Parasitology 14-21: Arthropods
1. What is a discal cell? 2. Discal cells are ONLY found in what suborder of Diperta flies?
1. A space between branched veins that forms a hexagonal or pentagonal box, which 3 veins emerging from the discal cell to reach the margin 2. Brachycera (large flies)
You have two ticks of the same genus but from different species. Both ticks have the following characteristics: -Banded legs -Presence of festoons -Long and slender mouthparts -Rectangular basis capituli Both ticks have an ornate scutum, but tick A has a single white/yellowish mark of color, and tick B has multiple colors throughout the scutum (green, yellow, orange, etc.) 1. Identify tick A and tick B 2. Which one is a problem in the US?
1. A: Amblyomma americanum; B: Amblyomma variegatum 2. A. americanum
1. Infestation by mites is termed ____________. 2. Severe dermatitis caused by mites is termed ________.
1. Acariasis 2. Mange
1. The lone star is the common name for what Ixodid species? What gives it its name? 2. What type of life cycle does this tick have? 3. What types of hosts does it infest? 4. This tick is a vector for what four pathogens?
1. Amblyomma americanum. Named the lone star because it has a single white/yellowish spot on its scutum 2. 3 host 3. Cattle (+ wild and domestic animals) 4. Rickettsia rickettsii, Francisella tularensis, Borrelia burgdorferi, and Ehrlichia
1. What two genera of Ixodid ticks have highly ornate scuta? 2. How can you tell these two apart?
1. Amblyomma and Dermacentor 2. By the mouthparts! Amblyomma has long and slender mouthparts, whereas Dermacentor has short mouthparts.
There are two suborders of the order Phthiraptera (lice) that are classified by feeding mechanism: 1. ___________ contains lice that pierce and suck. This includes Haematopinus, Linognathus, Solenoptes, Pediculus, and Pthirus. This suborder infests (mammals/birds/both). 2. __________ contains lice that bite and chew. It is further divided into two groups: ____________, which contains Damalinia, Felicola, and Trichodectes, and __________, which contains Menopon and Menacanthus. This suborder infests (mammals/birds/both).
1. Anoplura, mammals 2. Mallophaga, Ischocera, Amblycera, both
General life cycle of mites: 1. Mites (are/are not) obligatory parasites. 2. All stages occur on the ________. 3. Transmission is by _________. 4. The life cycle may be completed in 4 weeks or as soon as 8 days. There can be up to __(#)__ nymphal stages.
1. Are 2. Host 3. Contact 4. Three
Match the Argasid (soft tick) species with the following descriptions. 1. Birds 2. Cattle, humans 3. Non-parasitic adults 4. May cause tick toxicosis 5. Inflammation and waxy exudation from ears 6. Vector of Borrelia anserina 7. Feeding of larvae and nymph can cause anemia 8. One-host tick
1. Argas pesicus 2. Ornithodoros coraceus 3. Otobius megnini 4. Ornithodoros coriaceus 5. Otobius megnini 6. Argas pesicus 7. Otobius megnini 8. Otobius megnini
Name the species associated with the common names: 1. Fowl tick 2. Spinose ear tick 3. Pajaroello tick
1. Argas pesicus 2. Otobius megnini 3. Ornithodoros coraceus
There are two major groups/families of ticks. 1. __________ are considered soft ticks because they lack a scutum. 2. ___________ are considered hard ticks because they have a scutum.
1. Argasidae 2. Ixodidae
1. What is the pattern of progression of tick paralysis? 2. How do we treat tick paralysis?
1. Begins in the rear and spreads cranially. (Can be fatal if diaphragm/intercostals are reached) 2. No treatment necessary. Removal of the tick can reverse tick paralysis.
What are 4 general characteristics of arthropods?
1. Bilateral symmetry 2. Elongate segmented body (besides the head) 3. Paired and jointed appendages 4. Hard chitinous exoskeleton
1. What is flea dirt? 2. How does it contribute to the flea life cycle? 3. What type of life cycle do fleas have?
1. Blood-rich feces of adult fleas 2. Larvae feed on flea dirt (are coprophagic) 3. Holometabolous (complete)
1. Which pathogen(s) are transmitted from Dermanyssus gallinae? 2. Which pathogen(s) are transmissted from Ornithonyssus sylviarum?
1. Borrelia anserina 2. Fowlpox, Newcastle Disease, St. Louis encephalitis, and Chlamydia
1. If a mite has short legs, you know it is a (burrowing/non-burrowing mite). 2. If a mite has long legs, you know it is a (burrowing/non-burrowing) mite.
1. Burrowing 2. Non-burrowing
1. What three families of Diptera are causative agents of myiasis? 2. These families are all in what suborder?
1. Calliphoridae, Sarcophagidae, Oestridae 2. Cyclorrhapha
1. What genus is the agent of walking dandruff? 2. What gives walking dandruff its name?
1. Cheyletiella 2. Cheyletiella is a fur mite that causes skin cells to shed on the fur. Mites move between these scales and are large enough to carry them, so skin flakes can be seen moving when observing the skin, hence "walking dandruff."
Who am I? 1. This fur mite commonly affects the face of cats and causes walking dandruff, a condition that gives dandruff a "walking" appearance due to high mobility of adult mites crawling beneath skin flakes. 2. This fur mite is found in rabbits and is predaceous on other mites in the fur. If prey is absent, these mites may bite the rabbit's skin. They also may persist in the environment for long periods of time.
1. Cheyletiella blackei 2. Cheyletiella parastivorax
Ovipositing females are attracted to open wounds and sores, genital openings, and head orifices. Larvae penetrate tissues and feed in head-down position with spiracles open to the air. Also known as primary blue flies. 1. Who am I? 2. What type of myiasis is it?
1. Chliomyia hominivorax 2. Obligatory traumatic myiasis
Chorioptes bovis appears similarly to Psoroptes. 1. What is the major difference between the two? 2. How does this difference account for the difference in pathogenicity between the two?
1. Chorioptes has short mouthparts, whereas Psoroptes has pointed mouthparts. 2. Short mouthparts cause less damage than pointed mouthparts, so Chorioptes is much less pathogenic than Psoroptes.
Commonly known as the Tumbu fly. Host picks up eggs in the environment, and contact with skin induces hatching. Larvae penetrate the skin, creating a small pocket to allow for breathing. Coating with petroleum jelly induces the larvae to exit the pockets. 1. Who am I? 2. What type of myiasis is it?
1. Cordylobia anthropophaga 2. Obligatory cutaneous myiasis
1. Mosquitos are members of the _________ family. 2. There are three important genera in this family: _________, _________, and __________. 3. They are (diurnal/nocturnal). 4. Only _________ are parasitic. 5. Females lay eggs in or around __________. 6. ________ and ________ stages are aquatic. They attach to the water surface and use a structure called a ________ to breathe.
1. Culicidae 2. Anopheles, Aedes, Culex 3. Nocturnal 4. Females 5. Stagnated water bodies 6. Larval, pupal, trumpet
-Cattle chewing louse -Very common -Prefer top of head, shoulders, neck, back, and rump -Feed on hair shafts, dermal scales, and blood scabs -Cattle rub and scratch, leading to alopecia 1. Who am I? 2. Ischnocera or Amblycera? 3. How many claws do I have on each leg?
1. Damalina bovis 2. Ischnocera 3. One (bc it infests mammals)
What are two ways myiatic flies are classified?
1. Degree of dependency on vertebrate host (facultative vs obligatory) 2. Location or mode of invasion (enteric, urogenital, traumatic, cutaneous, nasopharyngeal)
1. What is the easiest way to distinguish a Demodex infection from a Sarcoptes infection? 2. What features of each life cycle account for this difference?
1. Demodex does not cause pruritus, whereas Sarcoptes causes severe pruritus. 2. Demodex and Sarcoptes are both burrowing mites. However, Demodex burrows into hair follicles and sebaceous glands, which does not result in a severe host response, whereas Sarcoptes burrows into the epidermis, creating a robust host response that results in severe pruritus.
