Parasitology - protosoology (protosoa),

helmintology(worms),

enthomology(insects)• Laboratory diagnosis: - life cycle of parasits,

material v laboratory dg

• Protozoa – intestinal, genital, urinary, blood, tissue

• Worms - Helmints: Nematodes, Cestodes,Trematodes

• Ectoparasits: louse, ticks, flies – important as vectors

Diagnosis• Problematic, not ususal outside endematic areas• Nonspecific clinical manigestation• eosinophilia in helmintoses – not constant sign• Importance of history – personal, travellers, social, economic, food,

therapy• Conditions for successful dg: • - think on parasitosis,• - correct sampling – right sample, with good method at right time, sent

in appropriate conditions to the lab that is able to identify the parasit, good interpretation:

• Knowledge of life cycle is principal

Life cycle of parasits -terminology

• Complex life cycle – key to diagnosis• Host – hosts• Definitive host – parasit finishes the growing cycle and is

becoming adult in it• Not typical host - parasit cannot develop in it • Transient host – larves are developing in it but sexual

multiplication is not performed• Helmints : egg - larva - (cyste) – adult worm

Protozoa :trofozoit - motile, cyste – non motile - sexual multiplication - zygota - asexual- schizonts, sporogons

Patogenesis• Chronic infections• Protosoa – In strong immunity reaction –

imunopathologic signs – symptoms hypersensitivity, cross reacting antigens (tissue devastation) and autoimunity

• Worms – mechanic, big, metabolism – direct injury (elefantiosis)

- imunity and inflamation – indirect immunopathological reaction

Imunity

• production of IgE• Worms stimulates CD4Th lymfocytes – they secrete IL-

4, IL-5• ADCC – via eosinophils and IgE – elimination of

worms – basic protein in granulesof eosinophils is toxic for worms

• CD4 - activation of macrophages – elimination of parasits = Production of granuloms in organs, fibrosis, tissue devastation

• I.c. parasits activate cytotoxic lymphocytes – interference of disseminations

How parasits escape human immunity

• = chronicity• In-borne nonspecific mechanisms – faibly

efficient• Specific mechanisms – antigenic mimicry – the

surface of the parasit is covered with host antigens, komplexes of Ag-Ab, i.c.localisation of parasits, antigenic variation during infection

• - size, motility, cover of albunim, extreme production of antigen imunity overload, imnosuression

Therapia

• Less structutres• Toxic • Knowledge of the life cycle of parasit is primary• Eucaryotic cells of parasits – toxicita – selective

toxicity can be achieved by changes of the molecule by metabolising of it in the body of parasit, acumulation of the molecule in the body of parasit

• Chronicity – long term therapy• Tissue localisation, encystation• Socioeconomic conditions, climatic factors

Stool for parasitological examination• Macroscopy – blood, mucous, adult worms• Microscopy - native smear - FS, iode – motility,

eggs of helmints, cysts of protosoa, ery, leu• Concentration methods – separation of cysts of

protosoa and eggs of helmints from other material in the stool

• Stainning - identification – smear of native stool + hematoxylin eosin, trichrome

Other material acc.to clinical manifestation

• Perianal - Enterobius vermicularis• Sigmoidoscopy - Entamoeba histolytica• Duodenal aspiration - Giardia lamblia• Biopsia of abscesse of liver - Entamoeba histolytica• Sputum - Ascaris lumbricoides, Strongyloides, • Urine - Schistosoma • Urogenital sample - Trichomonas • Blood - (malaria, trypanosomiosis, leishmaniosis, filariosis)

smear, thick drop - staining acc. Giemsa, HeO, • Serum

Protosoa

• Amoeba - Entamoeba histolytica, Entamoeba coli, Naegleria fowleri, Acanthamoeba, Endolimax nana

• Flagelata - Giardia lamblia, Trichomonas vaginalis, Leishmania, Trypanosoma

• Ciliata - Balantidium coli• Coccidia a Sporosoa - Cryptosporidium,

Blastocystis, Microsporidia, Plasmodia, Babesia,, Toxoplasma

Nematodes -worms• Enterobius vermicularis, Ascaris lumbricoides, Toxocara

canis,cati, Trichuris trichiura, Ancylostoma duodenale, Strongyloides stercoralis, Trichinella spiralis, Wuchereria bancrofti, Dracunculus medinensis – aesculape´s bat

• Nonsegmented body, adult worms living in the GIT - diagnosis: identification of eggs in the stool (morphology of eggs)

• Filariae – thin worms parasiting in eye, skin, tissues, transmitted by insects. Larval stage - microfilariae penetrate to blood and are transmitted by suckling insect

