Skin Parasites Flashcards
What kinds of diseases can fleas spread?
Diphyllidium, bubonic plague, mxymatosis
What is the Scientific name for fleas?
Siphonaptera
What are the 4 most important flea species? Which is most common in cats and dogs?
Ctenocephalides Felis (cat flea) and C. Canis, Pulex irritans (human flea), ceratophyllus gallinae (poultry flea). Cat flea most common.
How is identification of flea species aided?
Ventral (Genal) and Posterior (Pronotal) combs on the head.
What are the 4 main stages in flea life cycle? What is important about eggs?
Adult, Egg, Larva, Pupa. Egg is not sticky, so it falls off. 95% of flea population not on the animal.
How long is a flea lifecycle?
3-4 weeks.
What is Juvenile Hormone?
A hormone required for development of parasites (skin).
What is the scientific name for lice?
Phthiraptera
What disease do lice cause?
Pediculosis
What are the morphological differences between chewing lice and sucking lice?
Chewing lice have a broad head and thinner claws. Sucking lice have a narrow head and large, powerful legs.
What are the stages in a louse life cycle? How long does it usually take?
Adult, egg ‘nit’, Nymph. Usually takes 2-3 weeks.
How many species of chewing/sucking lice do cattle have?
1 chewing, several sucking.
How many species of chewing/sucking lice do sheep have?
1 chewing, 2 sucking. Rare until recently (due to less dipping)
How many species of chewing/sucking lice do pigs have?
1 sucking louse. Large and easily seen. Common.
How many species of chewing/sucking lice do horses have?
1 chewing, 1 sucking louse.
How many species of chewing/sucking lice do dogs have?
Usually chewing louse Trichodectes or sucking louse Lingognathus
How many species of chewing/sucking lice do cats have?
1 chewing louse of important, Felicola.
How many species of chewing/sucking lice do poultry have?
Many species of chewing louse, no sucking lice.
Are ticks insects?
No, they are Acarina. They are temporary parasites (spent small amount of time on host).
What is special about tick feeding?
They feed continuously. Saliva contains histamine blocking agents, anti-coagulants etc.
What are the stages in a tick life cycle? What is special about ‘seed ticks’?
Adult (4 pairs of legs), egg, larve ‘seed tick’ (3 pairs of legs), Nymph (4 pairs of legs).
How can ticks be divided?
Hard ticks and soft ticks.
What are the 3 main parts of the tick mouthparts?
Chelicarae (Puncture skin), Hypostome (pushed through hole and anchor), Palp (sensory organs)
How do you recognise a hard tick?
It has a hard Scutum, and prominent mouth parts. Scutum covers all of male, part of dorsal surface of female. May have festoons.
How is the life cycle of hard ticks categorised?
1, 2, or 3 host ticks depending on the number of hosts they attack to during their lifecycle.
How would you recognise a soft tick?
No Scutum, mouthparts not visible dorsally.
What are the 5 main ticks of importance in the UK?
Ixodes ricinus, Ixodes canisuga (dog tick), Ixodes hexagonus (hedgehog tick), Haemophysalis sp (mainly cattle - Babesia major), Dermacentor sp (sheep in Wales)
What is the more common name of Ixodes ricinus?
Castor bean tick
What diseases are spread by Ixodes ricinus?
Lyme disease (human), Louping Ill, tick borne fever, tick pyaemia, red water fever (Babesia divergens)
What is important about the Ixodes ricinus lifecycle?
Three tick host, lifecycle is 3 years. Spends most of time on the ground.
What condition do mites cause?
Mange.
How can mites be categorised?
Burrowing (sub-surface) or Non-burrowing
Where do mites spend most of their lifecycle?
On the host
Name the three main burrowing mites
Sarcoptes, Knemidocoptes, Demodex
Name the 3 main burrowing mites
Psoroptes, Chorioptes and Otodectes
What is the important Sarcoptes species? How would you recognise it?
Sarcoptes scabiei. Small round mite, it has short legs and dorsal spines.
What is the lifecycle of Sarcoptes?
