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Parasitology Review by Margie Morgan
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Parasitology ReviewParasitology Review
Margie MorganMargie Morgan
Clinical presentationClinical presentation
Travel history or poor sanitation put you at Travel history or poor sanitation put you at the highest risk for parasitic infectionthe highest risk for parasitic infection
Sporadic symptoms, Sporadic symptoms, Poor immune status higher riskPoor immune status higher risk Dysentery not common (amebiasis)Dysentery not common (amebiasis) Most usual symptoms:Most usual symptoms:
• Abdominal pain, cramping, long term nausea, Abdominal pain, cramping, long term nausea, and malaise, mucous in stool, and +/- feverand malaise, mucous in stool, and +/- fever
Laboratory DiagnosisLaboratory Diagnosis
Currently based on Currently based on microscopic exam, however microscopic exam, however molecular panels are in the molecular panels are in the near futurenear future• StoolStool• Non-stoolNon-stool
Perianal specimenPerianal specimen Sigmoidoscopic specimenSigmoidoscopic specimen Duodenal aspiratesDuodenal aspirates Liver abscessLiver abscess SputumSputum UrineUrine UrogenitalUrogenital
• BloodBlood• TissueTissue
Limited Limited utility/availability of:utility/availability of:• SerologySerology• Fluorescent stainsFluorescent stains• PCRPCR
Two-vial collection kit for StoolTwo-vial collection kit for Stool10% formalin10% formalin Concentration with Concentration with
ethyl acetate to ethyl acetate to eliminate fecal debriseliminate fecal debris
Wet mount and DFA Wet mount and DFA stainingstaining
Helminth eggs, larvae, Helminth eggs, larvae, microsporidia, and microsporidia, and protozoan cystsprotozoan cysts
PVA with fixativePVA with fixative Polyvinyl alcoholPolyvinyl alcohol Permanent stained Permanent stained
smearsmear• Trichrome stainTrichrome stain
Protozoan Protozoan trophozoites and cyststrophozoites and cysts
Mercury based Mercury based fixatives being phased fixatives being phased out for safetyout for safety – – Zinc Zinc fixatives are now usedfixatives are now used
Most Common Pathogens Most Common Pathogens ProtozoaProtozoa
• Intestinal & urogenitalIntestinal & urogenital E histolytica, Blastocystis hominis, Giardia lamblia, E histolytica, Blastocystis hominis, Giardia lamblia,
Dientamoeba fragilis, Balantidium coli, Cryptosporidium Dientamoeba fragilis, Balantidium coli, Cryptosporidium sp., Cyclospora sp, Cyclospora, (Isospora) belli, sp., Cyclospora sp, Cyclospora, (Isospora) belli, andand MicrosporidiaMicrosporidia
• Blood & tissueBlood & tissue Plasmodium, Babesia, TrypanosomesPlasmodium, Babesia, Trypanosomes Toxoplasma gondii, LeishmaniaToxoplasma gondii, Leishmania Naegleria, Acanthamoeba, BalamuthiaNaegleria, Acanthamoeba, Balamuthia
HelminthsHelminths• NematodesNematodes
Ascaris, Trichuris, hookworm, pinworm, and StrongyloidesAscaris, Trichuris, hookworm, pinworm, and Strongyloides• CestodesCestodes
Taenia, Hymenolepis, DiphyllobothriumTaenia, Hymenolepis, Diphyllobothrium• TrematodesTrematodes
Fasciola, Fasciolopsis, Schistosoma, Paragonimus, Fasciola, Fasciolopsis, Schistosoma, Paragonimus, ClonorchisClonorchis
PROTOZOAPROTOZOA Amebae (found in stool)Amebae (found in stool)
• Entamoeba coli Entamoeba coli • Entamoeba histolytica Entamoeba histolytica • Endolimax nanaEndolimax nana• Iodamoeba butschliiIodamoeba butschlii• Dientamoeba fragilisDientamoeba fragilis
Flagellates (found in stool)Flagellates (found in stool)• Giardia lambliaGiardia lamblia• Chilomastix mesniliChilomastix mesnili
Ciliates, Coccidia, BlastocystisCiliates, Coccidia, Blastocystis• BalantidiumBalantidium• CryptosporidiumCryptosporidium• Isospora belliIsospora belli• SarcocystisSarcocystis• CyclosporaCyclospora• MicrosporidiumMicrosporidium• Blastocystis hominisBlastocystis hominis
Blood-Borne ProtozoaBlood-Borne Protozoa• BabesiaBabesia• LeishmaniaLeishmania• Trypanosoma bruceiTrypanosoma brucei• T. cruziT. cruzi• PlasmodiumPlasmodium
Other Other • ToxoplasmaToxoplasma• Naegleria fowleriNaegleria fowleri• AcanthamoebaAcanthamoeba
Protozoa Found in Stool: Amebae Protozoa Found in Stool: Amebae pathogen
Intestinal amoebaIntestinal amoeba Entamoeba coliEntamoeba coli
Entamoeba histolytica/disparEntamoeba histolytica/dispar Entamoeba hartmanniEntamoeba hartmanni
Endolimax nanaEndolimax nana Iodamoeba butschliiIodamoeba butschlii
Entamoeba histolytica/disparEntamoeba histolytica/dispar
E. histolytica is a pathogen and E. dispar is a nonpathogenic E. histolytica is a pathogen and E. dispar is a nonpathogenic species that can also occur in the large intestine. species that can also occur in the large intestine. Morphologically indistinguishableMorphologically indistinguishable
E histolyticaE histolytica• Cysts = infectious form Cysts = infectious form • trophozoites = invasive formtrophozoites = invasive form• Contaminated water and poor sanitationContaminated water and poor sanitation• Colon biopsy shows “flask-shaped” ulcerColon biopsy shows “flask-shaped” ulcer• Non-intestinal disease = extraintestinal amebiasis (liver Non-intestinal disease = extraintestinal amebiasis (liver
