Classifiaction & Visualization of Infective Agents - Y2S2

7/28/2019 Classifiaction & Visualization of Infective Agents - Y2S2

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Classification & Visualization

of Infective AgentsRumala Morel

Department of Parasitology


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INFECTION MODULE 1 Y2S2

SYSTEMATIC STUDY

OF

INFECTIVE AGENTS


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Infective Agents

Viruses

Bacteria

FungiProtozoa

Helminths

(Prions) Infective proteinsArthropods

Ectoparasites & vectors of disease

Spongiform

encephalopathy


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Visualizing microorganisms

Different stains

Microscopy- Light Microscopy

bright fieldphase contrast

dark ground

fluorescentElectron Microscopy


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1. CONDENSER lens

focuses light on the

specimen

2. Light then passesthrough OCULAR &

OBJECTIVE lenses

Magnified Image

Bright field Microscope


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Howdoesit

work?


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Dark ground

microscopy


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Phase contrast

microscopy

Dark ground

microscopy


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Visualization 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. malaria

Technique depends on the degree of

magnification needed.

SIZE OF THE PARASITE


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Biological classification

Carolus Linnaeus 18th century

(Systema naturae - 1735)

Grouped species according to

shared physical characteristics.

Introduced

Binominal classification:

Genus & specieseg. Homo sapiens
http://en.wikipedia.org/wiki/Carolus_Linnaeushttp://en.wikipedia.org/wiki/Carolus_Linnaeus


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First sorted into large groups and thereafter

subdivided to contain fewer and fewer organismbut sharing more and more common features

Biological classification - by Linnaeus - 18th century

Kingdom

Phylum

Family

Class

Order

Genus

species

Genus species

Binomial system

Plasmodium falciparum

Naming organism

Scientific names

italicize OR underline


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PROKARYOTE

Eg. bacteria

EUKARYOTE

Eg. protozoa


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Virus = an infectious agent,

consisting of genetic materialDNA or RNA wrapped up in a

protein coat.

100 x smaller than bacteria

Invades living cells and uses

them to keep itself alive and to

replicate itself.

Some viruses can cause life-

long and chronic infections

eg. Herpes viruses

Viruses


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Viral classification

DNA or RNA

Size and Morphology

Susceptibility to physical & chemical agents

Symptoms

Pathology

Host and tissue tropism

Transmission

Immunological properties


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VIRUSES


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DNA RNA

Parvoviridae Papovaviridae

Adenoviridae

Herpesviridae Poxviridae

Hepadnaviridae

Picornaviridae

Reoviridae Togaviridae

Arenaviridae Coronaviridae Retroviridae Bunyaviridae Orthomyxoviridae Paramyxoviridae Rhabdoviridae

VIRUSES


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SHAPEBacteria

Classification

is based on SHAPE


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Bacteria

Gram POSITIVE Cocci Gram NEGATIVE Bacilli

Gram POSITIVE Bacilli Gram NEGATIVE Cocci

in clusters in chains


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Fungi

Yeasts & Moulds


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Yeast

Cryptococcus

Yeast-like

Candida

Moulds

Dermatophytes

Dimorphic fungi

Histoplasma


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Parasites

Sporozoa Amoebae

FlagellatesMicrosporidia

Roundworms Flatworms

Cestodes Trematodes

Nematodes

Ciliates

HelminthsProtozoa

Arthropods


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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-living

Protozoa

Binary division

P ti t ( t )


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Protista (protozoans unicellular, eukaryotic)

(1)AMOEBAE

Trophozoites & Cyst(growing stage)

pseudopodia

(false feet)(3) CILIATES

Balantidium coli- cilia(2) FLAGELLATESGiardia lamblia

flagella

(4) A i l


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(4).Apicomplexa

= SPOROZOA

No organelle for

motility

(5). MICROSPORIDIA

spore-forming

Plasmodium Coccidia

PARASITIC PROTOZOA


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PARASITIC PROTOZOA

1.Sporozoa

2.Amoebae

3.Flagellates

5. Microsporidia

Toxoplasma gondii toxoplasmosis

Cryptospordium spp. - diarrhoea

Entamoeba histolytica amoebiasis

Giardia intestinalis diarrhoea

Trichomonas vaginalis trichomoniasis

Leishmania spp. leishmaniasisTrypanosoma spp. - trypanosomiasis

4. Ciliates Balantidium coli- balantidiasis

Plasmodiumspp.- malaria

Babesia - babesiosis

b).Coccidia

a).others


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200 million cases of malaria annually

Killed more humans than any other disease.

1 million deaths /year. 90% in sub-Saharan Africa, an

African child dies of malaria every 30 sec.

