Lab Flashcards
1
Q
What?
Size?
Describe?
A
- E. histolytica/dispar trophozoite
- unless hematophagocytic, in which case histolytica
*
2
Q
What?
Size?
Describe.
A
- Entameba histolytica/dispar
- 10-15 µm
- 1-4 nuclei
3
Q
What?
Size?
Describe?
A
- Entameba coli
- 15-25 µm
- large round cysts with well defined membrane
- mostly clear nuclei, 4-8
- usually mature cysts
4
Q
What?
Size?
Describe.
A
- Endolimax nana
- small, 7-9 µm
- oval or round shape
- 4 hole like nuclei, not always clear
5
Q
What?
Size?
Describe
Pathogenic?
A
- Blastocystis hominis
- 8-15 µm
- 4 peripheral nuclei with large central vacuole
6
Q
What?
Size?
Describe
Pathogenic?
A
- Giardia cyst
- 10-15 µm
- oval shape (sometimes round)
- axostyle visible in most cysts
7
Q
Describe 5 features of this thin film field.
A
- Normal RBC size
- No stippling
- Early ring trophozoite
- Ring forms with double chromatin dots
- Multiple invasions (4,2)
8
Q
Describe 5 features.
A
- Banana shaped paired parasites
- Single well defined chromatin nucleus
- Scattered haemazoin pigment
- Male (bottom) female (top)
- Falciparum Gametocytes
9
Q
Describe 5 features
A
- Associated with many young ring forms.
- Small and compact
- 12-30 merozoites in compact cluster
- Pigment: single dark mass
- Falciparum Schizont
10
Q
Describe 5 features
A
- 3 red blood cells infected with malaria parasites
- Normal RBC size
- One cell with multiple invasions
- Red cells with maurers clefts
- Falciparum late trophozoite
11
Q
Describe 5 features.
A
- Enlarged RBCs
- Shuffners dots
- Amoeboid appearance
- Single chromatin dot with irregular cytoplasm
- P vivax late trophozoite
12
Q
Describe 5 features
A
- Englarged red blood cell
- Shuffners dots
- Irregular mass of pigmented cytoplasm
- Dividing chromatin dots
- Developing Vivax shizont
13
Q
Describe 5 features
A
- Enlarged RBC
- Shuffners dots
- 12-24 merozoites, usually 16, in irregular cluster.
- Loose mass of haemozoin pigmentation
- Mature Vivax Shizont
14
Q
Diagnose blood film.
A
Mixed Falciparum and Vivax infection
15
Q
Describe 5 features
A
- Two parasitised red blood cells
- Fimbriated
- Compact oval shape
- Shuffners Dots
- Regular fleshy cytoplasm
- P Ovale trophozoite
16
Q
Describe 5 features
A
- Microcytic parasitised red blood cell
- Band form cytoplasma
- Haemozoin pigmentation
- No Shuffners dots
- P malariae trophozoite
17
Q
Describe 5 features
A
- Microcytic RBC
- 6-12 merozoites
- Rosette formation
- Coarse haemozoin pigmentation
- P malariae Shizont
18
Q
What is this?
How do you distinguish?
Vector for what diseases?
When does it feed?
Which is the main species transmitting malaria in Sub-Saharan Africa?
A
- Anopheles
- Distinguish by:
- Feeding position: tail up
- spots on leading edge of wings
- long palps for both. Males can be distinguished from females by their bushy (plumose) antennae as in the picture below and by the fact that males have clubbed palps (not visible in this picture)
- Females can be distinguished from Culicine females by the fact that Culicine females have short palps (not shown here).
- Male anopheles and culicines both have long palps, but those of the culicine are not clubbed.
- Vector for:
- Malaria - main species is A. gambiae
- O’Nyong Nyong
- Filiariasis: Wucheria bancrofti & Brugia malayi and B. timori
- nb (all are nocturnally periodic in keeping with biting habits of the vector)
*
- nb (all are nocturnally periodic in keeping with biting habits of the vector)
19
Q
What is this?
Distinguishing features?
Vector for which diseases?
A
- Aedes
- Features
- white markings and lyre-like pattern on thorax
- horizontal body position
- Diseases
- Dengue
- Yellow Fever
- Chikungunya
- Zika
- Rift Valley Fever: note not the only mosquito transmitting RVF, but important due to trans-ovarial transmission, dessication resistance, triggering outbreaks after rains.
20
Q
- What species are portrayed in this picture?
- How can you distinguish the sexes?
- Vector for what diseases?
- Contrast with the main malaria vector
A
- Male (left) and female culicine
- Male has plumose antennae, female does not (same diff as anopheles)
- Male culicine has non-clubbed long palps
- Female has short palps.
- Culicines vector for Japanese encephalitis (Culex tritaenorhynchus), West Nile Fever
- Culex quinquefasciatus is primary vector for urban filiariasis worldwide except SSA (where Anopheles gambiae)
- Male anopheline
- plumose antennae
- long clubbed palps.
- Female anophelene
- pilose antennae
- long non-clubbed palps
21
Q
- What mosquito is this?
- Distinguishing features?
- For which disease are these the vector?
- Biting habits?