abscess)abscess) SerologySerology
Entamoeba histolytica/dispar
Cysts <= 10 umIn diameter Up to 4 nuclei in the cyst
Clean chromatinBulls-eye nucleoli
Entamoeba histolytica/disparEntamoeba histolytica/dispar
Trophozoites & Cysts
Trophozoite with ingested rbcs
Amebic abscessAmebic abscess
Flask-shaped ulcer of intestinal amebiasis
Amebic liver abscessEntamoeba histolyticaSerology – high % positive in extra-intestinal cases
Entamoeba coli cyst and trophozoite
Cyst >=15 mmUp to 8 nucleiShed from hostLives in environment
Trophozoite is the form that invades intestines
Nucleus has a chromatin ringThe cytoplasm appears dirty
Entamoeba coliEntamoeba coli
Trophozoites & Cysts
Endolimax nana trophozoite
Mostly thought to be a non-pathogen, Seen in HIV/AIDS patients, Some literature suggesting it can cause intermittent or chronic diarrhea
Iodamoeba butschlii cysts with starchStaining inclusion
Iodine preparation – name from appearance with iodine staining
FlagellatesFlagellates Giardia lambliaGiardia lamblia Dientamoeba fragilisDientamoeba fragilis Trichomonas vaginalisTrichomonas vaginalis
Protozoa Found in Stool: FlagellatesProtozoa Found in Stool: Flagellates
Giardia lambliaGiardia lamblia Contaminated water, Contaminated water,
undercooked foodsundercooked foods Mild diarrhea to severe Mild diarrhea to severe
malabsorptionmalabsorption Foul, watery diarrheaFoul, watery diarrhea Day-care center outbreaksDay-care center outbreaks Cysts/trophozoites may be Cysts/trophozoites may be
seen in stool, but can be seen in stool, but can be hard to find; Fluorescent hard to find; Fluorescent stains availablestains available
Duodenal aspirationsDuodenal aspirations
TROPHOZOITE“falling leaf” motility
CYSTS
Giardia lamblia trophozoiteWaxing and waning symptomsCan be irregularly Shed in stool material& can be difficult to find
Russia & Mexico-Hot beds
Only invades intestine
Flagyl (Metronidazole) is drug of choice
Giardia lamblia cysts
Giardia lamblia Giardia lamblia cystscysts
Giardia lamblia Giardia lamblia trophozoitestrophozoites
Only invades intestinal tissue
Chilomastix mesniliChilomastix mesnili cyst cyst NonpathogenNonpathogen Mimics Giardia lamblia Mimics Giardia lamblia
cyst – except for clear cyst – except for clear space at end of cystspace at end of cyst
Internal structure looks Internal structure looks like “shepherd’s crook” like “shepherd’s crook” or safety pinor safety pin
Chilomastix mesnili cyst
Clearing Nipple Chilomastix mesnili trophozoite
Dientamoeba fragilisDientamoeba fragilis Diarrhea, anal pruritusDiarrhea, anal pruritus Co-infection with Co-infection with EnterobiusEnterobius
(pinworm)(pinworm)
Trichomonas vaginalisTrichomonas vaginalis Urogenital Urogenital
protozoanprotozoan Scant, watery Scant, watery
vaginal dischargevaginal discharge Four flagella, short Four flagella, short
undulating undulating membranemembrane
Protozoa Found in Stool: Protozoa Found in Stool: Ciliates, Coccidia, Ciliates, Coccidia, BlastocystisBlastocystis
CiliatesCiliates
Balantidium coliBalantidium coli• Mainly in swineMainly in swine• Contact with swine & poor hygieneContact with swine & poor hygiene• Only ciliate that’s pathogenic to humansOnly ciliate that’s pathogenic to humans• Similar disease as amebiasis, but Similar disease as amebiasis, but
extraintestinal invasion rareextraintestinal invasion rare• Largest (50-200 um) trophozoite; Largest (50-200 um) trophozoite;
surface covered with cilia; macronucleussurface covered with cilia; macronucleus• Cyst 40-60 umCyst 40-60 um• Readily identified in fresh, wet mountsReadily identified in fresh, wet mounts
In intestine can cause flask-shaped ulcers like those caused by E. histolytica
Only protozoa with cilia
50 microns
Intestinal Sporozoa (coccidia)Intestinal Sporozoa (coccidia) IsosporaIsospora CryptosporidiumCryptosporidium CyclosporaCyclospora SarcocystisSarcocystis
All are Partial acid fast +
Isospora belliIsospora belli Contaminated food/water, oral-analContaminated food/water, oral-anal Found most commonly in HIV/AIDSFound most commonly in HIV/AIDS Infects intestinal epitheliumInfects intestinal epithelium Malabsorption syndrome mimicking Malabsorption syndrome mimicking
giardiasisgiardiasis
Modified acid fast stain
Isospora belliIsospora belli
Cryptosporidium parvumCryptosporidium parvum Contaminated waterContaminated water Resistant to usual water-purification Resistant to usual water-purification
procedures (chlorination, ozone)procedures (chlorination, ozone) Daycare center outbreaks (fecal-oral)Daycare center outbreaks (fecal-oral) Watery diarrhea; more severe in Watery diarrhea; more severe in
AIDSAIDS
CryptosporidiumCryptosporidiumPartial Acid Fast Positive
Direct Fluorescence Antibody stain – Cryptosporidium parvum
Enzyme immunoassay for the antigen of C. parvum is also available.