Match the Argasid (soft tick) species with the following descriptions. 1. Nymphs are roughly octagonal and have spines 2. Surface is very leathery, and sometimes the mouthpart projects slightly forward 3. Adults are rounded posteriorly and slightly taper anteriorly 4. Adults have well-defined margins and are dorsoventrally flattened
1. Otobius megnini 2. Ornithodoros coriaceus 3. Otobius megnini 4. Argas pesicus
Arthropod reproductive system: 1. Females have __________, which are linked by an __________ to an ____________. 2. The female tract has _____________, in which stored sperm may remain viable for long periods. 3. Males have ____________, which are linked by sperm tubes to a _________ and ______________. 4. The sperm is enclosed in a packet of secretion called a ___________.
1. Paired ovaries, oviduct, ovipositor 2. Spermatheca 3. Paired testes, vas deferens, external genitalia 4. Spermatophore
Mites can be classified into burrowing vs non-burrowing. The burrowing mites consist of two families: 1. The first family is __________, which contains three genera. These three genera are _________, __________, and _________. 2. The other family is _________. It only contains one genus, which is _________.
1. Sarcoptidae: Sarcoptes, Notoedres, Knemidocoptes 2. Demodicidae: Demodex (So Nice to Knit Daily)
This condition caused by mites that burrow into the skin of legs and shanks of domestic fowl and deposit eggs. It is characterized by lifting of the scales, swelling of the underlying tissue, and encrustation with dry serous exudate. 1. What is the name of the disease? 2. What is the species of mite that causes it?
1. Scaly leg disease 2. Knemidocoptes mutans
Name 5 structures that are useful for identification of Ixodid species.
1. Scutum: ornate vs inornate 2. Mouthpart: short, long and slender, or arrowhead shape 3. Festoons: presence vs absence 4. Legs: banded vs non-banded 5. Basis capituli: hexagonal vs rectangular
1. What family contains flies commonly known as "black flies" or "buffalo gnats"? 2. Where do these names come from?
1. Simuliidae (Simulium sp.) 2. Black flies because they are black. Buffalo gnats because their mesothorax is humped, giving a "buffalo" appearance.
Sarcoptes life cycle: 1. Where does mating occur? 2. Where do females lay eggs?
1. Skin surface 2. Burrows in the epidermis
Describe the kinetics of Ixodid (hard tick) feeding and engorgement.
1. Slow engorgement phase: establishment at bite site (cement), salivation, and growth of new tissues 2. Pathogen transmission ~2d 3. Rapid engorgement: "The Big Sip;" exponential increase in blood ingestion after ~5-6d of slow engorgement
1. How is Otodectes cynotis most likely acquired? 2. Animals may be asymptomatic but they may also have severe otitis. What is most commonly observed in symptomatic animals?
1. Suckling 2. Brown waxy exudate in the ears ("coffee grounds")
There are three major genera of the Tabanidae family of the Brachycera suborder: 1. ________: horse fly with 4 antennal rings and clear wings 2. _________: deer fly with 5 antennal rings and mottled wings 3. ________: deer/mango fly with 4 antennal rings and dark banded colored wings
1. Tabanus 2. Haematopota 3. Chrysops
1. What is the most important reason for why we study ticks? 2. What is the most important reason for why we study mites?
1. They are vectors for a number of important pathogens. 2. For the amount of dermatitis and tissue damage they cause
Name the three routes of disease transmission in Ixodid ticks.
1. Transovarial (vertical) 2. Transstadial 3. Ingestion (Hepalozoon canis)
-Dog chewing louse -Can be harmful to dogs, especially puppies and debilitated dogs -Feeds on tissue debris -Causes intense pruritus, sleeplessness, nervousness, and matted coat 1. Who am I? 2. Ischnocera or Amblycera? 3. How many claws do I have on each leg? 4. What pathogen do I transmit?
1. Trichodectes canis 2. Ischnocera 3. One (bc it infests mammals) 4. Diplydium caninum
Name the species of lice that transmits each pathogen: 1. Diplydium caninum 2. Rickettsia prowazeki (epidemic typhus) 3. Eperythrozoon suis 4. Borrelia recurrentis (epidemic relapsing fever)
1. Trichodectes canis 2. Pediculus humanus 3. Haematopinus suis 4. Pediculus humanus
1. _________ is commonly known as jiggers/chiggers/Chigoe fleas. 2. It infests _______ and ________. 3. Reservoir hosts include many other ________. 4. They lack _________ and have a ________ head. 5. Mating occurs on the ___________. After fertilization, females burrow into the ______ and form a pocket. 6. Once females are __________, they cause serious pain, inflammation, itching, and ulceration. 7. Secondary infections can cause _______ or _________.
1. Tunga penetrans 2. Humans, pigs 3. Mammals 4. Ctenidae, truncated 5. Skin surface, skin 6. Engorged 7. Tetanus, gangrene
1. Ticks (are/are not) obligate parasites, meaning they must have a host in order to survive. 2. Ticks are _______ feeders. 3. Ticks (are/are not) host-specific.
1. are 2. blood 3. are not (host preference but not host specific)
General morphology of mites: 1. Gas exchange may be via ___________ or __________. 2. Body consists of an anterior, mouthpart-bearing __________ and a sac-like body that bears legs and genitalia. 3. Mouthparts are suited strictly for ______ feeding. They consist of three parts: __________, ____________, and _________. 4. The legs have a segment not seen in Hexapoda: the __________. 5. The legs have a distal ________. 6. It consists of two parts: ___________ (stalk) and _________ (sucker), which may also bear the terminal claws.
1. integument, stigmata 2. capitulum 3. fluid, hypostome (medial), chelicerae, palps 4. patella 5. pre-tarsus 6. pedicel, caruncle
1. Most Dermacentor species are _____-host ticks, such as D. andersoni, D. variabilis, and D. reticulatus. 2. Some are _____-host ticks, such as D. nitens and D. albipictus. 3. Immature stages feed on ________ and __________. 4. Adults feed on _______ and __________. 5. Can cause tick paralysis. 6. Common in areas with ___________.
1. three 2. one 3. rodents, small mammals 4. large animals, humans 6. scrubby vegetation
1. Describe the two strategies used by Ixodid ticks to detect and attach to hosts. 2. How can these ticks sense the presence of a host?
1a. Hunting: some species lurk near places where hosts may rest, and upon stimulus, they actively pursue the host 1b. Ambush: many tick species cling to leaves or grasses and wait for a host to pass by, an act called questing 2. Haller's organ allows ticks to determine the presence of hosts through breath, pheromones, body heat, moisture, CO2 changes, and/or vibrations
What is the difference between acariasis and mange?
Acariasis describes a general infestation by mites, whereas mange refers to severe dermatitis caused by mite infestation.
Insects of holometabolous (complete) life cycles have larvae with different feeding habits/mechanisms from adults. What are these differences?
Adults suck fluid, and larvae use mandibles to ingest particles.
What is the difference between female Ixodids (hard ticks) and Argasids (soft ticks) after they lay eggs?
After engorgement, Ixodids lay their eggs and die, whereas Argasids feed, lay their eggs in the environment (cracks and crevices), and then can return to a host to feed again.
Insects have two types of life cycles. What is the major difference between the two?
All life stages of heterometabolous (incomplete) life cycles (larvae, nymph, and adult) are morphologically similar, whereas the larvae, nymph, and adult stages of holometabolous (complete) life cycles are morphologically different.
The "Gulf Coast Tick" is a serious pest of cattle. What is the scientific name for this tick?
Amblyomma maculatum
What is IPM (integrated pest management), and what is the goal of IPM?
An ecosystem-based approach to handling pests. The goal is not to completely eradicate but to keep populations low enough not to cause problems. Can include physical/chemical barriers, environmental manipulation, biological measures, or chemical pesticides.
