Blood Films & Smears

Question 1

Answer 1

Trypanosoma Cruzi
Trypomastigotes

Chunky kinetoplasts

Haemoflagellate/Blood protozoa causing Chagas Disease
Vector: Panstrongylus Triatomine bugs

Thin blood film

Question 2

Answer 2

Trypanosoma brucei
Trypomastigotes

Small kinetoplasts

Haemoflagellate/Blood protozoa causing Human African Trypanosomiasis (HAT) or African Sleeping Sickness
Vector: Glossina Tsetse Fly

Thin blood film

Question 3

Answer 3

P.vivax
Trophozoite

Enlarged RBC with irregular ring & Schuffners dots

Question 4

Answer 4

P.vivax
Gametocyte

Filling the whole enlarged RBC

Question 5

Answer 5

P.vivax

Gametocyte on the left
Schizont on the right

Both are enlarged RBC’s

Question 6

Answer 6

P.falciparum
Trophozoites

See double chromatin (headphones) & accole forms in normal sized RBC

Question 7

Answer 7

P.falciparum
Trophozoite

Neat parasite with Maurer’ clefts in normal sized RBC

Question 8

Answer 8

P.falciparum
Trophozoites

Neat rings with Maurer’s clefts in normal sized RBC
& an accole form

Question 9

Answer 9

P.vivax
Trophozoite

Enlarged RBC with untidy parasite, Schuffners dots & some pigment

Question 10

Answer 10

P.malariae
Gametocyte

Smaller RBC completely filled

Question 11

Answer 11

P.vivax
Schizont

Enlarged RBC with Schuffners dots & pigment

Question 12

Answer 12

P.ovale
Gametocyte

Oval, fimbriated cell with coarse James’ dots & parasite does not fill the cell

Question 13

Answer 13

P.ovale
Gametocyte

Slightly fimbriated cell with coarse James’ dots & parasite does not fill the slightly enlarged cell

Question 14

Answer 14

P.vivax
Early schizont

Enlarged, plastic cell with untidy parasite with 2 nuclei & schuffners dots

Question 15

Answer 15

P.falciparum
Schizont

Normal sized RBC containing maurer’s clefts, neat parasite with multiple nuclei that does not fill the cell & a clump of black pigment

Question 16

Answer 16

P.falciparum
Schizont

Normal sized RBC containing neat parasite with multiple nuclei that does not fill the cell & a clump of black pigment

Question 17

Answer 17

P.vivax
Trophozoite

Enlarged RBC, Schuffners dots, irregular/untidy parasite

Question 18

Answer 18

P.vivax
Trophozoite

Enlarged, plastic RBC with Schuffners dots & untidy/irregular cytoplasm

Question 19

Answer 19

Leishmania
Amastigotes

Seen outside RBC’s

Thin blood film

Question 20

Answer 20

Leishmania
Promastigotes

Seen outside RBC’s
Position of the kinetoplast near flagellum

Thik blood film

Question 21

Answer 21

P.falciparum
Trophozoite

Accole form with Maurer’s clefts

Question 22

How do you calculate parasitaemia percentage?

Answer 22

1. Count the number of parasitised cells (not number of parasites) in a field of view
2. Count the number of parasitised cells (X) in 8 consecutive fields, either in an upwards or downwards direction.
3. Calc %=(X÷2)/10

ALWAYS calculate percentage parasitaemia for P.falciparum infections

There are ~250 RBC’s per field of view

Question 23

Answer 23

P.falciparum
Trophozoite

Headphones in normal sized RBC

Question 24

Answer 24

P.falciparum
Trophozoites

Multiple parasites in normal sized RBC - 2x accole forms

Question 25

# What does this show?

Answer 25

***Plasmodium spp.*** on Thick Blood Film The WBC's are purple and the background is pale. The RBC's are lysed, releasing the parasites

Question 26

Answer 26

***Brugia timori*** microfilariae on Thick Blood Film Large microfilariae Has a sheath that stains pink 3 nuclei in tail (.’. **T**ri-nucleated for **T**imori) Disease: **Lymphatic Filariasis** Vector: Culicine Mosquitoes Tx: DEC (diethylcarbamazine) +/- Doxy | Thick bloodfilms for microfilariae, also stained with Giemsa

Question 27

Answer 27

***Onchocerca volvulus*** microfilariae on Dry smear impressions from skin snip Large microfilariae NO sheath Empty globular head & empty blunt tail (**O** = nothing .’. empty) Disease: **Subcutaneous Filariasis** & Onchocerciasis - River blindness Vector: Simulium Black fly Tx: Ivermectin +/- Doxy. NOT DEC. (Caution if Loaloa coinfection) | Also stained with Giemsa

Question 28

Answer 28

***Brugia malayi*** microfilariae on Thick Blood Film Large microfilariae Has a sheath that stains pink 2 nuclei in tail (.’. **B**i-nucleated for **B**rugia) Disease: **Lymphatic Filariasis** Vector: Culicine Mosquitoes Tx: DEC (diethylcarbamazine) +/- Doxy | Thick bloodfilms for microfilariae, also stained with Giemsa

Question 29

Answer 29

***Brugia malayi*** microfilariae on Thick Blood Film Large microfilariae Has a sheath that stains pink 2 nuclei in tail (.’. **B**i-nucleated for **B**rugia) Disease: **Lymphatic Filariasis** Vector: Culicine Mosquitoes Tx: DEC (diethylcarbamazine) +/- Doxy | Thick bloodfilms for microfilariae, also stained with Giemsa

