parasitology lab notes

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parasitology lab notes

  1. 1. Lab 9: TICKS!!!
  2. 2. General Tick Anatomy <ul><li>Ticks have small, compressed, leathery bodies </li></ul><ul><li>2 types of ticks – </li></ul><ul><ul><li>Aragasid: soft ticks – no scutum </li></ul></ul><ul><ul><li>Ixodid: hard ticks – have scutum </li></ul></ul><ul><li>Mouthparts cannot be seen when viewed dorsally </li></ul><ul><li>8 legs, claws on end </li></ul><ul><li>Head is called capitulum – extends out in hard ticks but not in soft </li></ul><ul><li>In male Ixodid ticks, scutum covers the entire dorsal surface. In females, scutum is smaller & is almost completely obscured during engorgement </li></ul>Ixodid Tick Aragasid Tick
  3. 3. General Tick Anatomy: Part 2 <ul><li>Mouthparts: </li></ul><ul><ul><li>2 palps (think of them like lips) – move out of the way while feeding and don’t penetrate host’s skin </li></ul></ul><ul><ul><li>2 chelicerae – cuts through host’s skin </li></ul></ul><ul><ul><li>1 barbed, needle-like hypostome – used to suck blood </li></ul></ul><ul><li>Larvae have only 6 legs </li></ul><ul><li>Nymphs have 8 legs, but lack a genital pore </li></ul>Larva Nymph
  4. 4. General Tick Lifecycle <ul><li>Ticks copulate </li></ul><ul><li>Female engorges on blood & drops to ground </li></ul><ul><li>Female lays thousands of eggs & dies </li></ul><ul><li>Eggs hatch & larvae crawl onto vegetation, climb onto passing animals, MUST FEED ON BLOOD TO MOLT </li></ul><ul><li>Molt into nymphs, MUST FEED ON BLOOD TO MOLT </li></ul><ul><li>Adults crawl onto vegetation & climb onto passing animals </li></ul><ul><li>Can have 1, 2 or 3 hosts </li></ul><ul><li>Activities are limited during winter months </li></ul><ul><li>Ticks avoid temperature extremes </li></ul>
  5. 5. Importance of Studying Ticks <ul><li>Ticks are voracious blood feeders – can cause anemia, fever, splenomegaly </li></ul><ul><li>Ticks can transmit many different disease causing bacteria (esp. rickettsial ), viruses & fungi </li></ul><ul><li>Female ticks secrete toxins in salivary glands that can induce temporary paralysis </li></ul>Female hard tick Laying eggs Engorged female hard tick
  6. 6. Otobius megnini : Spinous Ear Tick <ul><li>1 host soft tick </li></ul><ul><li>Can cause deep ulcerations in the ear – very irritating! </li></ul><ul><li>Will see animal shaking head frequently, can see with an otoscope </li></ul><ul><li>Infested pinna will droop – HALLMARK SIGN!!! </li></ul><ul><li>Usually occur in large numbers </li></ul><ul><li>Can see in dogs & cats, but also frequently in large animals (horses, cattle, sheep, goats) </li></ul><ul><li>Only larvae & nymphs take blood meals – adults are free living in environment </li></ul><ul><li>Prefer dry protected areas </li></ul><ul><li>Usually associated with Southwest US </li></ul>
  7. 7. Argas persicus : Fowl Tick <ul><li>Soft tick of fowl </li></ul><ul><li>Economic pests! Cause farmers to lose a lot of money </li></ul><ul><li>Occurs in large numbers, stresses chickens leading to low egg production </li></ul><ul><li>Can also induce anemia </li></ul><ul><li>Live in cracks & crevices of wood – contaminated bedding </li></ul>
  8. 8. Rhipicephalus sanguineus : Brown Dog Tick <ul><li>Hard tick </li></ul><ul><li>Very common in this area </li></ul><ul><li>Intermediate host for Babesia canis , Ehrlichia canis, and Anaplasma </li></ul><ul><li>Found both indoor & outdoor </li></ul><ul><li>Severe infestation can lead to heavy blood losses, severe anemia </li></ul><ul><li>Inornate brown color, head looks hexagonal </li></ul>Engorged female Female Male Nymph
