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Parasitology > Review Questions Exam # 1 > Flashcards

Review Questions Exam # 1 Flashcards

1
Q

What are the key characteristics of “Parasitism”?

A
  • Form of symbiosis.
  • Parasites must depend on the host for survival
  • Have adverse effects on host.
  • Has greater fecundity than host.
  • Is usually smaller than the host.
  • Doesn’t want to kill its host.
  • Are over dispersed among the host population (macro-parasites).
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2
Q

What is the difference between direct and indirect lifecycle?

A

Direct Lifecycle: Larvae/ egg of parasite have free living stage . No intermediate hosts.

Indirect lifecycle: Sexual reproduction occurs in the definitive host, but there are intermediate hosts that could transport the parasite/ allow for larval development and/or paratenic hosts that are just for transport. There are no free living stages.

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3
Q

What are the shed stage and infective stage of a parasite?

A

• Shed stage of a parasite (L1 -L2)
◦ Stage that eggs can be found. Diagnostic phase.
• Infective stage is L3 (L1 in urine in some species) ◦ Infect definitive host

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4
Q

What is the biological role of Intermediate hosts and paratenic hosts in a parasite’s lifecycle? Do parasites need paratenic hosts to complete their lifecycle?

A

Not all parasites need paratenic hosts to complete their lifecycles only some. Intermediate hosts allow for larval development and transport of parasites while paratenic hosts do not allow for larval development.

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5
Q

A dog is considered as the definitive host of Toxocara canis, why?

A

Main host. Supports sexual reproduction of the parasite. Parasite reaches sexual maturity within this host

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6
Q

What are two key differences between a microparasite and a macroparasite?

A

Microparasite
• Tiny, unicellular, microscopic
• Multiply within hosts
• Short lifecycle

Macroparasite
• Large, multicellular, adult microscopic • Reproduce in definitive hosts
• Generally longer lifecycles

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7
Q

What is a facultative parasite?

A

Both parasitic and non parasitic life cycle. Opportunistic parasite- can complete its life cycle without hosts.

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8
Q

What is the name given to a parasite which doesn’t have a free-living stage?

A

Obligatory parasite

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9
Q

What are spurious parasites? What would you call a pollen particle that looks like an egg?

A

Spurious parasite: Is a parasite found in an unusual host. You would call a pollen particle that looks like an egg an pseudoparasite.

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10
Q

What is the general body plan of Nematodes, cestodes, trematodes, arachnids, insects and
protozoa? Overall morphology (E.g. round, flat, segmented…., macroscopic vs microscopic)

A

Nematodes: Round (worms) non segmented, cylindrical with tapered ends, elongated, , macroscopic, complete digestive system. Multicellular

Cestodes: Dorsally flattened, with segments, macroscopic, multicellular, head with suckers, may contain hooks.

Trematodes: Oval shaped, flat, macroscopic, multicellular, leaf like body, Two suckers, oral and ventral

Arachnids: 8 legs, 2 body segments) macroscopic, multicellular

Insects: 6 legs, 3 body segments), macroscopic, multicellular

Protazoa : Unicellular, microscopic

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11
Q

List the main transmission routes of parasites?

A
  • Fecal- oral
  • Skin (per-cutaneous)
  • Vector transmission/ inoculation
  • Direct contact
    • Sexual transmission
    • vertical transmission
    • Iatrogenic
    • Transmammary/lactogenic
    • Trans placental/ prenatal
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12
Q

What are the common names of nematodes, cestodes and trematodes?

A

Nematode- roundworm Cestode- Tapeworm Trematode: Flukes

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13
Q

What is the outer covering of a nematode, cestode, trematode?

A

Nematode: Chitinous Cuticle
Cestode: Tegument Trematode: Tegument

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14
Q

Do nematodes have sexual dimorphism? What about cestodes, and trematodes?

A

Nematodes have sexual dimorphism. Males are smaller than females, Copulatory bursa in males.

Cestodes: They are hermaphrodites They have self fertilization

Trematodes: Also hermaphrodites other than schistostomes

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15
Q

Which larval stage is generally the infective stage in the case of nematodes? Which stages of larvae are inside the definitive host?

