Lab Exercises
THE MITES
NON-BURROWING MITES
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A "tick'like" mesostigmated mite |
Family Dermanyssidae
These are tick-like mites with an ovoid body shape. They have a pair of
spiracles between the third and fourth coxae. In life, they use their long legs
to move about both on the host and in its nest or bedding.
Ornithonyssus sylviarum: northern fowl mite.
Pneumonyssus caninum: nasal cavity and sinuses of dogs
Dermanyssus gallinae: chicken mite (a.k.a. "red mite")
Family Chyletidae
This family has palptibial claws curved ventrally and usually greatly enlarged. Parasites of birds and small mammals
Cheyletiella parasitivorax: rabbits
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Cheyletiella parasitivorax
Note: The body has a "waist" and the large palps have pinchers on their ends. |
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Family Psoroptidae
This family has long terminal setae on legs III and legs IV may be reduced, usually with claws; males with anal suckers. These are skin parasites of mammals.
Psoroptes ovis: sheep and cattle; causes "sheep scab" (Psoroptic mange)
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Psoroptes ovis |
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Psoroptic mange ("sheep scab") |
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Psoroptes ovis
life cycle |
Chorioptes bovis: sheep, cattle, goats and horses
Otodectes cyanotis: dogs and cats
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Chorioptes bovis
Otodectes cyanotis
The red arrow points to
the epimeres of legs I and II,
which converge. |
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BURROWING MITES
Family Sarcoptidae
Mites in this family are rounded or sac-like with short legs.
Sarcoptes scabiei: all domestic animals and humans; causes sarcoptic mange (or "scabies" in humans).
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Sarcoptes scabiei
Note the pretarsi of legs I and II (arrows) are in the form of simple (unsegmented) stalked pedicels and suckers. |
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Sarcoptes scabiei A skin scraping showing eggs (black arrows) and an adult (red arrow). |
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Notoedres cati: cats
This mite is similar in appearance to Sarcoptes but is smaller.
(Sarcoptes is rare on cats.) Knemidocoptes sp.: poultry (a.k.a. "scaly-leg" mite)
This mite also resembles Sarcoptes in shape but the legs have claw-like structures instead of suckers.
(Sarcoptes is not found on poultry.)
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Notoedres cati
Knemidocoptes |
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Family Demodicidae
Elongated, annulated, worm-like species found in hair follicles, and the surface glands and ducts of vertebrates.
Demodex canis: dogs
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Demodex canis
Section through skin of a dog with demodectic mange. While no mites are seen in this section note the pathology present. |
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THE TICKS
Family Argasidae: The Soft Ticks
Ticks in this family have no scutum (hard shield-like plate on dorsal surface) but have a leathery cuticle. The mouthparts are not visible from the dorsal side.
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Soft Ticks
Argas is to the left and Otobius is to the right.
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Family Ixodidae: The Hard Ticks
These ticks possess a rigid, chitinous scutum on their dorsal surface and their mouthparts appear at the anterior end of the body when viewed from the dorsal aspect.
Ixodes scapularis (a.k.a. deer tick and black-legged tick): vector of Borrelia burgdorferi (Lyme disease agent)
To learn more about Lyme disease, check out the following Web sites: http://www.niaid.nih.gov/publications/lyme/niaid%20lymedisbookf2.pdf and http://www.cdc.gov/ncidod/dvbid/lyme/index.htm
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Ixodes scapularis Ventral side of an engorged female.
Note the preanal groove (characteristic of genus). |
Ixodes scapularis From left to right:
Nymph, adult female, and adult male. |
Click here to link to the Ixodes scapularis life cycle.
Haemaphysalis sp.
Amblyomma americanum (a.k.a. Lone Star Tick)
Dermacentor variabilis (a.k.a. American Dog Tick) - rodents and other small mammals (larval and nymphal stages);
middle-sized to large mammals including dogs and humans (adults)
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Dermacentor variabilis From left to right:
Unengorged adult female, engorged adult female, and unengorged adult male. |
Dermacentor variabilis female laying eggs.
Note the number of eggs laid by one tick. |
Rhipicephalus sanguineus: (a.k.a. Brown Dog Tick) - dogs
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Rhipicephalus sanguineus
Engorged adult female |
Rhipicephalus sanguineus
Larval tick (left) and egg (upper right) |
Rhipicephalus sanguineus
Note the short mouthparts. |
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