Name this Argasid (soft tick) species! -Typical lair ectoparasite -Nocturnal: hides in protected areas during the day and attacks hosts at night -Vector of avian Borrelia anserina -Well-defined margins, dorsoventrally flattened
Argas pesicus (The fowl tick)
Who has this kind of life cycle? -Adults feed repeatedly and mate outside of the host -Females lay up to 500 eggs in cracks and crevices after each blood meal -They live in host's proximity, which makes repeated feeding possible
Argasids (soft ticks)
Name the genus! -The Blue Tick -One-host tick -Infests all mammals and birds, but mainly infests cattle -Vectors of Babesia bovis, Texas Cattle Fever, or bovine piroplasmosis (+ a range of other pathogens) -Range once covered the Southern US and Mexico, but is now eradicated from the Southern US (Was a separate genus but now classified as Rhipicephalus)
Boophilus
Name the genus! -No bands on legs -Short palps -Inornate scutum -Hexagonal basis capituli -No festoons
Boophilus (Hexagonal basis capituli + NO festoons = Boophilus)
Argas pesicus is a vector for what avian pathogen?
Borrelia anserina
What is the main advantage of burrowing for Sarcoptes species?
Burrowing creates a high inflammatory response in the host skin, which releases fluids that the mites are able to feed on.
Arachnids do not have a true head. What do they have instead?
Cephalothorax: fused head and thorax
Name the family of Diptera! -Very small (1.5-5mm), "no-see-ums" -Immature stages are aquatic or semiaquatic → found in mud, moist soil, or decaying plant litter -Humped thorax and mottled wings -Hypersensitivity reactions can occur with bites and cause intense pruritus
Ceratopogonidae (Culicoides spp., biting midges or sun flies, Nematocera suborder)
Name the genus! -Chelicerae is blade-like and used for cutting -Palps bear claws -Body is slightly elongated and has a "waist" that appears like a shield or hourglass -Pedicels are comb-like -Adults are highly mobile
Cheyletiella (Shield-shape and palps with claws = Cheyletiella, Highly mobile adults = walking dandruff)
1. Who am I? -Non-burrowing mite -Produces mange restricted to certain parts of the body, such as feet, tail or neck, hooves, and lower hind limbs in cattle and horses -Short mouthparts
Chorioptes bovis
Who am I? -Infest dogs and cats -Has eyes, pronotal and genal combs, and a rounded head -Causes flea bite allergic dermatitis -Transmits Diplydium caninum, Rickettsia typhi (murine typhus), and Bartonella henselae (cat scratch disease)
Ctenocephalus (C. canis in dogs and C. cati in cats)
Simulium spp. (Simuliidae) and Culicoides spp. (Ceratopogonidae) both have humped thoraces. How can you tell the difference between the two?
Culicoides have mottled wings and are much smaller than Simulium.
Agent of obligate cutaneous myiasis in small mammals. Causes formation of large dermal tumors
Cuterebra
Name the genus! (Hint: I'm a mite) -Elongated, cigar-shaped body -Short, stumpy legs on anterior body -Striations on the abdomen
Demodex (Cigar-shaped body = Demodex)
Name the genus! -Banded legs -Short mouthparts -Rectangular basis capituli -Highly ornate scutum -Presence of festoons
Dermacentor (Highly ornate scutum + short mouthparts = Dermacentor)
Who am I? -American Dog Tick -Common pest of dogs and readily attacks humans -Vector of Ehrlichia chaffensis, Rickettsia rickettsii, Borrelia burgdorferi, and Francisella tularensis -Peaks of larval and adult activity may occur in spring and late summer
Dermacentor variabilis
This family of non-burrowing mites consists of large mites with long legs and a grey-white body that becomes red or black when engorged. They feed on the blood of birds but readily leave the host to attack other mammals, such as humans.
Dermanyssidae (Dermanyssus and Ornithonyssus)
Who am I? -Classic lair ectoparasite: spend most of the time away from hosts, with adults and nymphs returning to feed at night and hide in cracks and crevices during the day -Highly resistant to starvation -Bites cause severe anemia and irritation, leading to decreased egg production, increased susceptibility to disease, and exsanguination in hatchlings -Can transmit Borrelia anserina -Commonly known as the Red or Chicken Mite and is the most common mite of poultry
Dermanyssus gallinae
What is the most common mite of poultry?
Dermanyssus gallinae (Red or Chicken Mite)
What type of environment do Argasids (soft ticks) live in?
Deserts and dry conditions (remember, resistant to desiccation)
Members of the order _________ are involved in transmission of more disease agents of man and animals than any other group of arthropods.
Diptera
________ and some ________ are groups of arthropods with wings. No other groups have wings!
Diptera (flies), Hemiptera (bugs)
Who am I? -Stick tight flea of birds, important mainly for domestic poultry -Lack pronotal and genal combs (no ctenidae) -Has eyes -Head is truncated anteriorly -Females aggregate on bare areas, such as head, combs, wattles. After feeding, they burrow into the skin and remain for 2-6 weeks. -Clinical signs include ulceration with secondary bacterial infection, anemia, reduced growth, and poor egg production
Echidnophaga gallinacea
This tick is the Western counterpart to Ixodes scapularis and is a vector of Borrelia burgdorferi. It also can cause tick paralysis (ascending flaccid paralysis caused by toxins in the saliva). Who is it?
Ixodes pacificus
What genus is the burrowing mite of birds?
Knemidocoptes
Which stage of Argas pesicus is attached to the host the longest?
Larvae (5 days, nymphs and adults feed for brief periods, females engorge within 45 min)
Which stages of Otobius megnini are parasitic?
Larvae and nymphs ONLY (NOT adults!)
What types of pathogens are transmitted by Phlebotomus spp. (Psychodidae)?
Leishmania (protozoa) and Bartonella bacilliformes (bacterial agent of Carrion's disease in humans)
Unlike fleas, environmental/habitat fumigation against lice is usually not required. Why?
Lice spend their entire life cycles on the host. They only leave the host if they must seek out a new host or if the host's temperature drops too low. Lice don't survive well in the environment, so fumigation is unnecessary. The best method for control is to treat the animal.
How can you tell whether a louse infests birds or mammals just by looking at it?
Lice that infest mammals have one tarsal claw on each leg, whereas lice that infest birds have two tarsal claws on each leg.
What types of pathogens are transmitted by Culicoides spp. (Ceratopogonidae)?
Onchocerca, Leucocytozoon, Haemoproteus, Hepatocystis, and many arboviruses
A single flea bite of Ctenocephalus can cause flea bite allergic dermatitis. Why is the body so sensitive to the bite?
Oral secretions are released during the bite, causing a robust inflammatory response that is really itchy.
Vector of African Swine Fever
Ornithodoros porcinus
Vector of spirochete agent of relapsing fever, Borrelia recurrentis
Ornithodoros turicata
Who am I? -Northern fowl mite -Spend entire life on the host -Predominantly found at the base of feathers, particularly around the vent with signs of feather matting and scabbing -Heavy infestations show greyish-black discoloration of the feathers, thickened and crusty skin, restlessness, and weight loss -Transmits fowlpox, Newcastle disease, St. Louis encephalitis, and chlamydiosis
Ornithonyssus sylviarum
Who am I? -Auricular mites of cats, dogs, ferrets, and foxes -Non-burrowing
Otodectes cynotis
Your patient is a puppy that presents with head-shaking and excoriation of the ears. You take a peek in the ears and notice a brown, waxy exudate that looks like coffee grounds. You swab the wax and observe a large number of mites. What species of mites are you most suspicious of?
Otodectes cynotis
Otodectes cynotis appears similarly to Psoroptes. What is the major difference between the two?
Otodectes has cup-shaped pedicels, whereas Psoroptes has funnel-shaped pedicels.
What is the difference between active and passive arthropod vectors?
Passive vectors transmit through contact and do not bite (ie housefly), whereas active vectors transmit through bites and exchange of fluids (ie mosquito).
