25 - ectoparasites

new world screwworm life cycle

1. fem attracted to scent of open wounds + lay 250-500 eggs

2. larvae hatch, then burrow into + feed on tissue

3. after ~7days, larvae drop to ground to pupate

4. develop to adults 7-54 days later

new world screwworm pathology

livestock, pets, wildlige, rarely birds + humans

• myiasis = larvae (maggots) burrow into flesh of living animal

  • lethargy, pain, head-shaking, biting at wound

  • often fatal

new world screwworm treatment

• remove larvae

• wound care

• insecticides

• pain management

• environmental decontamination

• new = dectomax

new world screwworm control

SIT (sterile insect technique)

• NWS flies rared in mass

• pupae sterilized w/ gamma radiation

• flie mass-released

• mating w/ sterile males produce nonviable eggs

tick life cycle

ex.) ixodes scapularis

• 2 yr cycle

• after hatching, each stage needs blood meal

ixodes scapularis

deer tick, blacklegged tick

transmits:

• Babesia microti

• Borrelia burgdorferi

amblyomma americanum

lone star tick

transmits:

• bourbon virus

• tularemia

alpha-gal syndrome (AGS)

red meat allergy

• high levels of AGS found in red meat

• also found in milk

• ppl with AGS may also be sensitive to alpha-gal found in red meat products

dermacentor albipictus

winter tick, moose tick

• humans rarely host

• moose usual hose:

  • skin inflammation, itching

  • hair loss

  • excessive gromming → ghost moose

mosquitoes life cycle

1. females lay eggs on water

2. hatch w/in 2-3 days

3. larvae

4. larvae live in water → pupa in 4-10 days

5. pupa live in water → adult w/in 2-3 days

mosquito olfaction

chemosensory system

detect + identify chemical cues in env

uses:

• antennae, proboscis + palpus

• olfactory receptors

• abt 80 types of OSN

• signals processed in olfactory slomerulus in brain

mosquito kairomone

chemical signal that benefits individuals of a species that receives it & harms the emitter

• exhaled breath

• body odor

• urine

mosquito biological control

• plant-borne molecules

effective against larvae

few ppm → nanomosquitocides

mosquito biological control

• mosquito predators (larvivores)

• Fish

• Copepods

• Amphibians (tadpoles)

mosquito biological control

• entomopathogenic fungi

Produce infective spores

→ Attach to & penetrate cuticle of adults

→ Release toxins

→ Kill mosquitoes

vector competence

ability of a particular vector to become infected with & transmit a specific pathogen

• in lab: allow uninfected potential vectors to feed on animals infected w/ pathogen

vectorial capacity

ability of vector pop to transmit pathogens to a host

1. vector biting rite

2. taking relatively large blood meal

3. probability of vector survival

4. vector density

5. good dispersal ability