Lecture 21. Overview of Arthropods in Companion and Production Animals

what is the largest phylum

arthropoda

arthropoda accounts for _____% of biodiversity in cambrian period

90%

the arthropoda phylum is diverse through its...

1. body forms

2. habitats/niches

3. adaptations (intersexuality, gynandromorphy, hermaphroditism)

why are arthropods of veterinary importance

1. potential to cause disease

2. role as IH/PH to protozoa and helminths

3. vectors of infectious diseases (viruses, rickettsia, bacteria)

what is myasis

larval migration

what are the two subphylums of arthropoda

1. chelicerata (arachnida--> ticks, mites, spiders)

2. mandibulata (insecta--> bugs, flies, fleas, lice)

what are some morphological characteristics of arthropods

1. jointed appendages

2. chitinous exoskeleton

3. 3-segment body (bilaterally symmetrical)

4. primitive CNS (ladder-like w/ paired ventral nerve cords)

5. respiratory system

same habitat through lifecycle (form emerging from egg looks like adult) describes what metamorphosis

simple metamorphosis

different habitats through lifecycle (form emerging from egg looks nothing like adult) describes what metamorphosis

complex metamorphosis

trans-stadial transmission of virus means

transmitted from one dvlp stage to the other

what is the most common transmission biology method about ticks

trans-stadial

trans-ovarial transmission of viruses means

transmitted into eggs of adult (vertical transmission)

how do pyrethrins (natural) and pyrethroids (in lab) function against arthropods

voltage gated Na channels, hyper excitable nerve cells, and spastic muscle paralysis

how do organophosphate/carbamates function against arthropods

nicotinic like effect and cholinergic toxicity

how do macrocyclic lactones function against arthropods

GABA regulated chloride channels and muscular paralysis

how do macrocyclic lactones (spinosad "comfortis") function against arthropods

nicotinic acetylcholine antagonist, involuntary muscle contractions and tremors, stim GABA channels

fipronil (frontline) is a GABA mediated chloride channel blocker that acts against what species

fleas, lice, flies (NOT TICKS)

isoxalines (afoxolaner "NexGard"/ furlaner "Bravecto") is a GABA mediated chloride channel blocker that acts against what species

ticks, fleas, mosquitoes

how do GABA mediated chloride channel blocker function against arthropods

block passage of chloride through GABA channels in nerve and muscle cells leaded to paralysis and death