Larvae of this Diptera species invade open wounds of sheep, cattle, and other domestic animals (+ humans) and feed on necrotic tissues. They secrete a bactericidal compound called allantoin. Because of this, they are used as surgical maggots.
Phaenia serratica (of Calliphoridae)
Name the genus! -No bands on legs -Short palps -Inornate scutum -Hexagonal basis capituli -Presence of festoons
Rhipicephalus (Hexagonal basis capituli + festoons = Rhipicephalus)
Which tick species is the most widely distributed tick in the world?
Rhipicephalus sanguineus
Microbio review! Who is the agent of Rocky Mountain Spotted fever, a common bacteria spread by many of the ticks we've learned about?
Rickettsia rickettsii
Who am I? -Rocky Mountain Wood Tick -Pests of large mammals, such as cattle, horses, and sheep -Commonly in brush or scrub vegetation in the Western US -Vector of Colorado Tick Fever virus to humans -Probably the most common agent of tick paralysis
Rocky Mountain Wood Tick
Name the genus! -Short mouthparts -No eyes or stigmata -Circular: flat ventrally and convex dorsally -Stubby legs: the 3rd and 4th pairs cannot be seen dorsally -Has many transverse striations/ridges -Has a patch of triangular scales -1st two pairs of pretarsi bear terminal suckers
Sarcoptes (Triangular scales = Sarcoptes!)
Your patient is a dog that presents with severe pruritus, erythema, and alopecia. The skin is thickened and crusty. The owner notes that the lesions first appeared on the head and hears but quickly spread to the rest of the body. You see beginning signs of infection in areas where the dog was scratching the most. You take a skin scrape and observe a microscopic organism with a patch of triangular scales. What is your diagnosis?
Sarcoptes scabei var. canis
Name the species! -Causes "black muzzle" of sheep -Condition is primarily on face -Wooly parts of animal are usually not affected
Sarcoptes scabei var. ovis
Who am I? -Has pronotal and genal combs -Has eyes -Can congregate in the ears of rabbits and can affect dogs and cats that hunt rabbits -Mouthparts embed in the skin of the host for long periods -Causes a lot of irritation and tissue damage -Transmits myxomatosis
Spilopsyllus cuniculi (rabbit flea)
Who am I? -4 longitudinal stripes on the thorax -Each abdominal segment contains 3 black dots -Feed on many hosts in rapid succession due to painful bites -Transmit Trypanosoma (mechanical), Habronemosis, Hymenolepis, anthrax, and Dermatophilosis -Larvae and pupal stages reside in stable habitat -Blood feeders
Stomoxys calcitrans
What species is commonly known as the stable fly? Where does this name come from?
Stomoxys calcitrans. Called stable fly because reproductive requirements are met in stable environments (where larvae and pupae reside)
Who am I? -Lack pronotal and genal combs (no ctenidae) -Has eyes -Rounded head anteriorly -Important vector for plague (Y. pestis) and murine typhus -Commonly known as Oriental Rat Flea
Xenopsylla cheopis
The study of arthropods
entomology
All life stages of Rhipicephalus sanguineus are found on dogs, usually ones that live outdoors (T/F).
false (All life stages are found on dogs, but usually it's indoor dogs!)
Only female adult fleas are parasitic (T/F).
false (Both sexes can feed on blood, but it is true that only adults are parasitic.)
Fleas are host-specific. Their species names come from the host they infest (T/F).
false (Fleas are NOT host-specific.)
Glossina is commonly known as the Tse Tse fly. Females deposit eggs into the skin of the host (T/F).
false (Glossina is larviparous, meaning it lays larvae, NOT EGGS. Eggs hatch in oviduct before being laid by the female)
Entomology is the study of insects (T/F).
false (Is the study of arthropods. Insects are just one class of arthropods, so entomology is the study of more than just insects.)
Female Sarcoptes mites create burrows in the epidermis, where they mate and lay eggs (T/F).
false (Mating occurs on the skin, and males remain on the skin surface for the entire life cycle. Only a single female enters the burrow and lays eggs.)
Female Notoedres mites create burrows in the epidermis to lay eggs. Only a single female occupies a burrow at a time (T/F).
false (Multiple females can occupy the burrow. Also, the burrows for Notoedres are called nests.)
Wings and six legs are defining characteristics of insects (T/F).
false (Not all insects have wings. Only diptera [flies] and some hemiptera [bugs] have wings.)
The genital aperture of ticks can be found on its unsegmented abdomen, just anterior to the anal opening (T/F).
false (The genital aperture is found on the "chest" of the tick, whereas the anal opening is located much more posteriorly).
Culicoides spp. are mosquitos and part of the Culicidae family (T/F).
false (They are biting midges/sun flies and are part of the Ceratopogonidae family)
Lice can withstand starvation and extreme temperatures, making them difficult to control (T/F).
false (they cannot withstand starvation or extreme temperatures)
What is the term for the circulatory fluid of arthropods?
hemolymph
Term for infestation of organs and tissues of vertebrates by larvae of Dipterans. Required for larval development in species that do it.
myiasis
Insects that lay larvae that feed on other insects. Can be used as a method of IPM (integrated pest management).
parasitoids
The ________ is a structure in arachnids that is an opening on the cuticle to the respiratory system. In insects, it is called a ________.
stigmata, spiracle
Female Sarcoptes mites create burrows in the epidermis to lay eggs. Only a single female occupies a burrow at a time (T/F).
true
Lice are largely host-specific (T/F).
true
Severe cases of Sarcoptes scabei infection can lead to anorexia, blindness, and hearing loss (T/F).
true
Ixodids (hard ticks) do not transfer to another host during the feeding process (T/F).
true (Ticks are cemented to the host skin)
Mites have nearly identical morphology to ticks (T/F).
true (but are much smaller!)
Fill in the blanks for the genus or species of mites that is controlled by each treatment: 1. Emulsion or suspension sprays of malathion, coumaphos, or rabon and carbaryl or Sevin (carbamate) to poultry houses 2. In cattle, responds to macrocyclic lactones (ie Ivermectin) 3. In dogs, sheep, goats, beef cattle, swine, and horses, responds to topical or parenteral macrocyclic lactones (ie Ivermectin) 4. Ear mites that respond to topical formulations of macrocyclic lactones (ie milbemycin oxime, selamectin, and moxidectin) 5. Effectively controlled by selamectin, moxidectin, and milbemycin
1. Dermanyssus gallinae 2. Chorioptes bovis 3. Sarcoptic mange (Sarcoptes) 4. Otodectes 5. Sarcoptes and Demodex
Arthropod body systems: 1. The circulatory system lies ________. 2. The nervous system lies _________. 3. Describe the two ways gas exchange can occur. 4. The integument is comprised of a __________, which is secreted by an underlying layer of ____________. 5. The excretory system is comprised of ____________ that are continuous with the hindgut lumen and removes nitrogenous wastes from hemolymph and void into hindgut.
1. Dorsal 2. Ventral 3. Through the cuticle (skin) or through the stigmata (in arachnids) or spiracle (insects) → trachea → tracheole → tissue cells 4. Multilayered cuticle, epidermis 5. Malpighian tubules
Things about lice (Phthiraptera): 1. Lice are wingless and __________ flattened ectoparasites. 2. Their legs contain __________ that are adapted for grasping hair. 3. Their eggs are called _________, and they are whitish, grossly visible, and glued to the shafts of hair or feathers. 4. They have mouthparts adapted for sucking (aka ________ mouthparts) or chewing (aka ________ mouthparts). 5. Heavy lice infestation is called __________.
1. Dorsoventrally 2. Tarsal claws 3. Nits 4. Haustellate, mandibulate 5. Pediculosis
1. Where do Simuliidae flies lay eggs? Why do they lay their eggs here? 2. Where do immature stages reside? 3. What types of pathogens do they transmit?
1. Fast flowing water. Oxygen requirement is high for egg development. 2. Attached to rocks in flowing streams 3. Onchocerca, Plasmodium, Haemoproteus, Leucocytozoon, EEE
Describe the feeding habits of Argasids (soft ticks).
