Parasitology & mycology review

Prof. Muhammad Akram HossainProf. Muhammad Akram Hossain
MMC

Principle of diagnosis Lab Dx of Microbial diseases
Demonstration of causative agents by
microscopy commonly practiced for parasitic
diseases & fungal diseases
Isolation and identification of causative agent
by artificial culture - (C/S) commonly practiced
for bacterial diseases.for bacterial diseases.
Detection of antibody or antigen from blood
or other body fluids practiced for viral diseases
& some bacterial & parasitic diseases
Detection of Nucleic acid segment (DNA or
RNA)
Prof. Muhammad Akram Parasitology & Mycology Review 2

Specimen : according to site of infection
Microscopic Examination :
Light microscopy / DGM / FM / EM
Unstained preparation
stained smear -Gram, AFB, Fluorescence
Isolation & identification : Bacteriological, fungal,
protozoal Culture, Cell culture for viruses
Steps involved in Lab Dx of Microbial diseases
protozoal Culture, Cell culture for viruses
Identification by standard biochemical & serological test
Immunological test : detection of Ag or Ab by LAT,
ELISA etc
Detection of gene: NA based techniques by PCR etc
Special tests : Toxigenicity tests

Formula for Lab Dx of Parasitic diseases
Almost all parasitic diseases can be diagnosed
by M/E examination of appropriate specimen
and finding some structure of the parasites.
Specimen: depends on site of infection
Blood, stool, HVS, BM, etc
Protozoal structureProtozoal structure
Cyst, trophozoite, Oocyst, special - LD bodies, schizont etc
Metazoal structure
Ova, larva, segments

Examples of Lab Dx of Parasitic diseases by M/E
Amoebiasis
By M/E of stool for Cyst or trophozoite, Liver aspirate for trophozoite
Giardiasis
By M/E of stool for Cyst or trophozoite
Trichomoniasis
By M/E of vaginal discharge for trophozoite
MalariaMalaria
By M/E of PBF for schizont, merozoite, gametocytes etc (MP)
Kala-azar
By M/E of BM, Spleen or LN for LD bodies
Cryptosporidiasis
By M/E of ZN stained smear of stool for Oocyst

•Kala-azar -
By culture & immunological tests
• Malaria-
•by immunological test by detecting Ag/Ab
Dx of Parasitic diseases by other tests
•Hydatid disease
By immunological tests
Casoni’s test (traditional)
Indirect haemagglutination test (IHA) - modern
•Filariasis -
By detecting antibody - Occult filariasis (CFT, IFAT)
By detecting antigen - classical filariasis (ICT)

Lab Dx of kala-azar
Principle :
Kala-azar can be diagnosed by demonstration of the parasite (LD
bodies) from the BM, Spleen or L.node aspirate and by
detection of antibody and antigen by immunological tests and
the organism can also cultured if facilities are available.
Steps:Steps:
Specimen: Bone marrow/ spleen / lymphnode aspirate or serum
M/E : leishman stained smear shows LD bodies
Culture : can be cultured in NNN medium at 220C for 1-2 weeks
Serological tests:
Specific : IFAT, DAT, ICT , CFT for detection of antibody
Nonspecific: Aldehyde test for detection of high Globulin.

What is black water fever? Why it is so called?
A complication of P.falciparum malaria where colour
of urine becomes black due to intravascular hemoysis.

Lab Dx of malaria
Principle :
Malaria can be diagnosed by demonstration of the parasite (ring
form, schizonts, gametocytes etc ) from the Peripheral blood film, and
by detection of antigen by immunological tests
Steps:
Specimen: Blood
M/E : leishman / Giemsa stained smear of thick and thin blood filmsM/E : leishman / Giemsa stained smear of thick and thin blood films
demonstrates the parasites and species can also be identified by seeing the
morphology.
Culture : rarely done
Serological tests:
Specific : ICT for detection of antigen / antibody

What is protozoa? 5 common protozoa disease in Our
country? What are rare protozoal disease in BD
The word Protozoa is derived from “Proto”-primitive,
“Zoo” -life i.e. Primitive life or first life.
Common protozoa disease in BD
Amoebiasis
Giardiasis Toxoplasmosis - ??Giardiasis
Malaria
Kalazar
Trichomoniasis
Rare protozoal diseases
Sleeping sickness
Chagas disease
Cryptosporidiasis
Toxoplasmosis - ??

