Classifiaction & visualization of infective agents

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Classifiaction & visualization of infective agents

  1. 1. 1Classification & Visualizationof Infective AgentsRumala MorelDepartment of Parasitology
  2. 2. INFECTION MODULE 1 – Y2S2SYSTEMATIC STUDYOFINFECTIVE AGENTS
  3. 3. 3Infective AgentsVirusesBacteriaFungiProtozoaHelminths(Prions) – Infective proteinsArthropodsEctoparasites & vectors of diseaseSpongiformencephalopathy
  4. 4. 6/12/2013Visualizing microorganisms• Different stains• Microscopy - Light Microscopybright fieldphase contrastdark groundfluorescentElectron Microscopy
  5. 5. 6/12/20131. CONDENSER lensfocuses light on thespecimen2. Light then passesthrough OCULAR &OBJECTIVE lensesMagnified ImageBright field Microscope
  6. 6. 6/12/2013Dark groundmicroscopy
  7. 7. 6/12/2013Phase contrastmicroscopyDark groundmicroscopy
  8. 8. 9Visualization of Parasites• Hand lens /magnifying glass– helminth adults, arthopods• Light Microscopy– Low power x10 – helminth eggs– High power x40 – protozoan cysts &trophozoites– Oil immersion x100 – protozoa eg. malariaTechnique depends on the degree ofmagnification needed.SIZE OF THE PARASITE
  9. 9. 10Biological classificationCarolus Linnaeus – 18th century(Systema naturae - 1735)Grouped species according toshared physical characteristics.IntroducedBinominal classification:Genus & specieseg. Homo sapiens
  10. 10. 11First sorted into large groups and thereaftersubdivided to contain fewer and fewer organismbut sharing more and more common featuresBiological classification - by Linnaeus - 18th centuryKingdomPhylumFamilyClassOrderGenusspeciesGenus speciesBinomial systemPlasmodium falciparumNaming organismScientific namesitalicize OR underline
  11. 11. 12PROKARYOTEEg. bacteriaEUKARYOTEEg. protozoa
  12. 12. 13Virus = an infectiousagent, consisting of geneticmaterial DNA or RNA wrapped upin a protein coat.100 x smaller than bacteriaInvades living cells and usesthem to keep itself alive and toreplicate itself.Some viruses can cause life-long and chronic infectionseg. Herpes virusesViruses
  13. 13. Viral classification• DNA or RNA• Size and Morphology• Susceptibility to physical & chemical agents• Symptoms• Pathology• Host and tissue tropism• Transmission• Immunological properties
  14. 14. VIRUSES
  15. 15. DNA RNA• Parvoviridae• Papovaviridae• Adenoviridae• Herpesviridae• Poxviridae• Hepadnaviridae• Picornaviridae• Reoviridae• Togaviridae• Arenaviridae• Coronaviridae• Retroviridae• Bunyaviridae• Orthomyxoviridae• Paramyxoviridae• RhabdoviridaeVIRUSES
  16. 16. 6/12/2013SHAPEBacteriaClassificationis based on SHAPE
  17. 17. 19BacteriaGram POSITIVE Cocci Gram NEGATIVE BacilliGram POSITIVE Bacilli Gram NEGATIVE Cocciin clusters in chains
  18. 18. 20FungiYeasts & Moulds
  19. 19. 21YeastCryptococcusYeast-likeCandidaMouldsDermatophytesDimorphic fungiHistoplasma
  20. 20. 22ParasitesSporozoa AmoebaeFlagellatesMicrosporidiaRoundworms FlatwormsCestodes TrematodesNematodesCiliatesHelminthsProtozoaArthropods
  21. 21. 23• Unicellular• Animal like cells - heterotrophic nutrition -require preformed organic substances• Classified according to method oflocomotion• Trophozoites - actively feed and multiply• Cysts - resistant walls• Most free-livingProtozoaBinary division
  22. 22. 24Protista (protozoans – unicellular, eukaryotic)(1)AMOEBAETrophozoites & Cyst(growing stage)pseudopodia(false feet)(3) CILIATESBalantidium coli- cilia(2) FLAGELLATESGiardia lambliaflagella
  23. 23. 25(4).Apicomplexa= SPOROZOANo organelle formotility(5). MICROSPORIDIAspore-formingPlasmodium Coccidia
  24. 24. 26PARASITIC PROTOZOA1.Sporozoa2.Amoebae3.Flagellates5. MicrosporidiaToxoplasma gondii – toxoplasmosisCryptospordium spp. - diarrhoeaEntamoeba histolytica – amoebiasisGiardia intestinalis – diarrhoeaTrichomonas vaginalis – trichomoniasisLeishmania spp. – leishmaniasisTrypanosoma spp. - trypanosomiasis4. Ciliates Balantidium coli - balantidiasisPlasmodium spp.- malariaBabesia - babesiosisb).Coccidiaa).others