1. Feed rapidly 2. Short periods of attachment → each nymphal stage feeds on a different host and drops after a blood meal 3. Lair ectoparasites: mate in environment and lay eggs in cracks and crevices 4. Adults live in host proximity to allow for multiple repeated quick blood meals followed by hiding in the nest.
How do fleas transmit Yersinia pestis, agent of plague?
1. Flea takes blood meal and becomes infected with Y. pestis. 2. Y. pestis multiplies in the flea, leading to gut blockage. 3. The flea tries to continue sucking blood but instead regurgitates into the feeding lesion, transmitting Y. pestis to a new host.
Match each description to lice, fleas, or both: 1. Holometabolous (complete) life cycle 2. Host-specific 3. Spend entire life cycle on the host 4. Coprophagic larvae 5. Laterally compressed 6. Have ctenidae 7. Have haustellate mouthparts 8. Pediculosis 9. Transmits Diplydium caninum
1. Fleas 2. Lice 3. Lice 4. Fleas 5. Fleas 6. Fleas 7. Both (Adult fleas + Anoplura lice, haustellate mouthparts = pierce and suck) 8. Lice 9. Both (Ctenocephalus [flea] and Trichodectes canis [louse])
Give the common name for each of the following groups of arthropods: 1. Diptera 2. Siphonaptera 3. Phthiraptera 4. Hemiptera 5. Scorpionida 6. Araneida 7. Acarina
1. Flies 2. Fleas 3. Lice 4. Bugs 5. Scorpions 6. Spiders 7. Ticks and mites
1. Why are Tabanidae bites so painful? 2. How does this contribute to potency of pathogen transmission? 3. What types of pathogens do they transmit?
1. Flies cut skin rather than pierce it (scissor-like mouthparts) 2. Because bites are painful, this causes animals to flee when bitten, leading to interrupted feeding that requires feeding on many animals to be sustained. This is why Tabanidae is regarded as the most potent mechanical vector of any disease. 3. Trypanosoma, Loa loa, Pasteurella tularensis, Anthrax
1. Demodex predilection sites include _________ and __________. 2. Species are named after the species they infect. BUT, there are two exceptions: -D. folliculorum, which infects ________. -D. phylloides, which infects ________.
1. Follicles, sebaceous glands 2. Humans, pigs
Commonly known as "horse bots." Larvae are restricted to digestive tracts of equids. Females oviposit in hair on forelegs, nose, lower jaw, or grass. Eggs hatch, and larvae migrate to the mouth and penetrate mucous membranes to go to stomach. Prior to pupation, larvae release hold on stomach lining and pass in feces. Pupation and adult emergence occur on the ground. 1. Who am I? 2. What type of myiasis is it?
1. Gasterophilus 2. Obligatory enteric
Flea morphology: 1. Fleas contain combs or ctenidae. The _______ comb is located on the head, and the ______ comb is located on the dorsum of the prothorax. 2. The 3rd pair of legs are long and adapted for _______. 3. In adults, mouthparts are adapted for _________, and in larvae, they are adapted for _________. 4. ________ in the gut of larvae can be seen. 5. Fleas are ________ compressed.
1. Genal, pronotal 2. Flea jumping 3. Piercing, chewing 4. Blood 5. Laterally
1. ___________ is commonly known as the short-nosed louse. 2. __________ affects pigs and transmits Eperythrozoon suis. 3. Its brownish color and abdominal spines makes it easy to identify. 4. It is part of the ___________ suborder. This means it infests (mammals/birds/both).
1. Haematopinus 2. Haematopinus suis 4. Anoplura, mammals
What three pathogens cause avian malaria?
1. Haemoproteus 2. Leucocytozoon sp. 3. Plasmodium spp.
Life cycle of Demodex: 1. All feeding stages inhabit _________ and __________. 2. Here, mites reside in a ______ posture. Females also lay eggs here. 3. Transmission is through ____________. 4. The life cycle occurs in 18-24 days.
1. Hair follicles, sebaceous glands 2. Head-downward 3. Prolonged contact (ie suckling, mating)
Morphology of Diptera ("True Flies") 1. Have two pairs of wings, one of which is recessed to form ____________ that are used for _________. 2. Has two eyes that are _____________ (not true eyes). 3. The ______ is the space between the two eyes. 4. The _______ arises from the 3rd antennal segment and contains shorthairs that can be used for sex identification. 5. The mouthpart is named the ___________ and contains a rostrum, a ____________ (sucking organ), and a labellum.
1. Halters, balance 2. Photosensitive 3. Frons 4. Arista 5. Proboscis, haustellum
Contrast hard ticks (Ixodidae) vs soft ticks (Argasidae) in the following characteristics: 1. Scutum 2. Sexual dimorphism 3. Placement of capitulum 4. Life cycle stages and number of hosts to feed on 5. Resistance to starvation and death. 6. Mating location
1. Hard ticks have a scutum, whereas soft ticks do not. 2. Hard ticks are sexually dimorphic, whereas soft ticks are not. 3. Hard ticks have anteriorly extended mouthparts, whereas soft ticks have ventrally recessed mouthparts. 4. Hard ticks have only one nymphal stage and feed on up to 3 hosts slowly, whereas soft ticks have up to 7 nymphal stages and feed on multiple hosts rapidly (one per nymphal stage). 5. Hard ticks are relatively susceptible to death, whereas soft ticks can survive without years for feeding and are resistant to desiccation. 6. Hard ticks mate on the host, whereas soft ticks mate in the environment (cracks and crevices).
What are the three parts of the insect body? What does each part contain?
1. Head: mouthparts, eyes, antennae 2. Thorax: 3 segments (pro-, meso-, and meta- thorax), 3 pairs of jointed legs, +/- wings 3. Abdomen: multisegmented, genitalia, excretory organs
1. The long-horned tick, or bush tick, is the common name for what Ixodid species? 2. What type of life cycle does this tick have? 3. What types of hosts does it infest? 4. This tick is a vector for what six pathogens?
1. Hemaphysalis longicornis 2. 3 host 3. Mammals and birds 4. Babesia, Ehrlichia, Viruses, Borrelia burgdorferi, Anaplasma, Theileria
1. Acarines have a __________ life cycle. 2. Life stages are punctuated by ___________. 3. What is the major difference between larvae and nymphs?
1. Heterometabolous (incomplete) 2. Blood feedings 3. Larvae have 6 legs, whereas nymphs have 8 legs.
Choose whether each description is for heterometabolous (incomplete) or holometabolous (complete) insect life cycles. 1. Same habitats and feeding habits as adults 2. Adults look different from larvae 3. Larvae live in different habitats than adults 4. All of the life cycle occurs on the host
1. Heterometabolous (incomplete) 2. Holometabolous (complete) 3. Holometabolous (complete) 4. Heterometabolous (incomplete)
There are two major classes of arthropods with significant veterinary importance: 1. ________: includes Diptera (flies), Siphonaptera (fleas), Phthiraptera (lice), and Hemiaptera (bugs) 2. _________: includes Scorpionida (scorpions), Araneida (spiders), and Acarina (ticks and mites) Others with not so much veterinary importance: 3. Chilopoda: aka ______________ (can inject venom) 4. Diplopoda: aka ____________ (secrete toxins that can cause irritation) 5. Crustacea: crustaceans; Of veterinary importance because they _____________.
1. Hexopoda/insecta 2. Arachnida 3. Centipedes 4. Millipedes 5. Can serve as intermediate hosts for some parasites
Why are arthropods highly successful and widely distributed? (List 3 reasons.)
1. High reproductive capacity 2. Any habitat works (genetic plasticity) 3. Numerous hosts to feed on
1. _________ is a family in the suborder Cyclorrhapha of Diptera flies that consists of louse flies and sheep keds. They are non-blood feeders. 2. These flies are _________, meaning eggs hatch and develop to the 3rd stage inside of the female before being laid. 3. ___________ is commonly known as the sheep ked. Females take blood, and in heavy infestations, sheep will scratch and bite wool, giving an emaciated or "unthrifty" appearance.
