Parasites/bacteriology Practical

Front 1

Identify the following parts of a nematode

Back 1

A= mouth, B= buccal capsule, C= Oesophagus, D= intestine, E= Ovary, F= testis, G= uterus, H= Egg, I= vulva, J= vagina, K= ovary, L= papilla, M= cloaca, N= ala, O= spicules.

Unlabelled line = anus

Front 2

Given your knowledge of the shape and general characteristics, what order is this parasite most likely from?

Back 2

Nematoda

Front 3

What structure of a nematode is this image showing in detail?

Back 3

Cuticle

Front 4

What is the name given to the paired flap-like structures shown on the nematode Toxocara cati?

Back 4

Cervical Alae

Front 5

What is the name given to an expansion of the cuticle surrounding the anterior tip of the nematode as seen in Cooperia oncophora?

Back 5

Cephalic dilation

Front 6

Identify the structure indicated on this nematode. (Hint: cuticle flap found on female Haemonchus contortus)

Back 6

Vulvar flap

Front 7

What is the structure shown in this image?

Back 7

Copulatory Bursa

Front 8

The digestive tract of a nematode can be divided into 5 divisions. What are they?

Back 8

Mouth or Stoma (opens into...)

Buccal capsule

oesophagus (=pharynx)

intestine

anus

Front 9

Identify the type of mouth found in the nematode shown (Trichostrongylus) and state what the nematode feeds/is likely to feed on.

Back 9

Simple mouth: Little or no buccal capsule and opnes directly into oesophagus. Feeds on liquids.

Front 10

Identify the type of mouth found in the nematode shown (Ascaris suum)

Back 10

Simple mouth with lips; thought to function in feeding but details unknown

Front 11

Identify the type of mouth in the nematode shown (Strongylus vulgaris) and state what/how this nematode is likely to feed on?

Back 11

Mouth with buccal capsule. Feeds by drawing plug of mucosa into the buccal capsule and releasing digestive enzymes. Damage to the mucosa is assisted by teeth (seen projecting in the buccal capsule)

Front 12

Identify the type of mouth in the nematode shown (Ancylostoma caninum) and state what/how the nematode is likely to feed on.

Back 12

Buccal capsule with cutting plates and teeth. Feeds by seeking out blood vessels in intestinal mucosa and biting into them to suck blood.

Front 13

From the following description determine the nematode and the order it is from: Roundworm parasite of the small intestine of the pig. From a group of nematodes that tend to get bigger as the host size increases. Females are bigger than males. Females are very fecund and can release a large amount of eggs.

Back 13

Order: Ascaridida

Species: Ascaris suum

Front 14

Identify the following nematode

Back 14

Ascaris suum

Front 15

Using the description of the egg, what order is it likely from:

8-64 cell morula, thin shelled, smooth, simple ellipsoid or oval eggs

Back 15

Order Stronglyida

Front 16

Based on the following description, what superfamily and order is parasite likely to be from?

Important superfamily in ruminants. Slender and hair-like. Males are bursate and females have prominent ovijector.

Back 16

Order Strongylida

Superfamily Trichostronglyoidea

Front 17

Identify the order that the following egg belongs to

Back 17

Order Strongylida

Front 18

Based on the following description, what Order and Superfamily is the parasite from?

Stout nematode. Have large, well-developed buccal capsules. Found in the large intestine and sometimes have teeth in their buccal capsules. Have two spicules and a well developed dorsal lobe of the copulatory bursa.

Back 18

Order Strongylida

Superfamily Strongyloidea

Front 19

Identify the Species, Superfamily and Order based: Small, simple mouthed (7-12mm) reddish-brown nematode. Found in sheep abomasum. Larvae develop coiled up in the glands within the fundic and pyloric areas emerging as late L4 or adults.

Back 19

Teladorsagia circumcincta

Front 20

True or false Haemonchus contortus is significantly bigger than Teladorsagia circumcincta

Back 20

True

Front 21

Identify the order and superfamily and subfamily based on the following description: Primarily found in colon and large intestine. Straight sided, shallow cylindrical or rectangular buccal capsule. Usually has a leaf crown and no teeth. Elongated dorsal lobe of the copulatory bursa

Back 21

Order Strongylida

Superfamily Strongyloidea

Subfamily Cyathostominae

Front 22

Which Superfamily is Haemonchus contortus from if we know that it is found in the abomasum of ruminants and has a posterior copulatory bursa and vulvar flap, very small buccal capsule and a small tooth?

Back 22

Trichostrongyloidea

Front 23

What characteristic is considered diagnostic of the Haemonchus genus?