A

Generally L3 is the infective stage (L1 can be in some parasites). The stages of larvae that are within the host are L3-L5

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16
Q

What is the general term given to inhibited larval development in the case of nematodes?

A

• HYPOBIOSIS in many nematode species (e.g Trichostrongyles)
◦ Inhibited larval development to avoid adverse conditions for development and
maturation – adaptation to host and environmental conditions.

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17
Q

What is the key difference between cyclophylidean and Pseudophylidian cestode? Just the head morphology?

A

The key difference between cyclophylidean and pseudophylidian is that cyclophylidean cestodes have non operculated eggs and have a sucker attachment at the head. In pseudophylidia, they have operculated eggs and a bothria

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18
Q

What are proglottids? What is a tegument?

A

Proglottids are the body segments of tape worms. Each proglottid has both male and female reproductive system present.
Tegument- is the skin like covering the parasite feeds through/ absorbs nutrients through. (in terms of cestodes).

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19
Q

What is unique about a Taeniid-type egg?

A

All Taenia species (Taenia spp., Echinococcus spp.) have same egg morphology- commonly called taeniid eggs.
◦ The Eggs have an embryo with 6 hooks (hexacanth larvae) and thick straight egg shell.

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20
Q

Do trematodes have a direct lifecycle? What are the most common intermediate hosts?

A

Trematodes always have an indirect life cycle. Must have 2-3 hosts. Intermediate host is always a snail/ slug (aquatic/ terrestrial)

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21
Q

What is a thorny-headed worm?

A

Acanthocephalans

  • Small phylum of highly specialized parasites of the vertebrate digestive tract
  • Retractable, spiny attachment organ or proboscis
  • No digestive tract, nutrient absorbed through the tegument
  • Sexes separate
  • Lifecycle indirect – Arthropod intermediate host (beetles)
    Examples
    ◦ Macracanthorhynchus – Swine,
    ◦ Oncicola – Canine
    Not a very common group of parasites**
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22
Q

What is the infective stage of most trematodes?

A

Metacercaria

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23
Q

General morphological difference (gross body) between arachnids and insects? No. of legs, segments?

A

Arachnids: 2 distinct body parts (Cephalothorax and abdomen) 8 legs as adults, sometimes 6 at nymph stage. No wings/ antennae

Insects: Three distinct body parts ( Head, Thorax, Abdomen, 6 legs (sometimes: 2 antennae, 2 pairs of wings)

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24
Q

What are the two categories of mites and lice? What are the key morphological differences between the categories of mites and lice? Or, what main feature would you look for if you had to identify these groups of mites and ticks?

A

Mites:
• Burrowing : under surface, small legs, round body, smaller
• Surface: on surface, longer legs, oval body, larger
Lice:
• Chewing Lice: Wider head (wider than thorax) Stout mandibles
• Sucking Louse: Head narrower than thorax. Piercing mouthparts

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25
Q

Do mites survive in the environment for a long time? Can a dog give mite to another dog? How?

A

Limited environmental survival, some species only. Yes they can via contact and grooming instruments. (Direct and indirect)

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26
Q

Same question as above for lice, ticks, fleas, and bugs.

A

Lice: Entire lifecycle is 20-40 days on host and can live 2-3 weeks off host but usually less than a week. Direct or indirect contact can transmit ( so direct contact and use of shared grooming tools ect.)

Fleas: Life cycle includes environmental time. Can be from sharing bedding, space, toys ect.

Bugs: Adults live for up to 1 year and may survive long period without feeding. Live mostly in environment. No because they do not live on the host, they come out and come into contact with host for blood meal.

Ticks: Life cycle seasonal: one year to multi year. In theory they can, because if a nymph happens to jump off the host and molt and then jump on another dog that could be possible

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27
Q

What is the plate on the back of a hard tick?

A

Scutum

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28
Q

Point out the key morphological difference between a hard tick and a soft tick? Which kind of tick survives the dry and hot conditions better?