False negatives may result due to low organisms numbers (Asymptomatic carriers) in both the EIA and DFA assays
Giardia
C. parvum
Combo stain for CryptosporidiumAnd Giardia lamblia
C. Parvum in intestine
C. Parvum in intestinejust below the plasma membrane
Cyclospora cayetanensisCyclospora cayetanensis Contaminated fruits and vegetablesContaminated fruits and vegetables Watery diarrhea; more sever in Watery diarrhea; more sever in
HIV/AIDSHIV/AIDS Infects upper small bowelInfects upper small bowel Found in vacuoles in cytoplasm of Found in vacuoles in cytoplasm of
jejunal epithelium, villous atrophy, jejunal epithelium, villous atrophy, crypt hyperplasiacrypt hyperplasia
Cyclospora cayetanensis
PAF +6-8 microns
Autofluorescence on FA scope
Also positive on Calcofluorwhite stain
MicrosporidiaMicrosporidia Obligate intracellular pathogenObligate intracellular pathogen Enterocytozoon and Encephalitozoon Enterocytozoon and Encephalitozoon
speciesspecies Primitive eukaryotic organism (fungi)Primitive eukaryotic organism (fungi) Many generaMany genera Infection by ingestion of sporesInfection by ingestion of spores Chronic diarrhea in AIDS patientsChronic diarrhea in AIDS patients Myositis, hepatitis, peritonitis, keratitisMyositis, hepatitis, peritonitis, keratitis
Microsporidia-Common in HIV/AIDS-Watery persistent diarrhea
Positive on modified Trichrome and Calcofluor white stains-Longer staining time will eventually allow for it to work its way into the spore
Blastocystis hominisBlastocystis hominis cysts cysts
Can be a pathogenCan be a pathogen Small #s: can be commensalSmall #s: can be commensal Large #s: pathogenicLarge #s: pathogenic Dirty H20 Dirty H20 Traveler’s diarrhea Traveler’s diarrhea Iodine wet mount
Nuclear blobs Around the periphery Trichrome
stain
None; None; self resolving. self resolving.
Maltese cross in rbcMaltese cross in rbcHemolytic anemia, Hemolytic anemia, Jaundice, fever, Jaundice, fever, hepatomegalyhepatomegaly
Ixodes tickIxodes tickBabesia microtiBabesia microti
Pentosam; Pentosam; Pentamidine Pentamidine isethionate. isethionate.
Intracellular Intracellular (macrophages) (macrophages) leishmanial bodies leishmanial bodies with kinetoplastwith kinetoplast
Visceral leishmaniasis Visceral leishmaniasis (Kala-azar), (Kala-azar), granulomatous skin granulomatous skin lesions lesions Iraq/Iran/AfghanistanIraq/Iran/Afghanistan
Phlebotomine Phlebotomine sandfly sandfly
Leishmania Leishmania donovani donovani
CNS: CNS: melarsoperolmelarsoperolNifurtimox and Nifurtimox and Benzonidazole. Benzonidazole.
Hemoflagellate in Hemoflagellate in blood or tissue. blood or tissue. C- or comma-C- or comma-shapedshaped
American American trypanosomiasis;trypanosomiasis;Chagas disease: Chagas disease: megacolon, cardiac megacolon, cardiac failure.failure.
Reduvid (kissing) Reduvid (kissing) bugbug
T. cruzi T. cruzi
Blood stage: Blood stage: Suramin or Suramin or petamidine petamidine isethionateisethionate
Hemoflagellate in Hemoflagellate in blood or lymph blood or lymph nodenode
African African trypanosomiasis; trypanosomiasis; Sleeping sicknessSleeping sicknessEncephalitis; Encephalitis; cardiac failurecardiac failure
Tsetse flyTsetse flyTrypanosoma Trypanosoma bruceibrucei
TreatmentTreatmentDiagnosisDiagnosisDisease/SymptomsDisease/SymptomsTransmissionTransmissionOrganismOrganism
Blood-Borne Protozoa
TrypanosomesTrypanosomes 2 different diseases2 different diseases
• Chagas disease (American Chagas disease (American trypanosomiasis)trypanosomiasis)
Trypanosoma cruziTrypanosoma cruzi Reduviid / Triatome (kissing) bugReduviid / Triatome (kissing) bug
• African sleeping sickness (African African sleeping sickness (African trypanosomiasis)trypanosomiasis)
T. brucei (gambiense T. brucei (gambiense andand rhodesiense) rhodesiense) Tsetse flyTsetse fly
Trypanosoma bruceiTrypanosoma brucei Sleeping Sleeping sickness (African trypanosomiasis)sickness (African trypanosomiasis)
Vector: Tsetse flyVector: Tsetse fly The two The two T. bruceiT. brucei species that cause species that cause
African trypanosomiasis are African trypanosomiasis are indistinguishable morphologically indistinguishable morphologically • T. b. gambienseT. b. gambiense• T. b. rhodesienseT. b. rhodesiense
A typical trypomastigote has:A typical trypomastigote has:• A small kinetoplast located at the posterior A small kinetoplast located at the posterior
endend• A centrally located nucleusA centrally located nucleus• An undulating membrane, andAn undulating membrane, and• A flagellum running along the undulating A flagellum running along the undulating
membrane, leaving the body at the membrane, leaving the body at the anterior endanterior end
• 14 to 33 µm in length14 to 33 µm in length Trypomastigotes are the only stage found Trypomastigotes are the only stage found
in patients. in patients.