Back 23

asymmetrical position of dorsal lobe of the copulatory bursa (positioned just to one side of the midline) (and sometimes the Y shaped spicules)

Front 24

What characteristic is considered diagnostic of the Trichostrongylus genus?

Back 24

The excretory pore (important for maintenance of fluid levels in the worm) has a small notch towards the anterior end of the worm

(Many worms have the excretory pore system, but only Trichostrongylus has the notch)

Front 25

Identify the superfamily of the worm Strongylus vulgaris from the description: Large buccal capsule with leaf crown. Dorsal gutter, two teeth (rounded), copulatory bursa with two spicules and a well developed dorsal lobe.

Back 25

Superfamily Strongyloidea

Front 26

What differentiates between Ancylostoma caninum and Uncinaria stenocephala which are both hookworm species?

Back 26

Ancylostoma caninum has 'toothed' cutting plates with 3 'teeth' on each plate. Uncinaria has smooth edged cutting plates.

Front 27

Based on the following description, what Order and Superfamily is the parasite likely to be from?

Relatively stout, small intestinal worms. Large buccal capsule with cutting plates and teeth. Blood feeders. Anterior end bent dorsally and are migratory species.

Back 27

Order Strongylida

Superfamily Ancylostomatoidea

Front 28

Which superfamily are Dictyocaulus spp. from? They are found in the bronchi and bronchioles of ruminants and equidae. They are long and hair-like and the egg contains the L1 when it laid.

Back 28

Trichostrongyloidea (strange because it's technically a lung worm) but they are the only species of this size that are found in the lungs of ruminants and horses. (Recent research suggests these may in fact be metastrongyloids)

Front 29

What differentiates Metastrongyloidea species such as Muellerius capillaris from Trichostrongyloidea species such as Dictyocaulus spp. ?

Back 29

Muellerius capillaris is found in the alveoli and the parenchyma of the lungs whereas Dictyocaulus spp. are found in the upper airways and larger bronchioles and bronchi of the animals.

Front 30

Identify the species: Found in the parenchyma of the lungs of ruminants, leaves greenish-grey lesions on the dorsal surface of lungs. Has lifecycle in mollusc or snail.

Back 30

Muellerius capillaris

Front 31

Indentify the order and the superfamily based on the following description: slender, mostly pulmonary parasites, L1 in egg when laid, migratory via the lymphatic-pulmonary route.

Back 31

Order Strongylida

Superfamily Metastrongyloidea (the "true" lung worms)

Front 32

Identify which of the following eggs is a typical strongylid egg and which is characteristic of Nematodirus spp. and list the differences between the two eggs.

Back 32

Top = typical Strongylid, Bottom = Nematodirus spp. egg.

Nematodirus spp. eggs: twice as big as normal strongylid eggs. Have 8 cell morula. Will hatch an L3. Need a period of chilling to stimulate hatching.

Strongylid eggs: 8-64 cell morula, thin shelled, 40-80microns, ellipsoid

Front 33

What kind of eggs is the McMaster counting method suitable for?

Back 33

All nematode eggs in faeces as well as coccidial occysts

Front 34

Put these steps for the McMaster faecal egg float method in the correct order.

1. Place 28mL of saturated salt in a bowl

2. Holding the pipette at a 45 degree angle quickly fill one chamber of the counting slide

3. Work the faeces through the sieve into the salt with the spoon

4. Scrape the faeces over the sieve into the bowl

5. Weight out 2g of faeces onto paper or into a container if very fluid

6. Discard the residue of the sieve and thoroughly mix the fluid by rocking the bowl to and fro, while simultaneously removing a sample with a pipette

7. Repeat mixing and sampling and fill the other chamber

8. Allow the slide to stand for at least 1-2 minutes

9. Count eggs systematically across the grids of both chambers

10. Using the 10X objective, focus on the air bubbles and gridlines, eggs are in the same planes

Back 34

5, 1, 4, 3, 6, 2, 7, 8, 10, 9

Front 35

State the equation you would apply to the number of eggs counted in the grid from 2g of faeces

Back 35

Total number of eggs in BOTH grids x 50 = number of eggs per gram of faeces

Front 36

Put the steps for the coverslip method for faecal egg floats in the correct order:

1. Carefully lift off the coverslip, keeping it horizontal and place it on the slide. The eggs and the oocysts will adhere to the surface tension of the coverslip and be transferred to the slide. Examine using a microscope

2. Stand the tube upright in a rack

3. Examine the whole coverslipe to identify all egg types present and to obtain the general assessment of their numbers

4. Carefully place a glass coverslip on the meniscus, taking care not to spill the suspension or leave any air bubbles

5. Leave the tube for at least 10-15 minutes by which time eggs and oocysts will have floated to the top

6. Thoroughly mix 0.5-1g of faeces with 10mL of saturated NaCl solution and pour the mixture through a sieve into a test tube. Add more salt solution to almost fill the tube and mix thoroughly.