A

Hard Tick:
• Mouthparts visible from above
• Found in habitats rich in
vertebrates.
• Plate on back called scutum
Soft Tick:
• Mouthparts invisible from above
• Lack Scutum.
• Found in animal burrows,
• Can survive hot and dry

Soft ticks survive dry/ hot conditions better.
conditions

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29
Q

On a three-host and one host ticks, which stages are found in the environment, and on the host?

A

One host tick: from oviposit to 6 legged larva. Then it completes two molts on the host.

Three host tick: Oviposit -> 6 legged larva, then feeds on host 1 and hops off and molts to 8 legged nymph, then feeds on 2nd host and hops off and molts to adult where it jumps on definitive host and feeds/ mates

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30
Q

How do ticks get on their hosts? Do they fly/Jump?

A

No jumping/ flying. They find a new host by questing and then grab onto the host when they walk by.

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31
Q

Where do you find bugs most of the time?

A

Mostly feed at night, during day hide in crevices

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32
Q

Can you differentiate burrowing vs surface mite based on length of legs?

A

Yes, burrowing mites have short stumpy legs while surface mites have long legs.

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33
Q

Which ectoparasite causes mange?

A

Mites: Specifically scarcoptes.

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34
Q

What is myiasis? Do the myiasis causing flies bite the host?

A

• Damage is caused by maggots (larvae) that feed on host tissues • Adults are non-biting

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35
Q

Which arthropod is most host specific and which is least host specific?

A

Order of decreasing host specificity
1.) Lice 2.) Mites 3.) Fleas 4.)Ticks 5.) Flies

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36
Q

What specialized organs do flagellates and apicomplexans have that help in locomotion and diagnosis?

A

Flagellates: Flagella Apicomplexan: Gliding locomotion

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37
Q

What is the active motile form of flagellates? What is the environmentally resistant stage?

A

Trophozoite is the motile form of flagellates.

Cysts are the non motile and environmentally resistant stage.

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38
Q

What are the roles of merogony, gametogony and sporogony in the lifecycle of an apicomplexan parasite?

A

Merogony: Asexual reproduction ( increase parasitic load within host)

Gametogony Sexual reproduction (Creates fertilized zygotes.

Sporogony: Sporulation of oocyst which become infectious to other dogs.

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39
Q

What is the definitive host in the case of blood Apicomplexa like Babesia?

A

The tick or arthropod vector is the definitive host. This is because it is where sexual reproduction can occur.

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40
Q

What are the key limitations of fecal smear as a parasitological test?

A
  • Negative result is inconclusive, positive result equally valid.
  • Conditions must be ideal i.e fresh sample, refrigerated not frozen,
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41
Q

What is the principle of the fecal flotation method?

A

Based on differential specific gravity of parasite eggs/cysts, fecal debris and flotation solution. Cysts/ eggs will float to top due to lower specific gravity

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42
Q

Which is the more sensitive test, passive, or active/centrifugal flotation? Why?

A

Centrifugal fecal floatation is more sensitive. This is because it will recover more eggs/ ova

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43
Q

Which fecal test is preferred for the diagnosis of trematode eggs? Why?

A

For eggs with higher specific gravity (e.g trematodes and acanthocephalan eggs) that do not float easily or eggs that are easily distorted by flotation solution

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44
Q

Which test is indicated for parasites shedding larvae in the feces?

A

• Baermann method

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45
Q

Would the Baermann technique be sensitive enough for old, frozen feces? Reason?

A

Larvae must migrate out of the feces into the water so it must have fresh feces with live larva

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46
Q

Why fecal testing for parasites may not always be reliable?

A

1.) Chances of false negatives (negative test result despite host having parasite)
• Sporadic shedding
• Prepatent period – Parasites not yet mature to shed eggs/larvae
• Single-sex nematode infections
• Senescent infections
• Old feces (hatched eggs)
2.) Chances of false positives (positive test result but no parasitism)
• Coprophagia/Predation – Spurious parasites
• Pseudoparasites
• Many parasite species shed identical eggs – Diagnostic challenge

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47
Q

What is the advantage of Knott’s test over direct smear?

A

More blood is being evaluated at one time so it is more sensitive because there is a higher likelihood you will have microfilaria present in a positive patient.

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48
Q

What tests would you choose to diagnose parasites that live on tissue, and don’t have any environmental stage?

