practice mid sem

Question 1

A structural component that is found in all viruses is the:

Capsid
Spikes
DNA
Envelope

Answer 1

Capsid

Question 2

In order for a virus to replicate:

The host cell must be undergoing mitosis

The capsid must enter the host cell nucleus

The host cell must lack a cell membrane

The genome must be released in the cytoplasm

Answer 2

The genome must be released in the cytoplasm

Question 3

Some viruses cause the production of inclusion bodies in the infected host cell. Inclusion bodies can consist of which of the following:

Components of virus particles
Centrioles formed by the virus
Viral mRNA
Cytoplasmic organelles

Answer 3

Components of virus particles

Question 4

which of the following virus detection methods is generally the least expensive:

Electron microscopy to view virus particles

Serological tests for viral antigen detection

Molecular tests (PCR) for viral nucleic acid detection

Virus isolation in cell culture

Answer 4

Serological tests for viral antigen detection

Question 5

Which of the following virus groups typically produce latent infections?

Parvoviruses
Retroviruses
Herpesviruses
Caliciviruses

Answer 5

Herpesviruses

Question 6

Some viruses can cause neoplastic transformation of the host cell (oncogenesis). Which of the following is NOT a mechanism by which viruses induce neoplastic transformation of cells:

“Switch on” host cell major histocompatibility genes

Possess an oncogene in the viral genome (v-onc)

“Switch off” host cell tumour suppressor genes

“Switch on” host cell oncogenes (c-onc)

Answer 6

“Switch on” host cell major histocompatibility genes

Question 7

The animal prion disease that appears to be able to cross the species barrier is which of the
following?

Chronic wasting disease

Scrapie

Bovine spongiform encephalopathy

Transmissible mink encephalopathy

Answer 7

Bovine spongiform encephalopathy

Question 8

Which of the following clinical signs occurs in sheep with the prion disease scrapie but NOT in
cattle with the prion disease bovine spongiform encephalopathy?

Loss of body condition

Behavioural changes

Pruritus (itching)

Incoordination

Answer 8

Pruritus (itching)

Question 9

Viruses undergo genetic change in every cycle of replication. This results in the production of
genetic variants (quasispecies), which may have different characteristics to the original virus.
Briefly describe FOUR (4) of the different characteristics that may be possessed by genetic
Variants.

Answer 9

Faster replication
Replicate in different cell/host
increased /decreased virulence
Evade immune system
Resistant to antiviral drug

Question 10

Briefly describe THREE (3) features of abnormal (disease-causing) prion proteins (PrP ) that
are different to features of normal host cell prion proteins (PrP ).

Answer 10

Beta sheets
Less soluble
Resistant to proteases

Question 11

Diarrhoea and vomiting in a young dog
A young dog presents with diarrhoea and vomiting and the veterinarian suspects that parvovirus is the cause. She submits a blood sample from the dog for antibody
testing. The laboratory result is positive for parvovirus antibodies.
What are THREE (3) possible interpretations of this result?

Answer 11

-May be maternally derived antibodies
-May be from current or previous infection
-May be antibodies from previous vaccination

Question 12

What other general approaches to the diagnosis of viral infections could have been taken to
diagnose the cause of the disease in this dog?

Answer 12

Detecting the Virus and Detecting Characteristic Pathology caused by Virus

Question 13

Describe the formation and development of an advanced blowfly strike lesion on sheep. In your answer, describe the factors that lead to initiation of the strike. Give the scientific name of the species MOST likely to have initiated the strike.

Answer 13

Build-up of faeces and urine on the wool, any dermatitis and/or fleece rot, and any wounds that may be present, lead to putrefactive sulfur-rich volatiles formed by bacterial decomposition that attracts Lucilia cuprina females. Females feed on protein, and lay lots of eggs. Large instars invade the tissues of the host and cause a wound. These are primary strike flies.