  9. 9. Dermacentor variabilis : American Dog Tick <ul><li>Also known as Wood Tick </li></ul><ul><li>Common in this area </li></ul><ul><li>Lives in grassy areas </li></ul><ul><li>Vector for Rocky Mountain Spotted Fever, Tularemia, Cytauxzoon felis </li></ul><ul><li>Can cause tick paralysis </li></ul><ul><li>Identified by rectangular shaped capitulum, females have white markings on dorsal shield, males can have markings all over </li></ul>
  10. 10. Amblyoma americanum : Lone Star Tick <ul><li>Found mostly in SE US – west to Texas </li></ul><ul><li>Some pockets in Jersey, Fire Island, NY & Prudence Island, RI </li></ul><ul><li>Vector for Tularemia, RMSF, Ehrlichiosis </li></ul><ul><li>Can produce anemia with heavy burden </li></ul><ul><li>Females identified by white spot on apex of scutum, males can have white specks all over </li></ul>Female Male Nymph
  11. 11. Amblyomma maculatum : Gulf Coast Tick <ul><li>Don’t see around here – but potential to carry home from vacation </li></ul><ul><li>Seen most along Gulf Coast (Florida, Alabama, Louisiana) </li></ul><ul><li>Lives in ear canals of horses, sheep, dogs & people </li></ul><ul><li>Causes ulcerations in ear – can lead to hematomas </li></ul><ul><li>Ulcerations can attract flies & maggots </li></ul><ul><li>Infested pinna will droop – HALLMARK SIGN!!! </li></ul><ul><li>Causes severe bites w/ tick paralysis possible, severe swelling </li></ul><ul><li>Have long palps, silvery markings on scutum </li></ul>
  12. 12. Boophilus annulatus: Texas Cattle Tick <ul><li>Eradicated from US in 1940s – still prevalent in Mexico </li></ul><ul><li>Because of eradication & potential for disease – must be reported immediately if seen </li></ul><ul><li>Vector for Babesia bovis/bigemina and Anaplasma marginale </li></ul><ul><li>Can cause severe anemia </li></ul><ul><li>Other signs incl. restlessness, rubbing/licking/biting/scratching at self </li></ul><ul><li>Looks similar to Rhipicephalus but has ridged palps </li></ul>
  13. 13. Ixodes scapularis : Deer Tick <ul><li>Also known as Black Legged Tick </li></ul><ul><li>Only tick in this area that transmits Borrelia burgdorferi – bacterial cause of Lyme Disease </li></ul><ul><li>Only females & nymphs will transmit Lyme Disease – tick must be attached for at least 48hrs before the bacteria will transfer (males only feed for ~ 24hrs) </li></ul><ul><li>CS of Lyme Disease – weakness, lethargy, sudden lameness, swelling of joints, fever, depression, reluctance to move </li></ul>
  14. 14. Proper Tick Removal <ul><li>Use forceps/tweezers to grasp the tick at the base (head) as close to the skin as possible </li></ul><ul><li>Push the skin away from the head and pull the tick straight out of the animal </li></ul><ul><li>Clean the area with soap & water immediately after removal </li></ul><ul><li>Save the tick if possible to help identify & diagnose if illness occurs </li></ul><ul><li>DON’T grasp the body of the tick, it will break away & leave the head still embedded in skin </li></ul><ul><li>DON’T burn the tick with a match </li></ul><ul><li>DON’T crush the tick while it is still embedded </li></ul><ul><li>DON’T use petroleum jelly or rubbing alcohol on the tick </li></ul>
  15. 15. For more cool information check out: http://science.howstuffworks.com/tick.htm/printable

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