Cestodes • Head - scolex, segmented body- Hermafrodit, male and female organs are present in every

segment - dif.dg. - They have not GIT, absorbtion of food. - Complex life cycle with transient host (sometimes - human –

larval stage of cysticercosis, echinococcosis)• Taenia solium, Taenia saginata, Diphylobotrium latum,

Echinococcus granulosus, Echinococcus multiloculare Hymenolepsis nana

Trematodes -• Usually hermafrodits (exception - Schistosoma)

• Need transient host (hosts)

• Fasciolopsis, Clonorchis, Paragonimus, Schistosoma

Nematodes -worms• Enterobius vermicularis, Ascaris lumbricoides, Toxocara

canis,cati, Trichuris trichiura, Ancylostoma duodenale, Strongyloides stercoralis, Trichinella spiralis, Wuchereria bancrofti, Dracunculus medinensis – aesculape´s bat

• Nonsegmented body, adult worms living in the GIT - diagnosis: identification of eggs in the stool (morphology of eggs)

• Filariae – thin worms parasiting in eye, skin, tissues, transmitted by insects. Larval stage - microfilariae penetrate to blood and are transmitted by suckling insect

Enterobius vermicularis

• Definitive host - human

• transient - none

• dg. – perianal sample – microscopy of eggs

• fecal oral transmission - autoinfection

Enterobius vermicularis

Ascaris lumbricoides

• Definitive host: human

• Larva migrans: intestin, colon - muc.membrane - blood- lung - cough - mouth - colon

• dg. Egg in stool

• Infection via contaminated food

• Symptoms acc.to localisation of the larva

Ascaris lumbricoides

Dracunculus

Cestodes • Head - scolex, segmented body- Hermafrodit, male and female organs are present in every

segment - dif.dg. - They have not GIT, absorbtion of food. - Complex life cycle with transient host (sometimes - human –

larval stage of cysticercosis, echinococcosis)• Taenia solium, Taenia saginata, Diphylobotrium latum,

Echinococcus granulosus, Echinococcus multiloculare Hymenolepsis nana

Taenia solium

• Definitive: pig

• transient: rat

• incidental: human in small intestin

• dg. serology

• Contaminated food

Echinococcus granulosus

• definitive: dog• transient:sheep• incidental: human• dg serology• transmission: cyste in meat• infection: mechanic pressure from

expanded cyst, prolonged growing, rupture of the cyst and dissemination

Echinococcus granulosus

Intestinal,brain and UG protosoa

• entamoeba histolytica

• entamoeba coli

• giardia lamblia

• naegleria fowleri, acanthamoeba

• trichomonas vaginalis

Entamoeba histolytica

• definitive: human

• dg.trofosoits in stool, serology

• dysenteria – diarhea with blood

Naegleria fowleri, Acantamoeba

• Free Living in water

• Human (via nose)

• dg.microscopy in CSF- identification of invasive strains)

• disease: purulent peracute meningitis

Trichomonas vaginalis

• Definitive: human

• transient: none

• dg. Cultivation - microscopy trophosoit - from vagina, urine

• Sexual transmission

• Therapy of both (all) partners

Blood and tissue protosoa

• Plasmodium vivax – tertiana• Plasmodium ovale – tertiana• Plasmodium malariae – quartana• Plasmodium falciparum – maligna tertiana

• Toxoplasma gondii• Pneumocystis carinii – jiroveci• Leishmania donovani – kala azar• Trypanosoma brucei gambiense – sleeping disease

rhodesiense

Toxoplazma gondii• Definitive: cat• transient: rat• incidental: human• dg. serology KFR, IgA, IgG, IgM• transmission: food borne, hand, annimal• disease: - intrauterine primoinfection

- generalised lymfadenopathy, encystation in organs – abortion, eye……..

Life cycle

• Cat swallow tissue cyst (in food) or oocyst (from excrements) – infection of epitelial cells of small intestin – asexual and sexual multiplication – formation of oocysts – excremetion during 1-2 weeks – cyst is nonsporulated = not infectious – outside the body after 1-5 days cysts sporulate – infectious during months, resistent to desinfection, freezing, drying, heating to 70 dg C for10 mins.

