Exam I Miscellaneous Material

Question 1

Describe what a Host Specific Parasite is.

Answer 1

a parasite that develops completely in only one type of host, e.g., dog

Question 2

Describe the term Broad Host Spectrum

Answer 2

(Non-Host Specific) Parasite - a parasite that can develop in different types of hosts, e.g., cattle, sheep, horses.

Question 3

Describe the term **Definitive or Final Host **

Answer 3

a host in which the parasite develops to its mature stage.

Question 4

Describe the term **Intermediate Host (IH) **

Answer 4

a host in which the parasite develops to that stage which is infective for the DH. The IH, with the infective stage generally encysted in some tissue, is usually part of the food chain of the DH. When the DH ingests the IH, the infective stage, enters the DH. For some helminths, the IH is a biting arthropod, and transmits the infective stage via its mouth parts when biting the host.

Question 5

Describe the term **Paratenic Host (PH) **

Answer 5

a host in which there is no development of a helminth, and in some instances protozoa, but one that transmits the infective stage of the parasite, and allows for its wider dissemination. The PH, with the infective stage of the parasite encysted in some tissue, usually is part of the food chain of other PHs or DHs. A PH is sometimes referred to as a transport host.

Question 6

Describe the term Biological Vector

Answer 6

a host, usually a biting arthropod, in which a protozoan parasite develops through either asexual or sexual multiplication, and transmits the parasite via its mouth parts on subsequent biting of a DH, or in its feces deposited on the DH as it is feeding.

Question 7

Describe the term infection

Answer 7

endoparasites such as helminths and protozoa infect the host internally

Question 8

Describe the term infestation

Answer 8

when ectoparasites such as acari and insects attach to or occupy the host

Question 9

The **predilection site **is:

Answer 9

preferred site in or on the host, which is characteristic for a parasite species

Question 10

The Aberrant site is:

Answer 10

the site in or on a host which is not a normal location for a parasite.

Question 11

List the general characteristics of insects.

Answer 11

• 3 pairs of legs
• A body divided into **head, **distinct thorax and abdomen
• A single pair of antennae

Question 12

Arachnids have _______ rather than antennae

Answer 12

palps

Question 13

The two families of ticks are ________ and _________

Answer 13

The two familes of ticks are Ixodidae (hard ticks) and Argasidae (soft ticks)

Question 14

Which family of ticks are known for having a rigid chitinous scutum that covers the entire dorsal surface of the adult male?

Answer 14

Ixodidae (hard ticks)

Question 15

True or False: **Helminths **include nematodes and cestodes, but not trematodes.

Answer 15

False.

Helminths (worms) include nematodes (roundworms), cestodes (tapeworms), and trematodes (flukes)

Question 16

True or False: Nematodes are primarily identified by their segmented, flat appearance

Answer 16

False.

Nematodes; or roundworms, are usually unsegmented, elongated, & cylindrical in shape.

Question 17

List the general characteristics of nematodes

Answer 17

• May be free-living or parasitic
• usually unsegmented, elongated, and **cylindrical **in shape
• An alimentary canal is present
• Sexes are usually **separate **and the females are generally longer than the males

That roundworm got a free _pa_ir of _un_sellable _el_f _cy_sts for _al_l _ca_mels

“what the fuck is Chris smoking?”

Question 18

Why are female nematodes typically longer than males?

Answer 18

Females hold the eggs

Question 19

With regard to nematodes, the L4, L5/immature adult, and adult always occur in the __________ host

Answer 19

definitive

Question 20

When no intermediate host is involved, the life cycle is considered to be ________.

Answer 20

direct

Question 21

When one or more intermediate hosts are involved, the life cycle is considered to be ________.

Answer 21

indirect

Question 22

True or false: The alimentary canal of a cestode can be seen at 10x under a microscope.

Answer 22

False.

The alimentary canal on a cestode (or tapeworm) can’t be seen under any magnification… because tapeworms don’t have an alimentary canal.

Boom.

Question 23

The body of a cestode is also known as the ________

Answer 23

strobila

The strobila includes the head, neck, and proglottids

Question 24

Cestode life cycles are ________.

(direct or indirect)

Answer 24

indirect

Question 25

List the general characteristics of trematodes

Answer 25

**Trematodes (or flukes) **are:

• dorso-ventrally flattened (leaf-like)
• Oral & ventral suckers for attachment
• Usually genitally independent; hermaphroditic

Question 26

Trematodes belong to the phylum ________ and the class ________

Answer 26

Trematodes belong to the phylum Platyhelminthes and the class Trematoda

Question 27

Are trematode life cycles direct or indirect?

Answer 27

indirect.

At least 1 intermediate host is required to complete the life cycle.

Larval stages develop & multiply asexually in a molluscan intermediate host.

Question 28

If we’re discussing a parasite whose larval stages develop and multiply asexually in a molluscan intermediate host, you know right away that that parasite belongs to which taxonomic class?

Answer 28

Trematoda

Question 29

How do humans become infected with Toxocara canis?

Answer 29

Ingestion of infective egg containing L₂

Question 30

How do humans become infected with Ancylostoma braziliense?

Answer 30

Percutaneously by L₃

Question 31

How do humans become infected with Strongyloides stercoralis?

Answer 31

Percutaneously by L₃

Question 32

How do humans become infected with Echinococcus granulosus?

Answer 32

Ingestion of the oncosphere

Question 33

How do humans become infected with Taenia crassiceps?

Answer 33

Ingestion of the oncosphere

Question 34

Which parasite is known for causing interdigital dermititis?

Answer 34

Uncinaria stenocephala

Question 35

When you hear ‘visceral larval migrans,’ which parasite should come to mind?

Answer 35

Toxocara canis

Question 36

When you hear ‘cutaneous larval migrans,’ which parasite should come to mind?

Answer 36

Ancylostoma brazilense

Question 37

Which parasites that we’ve covered have a Direct L₃ life cycle?

Answer 37

• Ancylostoma caninum
• Ancylostoma tubaeforme
• Ancylostoma brazilienze
• Uncinaria stenocephala
• Strongyloides stercoralis

So, make it easy on yourself and remember Ancylostoma spp., Uncinaria spp., and Strongyloides spp.

“My name is Leonard the 3rd, and I am an Awesome Undercover Spy… who is also direct”

…I’m getting worse at these

Question 38

Which parasites that we’ve gone over has an indirect L₃ life cycle?

Answer 38

• _P_hysaloptera spp.
• _A_. reconditum
• _D_ioctophyme renale
• _A_eleurostrongylus abstrusus
• _D_irofilaria immitis
• _S_pirocerca lupi

_*​*PA DADS_ (you know, like, Dads… from Pennsylvania) are indirect L₃

Question 39

Which parasites that we’ve gone over have a direct L₂ in egg life cycle?

Answer 39

• Toxocara canis
• Toxocara cati
• Toxoscaris leonina

Question 40

Which parasites that we’ve gone over have a direct L₁ in egg life cycle?

Answer 40

• Trichuris vulpis
• Capillaria spp. (can be indirect as well)

Question 41

Which parasites that we’ve gone over have a direct L₁ life cycle?

Answer 41

• Oslerus osleri

Question 42

List the larval stages of cestodes:

Answer 42

• cysticercus
• strobliocercus
• cysticercoid
• coenurus
• hyatid cyst

Question 43

What is the diagnostic method typically used with trematodes?

Answer 43

Fecal sedimentation

Question 44

The Baermann technique is used as a diagnostic tool in which parasites?

Answer 44

• Strongyloides stercoralis
• Oslerus osleri
• Aeleurostrongylus abstrusus