1. Hippoboscidae 2. Pupiparous 3. Melophagus ovinus
Commonly known as the warble fly. Larvae burrow under the skin and create a warble. Bee-like appearance. 1. Who am I? 2. What type of myiasis is it?
1. Hypoderma (H. bovis and H. lineatum) 2. Obligatory cutaneous myiasis
The Mallophaga suborder is further divided into two groups, based on antennae morphology: 1. ___________: antennae extend laterally from the head 2. ___________: antennae are recessed into grooves in the head 3. Both cut skin with the ________, causing bleeding. 4. They are part of the Mallophaga suborder, meaning they infest (mammals, birds, both).
1. Ischnocera (pictured) 2. Amblycera 3. Mandibles 4. Both
1. The deer tick is the common name for what Ixodid species? 2. What type of life cycle does this tick have? 3. What types of hosts does it infest? 4. This tick is a vector for what three pathogens?
1. Ixodes scapularis 2. 3 host (larvae: rodents, nymph: larger animals, adults: primarily deer) 3. All mammals and birds 4. Borrelia burgdorferi, Babesia spp., Ehrlichia spp.
Knemidocoptes appears similarly to both Sarcoptes and Notoedres. 1. How can you tell Knemidocoptes from Sarcoptes? 2. How can you tell Knemidocoptes from Notoedres?
1. Knemidocoptes lack triangular scales, and Sarcoptes has triangular scales (*unique feature of Sarcoptes) 2. If it's found in a skin scrape of birds, it's Knemidocoptes. If it's from a cat or rabbit (or other mammals), it's Notoedres.
Name the species that causes each disease: 1. Scaly leg disease in domestic fowl 2. Scaly face disease in parakeets 3. Depluming itch in poultry
1. Knemidocoptes mutans 2. Knemidocoptes pilae 3. Knemidocoptes gallinae (All are burrowing mites!)
1. How can you tell an Ixodid larvae from a nymph? 2. How can you tell a nymph from an adult?
1. Larvae have 3 pairs of legs, whereas nymphs have 4 pairs. 2. Nymphs do not have a genital opening, whereas adults do. If comparing a nymph to an adult male, nymphs only have a partial scutum (like females), whereas adult males have a completely covered scutum.
1. _________ is commonly known as the long-nosed louse. It can cause itching and alopecia. 2. _________ affects dogs. 3. _________ affects cattle. 4. It is part of the ___________ suborder. This means it infests (mammals/birds/both).
1. Linognathus 2. Linognathus setosus 3. Linognathus vituli 4. Anoplura, mammals
You have three dogs that are infected with Demodex. Based on their descriptions, name the type of infection it is and the prognosis of each. 1. Barky has slight alopecia in the face and paws, with slight thickening of the skin. The skin is dry and there is little erythema present. 2. Sparky has severe thickened, excoriated, and erythematous skin with small pustules all over that give a nasty smell. There is marked alopecia throughout his body. He is super red! 3. Ducky also has lesions spread all over his body, but the skin is crusty rather than pustular and not much erythema. However, the alopecia is also widespread, and the skin is thickened.
1. Localized. Early form. This infection is typically self-limiting, and lesions should resolve without further spread to the rest of the body. 2. Generalized: wet/purulent/follicular (aka RED MANGE). Sparky's condition is the most severe form and may be life-threatening. The pustules and erythema are evident of secondary bacterial infection. Euthanasia may be necessary. 3. Generalized: dry/squamous. Ducky's condition is less serious than the wet form but more so than the localized form.
1. How can you tell the difference between male and female Ixodids (hard ticks)? 2. What is the reason for this observed difference?
1. Males have a scutum that covers the entire dorsum, whereas females have a scutum that covers only the anterior half of the dorsum. 2. A partial dorsum allows the females to engorge more on blood, which allows them to produce high numbers of eggs.
-Chicken body louse -Found around the thigh, breast, and vent 1. Who am I? 2. Ischnocera or Amblycera? 3. How many claws do I have on each leg?
1. Menacanthus stramineus 2. Amblycera (infests birds, can't be ischno) 3. Two (bc it infests birds)
-Chicken feather shaft louse -Causes birds to pluck feathers 1. Who am I? 2. Ischnocera or Amblycera? 3. How many claws do I have on each leg?
1. Menopon gallinae 2. Amblycera (infests birds, can't be ischno) 3. Two (bc it infests birds)
Fleas can be categorized by their feeding habits: 1. Fleas that are ______________ include Ctenocephalides, Xenopsylla, Pulex, Spilopsyllus, and Ceratophyllus. 2. Fleas that have ___________ are also called "stick tight fleas" and include Echidnophaga. 3. Fleas that ____________ include Tunga.
1. Mobile on host skin 2. Long term attachment 3. Penetrate the skin
Choose the suborder of Diptera that matches the morphological description of the antennae: 1. 10-12 segments that can be either long and slender or round and short, with hairs between each segment 2. 3 segments, of which the 3rd segment (largest) bears 4-5 rings or undulations 3. 3 segments, of which the 3rd segment (largest) bears an arista
1. Nematocera (small flies) 2. Brachycera (large flies) 3. Cyclorrhapha (intermediate flies)
Choose the suborder of Diptera that matches the morphological description of the wing venation: 1. Minimal branching. Normally ~8 longitudinal veins, with 2 veins bifurcating before reaching the margin of the wing 2. Moderate branching. Longitudinal vein III branches and creates an angle that comes into contact with the angle created by longitudinal vein IV 3. Highly branched. A hexagon or pentagon box called a discal cell is present. 3 veins emerge from the discal cell and reach the margin
1. Nematocera (small) 2. Cyclorrhapha (medium) 3. Brachycera (large)
Diptera has three suborders: 1. ___________ are the small flies. It contains Culicidae (aka _________), Simuliidae (aka _______), Ceratopogonidae (aka __________), and Psychodidae (aka _______). 2. ___________ are the largest flies. It contains Tabanidae (aka _________ and __________). 3. __________ are the intermediate-sized flies. It contains Muscidae (aka __________ and ________), Calliphoridae (aka _________), Oestridae (aka ________), and Hippoboscidae (aka ________ and ________)
1. Nematocera: mosquitos, black flies, biting midges, sand flies 2. Brachycera: horse flies, deer flies 3. Cyclorrhapha: house flies, stable flies, blow flies, bot flies, louse flies, sheep keds
Describe the life cycle of Sarcoptes mites.
1. Non-gravid adult females and males move freely on the skin surface and mate. 2. Males remain on the skin surface while fertilized females burrow tunnels (called moulting pockets or burrows) in the epidermis of the host. They may also enter an existing burrow and extend a new pocket. Females then lay eggs in the burrows. 3. Nymphs and larvae move freely within the burrows and over the surface of the skin.
1. What species of Notoedres infects cats? What species infects rabbits? 2. Are these burrowing or non-burrowing mites? 3. Do they cause pruritus?
1. Notoedres cati, Notoedres cati var. cuniculi (cuniculi = rabbit) 2. Burrowing 3. Yes (similar life cycle to Sarcoptes)
Sarcoptes and Notoedres appear very similarly. What are two major ways we can tell them apart?
1. Notoedres lack triangular scales, whereas Sarcoptes has them (*unique feature of Sarcoptes) 2. Notoedres has thumbprint striations, whereas Sarcoptes has transverse striations.
General life cycle of lice: 1. Lice are completely __________. 2. The only times spent off of a host are to ________ or _________. 3. Transmission is mainly by _________. 4. The life cycle is _____________. The nymphs resemble adults. 5. The life cycle is based on the ___________ of the host. 6. The entire life cycle is spent on the _______.
