Fleas Flashcards
Define parasite
An organism that obtains nourishment and shelter on/in another organism without normally causing death
Define ectoparasite
Spend all or some of their lives parasitizing animals and usually live on or in the surface of the host skin
What is hyperparasitism?
Parasites that live on parasites
What are Parasitoids?
Not real parasites as they eventually kill their host
The parasites we look at are in the phylum ………………
Arthropoda
Fleas are in the class ……………
Insecta
Fleas are in the subclass ……………..
Holometabola
Is siphonaptera (“fleas”) a subclass, order or family?
order
What is the difference between male and female fleas?
The male has two large clasps and a coiled penis
Females have a more rounded back
What is the sensillium?
Sensory organ that allows them to sense CO2 and damp.
How do fleas breathe?
Through spiracles in the exoskeleton
What is the flea exoskeleton made of? What is its purpose?
The exoskeleton is made of chitin (A polysaccharide similar to cellulose) and protein.
It provides protection to the flea forming a hard outer layer, and provides a site for muscle attachment
What are the disadvantages of having an exoskeleton?
It limits absolute size due to oxygen diffusion but also each growth stage will require moulting of the cuticle
What is the flea digestive system made up of?
Foregut: pharynx, oesophagus, crop, proventriculus and gastric caecum
Midgut: Ventriculus
Hindgut: ileum, colon and rectum/anus
Do fleas undergo metamorphosis?
Holometabola undergo complete metamorphosis
What are the most common flea species in the UK?
Ctenocephalides felis(the cat flea) Ctenocephalides canis(the dog flea) Ceratophyllus gallinae (the European hen flea) Spilopsyllus cuniculi (the European rabbit flea) Archaeopsylla erinacei (European hedgehog flea)
Fleas can act as vectors for a wide range of pathogens, name a few:
Myxomatosis – caused by a poxvirus (myxoma virus Leporipoxvirus)
Bartonella henselae (cat scratch disease CSD)
Feline Infectious anaemia (Mycoplasma haemofelis)
Yersinia pestis - plague
Rickettsia felis – typhus
What GI parasite can fleas act as a vector for?
Dipylidium caninum, the dog tapeworm
The fleas eat tapeworm eggs and these eggs hatch in the flea where they develop. They eventually form cystercoids within the adult flea and the flea is eaten by the grooming animal.
Name the 6 types of adulticides for fleas
Organophosphates and carbamates
Pyrethroids and pyethrins
Fipronil
Neonicotinoids
How are Organophosphates and carbamates used to kill fleas?
They are Anti- acetylcholine (AchE) causing overstimulation of nicotinic synapses
Organophosphates bind irreversibly to AchE and Carbamates bind reversibly to AchE
They Kill and repel fleas
How are Pyrethroids and pyethrins used to kill fleas?
Act of Na channels in neurons, causing discharges and depolarisation
Come as powders, collars and sprays that kill and repel fleas
How is Fipronil used to kill fleas?
Interferes with GABA neurotransmission causing disinhibition of neurotransmission in inverts
Kills but does not repel fleas
How are Neonicotinoids
used to kill fleas?
Stimulate nicotinic receptors (like OPs but not via AchE) found in insects but not mammals so it is safe (but not for bees!)
Kills but does not repel fleas
What are the environmental chemicals used to control fleas?
Organophosphates
Pyrethroids
Insect growth regulators (IGRs)
Desiccants eg. sodium polyborate
What are the IGR’s and how do they work?
Lufenuron: Is an insect development inhibitor given orally or by injection. Stored in cat/dog fat and released into blood, so taken up by fleas. Inhibits chitin synthesis and deposition which prevents development of larvae in egg and subsequent moults
Methoprene: Is a juvenile hormone (JH) analog, given as spot on/ spray or for use in environment. JH’s promote larval/pupal growth but prevent pupae moulting to adults, so usually mixed with an insecticide (eg. With fipronil in frontline)
