – such as termites and flagellates. • The mutuals are – metabolically dependent on one another – one cannot survive in the absence of the other. Mutualism
- 20. Commensalism – is the association of two different organisms – in which one partner is benefited while the other neither benefited nor injured – such as E. coli and man • Organism that live on another living organism in complete harmony – Usually they do not cause any harm to host – Rather they usually have got some beneficial effect on host Commensalism
- 21. Parasitism • Parasitism – is the association of two different organisms – in which one partner is benefited while the other is injured – such as • Ascaris lumbricoides and man • Yersinia pestis and man • Hepatitis virus and man
- 22. in order to receive Parasite It is implied that they are harmful to the host A living organism that lives on another living organism nourishment and shelter
- 23. Some commensals or free living saprophytes can cause disease when there is low resistance in the host. Opportunist pathogens Organisms that can not live without a parasitic life. They must live on a host Obligate (strict) parasite Example of obligate parasite: Virus A few bacteria (Rickettsia, Chlamydia)
- 24. Parasite Endoparasite Ectoparasite temporary parasite permanent parasite obligatory parasite facultative parasite accidental parasite opportunistic parasite
- 25. Endoparasite
- 26. Ectoparasite
- 27. Host • Host – In parasitism • it supplies the parasite with nourishment and shelter • it is the injured partner • Carrier – A person who harbours parasite – has no clinical symptoms – is an important source of infection in epidemiology.
- 28. Types of Host • Definitive (final) host – harbours adult or – sexually reproductive stage of a parasite • Intermediate host – harbours larval or asexually reproductive stage of a parasite – according to priority they are classified into • first intermediate host • second intermediate host • third intermediate host
- 29. Reservoir hosts • Reservoir hosts – are the vertebrate hosts which harbour • the same species of parasite • at same stage as a human host – They are an important source of infection in epidemiology
- 30. Paratenic host • Paratenic host or transport host – is an abnormal host in which • some parasitic larvae can survive but • can’t develop into adults – If the larvae have a chance to enter their appropriate hosts • they can continue to develop into adults there • Example-Larva migrans
- 31. Mechanical Transmission Mechanical Transmission • Arthropods play a role of the – transportation of pathogens • which is not indispensable for the disease transmission – such as flies carry typhoid bacilli, ascarid eggs and amoebic cysts.
- 32. Biological Transmission • Biological Transmission – Pathogens have to spend • a part of their life cycle in the vector arthropods • in which they multiply or develop into infective stage and • then invade the human body • with the help of the arthropod – such as Anopheles mosquitoes transmit malaria.
- 33. Zoonosis • Zoonosis – refers to animal’s diseases • which can be transmitted to man – These animals • infected with parasites are called reservoir hosts
- 34. Larva migrans • Larva migrans – larvae living in their abnormal hosts • in which they can not grow into adults but • can wander everywhere and • cause the local and systemic pathological lesions of the hosts.
- 35. Human Parasitology Medical Helminthology Medical Protozoology Medical Arthropodology • Class Nematoda • Class Trematoda • Class Cestoda • Class Metacanthocephala • Class Lobosea • Class Zoomastigophorea • Class Sporozoa • Class Ciliophora • Class Insecta • Class Arachnida • Class Crustacea • Class Chilopoda
- 36. 2 types of parasites 1. Protozoa 2. Metazoa (Helminths) Unicellular parasite Multicellular parasite
- 37. Protozoa Unicellular organism Belong to Kingdom Protista Morphologically and functionally complete Eukaryotic
- 38. Taxonomic classification of protozoa Sub kingdom Phylum Sub-phylum Genus- examples Species- examples Protozoa Sarcomastig- ophora further divided into Sarcodina-- - move by pseudopodia Entamoeba E. histolytica Mastigophora move by flagella Giardia G. lamblia Apicomplexa no organelle of locomotion Plasmodium P. falciparum, P. vivax, P. malariae, P. ovale Ciliophora move by cillia Balantidium B. coli Microspora Spore-forming Enterocyto-zoa E. bienusi