1. Obligatory 2. Seek a new host, if the host temperature drops 3. Contact 4. Heterometabolous (incomplete) 5. Temperature 6. Host
1. What is the agent of false gid? 2. What is false gid?
1. Oestrus ovis 2. Disease in sheep characterized by lifting of forefeet in pawing motion, incoordination, ataxia, and other neurological signs when O. ovis larvae reach the frontal sinuses.
Commonly known as "sheep bots." Adult females deposit fluid filled with larvae around sheep nostrils. Irritation leads to increased mucus production that feeds the larvae. If severe enough, can cause false gid. Spines can be found on the ventral surface of the larvae, each segment having a thick brown structure. The dorsal surface is smooth. 1. Who am I? 2. What type of myiasis is it?
1. Oestrus ovis 2. Obligatory nasopharyngeal myiasis
Describe the three life cycles of Ixodids.
1. One host: ticks spend the entire parasitic development on a single host 2. Two host: larval and nymphal stages are spent on one host, drop onto the vegetation, and molt to an adult, which then finds a new host 3. Three host (two years): most common, each stage of development takes place on different hosts. After each stage feeds, they drop on vegetation to molt
Tick morphology: 1. The capitulum (head) of the cephalothorax contains two _______, which are used to anchor onto the skin of the host. These structures contain __(#)__ segments. 2. ___________ are two "blades" on the dorsal capitulum that are used to cut the skin of the host. 3. The _____________ is a ventral structure on the capitulum that is used to embed into the skin of the host. It contains a groove for passive blood flow. 4. The ____________ is the base of which these structures branch from. It can have a hexagonal or rectangular morphology, which is useful in tick identification. 5. Another structure useful for identification is the ___________, which is a hard covering on the dorsal surface. 6. The tick's unsegmented abdomen contains ___ pairs of jointed legs. 7. The _______ is the leg segment that attaches to the body. 8. _____________ is an organ that allows the tick to identify its surroundings through vibrations and changes in O2/CO2. It is located on the _______ of the leg.
1. Palps, 3 2. Chelicerae 3. Hypostome 4. Basis capituli 5. Scutum 6. 4 7. Coxa 8. Haller's organ, tarsus
1. Describe transovarial/vertical pathogen transmission of Ixodid ticks. 2. Describe transstadial transmission. 3. What is the major difference between the two in terms of infectivity?
1. Pathogen infects tissues of a tick after a blood meal, including the ovaries, where they infect all eggs produced and laid by the tick. Infection drops when larvae molt to nymphs. 2. Occurs when a pathogen infects the tick at any stage and remains with the vector as it subsequently molts 3. Transovarial transmission can only be infective at the larval stage, whereas transstadial transmission is infective at ALL stages
Common agent of fly strike in sheep. Females oviposit eggs in damp or soiled wool of living animals. Sheep temperature aids in egg hatching, and larvae may remain on skin or penetrate via wounds or natural openings. 1. Who am I? 2. What type of myiasis is it?
1. Phormia regina 2. Facultative traumatic/cutaneous myiasis
There are two groups within Cyclorrhapha (suborder of Diptera): 1. Those with __________ mouthparts: these are blood feeders. This includes ________, _________, and _________. 2. Those with _______ mouthparts: these are non-blood feeders. They are grouped into myiatic and non-myiatic flies. This includes _______ and _________.
1. Piercing/cutting. Stomoxys (stable fly), Glossina (TseTse fly), Haematopota (horn fly) 2. Sponging. Musca domestica (house fly), Musca autumnalis (face fly)
What types of pathogens are transmitted by mosquitos?
1. Plasmodium spp. 2. Filariae (ie D. immitis, Wuchereria) 3. Arboviruses (ie EEE, VEE) (+ more ie Leucocytozoon, WNV, Brugia spp.)
Antennae and eyes are useful for sex identification of Diptera flies. 1. If the shorthairs on the antennae are bushy, they are called __________. The fly is (male/female). 2. If the shorthairs on the antennae are sparse and wispy, they are called ________. The fly is (male/female). 3. If the eyes have a large space between them (large frons), they are called _________. The fly is (male/female). 4. If the eyes have minimal space between them (small frons), they are called _________. The fly is (male/female).
1. Plumose, male 2. Pilose, female 3. Dichoptic, female 4. Holoptic, male
How can you tell the difference between Anoplura (sucking lice) and Mallophaga (chewing lice) by their morphological characteristics?
1. Proportion of head to the thorax: Anoplura has a narrower head in relation to the thorax, whereas Mallophaga has a head that is nearly the same width as the thorax. 2. Number of claws: Anoplura always has one tarsal claw per leg (because they only infest mammals), whereas Mallophaga may have either one or two claws per leg (because they infest both birds and mammals).
1. What are the three parts of the insect thorax, in order from anterior to posterior? 2. Which one is the biggest, and why? 3. How are the legs distributed throughout the thorax?
1. Prothorax, mesothorax, and metathorax 2. Mesothorax: it bears the wings 3. Each thoracic segment bears a pair of jointed legs
Name the species of Psoroptes: 1. Sheep scab 2. Rabbit ear mite
1. Psoroptes ovis/bovis 2. Psoroptes cuniculi (cuniculi = rabbit)
There are 8 genera of non-burrowing mites. 1. The family Psoroptidae contains 3 genera: __________, _________, and __________. 2. The family Dermanyssidae contains 2 genera: ___________ and _________. 3. The family Cheyletidae contains 2 genera: ____________ and _________. 4. The remaining genus is __________. *Challenge: Answer this instead → Name all 8 genera of non-burrowing mites and the families they belong to.
1. Psoroptes, Chorioptes, Otodectes 2. Dermanyssus, Ornithonyssus 3. Cheyletiella, Psorergates 4. Trombicula
There are two species of lice that commonly infect humans: 1. ___________ is a crab louse primarily found in pubic and other coarse body hair. It is transmitted by physical contact. 2. ____________ is commonly known as the human head louse or human body louse. It transmits Rickettsia prowazeki (epidemic typhus) and Borrelia recurrentis (epidemic relapsing fever) 3. Both are part of the ___________ suborder. This means it infests (mammals/birds/both).
1. Pthirus pubis 2. Pediculus humanus 3. Anoplura, mammals
1. What is the major clinical sign of Argasid (soft tick) parasitism in birds? 2. Where are these ticks most commonly found on birds? 3. How is this diagnosed?
1. Reduced egg laying 2. Under the wings 3. Microscopic examination of ticks found in crevices in the pen
1. Which two genera of Ixodid ticks have hexagonal basis capituli? 2. How can you tell the two apart?
1. Rhipicephalus and Boophilus 2. Festoons! Rhipicephalus has festoons, whereas Boophilus does not. *Bonus! Boophilus is now eradicated in the US, whereas Rhipicephalus sanguineus is the most widely distributed tick worldwide.
1. The Brown Dog Tick/ Kennel Tick is the common name for what Ixodid species? What gives it the Brown Dog Tick name? 2. What type of life cycle does this tick have? 3. What types of hosts does it infest? 4. This tick is a vector for what kinds of pathogens? 5. Can it cause tick paralysis?
1. Rhipicephalus sanguineus. Named the "Brown Dog Tick" because it is the most common tick you will find on a dog! 2. 3 host 3. Dogs, livestock, and birds 4. Many protozoal, bacterial, viral, and rickettsial infestations (Ehrlichia canis, Babesia, Theileria, Hepatozoon canis, Rickettsia) 5. Yes
1. What genus of mites causes scabies? 2. Is this a burrowing or non-burrowing mite?
1. Sarcoptes 2. Burrowing
Female Sarcoptes mites create burrows in the host epidermis to lay eggs. They can either create a new burrow or enter an existing burrow, but if they do they must create an extending pocket. Why is this step necessary?
Extending the pocket induces a robust inflammatory response in the host skin. Mites need this because this response produces fluid that they feed on. If females enter an existing burrow but do not extend the pocket, the inflammatory response is not high enough to produce enough fluid.
Where is Otodectes cynotis primarily found?