- Resting habits?
A
- Mansonia
- yellow-brown, large and robust mosquitoes with heavy scaling on the wings
- mixed light and dark scales give the wings a speckled appearance - “4 distinct spots”, dark and dusty or shaggy appearance
- male has long palps, while the female has very short palps. They look similar to Culex in appearance except for the speckled wings.
- Important vector of filiariasis in Asia but not Africa. Mansonia mosquitoes transmit Brugia malayi, which is the nocturnally periodic form in areas of open swamps, and the subperiodic form in areas of swampy forest.
- Mostly nocturnal, most rest outdoors
22
Q
- What are these?
- How can you tell?
- Where do they breed?
- When do they bite?
- Vector for which diseases?
A
- distinctive white or silver coloured scales on a black background
- (it’s the pretty mosquito)
- sides of abdomen and legs have white markings
- Lyre - shaped pattern on thorax
- like all culicines males have long palps (not clubbed) & females have short palps
- breed in containers, water pots, old cans, tyres, leaf axiils, tree-holes and some rock pools
- bite by day
- vectors for : Yellow fever, dengue and DHF, chikungunya, Zika virus (all flaviviruses)
- filiarisis vectors in Pacific (W. bancrofti) and S.E. Asia (Brugia)
23
Q
Anopheline or culicine?
sex?
Which mosquitoes are culicine?
A
- the Culicinae are a subfamily containing 30 genera of which 3 are the most medically important:
- Aedes
- Culex
- Mansonia
24
Q
Identify the stage and species?
Distinguishing features?
A
- mosquito larvae as listed
- Anopheles breathe through pair of spiracles on ninth segment so swim horizontal to the water surface
- Culex have long siphon
- Aedes have short siphon
- Mansonia …? green
25
Q
Identify Stage and Species
Distinguishing features
A
- Anopheles eggs laid singly to float on the water surface. (note the float or water wings)
- culex eggs laid in vertical rows held together be water tension to form an egg raft
- Mansonia eggs laid in sticky mass glued to the underside of floating plants
- Aedes eggs are black, ovoid and laid singly on damp substrate, usually above waterline
- they resist dessication, so my lie dormant awaiting onset of rain to hatch out larvae
- consequently the arboviruses for which they are vector (Yellow fever, dengue, chikungunya, and in Americas, Zika) may be prone to epidemics after onset rains. Also important vector for RVF as they can transmit the infection transovarially and outbreaks also occur with onset of rains.
26
Q
What kind of mosquito is this?
What are the two most prominent species of this genera with respect to arbovirus transmission and which diseases does each transmit?
A
-
Aedes
- A aegypti: dengue, urban yellow fever, Chikungunya
- A. albopictus: dengue, Chikungunya
27
Q
- Describe the Sylvatic or rural cycle vs the urban cycle wrt Yellow Fever?
- Is there a similar zoonotic cycle for Dengue?
A
- different hosts, different vectors
- Yellow Fever a disease of monkeys in the sylvatic cycle that has jumped to man
- In Africa the sylvatic cycle vectors are Aedes africanus and A. bromelia, whereas A. aegypti is the urban vector
- In South America the sylvatic vectors are Haemogogus or Sabethus species and again, A. aegypti is the urban vector
- No zoonotic cycle for Dengue, humans are the only mammalian host.
29
Q
What is this mosquito and why does it matter where it lives?
A
- Aedes albopictus or Asian tiger mosquito
- very invasive species, has spread north very fast into Europe (including UK) and North America
- a competent vector for Chikungunya and Dengue (main one is Aedes aegypti) as well as possibly for many other arboviruses - eg West Nile, Zika
- spreading aggressively north see map, high risk of importing Chikungunya through travellers
30
Q
Identify these mosquitoes.
Which is the most common vector for filiariasis?
Which species and where?
how about elsewhere?
What determines the periodicity?
A
-
Wucheria bancrofti
- Anopheles gambiae is most common vector of nocturnally periodic Wucheria bancrofti in Sub-Saharan africa
- Americas, Asia, East Africa generally Culex quinquefasciatus, urban mosquito
- Papua New Guineau Mansonia uniformis
- Aedes for diurnally periodic Bancroftian filariasis in Asia and Pacific, nocturnally subperiodic form in Thailand
- Brugia is transmitted by various Mansonia, Anopheles, Aedes
- periodicity is an adaptation by the worm to primary vector species in an area
31
Q
Describe lifecycle of lympatic filiariasis?
How long does it take the microfilariae to develop into larvae in mosquito?
A
- 9-12 days to develop into L3’s in mosquito flight muscle
34
Q
- What is this?
- Vector for what?
- How transmitted?
- What is cutaneous sign of this disease?
A
- Chrysops
- vector for Loa Loa
- Calabar swellings
35
Q
- What is this?
- Vector for what? What are the symptoms?
- Where does the vector lay eggs?
- What is the geographic distribution of the associated disease/infection?
A
- Culicoides
- Vector for Mansonella perstans, also for some Wucheria in East Asia
- irritating skin lumps that disappear after a few hours or days
- widespread sub-Saharan Africa, parts of Central and South America, Caribbean
36
Q
- What is this?