Question 14

An acarine that is commonly responsible for paralysis in cats and dogs in South East
Queensland is

Sarcoptes scabiei
Rhipicephalus sanguineus
Ixodes holocyclus
Rhipicephalus microplus

Answer 14

Ixodes holocyclus

Question 15

Erlichia canis is a microbe responsible for canine erlichiosis. This species has recently been
reported from northern Australia and is transmitted to dogs by:

Haemaphysalis longicornis
Rhipicephalus microplus
Rhipicephalus australis
Rhipicephalus sanguineus

Answer 15

Rhipicephalus sanguineus

Question 16

Which of the following statements about the biology of hard ticks (family Ixodidae) is TRUE?

Adult ticks do not feed.

Adult female ticks are relatively slow feeders, engorging on blood over a matter of days.

The mouthparts of hard ticks sit on the ventral surface of the body.

Adult female ticks are intermittent feeders, dropping from the host and reinfecting a new host every few days

Answer 16

Adult female ticks are relatively slow feeders, engorging on blood over a matter of days.

Question 17

In hard ticks, a scutum is:

A feeding plate that is used with the hypostome to suck blood.

A sensory structure adjacent to the sucking mouthparts.

A hardened plate that partially or completely covers the abdomen.

A sensory structure on the foreleg that is used in questing.

Answer 17

A hardened plate that partially or completely covers the abdomen.

Question 18

Select all of the statements that apply to the life cycle of Ixodes holocyclus.

The tick displays low host specificity.

Adult females cement eggs to the fur or feathers of its host.

The tick species uses three hosts to complete its life cycle.

The larval stage has three pairs of legs.

The larval stage drops from the host and pupates to become an adult.

Adult females drop from the host to the ground after engorging on blood to lay eggs

Answer 18

The tick displays low host specificity.

The tick species uses three hosts to complete its life cycle.

The larval stage has three pairs of legs.

Adult females drop from the host to the ground after engorging on blood to lay eggs

Question 19

Factors that influence the geographical distribution of the tick species, Rhipicephalus
microplus, in Australia are:

Presence of wildlife reservoir hosts (for example possums) to sustain larvae of the parasites, sufficient rainfall (over 500 mm/year) and warm to hot temperatures.

Presence of bovine hosts, arid conditions (rainfall less than 500 mm/year) and warm to hot temperatures.

Presence of dogs, sufficient rainfall (over 500 mm/year) and warm to hot temperatures.

Presence of bovine hosts, sufficient rainfall (over 500 mm/year) and warm to hot temperatures.

Answer 19

Presence of bovine hosts, sufficient rainfall (over 500 mm/year) and warm to hot temperatures.

Question 20

The formal scientific name for the ear mite, a parasite responsible for severe itching in the
external ear canals of pups and kittens, is:

Sarcoptes scabiei
Haemaphysalis longicornis
Otodectes cyanotis
Psorergetes canis

Answer 20

Otodectes cyanotis

Question 21

In its life cycle, the pork tapeworm Taenia solium, uses:

dogs as definitive host, and pigs and humans as intermediate hosts.

humans as definitive host, and pigs and humans as intermediate hosts.

humans as definitive host, and pigs as the only intermediate host

Answer 21

humans as definitive host, and pigs and humans as intermediate hosts.

Question 22

The mature larva (metacestode) of Echinococcus granulosus is commonly called a:

3rd stage larva
Cysticercus
Coenurus
Hydatid cyst

Answer 22

Hydatid cyst

Question 23

An important feature of the life cycle of cestodes of the family Taeniidae is that all species in the family:

Use insects, such as fleas, as intermediate hosts.

Undergo asexual reproduction in snails.

Use copepods as first intermediate host.

Use mammals as intermediate hosts.

Answer 23

Use mammals as intermediate hosts.

Question 24

In the absence of anti-tapeworm medications, a way to minimise risk of infection of dogs with the dog tapeworm Dipylidium caninum is to:

Refrain from feeding offal of kangaroos or sheep to dogs.

Control scabies mites on the dogs.

Prevent dogs from feeding on reptiles or amphibians that may carry larval stages.

Control fleas in the environment of the dog.

Answer 24

Control fleas in the environment of the dog.

