Fleas

Question 1

Define parasite

Answer 1

An organism that obtains nourishment and shelter on/in another organism without normally causing death

Question 2

Define ectoparasite

Answer 2

Spend all or some of their lives parasitizing animals and usually live on or in the surface of the host skin

Question 3

What is hyperparasitism?

Answer 3

Parasites that live on parasites

Question 4

What are Parasitoids?

Answer 4

Not real parasites as they eventually kill their host

Question 5

The parasites we look at are in the phylum ………………

Answer 5

Arthropoda

Question 6

Fleas are in the class ……………

Answer 6

Insecta

Question 7

Fleas are in the subclass ……………..

Answer 7

Holometabola

Question 8

Is siphonaptera (“fleas”) a subclass, order or family?

Answer 8

order

Question 9

What is the difference between male and female fleas?

Answer 9

The male has two large clasps and a coiled penis

Females have a more rounded back

Question 10

What is the sensillium?

Answer 10

Sensory organ that allows them to sense CO2 and damp.

Question 11

How do fleas breathe?

Answer 11

Through spiracles in the exoskeleton

Question 12

What is the flea exoskeleton made of? What is its purpose?

Answer 12

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

Question 13

What are the disadvantages of having an exoskeleton?

Answer 13

It limits absolute size due to oxygen diffusion but also each growth stage will require moulting of the cuticle

Question 14

What is the flea digestive system made up of?

Answer 14

Foregut: pharynx, oesophagus, crop, proventriculus and gastric caecum
Midgut: Ventriculus
Hindgut: ileum, colon and rectum/anus

Question 15

Do fleas undergo metamorphosis?

Answer 15

Holometabola undergo complete metamorphosis

Question 16

What are the most common flea species in the UK?

Answer 16

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)

Question 17

Fleas can act as vectors for a wide range of pathogens, name a few:

Answer 17

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

Question 18

What GI parasite can fleas act as a vector for?

Answer 18

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.

Question 19

Name the 6 types of adulticides for fleas

Answer 19

Organophosphates and carbamates
Pyrethroids and pyethrins
Fipronil
Neonicotinoids

Question 20

How are Organophosphates and carbamates used to kill fleas?

Answer 20

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

Question 21

How are Pyrethroids and pyethrins used to kill fleas?

Answer 21

Act of Na channels in neurons, causing discharges and depolarisation
Come as powders, collars and sprays that kill and repel fleas

Question 22

How is Fipronil used to kill fleas?

Answer 22

Interferes with GABA neurotransmission causing disinhibition of neurotransmission in inverts
Kills but does not repel fleas

Question 23

How are Neonicotinoids

used to kill fleas?

Answer 23

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

Question 24

What are the environmental chemicals used to control fleas?

Answer 24

Organophosphates
Pyrethroids
Insect growth regulators (IGRs)
Desiccants eg. sodium polyborate

Question 25

What are the IGR’s and how do they work?

Answer 25

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)