- distinguishing characteristics
- Vector for what disease?\
- Habitat
A
- Blackfly (Simulium)
- stout body, humped thorax, clear colourless wings and short horn-like antennae
- Onchocerciasis volvulus/river blindness
- Mansonella
- fly is host for larval form transmitted with bite of female
- streams and flowing water, larvae attach themselves to vegetation and stones
43
Q
What?
Size?
Distinguishing features
A
- 15-40 µm
44
Q
What is this?
A
Microscopy (page 1 of 2)
- Wuchereria bancrofti
- The microfilaria of Wuchereria bancrofti are sheathed and measure 240-300 µm in stained blood smears and 275-320 µm in 2% formalin. They have a gently curved body, and a tail that is tapered to a point.
- The nuclear column (the cells that constitute the body of the microfilaria) is loosely packed; the cells can be visualized individually and do not extend to the tip of the tail. Microfilariae circulate in the blood.
45
Q
- What is this?
A
- Microscopy (page 1 of 2)
- Wuchereria bancrofti
- The microfilaria of Wuchereria bancrofti are sheathed and measure 240-300 µm in stained blood smears and 275-320 µm in 2% formalin.
- They have a gently curved body, and a tail that is tapered to a point.
- The nuclear column (the cells that constitute the body of the microfilaria) is loosely packed; the cells can be visualized individually and do not extend to the tip of the tail. Microfilariae circulate in the blood.
46
Q
- What is this?
A
- Onchocerca volvulus
- Microfilariae of Onchocerca volvulus are unsheathed and measure 300-315 µm in length.
- The tail tapers to a point and is often sharply bent.
- The nuclei do not extend to the tip of the tail. Microfilariae typically reside in skin but may be found in blood or urine during heavy infections, or invade the eye and cause a condition known as river blindness.
47
Q
What is this?
A
- Loa loa
- Microfilariae of Loa loa are sheathed an measure 230-250 µm long in stained blood smears and 270-300 µm in 2% formalin.
- The tail is tapered and nuclei extend to the tip of the tail. Microfilariae circulate in the blood.
48
Q
What is this?
A
- Loa loa
- Microfilariae of Loa loa are sheathed an measure 230-250 µm long in stained blood smears and 270-300 µm in 2% formalin.
- The tail is tapered and nuclei extend to the tip of the tail. Microfilariae circulate in the blood.
49
Q
What is this?
A
- Microfilariae of Mansonella perstans are unsheathed and measure 190-200 µm in stained blood smears and 180-225 µm in 2% formalin.
- The tail is blunt and nuclei extend to the tip of the tail. Microfilariae circulate in the blood.
50
Q
What is this?
A
- Microfilariae of M. ozzardi.
- Microfilariae of Mansonella ozzardi are unsheathed and measure 160-205 µm in stained blood smears and 200-255 µm in 2% formalin.
- The tail tapers to a point and the nuclei end well before the end of the tail.
- The end of the tail is also bent in a small hook-like shape. Microfilariae circulate in blood.
51
Q
What is this?
A
- Microfilariae of Mansonella streptocerca are unsheathed and measure 180-240 µm.
- The tail is been into a hook-like shape and the nuclei extend to the end of the tail.
- Microfilariae are found in skin and do not circulate in the blood.
52
Q
What is this?
A
- cryptosporidium
- ZN staining stain red
- 4-5 µm
53
Q
What is this?
A
- Cyclospora in saline
- 8-10 µm round bodies
54
Q
What is this?
A
- Cyclospora
- stain bright red or “crazed glass appearance”
- 8-10 µm round bodies
55
Q
What is this?
A
- cryptosporidium on left
- cyclospora on right
56
Q
What is this?
A
- cystisospora belli, immature, only one sporocyst
- 25-35 µm long
- Infection causes acute, nonbloody diarrhea with crampy abdominal pain, which can last for weeks and result in malabsorption and weight loss. In immunodepressed patients, and in infants and children, the diarrhea can be severe. Eosinophilia may be present (differently from other protozoan infections).
59
Q
What is this?
A
- Taenia
- round ova with thick dark brown outer shell,
- radially striated
- 45μm in size
- paler brown central oncosphere with hooks
61
Q
What is this?
A
- H.nana
- thick colourless outer shell
- central onchosphere with pale hooks
- Polar filaments (possibly some damaged ova)
- 45 μm in size
62
Q
What is this?
A
- D.latum ova
- oval shape
- symmetrical egg
- operculum at one end, 65 μm
63
Q
A
- Trichuris ova
- Barrel, oval shaped egg
- pale brown in colour
- clear mucoid (or polar) plugs either end.
- 50-55 μm
64
Q
A
- Hookworm ova
- Oval egg
- thin wall/shell, clear space
- between ovum and thin wall/outer shell
- 60-65 μm
66
Q
A
- Ascaris
- Thick dark brown corticated or mamillated/’bumpy’ coat if fertile egg
- Thick or ‘double’ wall/shell, clear colourless wall/shell if decorticated!
- Undeveloped or morulated ovum, or larvae if infective egg.
- (infertile egg below)
- 55-65μm