A
  • Tissue Digestion
  • KOH Digestion
  • PCR
  • Skin scrape
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49
Q

What are the limitations of immunological tests?

A
  • Measures immune response to exposure – not necessarily active infection
  • Cross-reactivity
  • Not universally available
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50
Q

What are the common GI nematodes that can infect dogs and cats?

A

Spirocerca lupi (Esophageal Worms), Physaloptera (Stomach worms)

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51
Q

Where can you find adult Spirocerca lupi most of the time?

A

Nodules in the Esophagus

52
Q

What is the common intermediate hosts for Spirocerca lupi?

A

Beetles (Coprophagic Beetles)

53
Q

Which regions of the Americas have a higher prevalence of Spirocerca?

A
  • Southern US and Brazil
54
Q

How can you diagnose Spirocerca lupi infection?

A

Radiograph, CT, Endoscopy for adults (Granulomatous, with evidence of ulceration and purulent exudate. )
Fecal Float for eggs (using sugar solution)

55
Q

Can you find a dog with esophageal nodules with Spirocerca but negative in fecal testing? Why?

A
  • Yes you can, this is because the egg laying phase is relatively short, and eggs are shed intermittently so higher chances of false negatives. Repeated fecals recommended.
56
Q

How common is Physaloptera in dogs and cats? Are they main hosts?

A
  • Infrequent in dogs, more common in cats. Main hosts are wild canids (I.e coyotes and foxes)
57
Q

Where in the GI tract do Physaloptera adults live?

A
  • Adults in the stomach
58
Q

What pathology does Physaloptera cause in case of heavy infections?

A
  • Gastritis, Chronic vomiting
59
Q

What is your best advice to control Spirocerca and Physaloptera in endemic areas?

A
  • Preventing access to insect intermediate hosts, parasitic hosts, and prevent contamination catteries / kennels. Physaloptera can also be prevented with monthly preventatives
60
Q

List common ascarids of dogs and cats.

A
  • Toxocara canis
  • Toxocara cati
  • Toxocaris leonina
  • Baylisascaris procyonis
61
Q

What are some common morphological characteristics of adult ascarids?

A
  • Cervical ale, spaghetti like, mouth w/ 3 fleshy lips and row of small tooth like projections, finger like projections ( in males T. Canis at tail end)
62
Q

What are the modes of transmission used by Toxocara canis?

A

Ingestion of infective eggs containing L3
Transplacental/ Prenatal infection
Transmammary infection
Ingestion of paratenic hosts

63
Q

Describe the general morphological characteristics of ascarid eggs.

A

T. Canis- spherical, pitted shelled eggs
T. Cati - similar to canis but smaller.
T. leonina - eggs oval shape, smooth shell
B. Procyonis - slightly smaller and darker than toxocara

64
Q

Are ascarid eggs readily infective when passed in feces?

A
  • No, typically infective after a couple weeks of being in the environment. T. cati is more infective.
65
Q

What is the infective stage for Toxocara canis?

A
  • Infective stage is eggs with L3
66
Q

What is a transplacental transmission? What ascarid uses this mode of transmission?

A
  • This is infection through the placenta where it is passed from mother to its puppies. This occurs in T. Canis.
67
Q

What are the common clinical signs of toxocariasis in puppies?

A

Respiratory signs: Cough, Rales, pneumonia( relatively rare)
Gastroenteritis: vomiting, mucoid diarrhea, distended abdomen ( pot bellied appearance), peritonitis ( due to intestinal perforation by adults), and death.

68
Q

How may puppies be born infected with Toxocara canis?

A

How may puppies be born infected with Toxocara canis?
- Transplacetal Transmission

69
Q

What happens to the ingested eggs (with Ls) in puppies and in older dogs?

A
  • Puppies < 6 months: Hepato-Tracheal Transmission. Results of adult worm in small intestines 
(GIT-> liver-> R heart -> lung, coughed up and swallowed -> Small intestine)
  • Dogs > 6 month somatic migration and will stay in tissue as inactive.
  • Must be breeding female is the only way transmission can occur after somatic migration
70
Q

What are the modes of transmission used by Toxocara cati?

