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Parasitic arthropods contd'

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L. tropica - Old World. L. mexicana - New World. Mucocutaneous leishmaniasis (espundia) ... 'Cottontail' strain. Field collected strain. Insecticide resistance. ... – PowerPoint PPT presentation

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Title: Parasitic arthropods contd'


1
Parasitic arthropodscontd.
Jo Hamilton Parasitology BS31820
6-14mm
5-7mm
2
(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.

3
(c). Flies - as vectors
  • Family Simuliidae - Blackflies.
  • Simulium damnosum - vector in Africa.
  • Simulium ochraceum - vector in New World.
  • Vector Onchocerca volvulus (river blindness).
  • In Australia Simulium spp. infect cattle O.
    gibsoni economic loss.

4
(c). Flies as vectors
  • Family Glossinidae, genus Glossina tsetse
    flies.
  • Hosts vectors of trypanosome protozoans.
  • Trypanosoma brucei species complex.
  • Sub-saharan Africa.

5
(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.

6
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?

7
Advances in the control of Ctenocephalides felis
(cat flea) on cats and dogs.
  • Michael K. Rust.
  • Trends in Parasitology 21232-236.

8
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.

9
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
  • gtUS1bn USA. 1.1billion euro in Western Europe.

10
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.

11
Questions?
12
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.

13
Flea biology
  • Immature fleas
  • Require RH gt50.
  • 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

14
Questions?
15
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)

16
Questions?
17
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.

18
Questions?
19
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

20
Insecticide resistance.
  • Cat fleas tend to develop resistance.
  • Limited reports of resistance to new compounds
  • Cottontail strain
  • Fieldcollected strain

21
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.

22
Questions?
23
Concluding remarks.
  • Challenge
  • develop control strategies that conserve these
    therapies.
  • Monitoring
  • Knowledge application
  • Stewardship
  • Vets pet owners

24
Questions?
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