- 40. Ectoplasm Cytoplasm Endoplasm 1. Pseudopodia 2.Flagella 3. Cilia Nucleus 1.Nucleus 2.Vacuoles Nuclear membrane, linin network, chromatin granules, karyosome
- 41. Reproduction • Asexual Multiplications – Simple binary fission, e.g., Entamoeba, Giardia – Multiple fission or Schizogony, e.g., Plasmodium • Sexual reproduction – Syngamy, e.g., Plasmodium – Conjugation, e.g., Balantidium
- 43. Rhizopoda They have pseudopodia EX: Entamoeba histolytica Amoeboid movement Amoebic dysentery
- 45. Mastigophora Possess flagella Giardia intestinalis Kala azar, PKDL Trichomonas vaginalis L. tropica Espundia Chronic enteritis, malabsorption Vaginitis, urethritis Leishmania donovani Oriental sore L. brasiliensis
- 46. Class Zoomastigophorea Leishmania sp Trichomonas vaginalis Giardia
- 47. Chagas disease (South America) Trypanosoma brucei Sleeping sickness (Africa) Trypanosoma cruzi
- 48. Sporozoa Alternation of generation- Asexual and sexual life cycle. Plasmodium vivax falciparum malariae ovale Malaria
- 49. Toxoplasma gondii Isospora hominis Isospora belli Toxoplasmosis, congenital anomaly Diarrhoea
- 50. Class Sporozoa • Plasmodium spp Toxopasma gondii Cryptosporidium Pneumocycstis carinii
- 51. Balantidium coli Ciliata They are ciliated Dysentery
- 52. Class Ciliophora – Balantidium coli
- 53. Trichomonas hominis Chilomastix mesnili Enteromonas hominis Embadomonas intestinalis Nonpathogenic protozoa Rhizopoda Entamoeba coli gingivalis Dientamoeba fragilis, Endolimax nana Iodamoeba butschlii Mastigophora
- 55. Helminths!
- 56. Helminthes multicellular Bilaterally symmetrical Have 3 germ layers Ectoderm Mesoderm Endoderm Phylum: Platyhelminthes Nemathelminthes
- 57. Taxonomic classification of helminths Sub kingdom Phylum Class Genus – examples Metazoa Nematodes Round worms; appear round in cross section, they have body cavities, a straight alimentary canal and an anus Ascaris (roundworm) Trichuris (whipworm) Ancylostoma (hookworm) Necator (hookworm) Enterobius (pinworm or threadworm) Strongyloides Platyhelminthes Flat worms; dorsoventrally flattened, no body cavity and, if present, the alimentary canal is blind ending Cestodes Adult tapeworms are found in the intestine of their host They have a head (scolex) with sucking organs, a segmented body but no alimentary canal Each body segment is hermaphrodite Taenia (tapeworm) Trematodes Non-segmented, usually leaf- shaped, with two suckers but no distinct head They have an alimentary canal and are usually hermaphrodite and leaf shaped Schistosomes are the exception. They are thread- like, and have separate sexes Fasciolopsis (liver fluke) Schistosoma (not leaf shaped!)
- 59. Cestode Flattened dorsoventrally Tape like Segmented No body cavity No alimentary canal Head has suckers (with or without hooks) Sex not separate Long Highly developed reproductive system Head with sucker neck body
- 60. Cestoda
- 61. Class Cestoda • Taenia solium Taenia saginata Echinococcus granulosus
- 64. Trematodes Flattened Leaf like Non segmented Head and ventral surface possesses suckers Partial alimentary canal Sex not separate( except schistosoma) sucker Alimentary canal
- 67. Nematode Cylindrical Elongated Unsegmented Complete alimentary canal Body cavity present Sex separate Body covered by cuticle male female male female
- 68. Nematoda
- 69. Class Nematoda Ascaris lumbricoides Trichuris trichiura Hookworm Enterobius vermicularis Filaria Trichinella spiralis
- 71. Class Trematoda Clonorchis sinensis Fasciolopsis buski Paragonimus westermani Schistosoma japonicum
- 72. Trematoda
- 73. Cestode Trematode Nematode Shape tape like leaf like cylindrical Segments present absent absent Body cavity absent absent present Sucker present present absent absent present (Incomplete) present (complete) Sex not separate not separate (ex. Schisto) separate Alimentary canal
- 75. Class Insecta Anopheles sinensis Lucilia sericata Lice Sandflies , Fleas
- 77. Class Arachnida Sarcopes scabiei follicle mite Ticks; Mites
- 78. Class Crustacea • Cambaroides • Potamon
- 80. Life cycle Life cycle • is the process of a – parasite’s growth – development and reproduction – which proceeds in • one or more different hosts • depending on the species of parasites
- 81. Infective Stage Infective Stage • is a stage – when a parasite can invade human body and – live in it
