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1-5mm. Parasitic arthropods cont’d. Jo Hamilton Parasitology BS31820. 6-14mm. 5-7mm. (c). Flies - as vectors. Family Psychodidae – sandflies. Vectors of Leishmania - protozoa. Cutaneous leishmaniasis: L. tropica - Old World. L. mexicana - New World.

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parasitic arthropods cont d
1-5mm

Parasitic arthropodscont’d.

Jo Hamilton

Parasitology

BS31820

6-14mm

5-7mm

slide2
(c). Flies - as vectors.
  • Family Psychodidae – sandflies.
  • Vectors of Leishmania - protozoa.
  • Cutaneous leishmaniasis:
    • L. tropica - Old World.
    • L. mexicana - New World.
  • Mucocutaneous leishmaniasis (espundia) - L. braziliensis.
  • Visceral leishmanisis(kala azar) - L. donovani.
slide3
(c). Flies - as vectors

Family Simuliidae - Blackflies.

  • Simulium damnosum - vector in Africa.
  • Simulium ochraceum - vector in New World.
  • Vector Onchocercavolvulus(‘river blindness’).
  • In Australia Simulium spp.infect cattle O. gibsoni – economic loss.
slide4
(c). Flies as vectors

Family Glossinidae, genus Glossina – tsetse flies.

  • Hosts & vectors of trypanosome protozoans.
  • Trypanosomabrucei species complex.
  • Sub-saharan Africa.
d hemipterans
(d). Hemipterans.

Up to 2.5cm

Class Insecta. Order Hemiptera.

  • Parasitism in 2 lineages.
  • Mouthparts - piercing/sucking.

1. Family Reduviidae.

Subfamily Triatominae.

2. Family Cimicidae - bedbugs.

slide6
Economic impact of vector-borne diseases.
  • Morbidity & mortality.
  • Human health & productivity.
  • Losses to draught & pack animals.
  • Milk & meat yields.
  • Damage to skins & hides & wool quality.
  • Losses in agriculture, companion animals & sport animals.
  • Fertiliser?
slide7
2-8mm

Advances in the control of Ctenocephalides felis (cat flea) on cats and dogs.

Michael K. Rust.

Trends in Parasitology21:232-236.

slide8
2-8mm

Introduction

  • Cat flea
  • Important ectoparasite - cats & dogs.
  • Topical & oral insecticides revolutionised control.
  • Eliminate need to treat environment.
  • Reduces flea allergic dermatitis (FAD).
  • Insecticidal resistance?
  • Extend longevity of these new compounds.
slide9
Flea control on cats & dogs
  • Cat flea, Ctenocephalides felis.
  • Most problematic.
  • Discomfort
    • Pets & owners (parasite psychosis)
  • Vectors
    • tapeworm
  • Cause flea allergic dermatitis (FAD).
  • Role in feline leukaemia & cat scratch fever?
  • Annual control expenditures
    • >US$1bn – USA. 1.1billion euro in Western Europe.
slide10
2-8mm

Flea control on cats & dogs

  • Revolutionary control products in past 10 years
    • systemic & topical
  • Eliminates need to treat environment
  • Only need to treat animal.
  • Determining efficacy of treatment in field difficult.
  • Comb - 5 mins – estimate flea population.
  • Flea distribution - head & neck.
slide11
2-8mm

Questions?

slide12
2-8mm

Flea biology

  • Where do flea infestations originate?
  • How do animals that live indoors get infected?
  • Reinfestation after successful treatment?
  • Feral animals reservoirs?
    • Lack of evidence.
  • Feral animals infected by fleas from companion animals.
  • Overlapping territories – transfer cycle.
    • Preventative use control products for pets exposed to outdoors.
slide13
Flea biology
  • Immature fleas:
  • Require RH >50%.
  • Temp 4 -35OC.
  • Feed on dried blood & yeast
    • Adult flea faecal blood
    • Cannibalism of non-fertile eggs
  • Adult male & female BSIs
    • Mating
    • On host
    • Male - fully fed 11min
    • Female – fully fed 25 min
slide15
Host-targeted therapy
  • Oral / topical treatments.
  • 1995 – registration of lufeneron.
  • Avermectins
  • Fipronil
  • Imidacloprid
  • Nitenpyram
  • Pyrethroids & pyrethrins
  • Insect growth regulators
    • Juvenile-hormone analogues (JHAs)
    • Insect developmental-inhibitors (IDIs)
slide17
Flea allergic dermatitis (FAD) studies.
  • Caused by hypersensitivity to flea saliva components
  • Individuals – varying severity.
  • New concept – oral & topicals can manage FAD.
  • If treatment prevents feeding – no allergen.
    • Continuous or episodic feeding = FAD.
    • Examples of compounds that inhibit feeding.
slide19
Insecticide resistance.
  • Pest status cat flea
  • Extend longevity of current treatments.
  • Monitoring programmes - insecticidal resistance.
  • Need bioassays – adults – larvae.
  • Background levels – resistance & susceptibility.
  • No universally susceptible strains
    • Use lab strains for baseline
    • Maintenance & distribution of lab strains for research
slide20
Insecticide resistance.
  • Cat fleas tend to develop resistance.
  • Limited reports of resistance to new compounds
    • “Cottontail” strain
    • Field–collected strain
slide21
Insecticide resistance.
  • Rdl gene mutations– associated with resistance
    • Cyclodienes
    • Fipronil
    • PCR-based diagnostics
    • Resistance in a UK field population
  • Promising technique for monitoring potential resistance.
slide23
Concluding remarks.
  • Challenge:
    • develop control strategies that conserve these therapies.
  • Monitoring
  • Knowledge application
  • Stewardship
    • Vets & pet owners
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