L4 - Tick and mites Flashcards
What are the general characteristics of Acarines (ticks and mites)?
No antennae
No compound eyes (may have simple eyes)
Adults have 4 pairs of legs
Mouthparts include chelicerae and palps
What are the two superorders of Acarines?
Parasitiformes – Includes ticks
Acariformes – Includes mites
What are the general body regions of ticks?
Cephalothorax (head and thorax combined)
Abdomen
What are the two main families of ticks?
Family Argasidae (Soft Ticks)
Family Ixodidae (Hard Ticks)
What are the stages of a hard tick’s life cycle?
Egg
Larva (6 legs)
Nymph (8 legs)
Adult male and female (8 legs)
What are the different types of tick life cycles?
1-host tick – All stages on one host
2-host tick – Larva and nymph on one host, adult on another
3-host tick – Each stage feeds on a different host
What is “questing” in ticks?
Larvae and nymphs climb grass and wave legs in response to CO₂ and movement.
Uses Haller’s organ to detect hosts
What are the negative effects of ticks on hosts?
Blood loss (up to 5ml per tick)
Irritation and hypersensitivity
Hide damage
Reduced growth rate
Paralysis from toxins
Transmission of protozoan parasites and other pathogens
Where is Ixodes holocyclus found, and why is it significant?
Found on the East Coast of Australia
Saliva contains a neuromuscular toxin causing ascending flaccid paralysis
Can cause esophageal dysfunction
Causes more human deaths in Australia than funnel-web spiders
Kills thousands of dogs and cats
Hosts: Bandicoots, possums, wild dogs
What is the life cycle of Ixodes holocyclus?
3-host tick
Life cycle takes 18 months
Larvae & adults: Spring
Nymphs: Autumn
Males rarely seen on hosts
What is the significance of Rhipicephalus australis?
1-host tick
Major problem in Northern Australia
Costs Australian cattle industry $146 million annually
Transmits tick fever
What are the key stages of Rhipicephalus australis’ life cycle?
Engorged female drops off cattle, lays eggs, then dies
Larvae hatch, quest for hosts
Larvae attach, feed, and molt into nymphs
Nymphs molt into adults
Total cycle: 21 days
Each female lays 3,000 eggs
What diseases does Rhipicephalus linnaei transmit?
Canine babesiosis (Hong Kong)
Rocky Mountain Spotted Fever (USA)
Canine Erlichiosis (Northern Australia) – Caused by Erlichia canis
What are the key differences between mites and ticks?
Mites are smaller than ticks
Mites lack rows of teeth on the hypostome
Most mites are free-living, but some are parasites
What are the life cycle stages of mites?
Egg
Larva (6 legs)
Nymphs (8 legs)
Adults (8 legs)
What are the three main groups of mites?
Mesostigmata – Legs positioned at the front
Prostigmata – Feather-like setae present
Astigmata – Front and back legs widely separated
Where does Demodex canis live and what does it cause?
Location: Hair follicles
Feeds on: Cytoplasm
Causes: Demodectic mange
Transmission: Contact during suckling
What are the two types of demodectic mange?
Localized – Around eyes, ears, muzzle
Generalized – Entire body affected (common in young, short-haired dogs)
What disease does Sarcoptes scabiei cause?
Scabies (Sarcoptic mange)
Burrows into superficial layers of the skin
Causes intense itching (pruritus), hyperkeratosis, alopecia
What is the transmission and significance of Sarcoptes scabiei?
Transmitted via direct contact
Can survive a few days off the host
Affects dogs, foxes, pigs, camels, ferrets, wombats, humans
What animals are affected by Otodectes?
Dogs and cats (especially puppies)
Highly contagious
Causes intense ear irritation
What is the historical significance of Psoroptes in Australia?
Introduced with sheep on the First Fleet
Eradicated by 1890 due to strict quarantine
What are the main control strategies for ticks and mites?
Chemical treatments (acaricides)
Resistant cattle breeds (Bos indicus)
Tick vaccines
Regular pet checks
Pasture spelling (destocking pastures for months)
