Parasitology -> Arthropods

Question 1

What orders compose the class Insecta?

Answer 1

Siphonaptera (fleas)
Phthiraptera (lice)
Diptera (flies)
Hemiptera (true bugs, bed bugs, kissing bugs)
Coleoptera (blister beetles)
Lepidoptera (urticating caterpillars)
Hymenoptera (bees, wasps, ants)

Question 2

What order composes Class Arachnida?

Answer 2

Acari (ticks and mites)

Question 3

How do insects differ from ticks and mites?

Answer 3

Insects have 3 body parts and 6 legs

Ticks and Mites have 2 body parts and 8 legs as an adult

Question 4

Where do parasitic arthropods typically harbor pathogens?

Answer 4

In the salivary glands

Question 5

What are the two types of life cycles of class Insecta?

Answer 5

Simple/Incomplete metamorphosis: immature stages look like small adults

Complex/complete metamorphosis: marked difference in morphology and structure between adults and immature stages

Question 6

What is the insect of Order Siphonaptera with the most veterinary importance? List common features.

Answer 6

Fleas
Macroscopic, brown, wingless, laterally compressed, complex metamorphosis

Question 7

What hosts do Ctenocephalides felis prefer?

Answer 7

Hosts: dogs, cats, ferrets, occasionally other animals

Most common flea of cats and dogs and is found worldwide

Question 8

Do adult of Ctenocephalides felis spread from host to host?

Answer 8

No, once an adult is on a host, it is considered a permanent ectoparasite that will feed as soon as it finds a host

Question 9

After an adult female of Ctenocephalides mates, how long will it take for her to start laying eggs?

Answer 9

24 hours

Question 10

Describe characteristics of Ctenocephalides felis larva and what they require to develop

Answer 10

Larva is slender, white, 2-5 mm, and may have dark appearance from blood ingestion

They require the ingestion of flea feces, and prefer high humidity

Question 11

Describe characteristics of Ctenocephalides felis pupa

Answer 11

The larva forms a sticky cocoon in which debris stick for camouflage
Adult can stay in pupa for up to 6 months, pupa is very tough and is not killed by pesticides

Question 12

Roughly how long does each stage of the Ctenocephalides felis life cycle last under perfect conditions?

Answer 12

Egg hatching -> 2 days
Larva -> 6 days
Pupa -> 6 days
~14 days total
Eggs compose 50% of an infection

Question 13

What is the clinical importance of Ctenocephalides felis?

Answer 13

Hypersensitivty rxn to saliva antigens -> flea allergy dermatitis
Range of pruritus and hair loss
Hot spots
Tapeworm vector
Anemia

Question 14

What is the significance of rodent fleas?

Answer 14

Usually host specific, but will bite dogs/cats if given the opportunity
Vector of Yersinia pestis

Question 15

What is the typical host of the sticktight flea (echidnophaga gallinacea)

Answer 15

Birds -> female stays attached

Question 16

What is the most medically important species of order phthiraptera? List general characteristics

Answer 16

Lice
small, wingless, dorsoventrally flattened, can be white, gray, or brown

Question 17

What are the two types of lice and what differentiates them?

Answer 17

Anoplura: sucking lice, only in mammals
Mallophaga: chewing lice, mammals and birds

Question 18

Where do lice spend their life cycle? How long does this take

Answer 18

Lice spend their entire life cycle on the host with eggs glued to feathers or hairs

Life cycle takes about 4 weeks

Question 19

How are lice often transmitted?

Answer 19

Direct contact or fomites

Question 20

Why would we see an increase of lice in the winter in animals housed outdoors?

Answer 20

Animals huddle together, coat and body temp is favorable, potential cause of increased stress

Question 21

Are we concerned about disease spread through lice in the US?

Answer 21

No, they are an insignificant vector here

Question 22

In what animals are lice infestations common?

Answer 22

Typically seen in food animals, wild birds, and wild mammals

Question 23

What are common features of the order diptera?

Answer 23

Adults have 1 pair of membranous wings
Undergo complete metamorphosis
Most have no parasitic stage

Question 24

What is the clinical relevance of Musca domestica (housefly)

Answer 24

They aren’t parasites, but can interfere with normal behavior and can serve as mechanical disease vectors

lay eggs in decaying organic material

Question 25

What is the clinical relevance of Musca autumnalis (face fly)

Answer 25

Females eat secretions (especially tears) for protein Eggs laid in FRESH manure primarily affect ruminants, horses importance: fly worry, irritation of eye mucosa, transmission of moraxella bovis (pink eye)

Question 26

Where do Haematobia irritans (horn fly) spend their life cycle and what part of the animal do they prefer?

