Arthropods Flashcards
(100 cards)
1
Q
Trichoptera (caddisfiles)
A
Arthropods→Insecta→Trichoptera
- vectors of potomac horse fever
- caused by bacteria (Neorickettsia risticii)
- bacteria contained in trematodes within the fly
- acquired by horses through ingestion of caddisflies in drinking water
- horse symptoms:
- acute enterocolitis
- abortion in pregnant mares
- laminitis
2
Q
Nematocera
A
Arthropods→Insecta→Dipteria→Nematocera
many long segmented antennae
3
Q
Culicidae
A
(mosquitoes)
Arthropods→Insecta→Dipteria→Nematocera→Culicidae→culex or anopheles
autogeny = sometimes females can undergo ovarian maturation without bloodmeal
vector of diseases:
- dirofilaria immitis (heartworm)
- west nile virus
- equine encephalitides
4
Q
Simulidae
A
(blackflies)
Arthropods→Insecta→Dipteria→Nematocera→Simulidae
- short antennae
- vicious biter, feeds by lacerating tissues and making a blood pool
- host can develop hypersensitivity
vector diseases?
- Leucocytozoon in birds
- Onchocerca in cattle, dogs, and humans
- causes river blindness in humans
5
Q
Ceratopogonidae
A
(midges)
Arthropods→Insecta→Dipteria→Nematocera→Ceratopogonidae
→Culicoides
can cause allergic dermatitis (”queensland itch”) in horses due to hypersensitivity reaction
vector diseases
- Orbiviruses:
- Blue tongue
- African horse sickness
6
Q
Psychodidae
A
(Phlebotomine sandfiles)
Arthropods→Insecta→Dipteria→Nematocera→Psychodidae
→Lutzomyia
wing veins radiate in straight lines (like a needle)
vector diseases:
- Leishmania
- dermal lesions
- lymphadenomegaly
- ocular disease
- onychogryposis (nail abnormalites)
7
Q
Brachycera
A
(Tabanids)
Arthropods→Insecta→Dipteria→Brachycera
- stout-bodied, up to hummingbird size
- stout three-segmented antennae
- feed through laceration and blood pooling
- attacks are painful
vector of disease:
- Trypanosoma evansi (surra disease)
- Trypanosome theilelri (nonpathogenic)
8
Q
Cyclorrhapia
A
Arthropods→Insecta→Dipteria→Cyclorrhapia
- larval forms have:
- hooks on mouth
- spiracles (breathing organs) at base
9
Q
Musca
A
(flith flies)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Muscidae→Musca
10
Q
Musca domestica
A
(house fly)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Muscidae→Musca
vector disease:
- Draschia
- Habronema
11
Q
Musca autumnalis
A
(face fly)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Muscidae→Musca
M. autumnalis stays inside over winters & outside over summers
vectors:
- Moraxella bovis, which causes infectious bovine keratoconjunctivitis (pinkeye)
12
Q
Stomoxys
A
(stable flies)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Muscidae→Stomoxys
→Stomoxys calcitrans
- long, pointed proboscis, palps shorter than proboscis
- both sexes feed on blood
vector disease:
- Habronema microstoma
13
Q
Haematobia
A
(horn files)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Muscidae→Haematobia
→Haematobia irritans
- palps same length as proboscis
-
eggs laid in cow manure
- can treat by removing manure more frequently
- eggs develop to new egg-laying adults within 2 weeks
14
Q
Glossinidae
A
(Tse Tses)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Glossinidae
- long, feather-like arista
vector disease:
- Trypanosoma brucei = African sleeping sickness in humans, Nagana in livestock
15
Q
Hippoboscidae
A
Arthropods→Insecta→Dipteria→Cyclorrhapia→Hippoboscidae
- Hippobosca equinus: horse ked
- Lipoptena cervi: deer ked
-
Melophagus ovinus: sheep ked
- entire lifecycle completed on sheep
16
Q
Sarcophagidae
A
(Flesh Files)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Sarcophagidae