Trypanosoma brucei gambiense in a blood film
Filamentous structures found in blood
TRYPANOSOMA GAMBIENSE
Trypanosoma cruziTrypanosoma cruzi Chagas Chagas (American trypanosomiasis)(American trypanosomiasis)
Vector: Reduvid/Triatoma (kissing) bugVector: Reduvid/Triatoma (kissing) bug TrypomastigotesTrypomastigotes are the only stage found in are the only stage found in
the the bloodblood of an infected person; may be seen in of an infected person; may be seen in CSF in CNS infectionsCSF in CNS infections
Motile circulating trypomastigotes are readily Motile circulating trypomastigotes are readily seen on slides of fresh anticoagulated blood in seen on slides of fresh anticoagulated blood in acute infection but are rarely detectable by acute infection but are rarely detectable by microscopy in chronic microscopy in chronic T. cruziT. cruzi infection. infection.
A typical A typical trypomastigotetrypomastigote has: has:• A large, subterminal or terminal kinetoplast, A large, subterminal or terminal kinetoplast, • A centrally located nucleus, A centrally located nucleus, • An undulating membrane, andAn undulating membrane, and• A flagellum running along the undulating A flagellum running along the undulating
membrane, leaving the body at the anterior end. membrane, leaving the body at the anterior end. • 12 to 30 µm in length. 12 to 30 µm in length.
AmastigoteAmastigote stage parasite may be seen in stage parasite may be seen in histopathology specimens from affected organs.histopathology specimens from affected organs.
C-shape
Trypanosoma cruzi- Possible cardiac infiltration->Chagas
Reduvid bug
LeishmaniaLeishmania Obligate intracellular parasiteObligate intracellular parasite Vector: female sand fly biteVector: female sand fly bite Visceral leishmaniasis (kala azar)Visceral leishmaniasis (kala azar)
• L. donovaniL. donovani Cutaneous leishmaniasisCutaneous leishmaniasis
• L. tropica L. tropica • L. braziliensisL. braziliensis
LeishmaniaLeishmania
Leishmania Leishmania amastigotesamastigotes • Macrophages filled with Macrophages filled with
amastigotes (arrows), several amastigotes (arrows), several of which have a clearly visible of which have a clearly visible nucleus and kinetoplastnucleus and kinetoplast
• Amastigotes are being freed Amastigotes are being freed from a rupturing macrophagefrom a rupturing macrophage
LeishmaniaLeishmania – Clinical Disease – Clinical Disease CutaneousCutaneous
• Single or few chronic, ulcerating Single or few chronic, ulcerating lesions; many specieslesions; many species
• Latin America, southern Europe, Latin America, southern Europe, Middle east, southern Asia, Middle east, southern Asia, AfricaAfrica
• Mucocutaneous in Latin AmericaMucocutaneous in Latin America VisceralVisceral
• primarily primarily L. donovani L. donovani complex complex (Asia), L. infantum/chagasi (Asia), L. infantum/chagasi (Africa and Latin America), (Africa and Latin America), othersothers
• Hepatosplenomegaly, anemia, Hepatosplenomegaly, anemia, cytopenias, systemic symptomscytopenias, systemic symptoms
• India, Bangladesh, Nepal, Sudan, India, Bangladesh, Nepal, Sudan, and Brazil and Brazil
• Important OI in HIV infectionImportant OI in HIV infection
LeishmaniaLeishmania DiagnosisDiagnosis
• Biopsy of infected tissue (skin, bone marrow)Biopsy of infected tissue (skin, bone marrow) Multiple, tiny 2-5 um amastigotes within histiocytesMultiple, tiny 2-5 um amastigotes within histiocytes Distinct Distinct kinetoplastkinetoplast (bar-like structure adjacent to (bar-like structure adjacent to
nucleus)nucleus)• PCRPCR• Urinary antigens (visceral)Urinary antigens (visceral)
DDx of multiple tiny intracellular organismsDDx of multiple tiny intracellular organisms• Leishmania – kinetoplastLeishmania – kinetoplast• Histoplasma – buddingHistoplasma – budding• Toxoplasma – somewhat curved, mostly Toxoplasma – somewhat curved, mostly
extracellularextracellular
Leishmania donovani
Kinetoplast next to nucleusSkin lesion
Sand Fly
BabesiaBabesia Protozoan: Protozoan: B. microti, B. divergensB. microti, B. divergens Zoonosis (deer, cattle, rodents; humans accidental host)Zoonosis (deer, cattle, rodents; humans accidental host) Transmission by Transmission by IxodesIxodes tick bite tick bite Infects red blood cellsInfects red blood cells Found world-wideFound world-wide B. microtiB. microti along the Northeast US along the Northeast US
• Nantucket Island, Martha’s vineyard, Shelter IslandNantucket Island, Martha’s vineyard, Shelter Island Malaria-like syndrome Malaria-like syndrome
• Fever but without periodicity, “B-symptoms”, hemolytic Fever but without periodicity, “B-symptoms”, hemolytic anemia, hemoglobinuria, renal failureanemia, hemoglobinuria, renal failure
Dx:Dx:• Blood smear examinationBlood smear examination