External ear canal (but may spread to other parts of the body)
Classify the type of myiasis based on degree of host dependency and location or mode of invasion: -Many species that normally are carrion (dead tissue) feeders but can secondarily invade living tissues -Female flies may be attracted to open wounds and oviposit -Example: Phaenia serratica used as surgical maggots or Phormia regina causing fly strike in sheep
Facultative cutaneous/traumatic
Classify the type of myiasis based on degree of host dependency and location or mode of invasion: -Infestations may result when foodstuffs contaminated with eggs or larvae of muscoid flies are ingested or when flies oviposit on perianal skin and migrate into the rectum -Flies involved are normally free living -Examples: Calliphora sp. (blow fly) and Sarcophaga sp. (flesh fly)
Facultative enteric
Who am I? -Feed on mammals, reptiles, and birds -Wings close like a pair of scissors at rest -Forward projecting proboscis -Biological vectors of Trypanosoma (sleeping sickness) -Larviparous: lay larvae with characteristic black knobs -Wing venation: hatchet cell (looks like a hatchet) -Blood feeders
Glossina (Tse Tse fly → Larviparous + hatchet cell = Glossina)
A hatchet cell wing venation pattern is unique to what genus of Diptera?
Glossina (Tse Tse fly)
Who am I? -Feeds on cattle, horses, and donkeys -Favors base of the horns, shoulders, belly, and back -Grey color with striped on the thorax -Dark spots on the abdomen -Transmits Stephanofilaria stilesis and Habronemosis in cattle, Parafilaria (summer sores) in horses and donkeys -Blood feeders
Haematopota (Lyperosia) irritans
What fly is commonly known as the horn fly? Where does it get its name?
Haematopota (Lyperosia) irritans. Horn fly because it prefers to feed at the base of the horns of cattle (+ shoulders, back, and belly)
Which part of the arthropod body is the only part that is not segmented?
Head
Name the genus! -Inornate scutum -Rectangular basis capituli -No bands on legs -Has festoons -Arrowhead mouthparts
Hemaphysalis (*Arrowhead mouthparts are the giveaway!)
Who am I? -3 host tick -Infest mammals and birds -Females reproduce parthogenetically (without males) -Highly invasive -Originally from NE Asia but has recently emerged and is rapidly spreading in the US -Important for blood loss and tissue damage -Vector for Babesia, Ehrlichia, Viruses, Borrelia burgdorferi, Anaplasma, and Theileria
Hemaphysalis longicornis
Where are ticks most commonly found on dogs?
Interdigital spaces and ears
Name the genus! -Inornate scutum -Rectangular basis capituli -No bands on legs -No festoons -Long mouthparts -Anterior portion of anal groove
Ixodes (*ONLY Ixodes has an anterior portion of the anal groove. Other genera have either a full groove or posterior half of a groove)
Name the two species! -Mouthparts adapted for sponging (don't bite aka non-blood feeders) -Thorax is grey with dark longitudinal stripes -Yellowish-brown abdomen -Bodies are covered with hair and sticky pads on each tarsus (used for passive transmission) -Transmit Parafilaria (summer sores), Habronema, Draschia, Thelezia (eye worm), Choanotaenia, and Moraxella (pink eye of cattle)
Musca domestica (house fly), Musca autumnalis (face fly)
What is the term for maggot deposition into tissues?
Myiasis
What is one of the main diagnostic features of demodecosis? (Demodex)
NO ITCHING (aka NO PRURITUS!)
This suborder of Diptera consists of small, delicate, blood-sucking flies and is commonly known as long-horned flies
Nematocera
Mulligan is diagnosed with a Demodex infection. Stephanie is worried that Leo will immediately get it and die because it is highly contagious, but Nimisha says it's unlikely if we keep them separated. Who is right? Why?
Nimisha! Demodex requires prolonged contact for transmission because they are deeply burrowed in hair follicles and sebaceous glands. Contact like this includes suckling and/or mating.
What is the difference between a mechanical vector and a biological vector?
No pathogen development occurs in mechanical vectors, whereas in biological vectors, development occurs.
Why are Onchocerca infections prevalent near areas with rivers?
Onchocerca is transmitted by Simulium sp. (black flies/buffalo gnats), which lay their eggs in fast flowing rivers.
What is the difference between primary and secondary blue flies?
Primary flies actively search for tissue to oviposit, whereas secondary flies oviposit on vegetation and wait for an animal to pick them up
What is the medical term for itchy skin?
Pruritus
Who am I? -Prefers wooled sheep -Legs project at an equidistance from the body, giving a crude star look -Bites cause intense irritation and pruritus -Large patches of fleece may be lost -May be dry scabs
Psorergates ovis (Crude star = Psorergates)
Name the genus! -Oval in shape -All legs project beyond the body margins -Pointed mouthparts -3-jointed pretarsi bearing funnel-shaped pedicels
Psoroptes (Long legs indicate non-burrowing mite. 3-jointed pretarsi with funnel-shaped pedicels tells you it's most likely Psoroptes)
Your patient is a sheep that presents with inflammation, exudation, yellow crust, and scab formation. There is a high loss of wool, intense itching, excoriation, and self-inflicted wounds. The sheep has lost weight and appears restless. You observe numerous thick-walled abscesses and are concerned for bacterial infection. What do you suspect?
Psoroptes ovis (sheep scab)
Your patient is a sheep that presents with pruritus and high loss of wool. You look at the herd history and note a history of Sarcoptes scabei var. ovis and Psoroptes ovis. Based on the history alone, which mite are you suspicious of, and why?
Psoroptes ovis. This infection causes diffuse wool loss, whereas Sarcoptes scabei var. ovis is primarily limited to the face ("black muzzle") and typically does not affect the wool.
Name the family! -Sand flies, Phlebotomus spp. -Bite mammals and reptiles, primarily on areas of exposed skin -Wings are lanceolate -Have a lot of bristles on the body, making them heavy and only able to travel short distances -Immature stages develop in moist dark places with lots of organic matter (ie rodent burrows) -Vectors of Leishmania and Bartonella bacilliformes, agent of Carrion's disease in humans
Psychodidae (of Nematocera suborder)
Who am I? -Lack pronotal and genal combs (no ctenidae) -Has eyes -Outer margin of the head is smooth -Believed to originate from pigs but can also infest dogs, cats, rats, and badgers -Causes dermatitis -Transmits Yersinia pestis (plague) -Commonly known as the Human Flea
Pulex irritans
What is red mange? Where does its name come from?
Red mange is a severe dermatitis caused by the generalized wet/purulent/follicular form of demodecosis (Demodex infection) that is characterized by widespread pustules and erythema. It's called red mange due to the severity of the erythema that is caused by secondary bacterial infections and inflammation.
The life cycle of Notoedres is very similar to Sarcoptes but with one major difference. What is it?
The burrows created by Notoedres are called nests because more than one female can occupy the burrow. (In Sarcoptes, only one female occupies the burrow.)
Demodicosis is the disease state of Demodex infestation. When does Demodex infestation result in demodicosis?
When the host's immune system is affected (Otherwise typically regarded as commensal of mammalian skin)
Why are male mosquitos non-parasitic?
Their mouthparts are changed so that they are unable to pierce the skin.
What is one feature unique to the life cycle of Otobius megnini, as compared to other Argasids (soft ticks)?
They are one-host ticks (other Argasids have multiple hosts, one for each nymphal stage)
Why is Demodex difficult to treat?
They burrow deep into the hair follicles and sebaceous glands, making them less accessible to topical acaricides.
Why are Phlebotomus spp. (Psychodidae) flies limited to flying short distances?
They have a lot of bristles over the body, making them heavy.
Why is lice-specific preventative unnecessary?
Virtually the entire spectrum of active ingredients in approved flea products are also active against lice. Flea preventative is also lice preventative!
Term for a type of wound that is characteristic of flea bites. Shows a circle of redness around the bite that is sometimes raised.
Wheal