large maggots, sunken spiracles (respiratory openings)
can be facultative parasites, with maggots resulting in myiasis (infection of skin with larva) in wounded or wet skin
17
Q
Calliphoridae
A
(Blow Flies)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Calliphoridae
- metallic blue, green, copper or black adults
-
most are scavengers or facultative parasites
- attracted to wet skin, wounds, necrotic tissue
In sheep causes…
- wool strike = developing larvae feed on scales and exudate on skin surface, and penetrate tissues
- affects areas stained by urine or feces (perineum, prepuce)
- toxins absorbed from myiasis can lead to death
18
Q
Cochilomyia hominivorax
A
(American screwworm)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Calliphoridae
pigmented tracheal trunks
this species a exception:
- obligate parasite
- cause primary myiasis (feed on living tissue)
- reportable bc disease can effect humans
fly control:
- release sterile males at Panama canal border
myiasis treatment:
- coumaphos spay or smear
- SQ ivermectin or doramectin prophylactically
19
Q
Oestridae
A
(Botflies)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Oestridae
- typically host-specific, site-specific parasites in larval stage (bots)
- adults do not feed, only reproduce
20
Q
Oestrus Ovis
A
(sheep nasal botfly)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Oestridae
- females deposit larvae in sheep nostrils
- larvae develop in mucosa of nasal cavity then front sinus, sneezed out and pupate
- heavy infection causes sneezing and nasal discharge
21
Q
Hypoderma
A
(Heelflies, GADFLIES)
Arthropods→Insecta→Dipteria→Cyclorrhapia→Oestridae
Hypoderma bovis
Hypoderma lineatum
- cattle often react to flies presence by galloping away
- adults ovipost on hairs of leg (1st stage)
22
Q
How do Hypoderma bovis migrate to 2nd & 3rd stage larvae?
A
Hypoderma bovis accumulate in spinal canal (2nd stage)
then they migrate to back of cow → 3rd stage larvae found in lumps on dorsum (warbles)
23
Q
How do Hypoderma lineatum migrate to 2nd & 3rd stage larvae?
A
-Hypoderma lineatum accumulate in esophagus (2nd stage)
- then they migrate to back of cow → 3rd stage larvae found in lumps on dorsum (warbles)
24
Q
how do we treat Hypoderma?
A
-
ivermectin, doramectin, eprinomectin, moxidectin
- macrocytic lactones
25
why do we not give organophosphate treatment for Hypoderma?
- **organophosphate treatment can cause host-parasite reactions**
- **bloat, salivation, ataxia, posterior paralysis**
- happens because toxins released from dying larvae
- can counteract with phenylbutazone pre-treatment or adrenaline
26
how can warbles be removed?
injecting 3% hydrogen peroxide into breathing hole
27
Gasterophilus
Arthropods→Insecta→Dipteria→Cyclorrhapia→Oestridae
- eggs deposited on horse hairs and location depends on species:
- ***G. nasalis:***
- **intermandibular space**
- ***G. hemorrhoidalis:***
- **lip hairs**
- ***G. intestinalis:***
- **forelegs and shoulder**
- 3rd stage larvae varies in location depending on species:
- ***G. nasalis:*** = **ampulla of duodenum**
- ***G. hemorrhoidalis:*** = **duodenum and rectum**
- ***G. intestinalis:*** = **nonglandular stomach near margo plicatus**
- treatment?
- **macrocyclic lactones for bots**
28
Cuterebra
Arthropods→Insecta→Dipteria→Cyclorrhapia→Oestridae
- adults rarely seen
- 3rd stage larva large, **dark-brown to black, with stout black spines**
- commonly in northeastern U.S.A around **late summer to early fall**
- **acquired from rodent and rabbit burrows**
where can **bots migrate if found in cervical subcutaneous connective tissue**?