Ring form only (mimics P. falciparum)Ring form only (mimics P. falciparum) Tetrads (unlike P. falciparum)Tetrads (unlike P. falciparum)
Maltese cross(tetrads)
Ixodes tick
Babesia
MALARIAMALARIA ProtozoanProtozoan Transmitted by the anopheles Transmitted by the anopheles
mosquitomosquito Endemic to tropical areasEndemic to tropical areas
Malaria SymptomsMalaria Symptoms Fever and chillsFever and chills SplenomegalySplenomegaly HeadacheHeadache Abdominal painAbdominal pain Diarrhea Diarrhea MyalgiaMyalgia Blackwater fever (hemolysis, Blackwater fever (hemolysis,
hemoglobinuria, renal failure) – P hemoglobinuria, renal failure) – P falciparum onlyfalciparum only
Malaria SymptomsMalaria Symptoms Fever patternFever pattern
ParasiteParasite DiseaseDiseasePlasmodium Plasmodium falciparumfalciparum
MalignantMalignant tertiantertian malariamalaria
P. vivaxP. vivax Benign Benign tertiantertian malaria malariaP. ovaleP. ovale Benign Benign tertiantertian malaria malariaP. malariaeP. malariae QuartanQuartan malaria malaria
Tertian = q 48 hours (every other day)Quartan = q 72 hours
MalariaMalaria Physical exam findingsPhysical exam findings
• FeverFever• SplenomegalySplenomegaly• P. falciparumP. falciparum
JaundiceJaundice HepatomegalyHepatomegaly Increase in respiratory rateIncrease in respiratory rate CNS involvementCNS involvement
Diagnosis: peripheral blood smear (gold standard)Diagnosis: peripheral blood smear (gold standard) Molecular tests are available but not yet widely Molecular tests are available but not yet widely
usedused
MalariaMalaria Distinction is between Distinction is between P. falciparumP. falciparum and and
non-falciparumnon-falciparum• P. falciparumP. falciparum = rapidly progressive and = rapidly progressive and
LETHAL LETHAL ((malignantmalignant tertian fever), often tertian fever), often chloroquine-resistant chloroquine-resistant
• Non-falciparum = rarely cause severe Non-falciparum = rarely cause severe manifestations, often chloroquine sensitivemanifestations, often chloroquine sensitive
Relapsing malariaRelapsing malaria• Dormant hepatic phaseDormant hepatic phase
Hypnozoites of Hypnozoites of P. vivaxP. vivax and and P. ovaleP. ovale
Two in the Liver/Two Not!!Two in the Liver/Two Not!!
Two types of malaria that Two types of malaria that don’tdon’t recur from recur from the liver: the liver: • P. falciparumP. falciparum – high incidence and severity – high incidence and severity• P. malariaeP. malariae – lower incidence and severity – lower incidence and severity
Two types of malaria that Two types of malaria that do do recur from the recur from the liver: liver: • P. vivaxP. vivax – high incidence, most of the world – high incidence, most of the world
except Western Africaexcept Western Africa• P. ovaleP. ovale – lower incidence, occupies the niche in – lower incidence, occupies the niche in
Western AfricaWestern Africa
MALARIA
Life Cycle of Plasmodium Species
RBC formsRBC forms
Ring form Ring form Trophozoite Trophozoite Schizont Schizont
Gametocyte
Merozoites(ruptured schizont)
PlasmodiumPlasmodium species species Plasmodium falciparumPlasmodium falciparum Plasmodium vivaxPlasmodium vivax Plasmodium ovalePlasmodium ovale Plasmodium malariaePlasmodium malariae
P. falciparumP. falciparum P. vivax, P. P. vivax, P. ovaleovale
P. malariaeP. malariae BabesiaBabesia
VectorVector MosquitoMosquito MosquitoMosquito MosquitoMosquito Ixodes tickIxodes tickRBC RBC Any RBCAny RBC Young RBC; Young RBC;
enlargedenlargedMature RBC;Mature RBC;Not enlargedNot enlarged
RingRing Multiple can Multiple can be seen; be seen; delicate; delicate;
“appliqu锓appliqué”
Rarely >1;Rarely >1;thickenedthickened
1-121-12Tetrads Tetrads
((Maltese Maltese crosscross))
DelicateDelicateRings onlyRings only
SchizontSchizont Rarely seenRarely seen Commonly seenCommonly seen ““rosette”rosette” nonenoneGametocyteGametocyte Banana-Banana-
shapedshapedRoundRound nonenone
Extra-RBC Extra-RBC formform
NoneNone NoneNone PresentPresent
Schüffner dotsSchüffner dots NoNo YesYes NoNoPigmentationPigmentation BrownBrown NoNoInfection rateInfection rate >2%>2% <2%<2% 5-10%5-10%Protective Protective polymorphismpolymorphismss
Hemoglobin S, Hemoglobin S, C,E, alpha and C,E, alpha and
beta thal, G6PDbeta thal, G6PD
Duffy negative Duffy negative (P. vivax)(P. vivax)
Dormant Dormant hepatic phase hepatic phase (relapse)(relapse)
NoNo YesYes NoNo
Malarial PreparationsMalarial Preparations
Thick smearThick smear Drop of blood on slideDrop of blood on slide Water rinse to Water rinse to
eliminate rbc’seliminate rbc’s Stain with Giemsa Stain with Giemsa
stain (not Wright-stain (not Wright-Giemsa) with Giemsa) with proper proper pHpH
Concentrated to spot Concentrated to spot malaria parasitesmalaria parasites
Thin smearThin smear Feather edge smearFeather edge smear For optimal For optimal
