Fleas Flashcards
Define ectoparasites
Spend some or all of their lives parasitising animals and usually live on or burrow into the surface of host’s skin
Define parasitoids
Parasites that will eventually kill the host
What are the 3 body parts of insects?
- Head
- Abdomen
- Thorax
Describe the anatomy of fleas
- Cones on legs (hairs that point backwards)
- Large hind legs for jumping
- Are Siphonaptera: suck through tube and have no wings
- Coiled internalised penis, ejected for copulation
- Sensilium detects CO2 levels, directing flea to food source
- Laterally flattened
Describe the structure of exoskeleton
- Aka cuticle
- Made of chitin
- Site of muscle attachment
- Limits absolute size and size of each growing stage
How does growth occur in fleas?
- Only through moulting
- Exoskeleton limits size of each stage
What are the layers of the exoskeleton?
- Exocuticle
- Endocuticle
- Epidermis
How is O2 transported around the body?
Dissolved in haemolymph
Describe the respiratory apparatus of insects
- Spiracles in exoskeleton are breathing holes
- Often covered by hairs and oil
- Oil stops water going in and drowing insect
Describe the digestive system of insects
- Tube with lots of absorption
- Major route of infectious agent transmission (mouth or back end)
- Most blood suckers eject substances while feeding e.g. anticoagulants
What are the 2 types of life cycle?
- Hemimetabola
- Holometabola
Define hemimetabola
- Partial metamorphism
- Nymphal stage instead of larval stage (i.e. small adults)
Define holometabola
- Full metamorphism
- Egg, larval, pupak and adult stages
- All look different
What is the main feature of orthoptera?
Straight wings
What is the main feature of diptera?
2 wings
What is the main feature of siphonaptera?
Tube no wings
Describe the feeding habits of fleas
- Adult males and females are obligate blood-sucking parasites
- Larvae live off detritus e.g. dandruff in carpets
Name the cat flea
Ctenophalides felis
Name the dog flea
Ctenophalides canis
- But are most commonly infected with felis
Name the hen flea
Ceratophyllus gallinae
Name the rabbit flea
Spilopsyllus cuniculi
- But pet rabbits most commonly infected with Ctenophalides felis
Name the european hedgehog flea
Arhaeopsylla erinacei
How can fleas be distinguished?
- Genal and pronotal cones
- Head shape
Compare the appearance of the cat, dog and hen flea
- Cat: genal and pronotal cones present
- Dog: more rounded head, pronotal and genal cones, first pronotal cone is smaller than the rest
- Hen: only genal cones
Describe the flea life cycle
- Adults lay eggs (~25/day)
- Eggs can last for months or hatch out in a week depending on conditions
- Hatch into larvae - 3 instas
- Then pupae
- Then adults
Describe the larval stage of fleas
- 3 stages of development (instars)
- Negatively phototrophic, positively geotrophic-
- Develop in 5-11 days
- Feed of detritus
Describe the pupal stage of fleas
- Approx 5mm long
- Pupa/cocoon covered in environmental debris
- 1 week to fully develop
- May remain within cocoon once fully developed until senses appropriate sitmuli
How can fleas cause disease?
- irritation
- Allergy
- Blood loss (anaemia)
- Spread of infections
Describe the direct effects of fleas
- Blood sucking adult females can suck 13.6u blood/day
- Severe infestation of young/old animals can lead to anaemia
- Substances in flea saliva act as allergens
- Result in inflammation and pruritus
Describe flea allergic dermatitis
- FAD
- Commonhypersensitivity reaction in cats and dogs
- Significantly more likely to have signs of FAD when from multi-pet households due to increased spread
- Sensitised animals intermittently exposed have greatest reaction
- Reduced reaction in sensitised, constantly exposed animals
Describe the indirect effects of fleas
- Vectors/hosts for wide range of pathogens
- Myxomatosis
- Bartonella henselae
- feline infectious anaemia
- Yersinia pestis (plague)
- Rickettsia felis
- Dipylidium caninum
Describe the role of fleas in the transmission of Dipylidium caninum
- Flea larvae eat tapeworm eggs
- Eggs hatch and develop within flea body cavity as flea develops
- Tapeworm larvae eventually form infective cysticercoid within adult flea
- Adult fleas eaten by host during grooming
- Cysticercoid enters digestive tract and develops into tapeworms
- Tapeworm eggs passed in faeces
Outline key points in flea control
- Adulticides
- Envionrmental
- removal of those on host
List adulticides effective against fleas
- Organophosphates
- Pyrethroids
- Carbamates
- Fipronil
Describe the use fo organophosphates and carbamates in flea control
- e.g.diazinon and carbofuran
- Anti-acetylcholinesterases
- Overstimulation of nicotininc synapses
- Organophosphates bind irreversibly to AchE, carbamates bind reversibly
- Kill and repel fleas
Describe the use of pyrethins and pyrethroids in flea control
- Act on Na channels in neurones, discharges and depolarisation
- Powders, collars, sprays
- Kill and repel felas
Describe the use of fiprinol in the control of fleas
- Interfere with GABA neurotransmission
- Disinhibition of neurotransmission in invertebrates
- Kills but does not repel fleas
- Spot on
Describe the use of neonicotinoids in the control of fleas
- Imidacloprid, nitempyram, dinoefuran
- Stimulate nicotinic receptors like OPs but not via AcheE
- Found in insects and not mammals so safe for mammals (but bees are a worry)
- Kill but do not repel fleas
- Spot-on
Describe insect growth regulators
- Either striaght hormones or analogues of those involved in life cycles of insects
- e.g. Lufernuron, Methoprene
Describe Lufenuron in flea control
- Inhibis chitin surface, prevents moulting, get soft and do not survive well
- Oral or by injection
- Stored in cat/dog’s fat and released into blood, taken up by fleas
- Prevents development of larvae in egg and subsequent moults
Describe methoprene in flea control
- Prevents pupae moulting into adults
- In nature, drop in this triggers moult to adulthood
- Juvelnile hormone (JH) analogue
- Spot on/spray or environmental use
- Usually mixed with insecticide e.g. fipronil
What is the dorsal vessels?
Vessel that runs along the dorsum of insects internally, carries haemolymph