7. Fill the test tube with salt solution using a pasteur pipette until there is a convex meniscus at the top

Back 36

6, 2, 7, 4, 5, 1, 3

Front 37

Identify the Order based on the following characteristics:

Very large, live in small intestine, no buccal capsule. 3 lips. Males have 2 spicules (usually one big and one short) but no copulatory bursa. Females are larger than males and are prolific egg layers

Back 37

Order Ascaridida

Front 38

Identify the following Nematode (Order)

Back 38

Order Ascaridida

Front 39

Identify the order which this egg belongs to

Back 39

Order Ascaridida. Eggs are irregular, proteinaceous and sticky on the outside. Have thick layer and contain a fresh single-celled zygote

Front 40

Identify the Order and genus that this egg belongs to

Back 40

Order Rhabditida, Genus Strongyloides

Front 41

Identify the Order and the species of the following worm

Back 41

Order Oxyurida, Oxyuris equi

Front 42

Identify the Order based on the following description:

tapering posterior ends (pin-like), wide anterior end, found in the colon and rectum, prominent oesophageal bulbs

Back 42

Order Oxyurida (pin-worms)

Front 43

Identify the order that this egg belongs to

Back 43

Order Oxyurida

Front 44

How would you distinguish between Dirofilaria immitis microfilariae and the Dipetalonema reconditum microfilariae?

Back 44

D. reconditum microfilariae is much smaller and found in the adipose tissue. D. immitis is found in the bloodstream

Front 45

Identify the Order, Family and Genus of the following nematode based on the description below: Narrowing anteriorly (whip-like), direct life cycle, no migration, Male has one spikey-sheathed spicule, donut stack oesophagus.

Back 45

Order Enoplid, Family Trichuridae, Genus Trichuris

Front 46

Identify the Order, family and Genus that the following egg belongs to

Back 46

Order Enoplid, Family Trichuridae, Genus Trichuris

Front 47

Identify the Order and species of the nematode shown

Back 47

Order Enoplida, Trichinella spiralis

Front 48

What is the species of the nematode L1 shown encysted in muscle here

Back 48

Trichinella spiralis

Front 49

Identify the Order, genus and species from this description:

Have scolex for attaching to gut wall. It has rostellum (2 rows of hooks) and 4 suckers to aid this. Rostellum not retractable in this genus. Has strobila and its body is a row of long developing segments or proglottids. Eggs are immediately infective for their host (sheep)

Back 49

Class Cestoda, Order Cyclophyllidea, Genus Taenia, Species: Taenia ovis

Front 50

Identify the Class, Order, Genus and species this egg belongs to

Back 50

Class Cestoda, Order Cyclophyllidea, Genus Taenia, Species: Taenia ovis

It is 1/3 the size of a strongylid egg.

Front 51

You find a cyst in the skeletal muscle of a sheep you are inspecting that looks much like the following. What is it most likely to be given its location and host?

Back 51

Taenia ovis

Front 52

What is this:

Back 52

Taenia ovis metacestode

Front 53

What kind of metacestode does taenia ovis form?

Back 53

Cysticercus

Front 54

How can we differentiate between Dipylidium caninum and taenia ovis?

Back 54

D. caninum has paired sexual organs and a genital pore on each lateral margin and it has a cysticercoid metacestode. They also release eggs in packets and not singularly as Taenia ovis do.

Front 55

What kind of metacestode does Dipylidium caninum form?

Back 55

Cysticercoid

Front 56

What order lays eggs like the ones shown?

Back 56

Pseudophyllidea

Front 57

Which class and specifically, species, produce this kind of egg?

Back 57

Class Trematoda, Species: Fasciola hepatica

Front 58

Which kind of bacteria, Gram-positive or Gram-negative, have less peptidoglycan in their cell wall?

Back 58

Gram Negative

Front 59

A purple gram-stain indicates...

Back 59

Gram-positive bacteria

Front 60

A pink-red gram-stain indicates...

Back 60

Gram-negative bacteria

Front 61

Why are do gram-negative bacteria not retain the original staining with Crystal violet, even after addition of trapping agent (Gram's idonine) when they are rinsed with acetone?