  25. 25. 27• 200 million cases of malaria annually• Killed more humans than any other disease.• 1 million deaths /year. 90% in sub-SaharanAfrica, an African child dies of malaria every 30sec.• Over half the worldspopulation live inmalarious areasMalariaFinger prick screening forMP = Malarial Parasite
  26. 26. 28• Main causative organism - Entamoeba histolytica• Other causes – Balantidium coli, Trichiuris trichiura• Invade colonic mucosa ulcersParasitic diarrhoea – Blood & mucousBlood & mucousdiarrhoea=Amoebic dysenteryPortal vein (blood)Liver Amoebic hepatitisAmoebic liver abscessEntamoeba trohpozoiteEntamoeba cyst
  27. 27. 29Parasitic watery diarrhoeaGiardia duodenaliscauses giardiasisCryptosporidiumspp. causescryptosporidiosisPersistent diarrhea inAIDS,otherimmunosuppressedCystTrophozoite
  28. 28. 30Toxoplasmaencephalitis –inAIDSCongenitalToxoplasmosisMicrocephaly
  29. 29. 313 types• Visceral – Mediterranean, India• Mucocutaneous (Espundia)– South America• Cutaneous – skin ulcersLeishmaniasisLeishmania donovaniIn Sri LankaVisceral,Cutaneous& Mucocutaneous
  30. 30. 32HelminthsROUNDWORMS=NEMATODESFLATWORMSTREMATODESCESTODES
  31. 31. 33NEMATODES Cylindrical Sexes separate- male smaller Muscular outer wall - organs are suspended in afalse body cavity (pseudo coelom) 4 moults in Life Cycle INTESTINAL TISSUEcuticlemuscle layerbodycavity
  32. 32. 34Enterobius vermicularis(kiri panuwa)Transmitted fromperson to personGEOHELMINTHS(soil transmitted worms)Ascaris lumbricoidesTrichuris triciuraStrongyloides stercoralisHookworms–Necator americanus (In SL)Ancylostoma duodenaleCommonest helminthiases (worm infections) in SLNematodes
  33. 33. 35Whipworm = Trichuris trichiuraSoil transmission similar to Ascaris+ direct feco -oralTrichiuris eggs Trichiuris adults Ascaris adults
  34. 34. 36HookwormsPallor/Anaemiadue to blood lossAdult – 1 cmSucking blood inintestine
  35. 35. 37Larva currens –Cutaneous LarvaMigrans = CLMDisseminated disease in immunosuppressedNO EGGS in stoolOnly rhabditiform larva in stoolsStrongyloidiasisStrongyloides stercoralis
  36. 36. 38
  37. 37. 39Phylum- PLATYHELMINTHESFlatworms• Class- Cestodes/Tapeworms• Class- Trematodes/Flukes
  38. 38. 40Features common to Cestodes 1• Morphology: Flat, ribbon like.• Location: Adults in intestinal tract ofvertebrates.• SizeEchinococcus granulosusTaeniafew milimeters 10 metres
  39. 39. 41• Head: “Scolex”/ “Hold-fast” organ - attach to host’sintestine• Scolex: sucking grooves, hooks or suckers• Hermaphrodite: segments have both testes &ovaries (male & female together)• No alimentary tract: absorption through body wall.Features common to Cestodes 2
  40. 40. 42Trematodes- flat & leaflike,sexes not separate(except in blood flukes)• Water borne[Schistosomes = blood flukes]• Food borne[tissue flukes]
  41. 41. 43Class- Trematodes• Blood Flukes• Tissue FlukesTissue flukeshermaphroditicSchistosomes2 sexes areseparate
  42. 42. 44ARTHROPODS 11. Mosquitos- transmit most important vector bornediseases in Sri Lanka2. Lice - Head louse & body louse- Pubic lousetransmit Louse-borne relapsing fever, Epidemic typhus,Trench fever3. Fleas - transmit plague, murine typhus4. Flies - sand fly – transmit leishmaniasisCLASS INSECTA
  43. 43. 45Mosquito borne diseases
  44. 44. 46Mosquito borne diseases• Arboviruses– Yellow fever– Dengue– Japaneseencephalitis [JE]– Chikungunya• Protozoa – Malaria• Helminth - FilariasisAnophelesMalariaAedes - DengueCulex – filariasis- JEControl – findmosquito larva& eliminatebreeding places
  45. 45. 47ARTHROPODS 2Mites - Scabies mite = Sarcoptes scabieii-Trombiculid mite larvae – transmitscrub typhusCLASS ARACHNIDATicks - transmit tick-borne viral encephalitis,rickettsiae&
  46. 46. 48Fleas are vectors ofPLAGUEScabies spreadbyscabies miteTicks spreadrickettsial &viraldisease

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