morphology, stain with morphology, stain with GiemsaGiemsa (not Wright- (not Wright-Giemsa) stain with Giemsa) stain with proper pHproper pH
SpeciationSpeciation of malaria of malaria Parasitemia (%)Parasitemia (%)
MalariaMalariaDiagnosisDiagnosis
Microscopy is most often usedMicroscopy is most often used Antigen detection – EIA availableAntigen detection – EIA available Molecular methods Molecular methods
P. ovaleP. ovale
“Rosette” schizont
P. malariaeP. malariae
P. vivaxP. vivax
Amoeboid ring form
P.Vivax – benign tertian malaria (every 48 hours), Duffy negative RBC is protectiveAfricans lack Duffy rbc antigen and this prevents rbc invasion.Untreated infections last several years; dormant in the liver for yearsPatients can survive years without treatment, but chronic infection can lead to brain, kidney and liver damage
P. falciparumP. falciparum
Malignant tertian malariaBlack water fever
P. falciparumP. falciparum
PlasmodiumPlasmodiumspeciesspecies
P. falcipriumP. falciprium Non-Non-FalciparumFalciparum
BabesiaBabesia
VectorVector MosquitoMosquito MosquitoMosquito Ixodes tickIxodes tickRBC RBC All RBCAll RBC Young RBCYoung RBCRingRing 1-31-3
delicatedelicateRarely >1Rarely >1thickenedthickened
1-121-12TetradsTetradsDelicateDelicateRings onlyRings only
GametocyteGametocyte Banana Banana shapedshaped
roundround nonenone
Extra-RBC Extra-RBC formform
NoneNone NoneNone PresentPresent
PigmentationPigmentation BlackBlack brownbrown nonenoneInfection rateInfection rate >2%>2% <2%<2% 5-10%5-10%Protective Protective polymorphispolymorphismsms
Hemoglobin S, Hemoglobin S, C,E, alpha and C,E, alpha and beta thal, G-6-beta thal, G-6-PDPD
Duffy negativeDuffy negative
Other ProtozoaOther Protozoa
• ToxoplasmaToxoplasma
OrganismOrganism TransmissionTransmission Disease/Disease/SymptomsSymptoms
DiagnosisDiagnosis TreatmentTreatment
Toxoplasma Toxoplasma gondiigondii
Oral from cat fecal Oral from cat fecal materialmaterialor meator meat
Adult: flu like;Adult: flu like;congenital: congenital: abortion, neonatal abortion, neonatal blindness and blindness and neuropathiesneuropathies
Intracellular (in Intracellular (in macrophages) macrophages) tachyzoites tachyzoites
SulphonamidesSulphonamides, , pyemethaminepyemethamine, possibly , possibly spiramycin spiramycin (non-FDA)(non-FDA)
Toxoplasma gondiiToxoplasma gondii Coccidian protozoanCoccidian protozoan House cat = definitive hostHouse cat = definitive host Ingestion of infective oocysts from contaminated Ingestion of infective oocysts from contaminated
cat fecescat feces Ingestion of improperly cooked meat from Ingestion of improperly cooked meat from
animals that serve as intermediate hosts animals that serve as intermediate hosts (rodents)(rodents)
SymptomsSymptoms• Predilection for lung, heart, lymphoid organs, CNS/eyePredilection for lung, heart, lymphoid organs, CNS/eye• Infectious mono-like; lymphadenitis, hepatitis, rash, Infectious mono-like; lymphadenitis, hepatitis, rash,
encephalomyelitis, myocarditis, chorioretinitisencephalomyelitis, myocarditis, chorioretinitis• Transplacental infectionTransplacental infection
11stst trimester trimester spontaneous abortion, stillbirth or severe spontaneous abortion, stillbirth or severe diseasedisease
22ndnd/3/3rdrd trimester trimester CNS infections (epilepsy, encephalitis, CNS infections (epilepsy, encephalitis, intracranial calcifications, MR, chorioretinitis, blindness, intracranial calcifications, MR, chorioretinitis, blindness, hearing loss), jaundice, rashhearing loss), jaundice, rash
• AIDS - Encephalitis; mass lesions in brainAIDS - Encephalitis; mass lesions in brain
Toxoplasmagondii
Strongly associated with young Kittens
Toxoplasma gondiiToxoplasma gondii DiagnosisDiagnosis
• Serology EIASerology EIA Anti-toxo IgM – congenital and acute Anti-toxo IgM – congenital and acute
infection; may persist for monthsinfection; may persist for months Anti-toxo IgG – common; if positive, Anti-toxo IgG – common; if positive,
gestations safe from intrauterine gestations safe from intrauterine toxoplasmosis infectiontoxoplasmosis infection
• PCRPCR
Toxoplasma gondii
Can be diagnosed by serology
Toxoplasma gondiiToxoplasma gondii
Toxoplasma gondiiToxoplasma gondii cyst in brain tissue cyst in brain tissue stained with hematoxylin and eosinstained with hematoxylin and eosin
Free-living AmoebaFree-living Amoeba Naegleria fowleriNaegleria fowleri AcanthamoebaAcanthamoeba BalamuthiaBalamuthia
Amoebic meningoencephalitisAmoebic meningoencephalitis Most commonly caused by Most commonly caused by Naegleria Naegleria
fowlerifowleri Granulomatous amoebic encephalitis Granulomatous amoebic encephalitis
or brain abscess(es) caused by or brain abscess(es) caused by AcanthamoebaAcanthamoeba and and BalamuthiaBalamuthia