•Filariasis
By M/E of PBF for larva (microfilaria)
•Intestinal helminthes
By M/E of stool for ova or larva
•Enterobiasis
By M/E of Peri-anal swab for ova ?
Examples of Lab Dx of Helminthic diseases by M/E
By M/E of Peri-anal swab for ova ?
•Taenia saginata or solium
By M/E of stool for segments or ova
What are the differences between ova of T.saginata & T.solium?
•Diphylobothriasis
By M/E of stool for ova or larva
•Schistosomiasis
By M/E of urine or stool ?

How many species of plasmodium are there?
Which spp. are found in Our country?
Plasmodium vivax – benign tertian malaria
Plasmodium falciparum – malignant tertian malaria
Plasmodium ovale – oval tertian malariaPlasmodium ovale –
Plasmodium malariae – quartan malaria
P.vivax and P.falciparum are found in Bangladesh

Which spp. of plasmodium is most dangerous
and why?
Plasmodium falciparum – is most dangerous because
It infects both young & old RBCs
Parasitaemia is heavyParasitaemia is heavy
Pernicious malaria/ cerebral malaria occurs
Mortality is high
Frequently drug resistant ( Resistant to
chloroquine)

How anaemia occurs in Kala-azar?
Following mechanisms are involved
Bone marrow depression due to infiltration by parasites.
Hemolysis
HyperspenismHyperspenism

What are organs for motility of
protozoa? examples
Protozoa are motile by
Pseudopodia – Entamoeba histolytica
Flagella – Giardia, Trichomonas, Leishmania
Cillia – Balantidium coliCillia – Balantidium coli

Which are the infective form following protozoa?
E. histolycia - Quadrinucleate cyst
G.lamblia - Cyst
Trichomonas vagialis - trophozoites (Cyst absent)
L.donovani - PromastigoteL.donovani - Promastigote
Plasmodium - Sporozoites
Toxoplasma - ?

No man can be a good teacher unless
be has feelings of warm affection
towards his pupils and a genuine
desire to impart to them what hedesire to impart to them what he
himself believes to be of value.
Bertrand Russel

What is the mechanism of megaloblastic anemia
by D.latum?
D.latum interferes with fat absorption by inhibiting
intrinsic factor

Men learn while they teach.
Seneca
To be proud of learning, is the greatest
ignorance.
Jeremy Taylor

Which parasite is found within RBC? Which are found in
Macrophage & which are found in plasma?
Ans: Malarial parasite (MP) is found within RBC,
L.donovani within Macrophage &T.bruci, T
cruzi, microfilaria in plasma

Name common helminthic disease in BD
Nematodes are common in our country
Ascariasis - commonest
Hook worm infestation* -
Enterobiasis
TrichiuriasisTrichiuriasis
Filariasis

Name helminthic disease uncommon in our
country?
Cestodes
Taenia saginatum, Taenia solium
Diphylobothrium latum
Echinococcus granulosus (Hydatid cyst)Echinococcus granulosus (Hydatid cyst)
H.nana
Trematodes
Schistosomes- S.japonicum, S.mansoni, S.heamtobium
Paragonimus westermani - lung flukes
Fasciola hepatica, Clnorchis sinensis, fasciolepsis buski

Which are the infective form following Helminths?
Ascaris lumbricoides - Mature ova
Hook worms - Filariform larva
S.stercoralis - Filariform larva
Enterobius vermicularis - OvaEnterobius vermicularis - Ova
Trichuris trchiura - Ova
W.bancrofti - 3rd stage larva

How can U diagnose Cryptosporidium in
Lab? Whom it causes diarrhoea?
Cryptoporidium causes persistent
diarrhoea i immnocopromised
persons ( AIDS patients).
It can be diagnosed in the lab byIt can be diagnosed in the lab by
modified Acid fast staining of
stool, where oocyts can be found.