A

Ingestion of infective eggs containing L3
Transmammary infection - Queens must be pregnant in order to infect kittens.
Ingestion of paratenic hosts

71
Q

Is it possible to differentiate T. cati and T. canis adults?

A

More prominent cervical ale. And prepotent period is longer than T canis.

72
Q

What are the modes of transmission used by Toxascaris leonina?

A

Ingestion of infective eggs containing L3
Ingestion of paratenic hosts

73
Q

What techniques are commonly used to diagnose ascarids in small animals?

A
  • Fecal Testing
74
Q

What is the natural host for Baylisascaris procyonis?

A
  • Racoon Roundworm
75
Q

Is infection by B. procyonis common in dogs?

A

Dogs can act as definitive or intermediate hosts.

76
Q

What are the modes of transmission used by B. procyonis?

A

Ingestion of infective eggs containing L3
Ingestion of paratenic hosts

77
Q

What ascarids are zoonotic? What disease(s) do they cause in humans?

A

T. cati- Visceral and Ocular Larva Migrans
T. canis- Visceral and Ocular Larva Migrans
B. procyonis- Ocular and Visceral (severe) Larva Migrans

78
Q

Why is it difficult to get rid of ascarid eggs in the environment?

A
  • Eggs can survive in the environment for years (sticky thick shell,
79
Q

List the common species of hookworms infecting dogs and cats.

A

Ancylostoma canium
Ancylostoma tubaeforme
Ancylostoma braziliense
Uncinaria stenocephala

80
Q

What is the site of infection of hookworms?

A

In the intestines

81
Q

What are the general morphological characteristics of adult hookworms (buccal cavity, teeth, cutting plates)?

A

Creamy white cuticle
Buccal capsule with teeth in some species, some have a buccal cavity with cutting plates

82
Q

What are the main clinical signs of hookworm infection in dogs?

A
  • Melena, weightless, and Anemia
83
Q

What is the key morphological feature of hookworm eggs? How is it different from roundworm eggs?

A
  • Slightly larger than A. Canis eggs, can be differentiated based on size in terms of mixed infections.
84
Q

What is the infective stage of Ancylostoma caninum?

A
  • L3
85
Q

What are the modes of transmission used by hookworms, any variations within the species covered in the class?

A
  • Ancylostoma canium: Via ingestion of L3, Skin penetration by L3, Ingestion of paratenic host, Transmammary.
    Ancylostoma tubaeforme: Via ingestion of L3, Skin penetration by L3, Ingestion of paratenic host.
    Ancylostoma braziliense: Percutaneous is primary route of infection.
    Uncinaria stenocephala: Via ingestion of L3.
86
Q

What are the two choices for hookworm L3 inside the host?

A
  • Normal Development vs. Arrested development
87
Q

What is the larval leak syndrome in Ancylostoma caninum?

A
  • Larval leak syndrome is that allows for refractory egg shedding. Arrested larvae will repopulate via arrested larvae in intestines (direct) or intestines in the somatic tissue (Tracheal migration).
88
Q

What are the main reasons of treatment failure in hookworms?

A
  • Larval leak syndrome, and Resistance to amtihelmintic drugs.
89
Q

Which hookworm species are more common in Gulf coast?

A
  • Ancylostoma brazilense
90
Q

If you find a hookworm egg in a fecal sample of a dog from Calgary, Canada, which species is it most likely to be? If it had a travel history to Florida which species should you consider?

A
  • Uncinaria stenocephala in canada, In Florida, Ancyostoma canium
91
Q

How can you diagnose hookworm infection in a dog? Technique?

A
  • fecal float ( centrifugal flotation), Coproantigen Elisa (idexxx) send out, clinical signs wold indicate reason to do testing.
92
Q

What do you recommend on control and management of hookworms and ascarids in endemic areas? When to start treatment?

A
  • Prevent environmental contamination with eggs, broad spectrum anthelmintic drugs, deworming schedule (treat prophylactically), and improvement of sanitation, in endemic areas wear shoes and gloves/ prevent direct contact with the son. Treat patients prophylactically
93
Q

Zoonotic disease caused by hookworms?