- **can migrate to ocular, nasal, oral regions, and brain**
leading to:
- **feline ischemic encephalopathy (FIE)**:
- thrombosis of **middle cerebral artery** due to migration or toxin secretion →
- **ischemic necrosis**
29
Siphonaptera
(fleas)
Arthropods→Insecta→Siphonaptera
- **wingless, laterally flattened adults**
- large abdomen
30
ctenocephalides
Arthropods→Insecta→Siphonaptera→ctenocephalides
- **ctenocephalides felis much more common than ctenocephalides canis**
- parasitize cats, dogs, cattle, and humans
- **genal and pronotal combs**
- **genal teeth run parallel to head**
- eggs laid on host, larvae can hatch on host
- larval fleas eat parent feces and organic debris
- **jumping from host to host NOT COMMON**
- **adults emerge by weeks 3-4**
- **feed immediately after getting on host**
31
what do ctenocephalides cause and diseases they vector?
- gravid females consume average 13.6 uL blood per day
- **an cause exsanguination of host (anemia)**
- **intermediate host of:**
- **tape worm, *Dipylidium canium***
- **nematode, *Acanthochelionema reconditum***
- can cause **flea allergy dermatitis** due to host hypersentitivity to flea saliva
32
how do we diagnose ctenocephalides ?
- comb through hair with a flea comb to collect adults
- **paper chromatography:** place detritus on paper and dampen with detergent solution to check for hemoglobin diffusion
- red halo → blood breakdown product → fleas present
33
how to treat and attack adult ctenocephalides?
- **Isoxazolines (afoxolaner, fluralaner, lotilaner, sarolaner)**
- nitenpyram, spinosad, selamectin, fipronil, imidacloprid, dinotefuran, flumethrin, indoxacarb
- **Fibpronil toxic to rabbits**
34
how to treat and attack larvae and pupae ctenocephalides?
- **insect growth regulators (lufenuron, pyriproxyfen, methoprene)**
- **prevents larvae and pupae development**
35
Echidnophaga
(sticktight flea)
Arthropods→Insecta→Siphonaptera→Echidnophaga
- **affects poultry, dogs, cats, rabbits, horses, humans**
- around eyes and cloaca, combs and wattles
- **no genal or pronotal combs**
36
Tunga
(Jigger, Chigoe)
Arthropods→Insecta→Siphonaptera→Tunga
- impregnated female **embed in skin of ankles and feet in humans & animals**
- painful lesions subject to secondary infection
37
Xenopsylla
(**rat fleas**), also attack humans
Arthropods→Insecta→Siphonaptera→Xenopsylla
- **no genal or pronotal combs, vertical rod on mesothorax**
- vector disease for:
- ***Yersinia pestis* (bubonic plague)**
- Ricketssia typhi (typhus)
38
Pulex
(human flea)
- **also affects swine and dogs**
Arthropods→Insecta→Siphonaptera→Pulex
- **no genal nor pronotal combs**
- no rod
39
Phthiraptera
(lice)
Arthropods→Insecta→Phthiraptera
- two main groups?
1. **Anoplura = blood sucking lice**
1. narrow head and piercing mouth parts
2. **Mallophaga = skin chewing lice**
1. broad head
40
Anoplura
(blood sucking lice)
Arthropods→Insecta→Phthiraptera→Anoplura
- **piercing mouthparts, narrow head**
- pincer-like claw for clinging to hair
- **parasitize placental animals only**
- **birds and reptiles not affected**
41
Haematopinus
Arthropods→Insecta→Phthiraptera→Anoplura→Haematopinus
- **all tarsal claws equal size**
- sclerotized lateral margins (bumps along side)
- vector disease:
- swinepox virus
- **horses: H. asini**
- **pigs: H. suis**
- **cattle: H. eurysternus**
- **common in North America**
- **can cause severe anemia**
42
Lingognathus & Solenopotes
Arthropods→Insecta→Phthiraptera→Anoplura→Lingognathus & Solenopotes
- first pair of tarsal claws smaller than second and third pairs
- cattle affected by:
- ***Lingognathus vituli***
- ***Solenopotes capillatus***
- dogs affected by:
- ***Lingognathus setosus***
43
Pthirus