Which cysts commonly found in the stool of child of
BD?What is difference in their pathogenesis? What is
character of stool ?
Cysts of E.histolytica, Giardia lamblia
E.histolytica causes lesion in the large intestine and
forms ulcer by invasion. Stool contains pus cells, RBC &
cysts or trophozoites of E.h.
G.lamblia causes lesion in the small intestine and do
not invade but by attachment with cup like dis
interferes with absorption of fat. stool contains fat cells
but no pus cells or RBC, & cysts or trophozoites of G.L

Which parasites causes anaemia & What type of
anaemia? With mechanism
Hook worm - Microcytic, hypochromic & Dimorphic
anaemia.
Plasmodium - Hemolytic anaemia
L. donovani - Normocytic anaemiaL. donovani - Normocytic anaemia
Diphylobothrium latum - megaloblastic anaemia

Between T.saginata & Solium which one is more dabgerous and
why? How can U differentiate them? What are the difference in
their ova?
T.solium is dangerous than T.saginata because
Cysticercus celulosae (larval stage of T. solium)
occurs in man.
Can be differentiated by N/E and M/E ofCan be differentiated by N/E and M/E of
segments.
T.saginata- longer, solium- broader
Rostellum & hooks - present in T.solium
Difference in genital organs
No difference in their ova

T. solium gravid segment T. saginata gravid segmentT. solium gravid segment T. saginata gravid segment
T. solium with hooks
T. saginata with no hooks

Which helminthic infection occur following ingestion of
meat and fish & vegetable?
Improperly cooked beef- T.saginata
Improperly cooked pork T.solium
Fish - Diphylobothrium latum
Raw Vegetable-Raw Vegetable-
E.histolytica
Giardia
Ascaris lumbricoides, Trichuris trichiura

Which are vector bone parasitic disease?
Mosquito-
Malaria, Filaria
Sandfly -
Kalazar
Tse Tse fly-Tse Tse fly-
Trypanosoma brucei
Reduvid bug
Trypanosoma cruzi
Deer fly/ Black fly
Onchocerca volvulus

What is the role Eosinophil & IgE in combating
helminthic infestation?
Help to expel helminths by ADCC mediated by IgE &
Eosniophil.

Which parasitic infection occurs with fondling of dogs? How?
What type of host is man? Lab diagnosis? What will happen if
explore it?
Echinocuccus granulosus
By ingestion of egg present in dogs faeces
Man is accidental intermediate host, Dof is theMan is accidental intermediate host, Dof is the
definitive host.
Can be diagnosed by immunological test
Casonis tes, IHA(Indirect haemagglutination test)
Possiblity of anaphylactic reaction and multiple cyst
in other parts og body

Which nematodes have heart lung migration?
Ascaris lumbricoides
Hook worms
Ankylostoma duodenale & Necator americanaAnkylostoma duodenale & Necator americana
Strongyloides stercorlais

Which one is the commonest helminthic infection In BD?
What are the clinical problem occurs with ascariasis?
Due to Adults & Larva
Adults
Spoliative action - PEM, Vitamin A deficinecy (night
blind ness)blind ness)
Mechanical - Obstruction in bile duct, Intestine
Toxic - Typhoid like fever, rash
Larva
Loefflers syndrome - Pneumonitis

Which ova can be found in the stool of Bangladeshi
children?
A.L
A.L
AD T.T

How can differentiate between P.vivax and
P.falciparum?
By the morphology in RBC & shape of
gametocytes.
P.vivax
P,falciparum
P,falciparum
gamete
P,falciparum

Which one infective form of E.histolytica? Why
trophozoites can not cause infection?
Infective form – Quadrinucleate cyst.
Trophozites can not cause infection because they are
destroyed by the gastric juice.

What is definitive and Intermediate host? Where Man is
intermediate host?
Definitive host – where parasite passes adult for
or sexual stage of life cycle.
Intermediate host – larval form or asexual stage
of multiplication takes place.
Man is the intermediate host in following cases-Man is the intermediate host in following cases-
Malaria
Hydatid cyst
Man is both definitive & Intermediate host
Taenia solium
Trichenella spirilim

How can U classify fungi morphologically?
Morphological classification of fungi
Yeasts –cryptoccus neoformans
rounded structure
Mould – Dermatophytes
Branching structure with hyphae & myceliaBranching structure with hyphae & mycelia
Yeast like- candida albicans
possess pseudohyphae
Dimorphic – Deep fungi
yeast within human tissue (370C)
Mould in environment 250C

Name the dermatophytes. Why they so called?
Where they infect?
Epidermophyton – skin
Microsporum – skin & hair
Trichophyton – skin, hair & nail
They are called dermatophytes because they haveThey are called dermatophytes because they have
affinity for dermis.