Over half the world's

population live in

malarious areas

Malaria

Finger prick screening for

MP = Malarial Parasite


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Main causative organism - Entamoeba histolytica Other causes Balantidium coli, Trichiuris trichiura

Invade colonic mucosa ulcers

Parasitic diarrhoea Blood & mucous

Blood & mucous

diarrhoea

=Amoebic dysenteryPortal vein (blood)

LiverAmoebic hepatitis

Amoebic liver abscess

Entamoeba trohpozoiteEntamoeba cyst


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Parasitic watery diarrhoea

Giardia duodenalis

causes giardiasis

Cryptosporidium

spp. causes

cryptosporidiosisPersistent diarrhea in

AIDS,

other immunosuppressed

CystTrophozoite

ToxoplasmaC it l


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Toxoplasma

encephalitis in

AIDS

Congenital

Toxoplasmosis

Microcephaly


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3 types Visceral Mediterranean, India Mucocutaneous (Espundia)

South America Cutaneous skin ulcers

Leishmaniasis

Leishmania donovani

In Sri LankaVisceral,Cutaneous

& Mucocutaneous


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Helminths

ROUNDWORMS=

NEMATODES

FLATWORMS

TREMATODESCESTODES

NEMATODES INTESTINAL


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NEMATODES

Cylindrical Sexes separate- male smaller

Muscular outer wall - organs are suspended in a

false body cavity (pseudo coelom)

4 moults in Life Cycle

INTESTINALTISSUE

cuticle

muscle layer

body

cavity

Commonest helminthiases (worm infections) in SL


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Enterobius vermicularis

(kiri panuwa)

Transmitted from

person to person

GEOHELMINTHS(soil transmitted worms)

Ascaris lumbricoides

Trichuris triciura

Strongyloides stercoralis

HookwormsNecator americanus (In SL)

Ancylostoma duodenale

Commonest helminthiases (worm infections) in SL

Nematodes

Whipworm = Trichuris trichiura


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Whipworm Trichuris trichiuraSoil transmission similar toAscaris

+ direct feco -oral

Trichiuris eggs Trichiuris adults Ascaris adults


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Hookworms

Pallor/Anaemia

due to blood loss

Adult 1 cm

Sucking blood in

intestine


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Larva currens Cutaneous LarvaMigrans = CLM

Disseminated disease in immunosuppressed

NO EGGS in stool

Only rhabditiform larva in stools

Strongyloidiasis

Strongyloides stercoralis


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Phylum- PLATYHELMINTHES

Flatworms

Class- Cestodes/Tapeworms

Class- Trematodes/Flukes

Features common to Cestodes 1


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Morphology: Flat, ribbon like.

Location: Adults in intestinal tract of

vertebrates.

Size

Echinococcus granulosus

Taenia

few milimeters 10 metres



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Head: Scolex/ Hold-fast organ - attach to hosts

intestine Scolex: sucking grooves, hooks or suckers

Hermaphrodite: segments have both testes &

ovaries (male & female together)

No alimentary tract: absorption through body wall.


Trematodes flat & leaflike


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Trematodes- flat & leaflike,

sexes not separate

(except in blood flukes)

Water borne

[Schistosomes = blood flukes]

Food borne

[tissue flukes]

Cl T t d


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Class- Trematodes

Blood Flukes Tissue Flukes

Tissue flukes

hermaphroditic

Schistosomes

2 sexes are

separate


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ARTHROPODS 1

1. Mosquitos- transmit most important vector borne

diseases in Sri Lanka

2. Lice - Head louse & body louse

- Pubic lousetransmit Louse-borne relapsing fever, Epidemic typhus,

Trench fever

3. Fleas - transmit plague, murine typhus

4. Flies - sand fly transmit leishmaniasis

CLASS INSECTA


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Mosquito borne diseases


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Mosquito borne diseases Arboviruses

Yellow fever

Dengue

Japanese

encephalitis [JE]

Chikungunya

Protozoa Malaria

Helminth - Filariasis

Anopheles

Malaria

Aedes - Dengue

Culex filariasis

- JE

Control findmosquito larva

& eliminate

breeding places

ARTHROPODS 2


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ARTHROPODS 2

Mites - Scabies mite = Sarcoptes scabieii

-Trombiculid mite larvae transmitscrub typhus

CLASS ARACHNIDATicks - transmit tick-borne viral encephalitis,

rickettsiae

&

Ticks spread


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Fleas are vectors ofPLAGUE

Scabies spread

by

scabies mite

p

rickettsial &

viral

disease

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Classifiaction & Visualization of Infective Agents - Y2S2