(human pubic lice)
Arthropods→Insecta→Phthiraptera→Anoplura→Pthirus
- large tarsal claws adapted to coarse hairs
- intense pruritus and papular dermatitis
- spread by close contact
- **may spread to dogs**
44
Pediculus
- *Pediculus humanus humanus*: human body louse
- **clings to clothing fibers rather than hairs**
- vector disease:
- ***Rickettsia prowazekii* (epidemic typhus)**
Arthropods→Insecta→Phthiraptera→Anoplura→Pediculus
45
Mallophaga
(chewing lice)
Arthropods→Insecta→Phthiraptera→Mallophaga
- **common in poultry**
- feed on epidermal scales, feathers, and sebaceous secretions
46
Bovicola
Arthropods→Insecta→Phthiraptera→Mallophaga→Bovicola
- ***Bovicola bovis*: cattle**
- ***Bovicola equi*: horses**
47
Trichodectes
Arthropods→Insecta→Phthiraptera→Mallophaga→Trichodectes
- ***Trichodectes canis*: dogs**
- chewing louse dogs
- **intermediate host:**
- ***Dipylidium caninum***
48
Felicola
Arthropods→Insecta→Phthiraptera→Mallophaga→Felicola
- ***Felciola subrostratus*: cats**
- chewing louse cats
49
Hemiptera
(bugs)
Arthropods→Insecta→Hemiptera
50
Reduviidae
(assassin/kissing bugs)
Arthropods→Insecta→Hemiptera→Reduviidae
- **can transmit protozoan: *Trypanosoma cruzi***
-> **“Chagas disease”, “American trypanosomiasis”**
- **transmitted through feces rubbed into wound (stercorarian transmission)**
51
Cimicidae
(bedbugs)
Arthropods→Insecta→Hemiptera→Cimicidae
- hide in crevices and attack at night
- blood feeders
- feed on humans, chickens, bats, nesting birds
- **no known vectored diseases**
52
Arachnids
Arthropods→Arachnids
- includes ticks and mites
- larval stages have 3 pairs of legs
- Nymphs and adults have 4 pairs of legs
- head, thorax, and abdomen fused
53
Ixodida
(Metastigmata) (ticks)
Arthropods→Arachnids→Ixodida
- blood suckers
- hypostome has backward-facing teeth, chelicerae have movable denticles
- vectors of many microbial diseases
54
what are tick toxicosis? [2]
- **tick paralysis:**
- ascending paralysis due to absorption of toxins from saliva of tick
- **red meat allergy:**
- associated with *Amblyomma americanum*
55
Argasidae
(soft ticks)
Arthropods→Arachnids→Ixodida →Argasidae
- **capitulum within ventral margin**
-**scutum absent**
- **lives in nests, burrows, and sleeping places**
- commonly in arid regions or drier habitats
- life stages: egg, larva, multiple nymphal stages, adults
- **Nymphs and adults feed repeatedly on hosts**
- **females lay clutch of eggs after each blood meal**
56
Argas
Arthropods→Arachnids→Ixodida→Argasidae→Argas
- flattened, ovoid, yellow-red ticks with **sharp lateral margin**
- leathery, wrinkled surfaces
- **mouthparts on ventral surface**
- **eggs laid in crevices**, hatch to larvae in 1-4 weeks
- can survive up to 2 years without a meal
- vector:
- *Borrelia anserina* in poultry and other birds
57
Ornithodoros
Arthropods→Arachnids→Ixodida→Argasidae→Ornithodoros
- globular body
- found in **cracks in avian roosts and nests, rodent burrows, and large animal resting places**
- vector:
- *Borrelia spp.* in humans (tick-borne relapsing fever)
- transovarian transmission from mother tick to offspring
58
Otobius
Otobius megnini (spinose ear tick)
Arthropods→Arachnids→Ixodida→Argasidae→Otobius
- covered in spines
- **larvae and nymphal stages in ear canals of cattle** remain on host for up to 4 months
- drop to ground to molt to adult stage
- **adults do not feed**; they mate and female deposits one clutch of eggs in the soil
59
Ixodidae
(hard ticks)
Arthropods→Arachnids→Ixodida→Ixodidae
**capitulum projecting outside anterior margin**
**scutum present**
- **stigmata (respiratory openings) behind last pair of legs**
- anterior end has basis capitulum and mouthparts
60
what is lifecycle of Ixodidae?