A
  • Cutaneous Larval Migrans
94
Q

What are the scientific names of threadworms and whipworms of dogs?

A 
Strongyloides stercoralis (thread worms) 
Trichuris vulpis (whip worm)
95
Q

What is the predilection site of Strongyloides stercoralis in a dog host?

A
  • adults (only females) in the crypts of the small intestine.
96
Q

What is unique about the lifecycle of Strongyloides stercoralis? How does reproduction occur inside the host and in the environment?

A
  • They could have a homophonic cycle ( parthenogenesis (asexual)) or a heterogonic cycle (sexual) Sexually reproducing free living stage and parthenogenic adult parasitic stage.
97
Q

What are the modes of transmission of Strongyloides stercoralis?

A

-Via ingestion of L3, Skin penetration by L3, Transmammary.

98
Q

What is the shed stage and infective stage of Strongyloides stercoralis?

A
  • L1 shed stage. Infective Is L3
99
Q

How do you diagnose threadworm in dogs? Technique?

A

L1 can be recovered by beaermann method (fresh species), may be seen in direct smear.

100
Q

What nematode can you find in the caecum of a dog?

A

Trichuris vulpis (whip worm)

101
Q

What are the general morphological characteristics of Trichuris vulpis – adults and eggs?

A

Adults have whip appearance, long and narrow anterior end with wider posterior end. Anterior is embedded in mucosa.
Eggs are brown, symmetrical, football shaped, bipolar plugs.

102
Q

What is the site of infection of Trichuris vulpis?

A

Infection site is Cecum and colon

103
Q

What is the infective stage of Trichuris vulpis?

A
  • L1 is infective state
104
Q

What is the key pathology is associated with Trichuris vulpis?

A
  • Anemia (severe infections)
  • Frequent defecation.
  • Inflammation in response to parasite causes ( Tenesmus, rectal prolapse, frank blood in feces, colitis, typhilitis (Cecum inflmmation), mucosal hemorrhage and necrosis, eosinophilia)
105
Q

What tests should be used for diagnosing hookworms and whipworms?

A
  • Centrifugal fecal flotation (hookworms and whipworms) Coproantigen Elisa (idexxx) send out (hookworms and whipworms), Colonoscopy to identify adults in situ
106
Q

Why are diagnosis and treatment of whipworms sometimes challenging?

A
  • Diagnosis: can be difficult, may need repeat fecal exam, eggs shed in low numbers, and have long pre patent period. Clinical signs can develop before patency,
  • Treatment: Long treatment Course, eggs are resistant to environment, in grass and dirt could be challenging to clean.
107
Q

What stage(s) you are targeting when doing environmental control for hookworms and whipworms?

A

L1- Whip worms,
L3 - Hook worms

108
Q

Which of the following is not true about parasitism?

a. It is a kind of symbiosis
b. The relationship can be harmful to both organisms
c. The host may die due to parasitism
d. Parasitism can undergo unnoticed

A

B- The relationship can be harmful to both organisms.

ONE BENEFITS, ONE IS HARMED

109
Q

What is the key characteristic of a micro-parasite?

a. Reproduce within the main host
b. Generation times can be longer
c. One micro parasite can produce many micro-parasites in the host (multiply)
d. Infections are generally long-lasting

A

c. One micro parasite can produce many micro-parasites in the host (multiply)

Microparasites reproduce asexually, can produce alot very quickly.

110
Q

Strongyloides can complete their lifecycle without a
host. What is the term used to describe this type of
parasite?
a. Obligatory parasite
b. Spurious parasite
c. Endoparasite
d. Facultative parasite

A

d. Facultative parasite
Both freeliving and non freeliving stages

111
Q

What is the term used for the role of coprophagous beetles in the life cycle of Spirocerca lupi?

a. Intermediate host
b. Paratenic host
c. Transport host
d. Definitive host

A

a. Intermediate host

( development can occur, no sexual reproduction, supports asexual reproduction)

112
Q

What differentiates Insects from arachnids

a. Their predilection site on the host
b. General pathogenicity on their host
c. Number of legs in their adult stages
d. Their role in disease transmission

