Phylum Acari

Question 1

What are the forms in Phylum Acari

Answer 1

Acariformes (mites), 0.5-3mm, body soft+hairy
Parasitiformes (ticks) 3-30mm, leathery and hairless

*ticks are bloodsucking + carry disease

Question 2

Sarcoptes scabiei (mite) size

Answer 2

f=0.4mm m=0.27mm

Question 3

Sarcoptes Scabiei mating and what does the males do.

Answer 3

Mature F+M mate only once. the males dont burrow into skin, they crawl + feed on it

Question 4

Sarcoptes scabiei life cycle

Answer 4

• F gets contact with skin + crawls into crevices (elbow, feet, fingers, genital)
• It penetrates the skin + make tunnel. can slice skin with sharp mouthparts +front legs.
• Other legs hv suckers to hold onto skin
• Burrows into skin and lays eggs (2-3 eggs per day). then it dies RIP
• 6 legged larvae hatch, finds hair follicles + feed. they molt into 8 legged nymphs then develop to adults.

Question 5

which mite is considered commensal and just survives on human skin

Answer 5

Demodex folliculorum

Question 5

which MITE is considered commensal and just survives on human skin and what does it cause

Answer 5

Demodex folliculorum
blepharitis and acne

Question 6

Ticks as vectors + what is transovarian transmission

Answer 6

• eat each stage of development they suck blood from
  dif animals. rodents, dogs/sheep, humans
• Transovarian transmission = infected female with virus/bacteria can transfer to its eggs/ next gen

Question 7

what is zoonoses

Answer 7

infection transmitted from animals to humans

Question 8

Ixodes ricinus (castor bean tick) size, main characteristic, disease

Answer 8

f=3.6mm m=2.8mm full=11mm
* can transmit agents for lymes disease ( caused by borrelia bulgdorferi)
* has a hard dorsal shield on abdomen

Question 9

Dermacentor marginatus (ornate sheep tick) disease caused.

Answer 9

hosts mainly mamals + seen in cent/south europe or Nor africa
* disease spread: spring summer encenphalitis, Q fever, tularemia

Question 10

Rhipicephalus sanguineous (brown dog tick)
what’s special abt it, characteristic, disease

Answer 10

special: can complete whole life cycle indoors
characteristic: curved legs

Its a vector for Rickettsia conorii ( causes Mediterranean spotted fever)
other disease = boutonneuse fever / tick typhus

Question 11

Hyaloma plumbeum ( bont leg ticks) disease

Answer 11

bites cause necrosis around and causes Crimean haemorrhagic fever

Question 12

How ticks spread disease

Answer 12

Through feeding
grasps onto skin , cuts surface and inserts feeing tube. tick will secrete saliva with anaesthetic properties so animal cant detect it. tick will then suck blood for several days. if host has bloodborne infection, tick will ingest the pathogens and transmitted onto next host

Question 13

basic lyfe cycle ticks

Answer 13

egg
6 leg larva
8 leg nymph
adult - needs to hv blood at every stage
- brown dog tick has same host for all stages
- ixodes require diff host each stage therefore takes 3 years to complete cycle.