- involves molt from larva to nymph, and nymph to adult
- 1-host ticks
- both molts completed without leaving host
- 2-host ticks
- nymphs leave host to molt to adult
- 3-host ticks
- larvae and nymphs leave host to molt to adult
61
what are the implications for 1, 2, or 3 host ticks might be on treatment and prevention of tick infestations on patients?
- **ticks that feed on only one host exclusively are much easier to treat/prevent**
- as there is no additional host required for the life cycle of the individual tick
- ticks with multiple hosts harder to eliminate and can transmit zoonotic disease easier
62
Ixodes
Arthropods→Arachnids→Ixodida→Ixodidae→Ixodes
- no eyes, festoons, nor scutal patterning
- **preanal groove**: anal groove forming an arch anterior to the anus
- **palps broadest at junction of second and third segments**
- ***Ixodes scapularis***
- common in northeast USA
- 3-host tick
- vector disease:
- ***Borrelia burgdorferi*** (Lyme disease)
- some species (*Ixode holocylus, Ixode pacificus*) can cause **tick paralysis**
63
Haemaphysalis
Arthropods→Arachnids→Ixodida→Ixodidae→Haemaphysalis
- no eyes nor scutal patterning, festoons present
- palps have **laterally flared** second segments
- *Haemaphysalis longicornis*
- invasive tick species
- vector for *Theileria orientalis* to large animals
- what is *Theileria orientalis?*
- tickborne **protozoal infection of cattle**
- lives in **red and white blood cells**
64
Rhipicephalus
Arthropods→Arachnids→Ixodida→Ixodidae→Rhipicephalus
- **hexagonal basis capitulum**
- eyes and festoons present
- scutum unpatterned
65
Rhipcephalus sanguineus
(brown dog tick)
Arthropods→Arachnids→Ixodida→Ixodidae→Rhipicephalus
- 3-host tick
- all stages feed on dogs
- egg to egg development in ~2months
- unfed adults can survive up to 1 year
- vector diseases?
- *Babesia canis* (canine piroplasmosis) with transovarial transmission
- *Ehrlichia canis* (canine monocytic ehrlichiosis) with interstadial transmission
66
Rhipcephalus (Boophilus) annulatus
(bovine tick)
Arthropods→Arachnids→Ixodida→Ixodidae→Rhipicephalus
- ridged palpi dorsally and laterally; no festoons
- **can vector bovine piroplasmosis with transovarial transmission**
- **eradication efforts have eliminated this tick from the USA**
- possible due to **1-host life cycle**
67
Dermacentor
Arthropods→Arachnids→Ixodida→Ixodidae→Dermacentor
- **rectangular basis capituli**
- **scutum patterned**
- *Demacentor variabilis* (american dog tick)
- 3-host tick:
- larvae and nymphs feed on small mammals
- adults feed on dogs, horses, cattle, wildlife, humans
- vector diseases?
- *Rickettsia rickettsii* (Rocky Mountain Spotted Fever)
- *Francisella tularensis* (Tularemia)
- can cause tick paralysis
68
Amblyomma
Arthropods→Arachnids→Ixodida→Ixodidae→Amblyomma
- **mouthparts longer than basis capitula**
- **scutum patterned**
- *Amblyomma americanum*:
- vector for protist:
- *Cytauxzoon felis*
- ** cause red meat allergy**
- *Amblyomma maculatum* (Gulf coast tick)
- vector for:
- *Hepatozoon americanum*
69
Mesostigmata
(mites)
Arthropods→Arachnids→Mesostigmata
- identifiable traits:
- **stigmata** (respiratory pore) in middle of the body
- between **third and fourth coxae**
- **chelicerae (piercing mouthparts)**
- **chelae (scissor-like structures)**
70
Ornithonyssus
Arthropods→Arachnids→Mesostigmata→Ornithonyssus
These mites mostly affect:
- **mites of poultry and rodents**
Visible distinguish:
- **stout chelicerae**
- **gut is dark red to black x**
70
what do bloodsucking mesostigmatid mites parasitize?