Question 30

Answer 30

***Wucheria bancrofti*** microfilariae on Thick Blood Film Large microfilariae Has a sheath that stains pink NO nuclei in tail Disease: **Lymphatic Filariasis** Vector: Culicine Mosquitoes Tx: DEC (diethylcarbamazine) +/- Doxy Dx: optimum time is at night (between 22:00-02:00) | Thick bloodfilms for microfilariae, also stained with Giemsa

Question 31

Answer 31

***Wucheria bancrofti*** microfilariae on Thick Blood Film Large microfilariae Has a sheath that stains pink NO nuclei in tail Disease: **Lymphatic Filariasis** Vector: Culicine Mosquitoes Tx: DEC (diethylcarbamazine) +/- Doxy Dx: optimum time is at night (between 22:00-02:00) | Thick bloodfilms for microfilariae, also stained with Giemsa

Question 32

Answer 32

***Loaloa*** microfilariae on Thick Blood Film Large microfilariae Has a sheath that does NOT stain pink .'. Ghost sheath Many nuclei in tail which go to the tip Disease: **Subcutaenous Filariasis** & African Eyeworm Vector: Chrysops deer fly Tx: Albendazole to dec. Mf then DEC (DEC & IVM can produce severe SE’s in high Mf counts) | Thick bloodfilms for microfilariae, also stained with Giemsa

Question 33

# What does this show?

Answer 33

***Plasmodium spp.*** on Thick Blood Film There is a large, dark purple WBC, a small pink platelet and a parasite with a dark purple nuclei & blue cytoplasm, on a pale background. The RBC's are lysed, releasing the parasites.

Question 34

Answer 34

***Plasmodium spp.*** Trophzoites on Thick Blood Film There are 2x parasites with a dark purple nuclei & blue cytoplasm, on a pale background. The RBC's are lysed, releasing the parasites.

Question 35

Answer 35

***P.falciparum*** Gametocyte on Thick Blood Film There is a neat banana shaped parasite, on a pale background where the RBC has lysed, releasing the parasite. | Difficult to speciate on thick films due to loss of RBC features

Question 36

Answer 36

***P.vivax*** Trophozoite on Thick Blood Film There are untidy parasites, on a pale background where the RBC has lysed, releasing the parasite. The pink skirt surrounding them is the remnants of the Schuffner's dots, giving you an idea of how large the RBC's would have been. | Difficult to speciate on thick films due to loss of RBC features

Question 37

Which blood films are more sensitive for ***Plasmodium spp.***?

Answer 37

Thick blood films Thick blood films are **not** fixed with methanol in order to lyse the RBC's

Question 38

Which blood films are better for estimating ***Plasmodium spp.*** percentage parasitaemia?

Answer 38

Thin blood films You can't estimate a percentage parasitaemia from a thick film as there are no red blood cells.

Question 39

A percentage parasitaemia should always be calculated for which infections?

Answer 39

***Plasmodium falciparum***

Question 40

Answer 40

***P.falciparum*** Gametocyte Neat banana shaped parasite with fine membrane from RBC

Question 41

Answer 41

***P.malariae*** Schizont Classic 'Daisy head' schizont with 8-10 merozoites, central pigment, filling the whole RBC which is slightly smaller in size.

Question 42

Answer 42

***P.falciparum*** Trophozoite Neat parasite with Maurer's clefts in normal sized RBC.

Question 43

Answer 43

***P.malariae*** Gametocyte See nucleus with scattered yellow/gold pigment in smaller RBC. Usually they fill the whole cell but there are no dots/stippling in cytoplasm which indicates *P.malariae*

Question 44

Answer 44

***P.ovale*** Trophozoite Neat parasite with thick loop of cytoplasm in normal sized RBC with fimbriations an coarse James' dots.

Question 45

Answer 45

***P.vivax*** Schizont 18-20 Merozoites filling the whole enlarged RBC with scattered pigment. Can just see schuffners dots around the peripheries.

Question 46

Answer 46

***P.vivax*** Trophozoite Ring parasite with Schuffners dots in enlarged RBC.

Question 47

Answer 47

***P.ovale*** Schizont Oval shaped RBC containing perfectly round parasite with merozoites and pigment, that does not fill the whole cell. May also see fimbriations

Question 48

Answer 48

***P.vivax*** Gametocyte Enlarged RBC completely filled by parasite with nucleus and scattered pigment. Can see Schuffners dots around peripheries of cell

Question 49

Answer 49

Lymphocyte Do not confuse with *P.vivax* Gametocyte - cell is large but much darker than parasite and there is no nucleus or pigement

Question 50

Answer 50

***Echinococcus*** protoscoleces Larval stage of canid tapeworm causing hydtid disease very small – see under x40 Can also see loose hooks in hydatid cyst aspirates | Wet aspirate: fluid from Hydatid cysts aka ‘Hydatid Sand’ (Condenser 2)

Question 51

Answer 51

***Echinococcus*** protoscoleces Larval stage of canid tapeworm causing hydatid disease very small – see under x40 Invaginated head & can clearly see hooks inside. | Wet aspirate: fluid from Hydatid cysts aka ‘Hydatid Sand’ (Condenser 2)