- 82. Mode of infection • Infective Route – is the specific entrance through which • the parasite invades the human body. • Infective Mode – means how the parasite • invades human body • such as the cercariae of the blood fluke actively penetrate the skin of a swimming man and • the infective ascaris eggs are swallowed by man
- 83. Parasites’ Harms to Man • Mechanical effects – of parasites on host tissues and organs • e. g. , biliary ascariasis and larva migrans • Depriving nourishment from hosts • e.g. hookworms suck blood • Toxic effect – e. g., mosquitoes, spiders and ticks introduce venom when they insert their mouth parts into the skin – Ascaron, histolysin secreted by parasite • Immuno-pathological lesion – schistosoma - liver cirrhosis, bladder cancer – hydatid fluid released from the rupture of a hydatid cyst anaphylaxis often results
- 84. (WHO) - Priority Diseases • 1. Schistosomiasis • 2. Malaria • 3. Filariasis • 4. Trypanosomiasis • 5. Leishmaniasis • 6. Leprosy (replaced by HIV/AIDS)
- 85. Why were they selected? • Schistosomiasis - 200,000,000 infected 500,000-1,000,000 deaths/year • Malaria - 500,000,000 infected 2,500,000 deaths/year • Filariasis - 250,000,000 infected • Trypanosomiasis - 25,000,000 infected 65,000 deaths/year • Leishmaniasis - 1,200,000 infected • Leprosy - 1,300,000 infected • Approximately 25% of world's population infected by one of these.
- 86. General Characteristics: • 1. Chronic diseases • 2. No effective vaccine • 3. No practical chemotherapy • 4. Affect young • 5. Affect underprivileged • 6. Vector-borne
- 87. Geographic Distribution Factors (Endemicity): • 1. Presence of a suitable host • 2. Habits of the host • 3. Escape from the host • 4. Favorable conditions outside of host • 5. Economic and social conditions
- 88. Presence of Diseases in a Population (Prevalence): • Factors required: • 1. Source • infected persons • carriers • animals
- 89. Presence of Diseases in a Population (Prevalence): • 2. Mode of transmission • direct • indirect • vectors • 3. Susceptible host • immunity
- 90. Three key links of disease transmission 1.Source of infection 2. Route of transmission 3. Susceptible people excrement mouth secretion food, water, finger skin or wound blood direct or indirect contact mucosa focus of placenta infection blood transfusion, injection, intermediate host, insects sucking blood, congenital , touch soil, water, grass
- 91. Diagnosis of Parasitic Infections: • 1. Clinical diagnosis • 2. Laboratory diagnosis
- 92. Treatment of Parasitic Infections: • 1. Medical and surgical • 2. Chemotherapy • 3. Adequate nutrition
- 93. Prevention and Control: • 1. Reduction in sources • 2. Education • 3. Destruction and/or control of reservoir hosts and vector
- 94. Key definitions: What is ….? • Medical parasitology: “the study and medical implications of parasites that infect humans” • A parasite: “a living organism that acquires some of its basic nutritional requirements through its intimate contact with another living organism and cause harm to the host”. Parasites may be simple unicellular protozoa or complex multicellular metazoa • Eukaryote: a cell with a well-defined chromosome in a membrane-bound nucleus. All parasitic organisms are eukaryotes • Protozoa: unicellular organisms, e.g. Plasmodium (malaria) • Metazoa: multicellular organisms, e.g. helminths (worms) and arthropods (ticks, lice) • An endoparasite: “a parasite that lives within another living organism” – e.g. malaria, Giardia • An ectoparasite: “a parasite that lives on the external surface of another living organism” – e.g. lice, ticks
- 95. Epidemiology • Although parasitic infections occur globally – the majority occur in tropical regions • where there is poverty, poor sanitation and personal hygiene • Often entire communities may be – infected with multiple, different organisms • which remain untreated because • treatment is neither accessible nor affordable
- 96. Epidemiology • Effective prevention and control requires – "mass intervention strategies” and – intense community education – Examples include: • General improved sanitation – pit latrines, fresh water wells, piped water • Vector control – insecticide impregnated bed nets – spraying of houses with residual insecticides – drainage, landfill • Mass screening and drug administration programmes – which may need to be repeated at regular intervals
- 97. Thank you for attention!