Clinical manifestation

• 1941 - Sabin – meningoencefalitída• - Pinkerton a Henderson – tyfoidné príznaky• 1951 - Siim – generalised lymphadenopathy - lymphocyto-monocytes proliferation in periferal blood

• gained toxoplasmosis• gained or reactivated toxoplasmosis in IDS• In borne – congenital toxoplasmosis• Eye toxoplasmosis

Gained toxoplasmosis

• Usually asymptomatic

• 10% - 20% cervical lymphadenopathy + flue like symptoms

• Clinicallly selfliminting – reactivation in IDS, in gravidity

Gained toxoplasmosis in IDS

• Primary infection or reactivation of anamnestic infection

• CNS , myocarditis, pneumonia

• AIDS pacients – encephfalitis, intracerebral lesions

Congenital toxoplasmosis

• In acute primoinfection of mother during pregnancy• Symptoms depends on the lenghth of gravidity during

primoinfection• Therapy can decrease the symptomatology• Acute diagnosis is important

• New borne can have - subclinical symptoms – without therapy usually getting worse - sy i.u. toxoplasmosis – hydrocefalus, calcifications in brain and liver, cataracta, microcephalus

Eye toxoplasmosis

• Ofthen asymptomatic untill the 2nd-3rd decenium

• Symotoms – rupture of the cyst in eye, tachysoits and bradysoits are released

• Chorioretinitis – unilateral – after gained infection – bilateral – after i.u. infection

Toxoplasma gondii protozoa i.c. parasit

• Infiects different warm-blood annimals• Cat is host for sexual stages of

Toxoplasmy gondii (schisonts) – main source

• 3 stages – tachysoits (trofosoits) – quick multiplication and destruction of the invaded tissue – bradysoits – slowly multipliing in tissue cysts – sporosoits (male and female gamonts) in oocysts – in cat excrements

Tachysoits free and i.c.

Bradysoits in tissue cysts

Neonsporulating adn sporulating cyst from cat stool

developmental stages of Toxoplasma gondii

Infection in men

• 1) food borne with inappropriately boiled food containing tissue cysts

• 2) transplantacentarly

• 3) accidentally by innoculation of tachysoits

• 4) swallowing of oocysts (sandy playgrounds., contaminated hands)

• 5) kontaminated trasfusion or transplantation

Pathogenesis• Swallowing of the cyst (bradysoit) or oocyst (sporosoit)• Releasing of microorganism • Invasion to the small intestin epitelium• Dissemination and multiplication intracelularly• Death of infected cells, releasing od tachysoits that invade

other cells• Reaction of immunity system, change of tachy to

bradysoits, formation of tissue cysts (in muscles, heart, brain)

• Reactivation during IDS – rupture of cysts, releasing of parasits

Direct proof

• Seldom positive

• Staining acc. Giemsa

• Immunofluorescence

• ELISA for antigen detection

• Tissue cultures

• Innoculation of mouses

• PCR

Laboratory results IgG IgM specific antibodies:– – without serological proof– + probable acute infection (+IgA from the same sample) or false positive IgM reaction (repetition of IgG and IgM from neuw sample – no changes)+ + probable infection 6 – 12 mnths ago.++ – probable infection 1 year ago

KFR – total antibody detection

CFR

titres above 8 are suspect for infection dynamicity

– increase of the titre after 14 days - acute – maps decrease of the infection after therapy and possible reactiovation of the infection CFR antibodies are life long persistent

Serology of toxoplasma gondi in pregnancy

• I. trimestre – test for IgM antibodies – detection of i.u. infection – positivity – indicate recetn infection current IgA positivity – acute infection – therapy of mother and screening of the baby

• IgG antibodies positive (seldome with IgM positivity) – not indicating acute infection, can result in reactivation of possible tissue cyst, thah has no relation to pregnancy and cannot be eliminated by therapy

• Increase of IgG antibodies – reactivation of past infection without threat of fetus health

Antenatal diagnosis of inborne toxoplasmosis

• Acute infection in pregnant mother

• Therapia

• Ultra sonography

• Amnionic fluid + fetal blood: PCR innoculation do mouses and tissue cultures

• Fetal blood: Toxo IgM and IgA, activity of liver ensyms

Newborne infection dg

• Isolation from placenta, umbilicus leucocytes• Clinical and laboratory test for tissue injury

detection• Špecific antibodies

– newborne serum CSF – mother serum

• IgG,M,A IgM,IgA• PCR• tachysoit

Sequelae of toxoplasma infection in women

• primary infection – possibility of fetal death – lethal infection of the fetus

• intrauterine infection and birth of ill baby

• Previous infection with cysts in tissue of gential tract – problems with conception and succesfull pregnancy (habitual abortions)

Plasmodium-malariae, falciparum • Definitive host:Anopheles • Transient host: human, monkey• dg.microscopy thick drop• Transmission insect bite• disease: malaria acc.to the rate of schizogonia- clinically as

fever attacks - tercianna, quartana,