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Classifiaction & visualization of infective agents


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  • 1. 1Classification & Visualizationof Infective AgentsRumala MorelDepartment of Parasitology
  • 3. 3Infective AgentsVirusesBacteriaFungiProtozoaHelminths(Prions) – Infective proteinsArthropodsEctoparasites & vectors of diseaseSpongiformencephalopathy
  • 4. 6/12/2013Visualizing microorganisms• Different stains• Microscopy - Light Microscopybright fieldphase contrastdark groundfluorescentElectron Microscopy
  • 5. 6/12/20131. CONDENSER lensfocuses light on thespecimen2. Light then passesthrough OCULAR &OBJECTIVE lensesMagnified ImageBright field Microscope
  • 6. 6/12/2013Dark groundmicroscopy
  • 7. 6/12/2013Phase contrastmicroscopyDark groundmicroscopy
  • 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. 10Biological classificationCarolus Linnaeus – 18th century(Systema naturae - 1735)Grouped species according toshared physical characteristics.IntroducedBinominal classification:Genus & specieseg. Homo sapiens
  • 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. 12PROKARYOTEEg. bacteriaEUKARYOTEEg. protozoa
  • 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. Viral classification• DNA or RNA• Size and Morphology• Susceptibility to physical & chemical agents• Symptoms• Pathology• Host and tissue tropism• Transmission• Immunological properties
  • 14. VIRUSES
  • 15. DNA RNA• Parvoviridae• Papovaviridae• Adenoviridae• Herpesviridae• Poxviridae• Hepadnaviridae• Picornaviridae• Reoviridae• Togaviridae• Arenaviridae• Coronaviridae• Retroviridae• Bunyaviridae• Orthomyxoviridae• Paramyxoviridae• RhabdoviridaeVIRUSES
  • 16. 6/12/2013SHAPEBacteriaClassificationis based on SHAPE
  • 17. 19BacteriaGram POSITIVE Cocci Gram NEGATIVE BacilliGram POSITIVE Bacilli Gram NEGATIVE Cocciin clusters in chains
  • 18. 20FungiYeasts & Moulds
  • 19. 21YeastCryptococcusYeast-likeCandidaMouldsDermatophytesDimorphic fungiHistoplasma
  • 20. 22ParasitesSporozoa AmoebaeFlagellatesMicrosporidiaRoundworms FlatwormsCestodes TrematodesNematodesCiliatesHelminthsProtozoaArthropods
  • 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. 24Protista (protozoans – unicellular, eukaryotic)(1)AMOEBAETrophozoites & Cyst(growing stage)pseudopodia(false feet)(3) CILIATESBalantidium coli- cilia(2) FLAGELLATESGiardia lambliaflagella
  • 23. 25(4).Apicomplexa= SPOROZOANo organelle formotility(5). MICROSPORIDIAspore-formingPlasmodium Coccidia
  • 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. 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. 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. 29Parasitic watery diarrhoeaGiardia duodenaliscauses giardiasisCryptosporidiumspp. causescryptosporidiosisPersistent diarrhea inAIDS,otherimmunosuppressedCystTrophozoite
  • 28. 30Toxoplasmaencephalitis –inAIDSCongenitalToxoplasmosisMicrocephaly
  • 29. 313 types• Visceral – Mediterranean, India• Mucocutaneous (Espundia)– South America• Cutaneous – skin ulcersLeishmaniasisLeishmania donovaniIn Sri LankaVisceral,Cutaneous& Mucocutaneous
  • 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. 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. 35Whipworm = Trichuris trichiuraSoil transmission similar to Ascaris+ direct feco -oralTrichiuris eggs Trichiuris adults Ascaris adults
  • 34. 36HookwormsPallor/Anaemiadue to blood lossAdult – 1 cmSucking blood inintestine
  • 35. 37Larva currens –Cutaneous LarvaMigrans = CLMDisseminated disease in immunosuppressedNO EGGS in stoolOnly rhabditiform larva in stoolsStrongyloidiasisStrongyloides stercoralis
  • 36. 38
  • 37. 39Phylum- PLATYHELMINTHESFlatworms• Class- Cestodes/Tapeworms• Class- Trematodes/Flukes
  • 38. 40Features common to Cestodes 1• Morphology: Flat, ribbon like.• Location: Adults in intestinal tract ofvertebrates.• SizeEchinococcus granulosusTaeniafew milimeters 10 metres
  • 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. 42Trematodes- flat & leaflike,sexes not separate(except in blood flukes)• Water borne[Schistosomes = blood flukes]• Food borne[tissue flukes]
  • 41. 43Class- Trematodes• Blood Flukes• Tissue FlukesTissue flukeshermaphroditicSchistosomes2 sexes areseparate
  • 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. 45Mosquito borne diseases
  • 44. 46Mosquito borne diseases• Arboviruses– Yellow fever– Dengue– Japaneseencephalitis [JE]– Chikungunya• Protozoa – Malaria• Helminth - FilariasisAnophelesMalariaAedes - DengueCulex – filariasis- JEControl – findmosquito larva& eliminatebreeding places
  • 45. 47ARTHROPODS 2Mites - Scabies mite = Sarcoptes scabieii-Trombiculid mite larvae – transmitscrub typhusCLASS ARACHNIDATicks - transmit tick-borne viral encephalitis,rickettsiae&
  • 46. 48Fleas are vectors ofPLAGUEScabies spreadbyscabies miteTicks spreadrickettsial &viraldisease