Back 61

They have an outer lipopolysaccharide layer that is washed away containing the first layer of stained peptidoglycans and leave the unstained inner peptidoglycan layer exposed. This leaves it available to take up the Safranin counter stain

Front 62

Put the steps for Gram staining in the correct order:

1. Allow the film to air-dry. A broth culture will require more time to dry to prevent in washing off the slide.

2. Using forceps, hold the slide at 45 degree angle and wash off the stain with Lugol's iodine.

3. Mark one side of a slide with a wax or diamond pencil.

4. Replace the slide on the rack and coverwith Lugol's Iondine. Leave for 2 minutes.

5. On the other side, within the marked area make a smear and using a wire loop, make a light suspension of bacterial colonies from agar plates in a drop of sterile saline.

6. Fix the film by passing it quickly through a Bunsen flame 3 times.

7. Cover the slide with 0.5% crystal violet. Leave for 1-2 minutes.

8. Using the forceps, hold the slide at 45 degrees and wash off the iodine by pouring acetone alcohol over the slide from the upper end and allowing it to run down over the slide.

9. Wash off the stain and blot dry gently using filter paper.

10. Counterstain with 0.5% Safranin and leave for 1-2 minutes.

11. Wash immediately under running water.

Back 62

3, 5, 1, 6, 7, 2, 4, 8, 11, 10, 9

Front 63

What stain is usually used for staining bacteria to observe bacterial capsules?

Back 63

India Ink or Nigrosin stain

Front 64

Put the method for staining for bacterial capsules in the correct order:

1. Allow the film to air-dry, giving more time to broth cultures. DO NOT HEAT FIX.

2. Allow to dry and observe the cells using immersion oil objective lens of the microscope.

3. Add a drop of india ink into the suspension and mix gently.

4. Rinse the slide with water (slowly dribbled from tap) and blot to remove excess fluid.

5. At one END of the slide make a VERY LIGHT suspension of bacterial colony in a drop of sterile saline.

6. Using another slide, make a culture smear by contacting the slide with the drop of suspension and then slowly pushing the slide towards the opposite end of the bottom slide.

7. When dry, flood the smear with crystal violet for 1 minute.

Back 64

5, 3, 6, 1, 7, 4, 2

Front 65

Where are bacteria with capsules commonly found in a veterinary setting?

Back 65

On catheters

Front 66

What are the biological advantages to having a capsule?

Back 66

Increased adherence to surfaces and prevention of drying out

Front 67

Give an examples of enriched media and where or for what it may be used

Back 67

Blood agar. Used for the growth of fastidious organisms such as streptococci. Sterile defibrinated blood is added as 5-10% of the total contents to the basal medium. This is the most commonly used medium in bacteriology.

Front 68

Give two examples of differential media mentioned in class and state what they are used to distinguish between.

Back 68

MacConkey agar and CIN agar

Used to distinguish between lactose fermenting and Non-lactose fermenting organisms

Front 69

List the selective media mentioned in class and state what they are selecting fore/inhibiting.

Back 69

Brilliant Green Agar (BGA): Inhibits the growth of most organisms other than Salmonella spp.

MacConkey agar: Selects primarily for members of the Enterobacteriaceae.

CIN agar: Selective and differential for Yersinia species

Aztreonam agar: selective for gram positive bacteria

Front 70

What is enrichment media used for and give an example of such a media.

Back 70

These are liquid media that are employed when you are trying to detect bacteria that may only be present in low numbers in the original sample. E.g. Selenite broth - inhibits growth of coliform organisms (such as E. coli and Klebsiella spp.), but allows Salmonella spp. to grow freely.

Front 71

What causes E. coli to turn pink when grown on MacConkey agar?

Back 71

When they grow they cause a pH change which causes a colour change due to the presence of indicator in the medium.

Front 72

Which type(s) of media ONLY grow Gram positive bacteria?

Back 72

Aztreonam

Front 73

Which type(s) of media ONLY grow Gram negative bacteria?

Back 73

MacConkey

Front 74

Match the following bacterial shapes to their names:

1. Coccus

2. Bacillus

3. Spirillum

4. Diploids

5. Streptococcus

6. Staphylococcus

A) Bacterial chains

B) Spiral shaped bacteria

C) Clusters resembling a bunch of grapes

D) Spherical bacteria

E) Paired bacteria

F) Rod Shaped bacteria

Back 74

1 = D, 2 = F, 3 = B, 4 = E, 5 = A, 6 = C