INSECTS

ACARIDS

Ctenocephalides felis◗ Most common flea on dogs and cats◗ Orange to dark brown, wingless ◗ Laterally compressed body◗ Long head, 6 notches bearing setae

dorsal border of hind tibia◗ Possible disease transmission:

•Bartonella henselae (cat scratch disease)

•Dipylidium caninum (tapeworm)

Ixodes spp. I. ricinus Forest tick I. hexagonus Hedgehog tick◗ 4 pairs of legs, long mouthparts ◗ Engorged female: light grey, bean-shaped◗ Male: legs visible due to small abdomen◗ Nymph: 4 pairs of legs, < 2.0 mm◗ Larva: 3 pairs of legs, yellowish, < 1.0 mm◗ Most common species found in Northern,

Western and Continental Europe. Found in areas of upland, moorland & woodland, parks & gardens

◗ Possible disease transmission: •Anaplasmosis•Lyme disease •Rickettsiosis •Tick-borne encephalitis

Sarcoptes scabieiDog sarcoptic mange mite◗ Seen in deep skin scrapings, difficult

to find◗ Best results from non-excoriated sites

e.g. ear margins, elbows, hocks◗ Oval white body, 4 pairs of short legs◗ Anterior legs have suckers, posterior

legs do not extend beyond body◗ Many transverse ridges and triangular

scales on dorsum

Notoedres cati Cat mange mite◗ Smaller than S. scabiei◗ Many concentric striations on dorsum

Ctenocephalides canis◗ Seen on dogs, less common than

C. felis

◗ Similar to C. felis in size and appearance

◗ Short head, 8 notches bearing setae on dorsal border of hind tibia

◗ Possible disease transmission

Linognathus setosus Sucking louse◗ Small pointed head with terminal

mouthparts

◗ Bluish-black in colour

Felicola subrostratus Chewing louse◗ Broad body

◗ Triangular head, pointed anteriorly

Cheyletiella spp. Fur mite, Walking dandruff◗ Saddle-shaped with a ‘waist’

◗ 4 pairs of legs

◗ Direct examination of coat brushings with magnifying glass

◗ Confirm microscopically by superficial skin scrapings or adhesive band test

Neotrombicula autumnalis Harvest mite, Chigger◗ 3 pairs of legs (larval stage only

parasite)

◗ Bright red pin-head dots, typically found between paws, on ears, or on eyelids

◗ Seasonal, autumn

◗ Confirm microscopically by superficial skin scrapings

Otodectes cynotis Ear mite◗ Visible in situ with otoscope (poor

sensitivity)

◗ Adults and eggs seen microscopically in ear cerumen

◗ Large white oval body

◗ 4 pairs of projecting legs (4th pair reduced in females)

◗ Whip-like setae attach terminally to 3rd and 4th pairs of legs

◗ Adult mites occasionally seen in skin scrapings from other body areas

Demodex spp.◗ Seen in deep skin scrapings from

areas of comedomes◗ Squeeze skin to extrude mites from

follicles◗ Hair plucks from dogs with foot lesions◗ Long cigar shaped body◗ 4 pairs of atrophied legs

FLEAS

TICKS

MITES

LICE

2-3 mm

0.5 mm 0.5 mm

0.1-0.2 mm 0.2 mm 0.05-0.1 mm0.2 mm 0.2 mm

2-3 mm 1-2 mm 1-1.5 mm

0.2-0.4 mm 0.5 mm

3-4 mm (unfed) 8-10 mm (engorged)

2-3 mm

0.2-0.4 mm 0.5 mm 0.25-0.3 mm

C. yagsuri Demodex caniC. blakei Demodex cati

Examining for ectoparasites◗ For ectoparasite examination the

light should not be too powerful. Lower the condenser for better definition.

◗ Use lowest objective lens x4 or x10 to examine the slide turn the objective lens up to look at something more closely.

◗ Ensure that your technique allows you to view the whole slide.

◗ The magnification of the objective lens is multiplied by the magnification of the ocular lens, generally x10, meaning that the overall magnification of the parasite elements is x40 to x100.

Visible with naked eye Zoonosis Visible under the microscope

Rhipicephalus sanguineus Brown dog tick ◗ 4 pairs of legs◗ Hexagonal base of capitulum◗ Inornate scutum◗ Eyes, festoons◗ IV coxae no larger than I-III◗ Common in Mediterrnean countries

and South-continental Europe ◗ Endophile tick living in kennels,

villages, gardens; likes warm climate, humid or arid

◗ Possible disease transmission:•Babesiosis•Ehrlichiosis•Rickettsiosis

Dermacentor reticulatusOrnated dog tick◗ 4 pairs of legs◗ Rectangular base of capitulum

(mouthparts including their base)◗ Ornate scutum (chitinous plate on

dorsum)◗ Eyes, festoons (notches on posterior

border of body)◗ IV coxae (proximal leg section) larger

than I to III◗ Commonly found in Western Europe ◗ Prefers parks, gardens, landscape,

river banks◗ Possible disease transmission:

•Babesiosis•Rickettsiosis

Eggs Eggs

Eggs Eggs EggsEggs Eggs

Trichodectes canis Chewing louse◗ Head is broader than it is long

◗ Broad yellowish body

◗ Antennae with 3 segments

1-2 mm

EggsEggs Eggs

3-4 mm (unfed) 10 mm (engorged)

3-4.5 mm (unfed) 12 mm (engorged)

3-4 mm 3-4 mm

ECTOPARASITES OF DOGS AND CATS

Cleaning and setting up the microscope 1. Dust eye pieces, condenser and

objective lenses with lens tissue. 2. Clean oil from oil immersion objective

with lens tissue. 3. Turn light on with power on low. 4. Turn up brightness until white light

visible. 5. Turn condenser up as far as possible. 6. Use low power x4 or preferably x10. 7. Place slide on stage. 8. Rack up until slide is in focus. 9. Close one eye and adjust eye piece

with fine focus then do the same with the other eye piece.

10. Hold pencil in light path.11. Move condenser up until pencil seen.12. Take out eyepiece and see circular

light.13. Open diaphragm until cycle tyre effect.14. Always leave the microscope with

stage lowered and cover, making sure the power is off and stage is clean.