What is taenia infection? Give examples
Infection by dermatophytes are known as Taenia
infection. According to site they are as follows-
Taenia capitis – (head)
Taenia – corporis ( body)Taenia – corporis ( body)
Taenia barbi (beard)
Taenia unguium –(fingers)
Athlets foot – (Ankle)

•What is dimporphism and why this occurs?
•Two morphological forms at different temperature.
•Mold - saprophytic - free living -at 25)C for existence
•Yeasts - in the hosts parasitic at 37)C
•What are the fungal spores?
•Are means of reporduction. Both asexual & sexual.•Are means of reporduction. Both asexual & sexual.
•Where fungi lives?
•Mostly in the environment
•candida - in the host as normal flora
•Are fungal disease communicable?
•No

•How can diagnose a fungal infection? What is the role of
KOH?
•Mostly by M/E after dissolving in alkaline solution
(KOH or NAOH), Calciflor white- a fluorescent dye
can stain the cell wall and helpful in tissues.
•Culture
•Serology
•DNA probe- coccidiodes immitis, Histoplasmosis,
Blastomycosis

•Why antibacterial agents do not act on fungi ?
•Target structures like cell wall, etc are absent..
•What is the significance of ergosterol in CM of fungi?
•Is the basis for antifungal drugs.
•Why bacteria do not multiply in fungal media?•Why bacteria do not multiply in fungal media?
•Due to high acidity of the medium and antimicrobial
agents like chloramphenicol & chlorhexidine

How can U clinically classify fungal
diseases?
Clinical classification-
Superficial- dermatophytes
Subcutaneous- Sporothrix shincki
Systemic – HistoplasmosisSystemic – Histoplasmosis
Oportunistic – Candidiasis, Cryptococcosis,
Aspergillosis

•Coccidiodes- C.immitis- Granulomatous lesion
of Bones, CNS
•Histoplasmosis - H.capsulatum (inside
macrophage) - Liver, spleen
What are systemic fungal infections?
macrophage) - Liver, spleen
•Blastomycosis - B.dermatitidis - skin
•paracoccidiodes - P.brasiliensis - lung &
disseminated
.

•Opportunistic
•Candidiasis - Candida albicans - mouth,
vagina, & disseminated
•Cryptococcosis - C.neoformans, capsulated,
pneumonia, meningitis
What are opportunistic fungal infections?
pneumonia, meningitis
•Aspergillosis - A.fumigatus - mold, fungus ball
in the lung, Allergic bronchopulmonary
aspergillosis (ABPA)
•Pneumocystis carinii - yeast like, pneumonia in
AIDS patients.

Which one is capsulated fungus? What is its structure?
Disease? How can be diagnosed?
Cryptococcus neoformans
It is a yeast
opportunistic infection in CNS, lungs
Pneumonia, meningitisPneumonia, meningitis
Capsule can be demonstrated by India ink
preparation also by immunological test (Ag
detection)

How can you diagnose a ringworm infection? Role of KOH?
Temp & time of culture? How species are identified?
Can be diagnosed by M/E of infected specimen
after dissolving in keratolytic solution like KOH,
NAOH, then by culture in Sabrauds dextrose agar
media.media.
Specimen – Skin scrapping, hair plucking, nail shaving
M/E – shows fungal structures like hyphi, mycelia etc.
KOH dissolves keratin layers
Culture incubated at 25 0c or room temp for 2-3 weeks.
Species is identified by M/E of growth, for
microconidia & macroconidia

Check list (Parasitology & Mycology)
•Name of common protozoal diseases with their causative agents,
Definitive host, Intermediate host, Mode of transmission and infection.
•Name of common helminthic diseases with their causative agents,
Definitive host, Intermediate host, Mode of transmission and infection.
•Lab diagnosis of malaria, kala-azar, Giardiasis, Intestinal and Hepatic
amoebiasis, Fialriasis, AL, AD, Enterobiais, Hydatid disease.
•Pathogenicity of AL, AD, EV, EH, LD, Malaria, Kalaazar, Filaria
•Morphological forms of fungi with examples
•Name of superficial fungal infection and fungi & lab diagnosis ( Use of
KOH in M/E), macroconidia & microconidia.
•Candidiasis in details
•Deep fungi - names
•Cryptoccus neoformans

Best wishes
for
all studentsall students

Parasitology & mycology review

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