**birds and rodents**, sometimes humans
71
Dermanyssus Gallinae
Arthropods→Arachnids→Mesostigmata→Dermanyssus Gallinae
- visible distinguish it?
- **long slender chelicerae** (wip-like), small chelae
- who do these mites mostly affect?
- **mites of poultry**
- blood loss can kill nestlings and reduce egg production
- hide in nests and roost during day, attack at night
72
Railletia
Arthropods→Arachnids→Mesostigmata→Railletia
Railletia auris
- these mites affect:
- **mites of ear in cattle**
- symptoms they cause:
- ulceration
- **blockage of auditory canal**
- **hearing loss**
- **circling, ataxia**
- **unilateral facial paralysis**
73
Pneumonyssoides
Pneumonyssoides caninum
Arthropods→Arachnids→Mesostigmata→Pneumonyssoides
These mites affect:
- **mite of nasal and paranasal sinuses of dogs**
symptoms do they cause:
- **chronic sneezing and epistaxis**
74
Varroa
Varroa destructor
Arthropods→Arachnids→Mesostigmata→Varroa
- large, dark red, ovoid mites
- suck hemolymph from adults and brood larvae
- who do these mites affect?
- **parasite of honeybees**
- **results in a huge losses of bees**
75
Astigmata
Arthropods→Arachnids→Astigmata
- identifiable traits:
- **lack stigmata** (no respiration pore)
- respiration through integument
- tarsi have pretarsi with:
- **pedicel** (stalk)
- **caruncle** (sucker)
76
which Astigmata have long, unsegmented pedicel? [3]
Sarcoptes, Notoedres, Knemidokoptes
77
which Astigmata have long, three segments pedicel? [1]
Psoroptes
78
which Astigmata have short pedicel? [2]
Chorioptes, Otodectes
79
Sarcoptes
Arthropods→Arachnids→Astigmata→Sarcoptidae→Sarcoptes
- their identifiable traits:
- **long, unsegmented pedicels**
- **anus on posterior edge of body**
- spines look like *triangles*
- infect hosts by:
- **burrow in tunnels under epidermis**
- symptoms do they cause:
- **intense pruitus, papules, erythema, crusts, and excorations develop**
- **progresses to hyperkeratosis**
80
Notoedres
Arthropods→Arachnids→Astigmata→Sarcoptidae→Notoedres
- identifiable traits:
- **long, unsegmented pedicels**
- **anus on *dorsal* surface of body**
- spines look like fish scales
- cause mange in cats, rats, rabbits, and sometimes humans
- this mange occur first in cats on...
- **starts of pinnae**, then spread to face, paws, and hindquarters
81
Knemidokoptes mutans
Arthropods→Arachnids→Astigmata→Knemidocoptidae→Knemidokoptes mutans
- They cause:
- **“scaly leg” in chickens, turkeys, and phesants**
- mites burrow in epidermis and cause scales to lift and become loosened
82
Knemidokoptes gallinae
Arthropods→Arachnids→Astigmata→Knemidocoptidae→Knemidokoptes gallinae
- depluming mites of chickens, pigeons, and geese
- They cause:
- **intense pruritus leads to feather pulling**
83
Psoroptes
Arthropods→Arachnids→Astigmata→Psoroptidae→Psoroptes
- identifiable traits:
- long legs, long pretarsi with **three segments**
84
Psoroptes ovis
Arthropods→Arachnids→Astigmata→Psoroptidae→Psoroptes
- causes scabies in cattle, sheep, and horses
- leads to:
- **intense pruritus with scabs, wool loss**
- **reportable disease**
- pierces skin surface at base of hairs to *feed on serum*
85
Psoroptes cuniculi
Arthropods→Arachnids→Astigmata→Psoroptidae→Psoroptes
- they cause:
- **ear canker in rabbits**
86
Chorioptes
Chorioptes bovis
Arthropods→Arachnids→Astigmata→Psoroptidae→Chorioptes
- **short pretarsi with unsegmented pedicels**
- males have turret-like lobes on posterior margin of body
- there are found:
- **commonly distributed on tail, escutcheon, and legs of cattle**
- also on tail/legs of sheep, horses, and goats
- **typically occur in late winter as mild pruritus**
87
Otodectes
Otodectes cynotis
Arthropods→Arachnids→Astigmata→Psoroptidae→Otodectes
- their identifiable traits:
- **short, unsegmented pedicels**
- nfests external ear canal, and adjacent skin of dogs
- symptoms they cause:
- intense irritation
- **dark cerumen (waxy debris) and tan flaky material in ear canal**
- **this leads to head shaking that can cause aural hematomas (rupture blood vessels)**
88
Prostigmata
Arthropods→Arachnids→Prostigmata
- stigmata anterior (in front) of first pair of legs
- includes free-living species and obligate parasites
89
Demodex
Arthropods→Arachnids→Prostigmata→Demodex
- tiny, worm like mites
- short stubby legs
- **live on skin, and in hair follicles and sebaceous glands of mammals**
90
Demodex canis
Arthropods→Arachnids→Prostigmata→Demodex
- acquired by puppies while nursing
- mange occurs:
- **3-6 months of age**
- symptoms causes:
- **erythema (red skin) and alopecia around eyes, mouth, and bony projection**
- **nonpruritic** - not itchy just hair loss
- typically, self-limiting and heal on own
- BUT, **cases that persist become generalized (entire body), may prove to be fatal**
91
Demodex injai
Arthropods→Arachnids→Prostigmata→Demodex
- twice the length of D. canis
- they live:
- **sebaceous glands**
- disrupt sebum production
- causing seborrheic dermatitis
92
Demodex cornei
Arthropods→Arachnids→Prostigmata→Demodex
- shorter and stouter than D. canis
- they live in:
- **stratum corneum**
93
Demodex gatoi
Arthropods→Arachnids→Prostigmata→Demodex
- shorter than D. cati
- associated with stratum corneum
- what is special about the **transmission**?
- **disease is transmissible between cats**
94
Demodex bovis
Arthropods→Arachnids→Prostigmata→Demodex
- this causes:
- **nodules on neck, eyelids, vulva, scrotum and forequarters in cattle**
95
Cheyletiella
Arthropods→Arachnids→Prostigmata→Cheyletiella
- identifiable trait:
- large papal claws
- *Cheyletiella yasguri*
- dogs
- this causes:
- **puppies develop dermatitis with exfoliative debris**
- *Cheyletiella blakei*
- cats
- *Cheyletiella parasitivorax*
- rabbits
96
Trombiculids
(chiggers)
Arthropods→Arachnids→Prostigmata→Trombiculids
- identifiable trait:
- **bright red/orange larvae**
- **larvae are parasitic (6 legs)**
- nymphs and adults free-living
- found on dogs, cats, sheep, and chickens
- remain on skin for several days
- they feed by:
- **inject saliva into skin, disintegrating (melt) host cells and suck with straw**
- this will cause:
- **intense pruritus, can persist after mite removal**
97
Pentastomids
(tongue worms)
Arthropods→Crustacea→Pentastomids
- specialized crustaceans
- adults live:
- **in respiratory passages of reptiles, birds, and mammals**
- usually snakes
- annulated body, 1 stoma with 4 retractable hooks
98
how does pentastomids life cycle work?
- **eggs ingested by intermediate hosts → develop into nymphs in host body**
- intermediate host = anything ingested by reptiles
- **nymphs in host tissues ingested by predators → mature to adults**
99
Linguatula
Arthropods→Crustacea→Pentastomids→Linguatula
- **live as adults in nasal and paranasal sinuses of dogs and cats**
- to be infected need to eat raw meat of intermediate host
- the intermediate hosts:
- **cattle, sheep, and rabbits**
- nymphs encysted in lymph nodes and serous membranes
- they cause:
- **nasal bleeding and inflammation**