Clinical scenario: swimming or Clinical scenario: swimming or diving in fresh-water poolsdiving in fresh-water pools
Brain tissue with Naegleria fowleri trophozoite
Naegleria fowleri-Found in warm fresh water-Breath-in through nose-> brain
Brain tissue with Naegleria fowleri trophozoites
Contact-lens keratitisContact-lens keratitis Caused by Caused by AcanthamoebaAcanthamoeba Can be cultured on a “lawn of Can be cultured on a “lawn of E. coliE. coli””
• Take corneal scapingsTake corneal scapings• Visible trail of ameba moving across Visible trail of ameba moving across
plate ingesting plate ingesting E. coliE. coli
AcanthamoebaAcanthamoeba
HELMINTHSHELMINTHS Nematodes (roundworms)Nematodes (roundworms) Trematodes (flukes)Trematodes (flukes) Cestodes (tapeworms)Cestodes (tapeworms)
NematodesNematodes EnterobiusEnterobius AscarisAscaris TrichurisTrichuris Necator and Ancylostoma Necator and Ancylostoma
(Hookworm)(Hookworm) Microfilaria – Wucheria, Brugia, Loa Microfilaria – Wucheria, Brugia, Loa
loa, Mansonella, and Onchocercaloa, Mansonella, and Onchocerca
Enterobius vermicularis (pinworm)Enterobius vermicularis (pinworm) Humans considered only hostHumans considered only host Females 8-13mm, males 2-5 mmFemales 8-13mm, males 2-5 mm Dwell in the cecumDwell in the cecum ¼-1/2 inch in thickness, white, lloks like ¼-1/2 inch in thickness, white, lloks like
string in stoolstring in stool Lay up to 15,000 eggsLay up to 15,000 eggs
• Oval with a flattened side: 50-60um by 20-30umOval with a flattened side: 50-60um by 20-30um Diagnosis- Scotch tape test or anal swabDiagnosis- Scotch tape test or anal swab Most common helminth in USMost common helminth in US
Enterobius vermicularis (pinworm) eggs
Asymmetrical eggs
Pinworm larvae
Ascaris lumbricoides (roundworm)Ascaris lumbricoides (roundworm)
1-1.2 billion people infected1-1.2 billion people infected• More common in childrenMore common in children
20,000 death20,000 death Largest helminth to affect humansLargest helminth to affect humans Females 20-35cm long, males 15-Females 20-35cm long, males 15-
30cm with a curved tale30cm with a curved tale• Can cause intestinal obstruction Can cause intestinal obstruction
Ascaris lumbricoides
Ascaris eggs
Unfertilized eggs-large & oval, mammillated layer is pronounced
Fertilized eggs- smaller, rounder, mammillated layer is less obvious
Trichuris Trichiura (whipworm)Trichuris Trichiura (whipworm) Soil transmittedSoil transmitted Can be similar to amebiasisCan be similar to amebiasis PVA preserved samples inferior to formalinPVA preserved samples inferior to formalin Adults attach to large intestine and are Adults attach to large intestine and are
rarely recoveredrarely recovered Thinnest part- headThinnest part- head Males are smaller than femalesMales are smaller than females
Trichuris trichiura
Necator americanus, Anclyostoma Necator americanus, Anclyostoma duodenale (Hookworms)duodenale (Hookworms)
Soil transmittedSoil transmitted 22ndnd most common helminth infection most common helminth infection Enter via exposed skinEnter via exposed skin
Necator or Ancylostoma – Hookworm egg
Hookworm life cycle
Strongyloides stercoralisStrongyloides stercoralis Soil transmittedSoil transmitted Larval form-does not have eggs or other formsLarval form-does not have eggs or other forms It has internal structuresIt has internal structures
Strongyloides larvae
Strongyloides stercoralis
Can be found in intestines or stoolsIn real sick can go to lung and cause pneumonia
Trichinella spiralis
-Tissue nematode-All stages occur in single host-usually an incidental findingin muscle
MicrofilariaeMicrofilariae SheathedSheathed
• Wucheria bancrofti Wucheria bancrofti and and Brugia malayiBrugia malayi Elephantiasis (lymphangitis/lymphedema)Elephantiasis (lymphangitis/lymphedema)
• Loa loaLoa loa Calabar swellings & migrating worms in the Calabar swellings & migrating worms in the
conjunctivaconjunctiva Not sheathedNot sheathed
• Onchocerca volvulusOnchocerca volvulus• MansonellaMansonella species species
Allergic skin reactions, edema, Calabar swellingsAllergic skin reactions, edema, Calabar swellings
How to tell them apartHow to tell them apart Are they sheathed?Are they sheathed?
• Yes: Wucheria, Brugia, Loa loaYes: Wucheria, Brugia, Loa loa• No: Onchocerca, MansonellaNo: Onchocerca, Mansonella
How far do nuclei extend?How far do nuclei extend?• Terminal and subterminal nucleus: Terminal and subterminal nucleus:
BrugiaBrugia• To the end: Loa loaTo the end: Loa loa
Identification of microfilariae is based on the presence of a sheath covering the larvae, as well as the distribution of nuclei in the tail region
A, W. bancrofti. B, B. malayi. C, L. loa. D, O. volvulus. E, Mansonella perstans. F, Mansonella streptocerca. G, Mansonella ozzardi.