A

c. Number of legs in their adult stages

113
Q

Which of these three is a nematode, the cestode, the trematode?

a. A-nematode, B-cestode C-Trematode
b. A,C – Cestode, B-Nematode
c. A-Cestode, B-Nematode, C-Trematode
d. A-Cestode, B-Trematode, C-Nematode

A

d. A-Cestode, B-Trematode, C-Nematode

114
Q

Which species is most likely to have a direct lifecycle?

a. A
b. B
c. C
d. A and B

A

c. C

115
Q

Which of these species is most likely to involve multiple intermediate hosts in their lifecycle?

a. A
b. B
c. C
d. B and C

A

b. B

Flukes have 2 intermediate hosts.

116
Q
  1. Which among the following is a characteristic feature of a nematode?
    a. Dorsoventrally flattened
    b. Absence of body cavity
    c. Complete digestive system
    d. Hermaphrodites
A

c. Complete digestive system

117
Q

What is a prepatent period?

a. The time duration between entry of an egg to the first appearance of egg/larvae in the feces of the host
b. The duration of active shedding of egg/larvae by the host
c. The age of the parasite
d. Time duration after the adults matures and starts laying eggs

A

a. The time duration between entry of an egg to the first appearance of egg/larvae in the feces of the host

118
Q

What is the general migration route in hepato-tracheal migration of parasitic stage?

a. Liver -> lung -> heart -> Trachea -> Intestine
b. Liver -> heart -> lungs -> Trachea -> Intestine
c. Liver -> heart -> lungs -> heart -> tissues
d. Liver -> tissues -> intestine

A

b. Liver -> heart -> lungs -> Trachea -> Intestine

119
Q

In the lifecycle of most trematodes, which larval stage is infective to the definitive hosts?

a. Cercaria
b. Metacercaria
c. Miracidium
d. Redia

A

b. Metacercaria

120
Q

11a. Based on your observation of these ectoparasites and information contained in your lecture slides, which of the following is a correct identification
a. A – Flea, B – Tick, C-Louse
b. A – Mosquito, B – Mite, C- Bug
c. A – Flea, B – Tick, C – Louse
d. A – Mite, B – Tick, C – Louse

A

a. A – Flea, B – Tick, C-Louse

121
Q

11b. Adults of which of these species hatch from the cocoon when a host is nearby?
a. A
b. B
c. C
d. A and C

A

a. A

122
Q

Which of the above group of ectoparasites has the highest host specificity?

a. A
b. B
c. C

A

c. C

123
Q

How does a mucosoflagellate (e.g Giardia) multiply in its hosts?

a. Sexual reproduction (mating of the two gametocytes)
b. Budding
c. Multiplication followed by fusion of gametes
d. Asexual multiplication – Binary fission

A

d. Asexual multiplication – Binary fission

124
Q

Jackie, a mix-bred dog from Northern Canada, was diagnosed with Spirocerca lupi infection three months after returning from a trip to Mexico. The diagnosis was based on the esophageal endoscopy and examination of nodules in the esophagus. Answer the following questions based on your knowledge of the parasite and the lifecycle figure below

13a. In the lifecycle of spirocerca lupi, what is true about the role of the beetles?
a. Beetle supports the development and amplification of the larval stages
b. Beetle only helps in the development of the larval stages to the infective stage
c. Larvae may develop even without beetle
d. Larvae may develop into adults in the beetles in rare cases

A

b. Beetle only helps in the development of the larval stages to the infective stage

125
Q

Jackie, a mix-bred dog from Northern Canada, was diagnosed with Spirocerca lupi infection three months after returning from a trip to Mexico. The diagnosis was based on the esophageal endoscopy and examination of nodules in the esophagus. Answer the following questions based on your knowledge of the parasite and the lifecycle figure below

13b. How might have Jackie acquired the parasite?
a. In Canada, during a walk to the woods
b. Through the food contaminated with feces containing S. lupi eggs
c. Eating a beetle while in Canada
d. Eating a wild rodent during a nature walk in Mexico

A

d. Eating a wild rodent during a nature walk in Mexico

126
Q
A

Parasitology (10 decks)

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