Answer 26

Adults are resident parasites that spend all their life on the host The flies prefer to sit on the dorsum (ventrum when hot) of primarily cattle

Question 27

Where do horn flies lay their eggs and how long does their life cycle typically take?

Answer 27

Horn flies lay their eggs in fresh manure, and their life cycle can be complete in 10-12 days

Question 28

What is the clinical significance of the horn fly?

Answer 28

They cause fly worry and fly bite dermatitis They can carry bacteria that cause mastitis Most important external parasite of cattle in the US

Question 29

What is the life cycle and important of Stomoxys calcitrans (stable fly)

Answer 29

resemble house fly, important biting fly Life cycle: visit host 1-2 times a day and bite lower body, legs, and feet, lay eggs in DECAYING matter and takes about 28-30 days to complete cycle Importance: FW, FBD, not important disease vector

Question 30

What is the life cycle and importance of family Tabanidae (horse, deer fly)

Answer 30

Large flies, stout body Life cycle: lay eggs near water Importance: annoyance, painful bites, mechanical vector of disease

Question 31

What is the life cycle and importance of culicidae (mosquitoes)?

Answer 31

Life cycle: lay eggs in water, variation between species in egg preference Importance: region is important, FBD, FW, disease vector

Question 32

What is the life cycle and importance of Simuliidae (black flies, buffalo gnats)?

Answer 32

Life cycle: lay eggs in rapidly moving water Importance: intense FW, can cause stampedes, FBD, disease vector, but limited in US (avian hemoprotozoa, EEE, vesicular stomatitis

Question 33

What is the importance and life cycle of Culicoides spp (no-see-ums, midges)?

Answer 33

Very tiny (control) Life cycle: larvae in moist soil or water Importance: FW, FBD in horses (sweet itch), transmits bluetounge, some nematodes

Question 34

What are distinguishing features of Hippoboscidae? How does this differ from other families?

Answer 34

Adults have a flat body, most common species (Melophagus ovinus) is wingless, includes "flat flies." Sheep and goat "ked"

Question 35

What are 3 methods of fly control?

Answer 35

Mechanical Manure control Pesticides

Question 36

What is myiasis?

Answer 36

Any infection due to the invasion of the tissues or cavities of the body by dipterous insects

Question 37

What are the two types of myiasis?

Answer 37

1. Cutaneous myiasis: fly strike, maggots 2. Internal myiasis: grubs, warbles, bots

Question 38

What type of larvae primarily cause fly strike (cutaneous)? What type of parasites are they?

Answer 38

Larvae of blow flies (Calliphorids) -> filth flies Larvae are facultative parasites

Question 39

What is the typically life cycle of fly strike causing larvae?

Answer 39

Eggs are laid in decaying organic material, but larvae feed on necrotic material They pupate on the ground and adult flies emerge Females are attracted to wound secretions

Question 40

How is myiasis by fly strike larvae typically diagnosed, treated, and prevented?

Answer 40

Diagnosis: finding maggots Treatment: remove maggots Prevention: wound spray and do procedures before fly season

Question 41

How does fly strike caused by Cochliomyia hominivorax (screw worm) differ from that caused by blow flies?

Answer 41

The larvae is an obligate parasite and requires living tissue, producing much more sever disease Sterile male release program control method

Question 42

What are distinguishing features of fly larvae that cause internal myiasis?

Answer 42

larvae are called bots, grubs, and/or warbles adults are hairy and resemble bees larvae are OBLIGATE internal parasite, then leaves to pupate in the environment

Question 43

What is the life cycle of Gasterophilus spp. (horse bots)?

Answer 43

Eggs are laid on face or legs of equids, eggs hatch and move to mouth where they move to stomach for 10-12 months, pass out in manure and pupate in soil Adult does not feed

Question 44

What are clinical signs associated with Gasterophilus spp? How is it typically diagnosed and treated?

Answer 44

Not very pathogenic, so no specific clinical signs, but there can be rare ulceration or perforation of stomach Diagnosis: see flies, eggs on legs Treatment: annual treatment in fall, eggs/larvae removal

Question 45

What is the life cycle of Cuterebra spp. (rodent bot flies)?

Answer 45

Common parasite of rodents, rabbits Eggs laid near burrows, along trails Larvae is picked up by host, develop in SQ host and then pupate on ground

Question 46

What are clinical signs associated with Cuterebra spp (rodent bot flies)? How is it treated?

Answer 46

Clinical signs: lump observed that develops an opening, may lead to secondary infection Treatment: careful removal Dogs/Cats may pick up

Question 47

What bugs of veterinary importance make up Order Hemiptera?

Answer 47

Bed Bugs (Cimex spp.) Kissing bugs (triatomid bugs)