Question 25

Nematodes having a small or vestigial mouth, a prominent bursa in males and that live in the stomach or small intestine of their hosts, belong to the Superfamily (Trichostrongyloidea, Strongyloidea, Ancylostomatoidea, Ascaridoidea → non-bursate)

Answer 25

Trichostrongyloidea,

Question 26

For trichostrongylid nematodes, hypobiosis is defined as: A period of arrested development in the eggs of nematodes. A period of arrested development of the nematodes on grass blades on pasture. This arrest is influenced by environmental factors. A period of arrested development that occurs after a nematode larva has entered a new host. This arrest is influenced by a range of factors in the host. A period of intense migration in development of the nematode, typified by tracheal migration.

Answer 26

A period of arrested development that occurs after a nematode larva has entered a new host. This arrest is influenced by a range of factors in the host.

Question 27

From the list below, select the different ways by which a dog can be infected with Ancylostoma caninum. By ingestion of second stage larvae in eggs. By ingestion of larvae from grass. By ingestion of an infected paratenic host. Through transfer with colostrum or milk from the mother. Through the bite of an infected mosquito. Through penetration of the dog's skin. Through ingestion of cat faeces.

Answer 27

By ingestion of larvae from grass. By ingestion of an infected paratenic host. Through transfer with colostrum or milk from the mother. Through penetration of the dog's skin.

Question 28

Angiostrongylus cantonensis infects dogs when: Dogs are bitten by infected mosquitoes. Dogs are bitten by infected Rhipicephalus sanguineus ticks. Dogs mouth or ingest infected terrestrial molluscs. Dogs mouth or ingest infected fleas.

Answer 28

Dogs mouth or ingest infected terrestrial molluscs.

Question 29

Members of the order Strongylida that have a well developed buccal capsule with an anterior leaf crown, and in which the males have a well developed bursa, belong to the Superfamily: Strongyloidea Rhabditoidea Ancylostomatoidea Metastrongyloidea

Answer 29

Strongyloidea

Question 30

From the following statements, select THREE (3) ways that Toxocara canis can infect its canine hosts. Ingestion of free third stage larvae from grass Trans-placental migration of infective larvae from pregnant bitch to pups Percutaneous migration of third stage larvae Ingestion of infected paratenic rodent hosts Ingestion of eggs containing second stage larvae

Answer 30

Trans-placental migration of infective larvae from pregnant bitch to pups Ingestion of infected paratenic rodent hosts Ingestion of eggs containing second stage larvae

Question 31

In order to enable escape of its offspring from the canine host, adult females of Dirofilaria immitis: lays eggs in the lungs. The eggs are coughed up by the dog and released with mucous. produce larvae, called microfilaria, that are laid directly into the blood stream. lay eggs that pass with the faeces. Produce eggs that hatch into larvae that burst through the lungs and pass with the faeces.

Answer 31

produce larvae, called microfilaria, that are laid directly into the blood stream.

Question 32

Oxyuris equi is transmitted from its host: by egg-bearing females wriggling onto the peri-anal regions of the host. by laying eggs that pass through the lungs and are coughed up by the host. by adult females in the small intestine passing eggs that exit with faeces. when mosquitoes imbibe blood that contains larvae of the parasite.

Answer 32

by egg-bearing females wriggling onto the peri-anal regions of the host.

Question 33

toxoplasma gondii, an apicomplexan parasite that forms cysts in multiple organs of many mammal species, uses (felines, canines, ruminants, humans) as definitive hosts.

Answer 33

felines

Question 34

In the life cycle of a typical coccidian parasite, the transmissive phase that passes from the host is called the (oocyst, egg, ovum, cyst).

Answer 34

oocyst,

Question 35

Select all options that are TRUE. Although anthelminthics (anti-worm medications) can be effective against Echinococcus granulosus infections, additional control strategies can include: careful disposal of human faeces, so that animals, such as sheep or kangaroos, do not ingest eggs. careful disposal of dog faeces, so that animals, such as sheep or kangaroos, do not ingest eggs. disposing (deep burial/burning) of animal carcases, so that dogs cannot eat tissues in the carcases contaminated by parasite material. drain contaminated swamps and dams in pastures where animals graze.

Answer 35

careful disposal of dog faeces, so that animals, such as sheep or kangaroos, do not ingest eggs. disposing (deep burial/burning) of animal carcases, so that dogs cannot eat tissues in the carcases