FilariaFilariaIdentificationIdentification
a.a. W. bancroftiW. bancrofti• Sheathed, nuclei Sheathed, nuclei
stop short of end of stop short of end of tailtail
b.b. B. malayiB. malayi• Sheathed, two small Sheathed, two small
nuclei in tailnuclei in tailc.c. O. volvulusO. volvulus
• Unsheathed, from Unsheathed, from skin, not bloodskin, not blood
d.d. Loa loaLoa loa• Sheathed, nuclei to Sheathed, nuclei to
continue to end of continue to end of tailtail
Wucheria bancrofti
Wuchereria bancroftiWuchereria bancrofti
Sheath
Brugia malayi
Brugia malayiBrugia malayi
Loa loa
Loa loaLoa loa (eye worm) (eye worm)
Mansonella perstans
OnchocerciasisOnchocerciasis
Black fly
Onchocerciasis
Trematodes (Flatworms)Trematodes (Flatworms)
Intestinal and Liver flukesIntestinal and Liver flukes• Fasciolopsis buskiFasciolopsis buski• Fasciola hepaticaFasciola hepatica
Liver flukesLiver flukes• Clonorchis sinensis (Chinese liver fluke)Clonorchis sinensis (Chinese liver fluke)
Paragonimus westermani – oriental lung flukeParagonimus westermani – oriental lung fluke SchistosomesSchistosomes
• S mansoni – intestinal bilharziasisS mansoni – intestinal bilharziasis• S haematobium - urinaryS haematobium - urinary• S japonicum – blood fluke, found in intestinesS japonicum – blood fluke, found in intestines
Intestinal and liver flukes
Fasciola hepatica
Distinct nose
Fasciolopsis buski Fasciola hepatica
Fasciolopsis buski
Fasciolopsis buski
Clonorchis sinensis
knobbin
Shouldersoperculates
Transmission: Crab or crayfishSymptoms: chest pain, hemoptysiscough, pulmonary infiltrates, cerebral lesionsDiagnosis: Eggs is sputum or feces
Egg is operculate, unembryonated, thick shell, asymmetrical and large
Paragonimus westermani
Schistosoma mansoniiParagonimus westermani
Schistosoma mansoni Schistosoma haematobium Schistosoma jajonicum
Cestodes (Tapeworms)Cestodes (Tapeworms)
ExamplesExamples Diphyllobothrium Diphyllobothrium
latumlatum Taenia saginataTaenia saginata Taenia soliumTaenia solium Hymenolepis nanaHymenolepis nana Hymenolepis diminutaHymenolepis diminuta Echinococcus Echinococcus
granulosisgranulosis
Flattened dorsoventrally, segmentedHead with armed or unarmed scolexProglottids immature, mature (sex organs)Gravid (with eggs)
Internal structure of proglottidsHermaphroditic-ovary, testes, vitellaria, uterus, genital pore and ducts
Lateral excretory and nervous system
No gut-tegument absorbs nutrients
Muscles-longitidinal and horizontal
Diphyllobothrium latum
Diphyllobothrium latumDiphyllobothrium latum Poorly-cooked fresh-water fish(salmon)Poorly-cooked fresh-water fish(salmon) Scandinavian, Russia, Canada, N. USA, Scandinavian, Russia, Canada, N. USA,
AlaskaAlaska Broad fish tapewormBroad fish tapeworm Longitudinal suckerLongitudinal sucker Eggs have non-shouldered operculum and Eggs have non-shouldered operculum and
knobknob• They are not embryonatedThey are not embryonated
Causes Vit B12 deficiencyCauses Vit B12 deficiency
Diphyllobothrium latum
Sucking plate
Diphyllobothrium latum
Taenia saginata
Beef tapeworm 4 suckers on scolex >13 uterine branches in proglottidsIngestion of cysticerci in beef
Intestinal infestationIngestion of eggs ->
Non-human pathogen
Taenia Solium
Pig tapewormRing of thorns/crown on scolex<13 uterine branches in proglottidsIngestion of cysticerci in pork
Intestinal infestationIngestion of eggs ->
Cysticercosis
Taenia Species – two speciesOutstanding characteristics
Taenia species
Taenia eggsIdentical eggs for the two species
Taenia saginata
Proglottid > 12 uterine branches
Taenia solium
Proglottis – fewer uterine branches(<=12 uterine branches)
Scolex - Ring of thorns
Cysticercosis
Caused by the ingestion of T. solium eggsNot eating infected pork
Cysts of Cysticercosis
Hymenolepis nana
Hymenolepis nanaMost common cestode recovered in USAWorm is 2-4 cmEgg has inner & outer shell separated
spaceWater /food contaminated by rodent droppings
Hooklets inside
Larger outer shellNo radial striations
Hymenolepis diminutaUncommon tapewormBig egg @ 80 microns in diameter
Echinococcus – hydatid cyst
Echinococcus – hydatid cyst
Short tapewormSand like materialContained in the cyst
Tapeworms
Relative size of Helminth eggsRelative size of Helminth eggs
http://www2.bc.cc.ca.us/bio16/pal/Parasitology.htm
Insects of interest – not already Insects of interest – not already mentionedmentioned
Maggots
Bot fly larvae
Extrudes from the skin
Ticks of importance
Soft tick -Expands with bloodengorgement
Hard Ticks
Black Widow spider
Hour glassOn tummy
FleaBody louse
Crab louse
Hair nitBody Louse
Scabies
Tiny
egg
s un
der s
kin
Mite