Female lays egg in egg laying pocket in epidermis. Egg hatch in under a week. Larvae make moulting pocket and become adults. All under a scab.
What important disease do Sarcoptes mites cause?
Sarcoptic mange.
How can you diagnose Sarcoptes?
Deep skin scrape, place on microscope. 10% KOH and warm. Look for adults and immature mites.
What is the treatment used for Sarcoptes mites?
Acaricides e.g. Ivermectin in farm animals.
What is important about the host of Knemidocoptes?
Only burrowing mite that occurs in birds.
How would you recognise Knemidocoptes mites?
Similar to Sarcoptes (round, short legs), but has a U shaped chitinous bar behind its head.
What 3 conditions are caused by Knemidocoptes mites in Poultry?
Scaly leg (K. Mutans), depluming itch (K. Gallinae), Scaly beak (K. Pilae)
Why is Demodex different to other burrowing mites?
Usually commensal in hair follicles and sebaceous glands.
How do you recognise Demodex mites?
Cigar shaped, 4 pairs of stumpy legs.
What two kinds of infection can Demodex cause?
Squamous demodecosis (less serious), pustular or follicular demodecosis
How do you diagnose Demodex? How do you distinguish between commensal and disease producing?
Liquid paraffin to skin, take deep skin scraping. High proportion of larvae and nymphs indicate active infection.
What is Psoroptes? What are the 3 most important species?
Non-burrowing mites. Ps. Ovis (sheep, cattle), Ps. Equi (horses), Ps. Cuniculi (rabbits, horses)
How would you recognise Psoroptes mites?
Long legs, oval shape, segmented Pedicels.
What is the main morphological differences for telling the difference between burrowing and non-burrowing mites?
Burrowing usually have short legs. Non-burrowing usually have long legs.
How would you tell the difference between Psoroptes and Chorioptes mites?
Psoroptes have segmented pedicels, Chorioptes have unsegmented pedicels.
What is the main disease caused by Psoroptes mites?
‘Sheep scab’ - primarily in late autumn or winter. Active in keratin layer
What are the hosts of Chorioptes?
Ruminants and horses
How do you recognise Chorioptes mites?
Long legs, oval shape, unsegmented pedicels.
Which is more pathogenically significant, Psoroptes or Chorioptes ?
Psoroptes
What is Otodectes? What important species is there?
Non-burrowing mite of cats and dogs. It inhabits the external ear. One species: O. Cynotis
How do you diagnose Otodectes?
Surface mite and location. (Closed chitinous bars on underside confirm ID)
What are Cheyletiella?
Non burrowing mites that infect cats , dogs, rabbits and humans. They cause scaly dermatitis (excessive scurf ‘walking dandruff’)
How would you recognise Cheytiella mites?
Long legs, waisted body, claw like palpable, combs on each leg.
What is Dermanyssus gallinae? What is important about its life cycle?
Non-burrowing mite of poultry. Spends most of time off host, feeds at night, eggs laid in housing. It sucks blood.
How would you recognise Dermanyssus gallinae?
Spider like long legs, becomes red.
What is Neotrombicula autumnalis?
Non-burrowing mite also known as Harvest mite. Paradises anything including humans.
Which stage in the lifecycle of N. autumnalis is parasitic?
Larva
How do you recognise N. autumnalis?
Surface mite, SIX legs, bright orange, hairy.
What are the main mites species infecting cattle? (5)
Sarcoptes, Demodex, Psoroptes, Chorioptes and Neotrombicula
What are the main mites species infecting sheep? (5)
Sarcoptes, Demodex, Psoroptes, Chorioptes and Neotrombicula
What are the main mites species infecting horses? (5)
Sarcoptes, Demodex, Psoroptes, Chorioptes and Neotrombicula
What are the main mites species infecting pigs? (3)
Sarcoptes, Demodex and Neotrombicula
What are the main mites species infecting dogs and cats? (5)
Sarcoptes, Demodex, Otodectes, Cheytiella and Neotrombicula
What are the main mites species infecting birds?
Knemidocoptes, Dermanyssus and Neotrombicula
