Introduction to ectoparasites Flashcards
What is the definition of a parasite?
An organism that lives on or in another living organism and obtains all or part of its nutrition from its host
What phylum are the majority of ectoparasite?
Arthropods
What are the three main classes of ectoparasite?
- Acari
- Insects
- Crustacea
What is an obligate ectoparasite?
A completely parasitic ectoparasite
What is a facultive ectoparasite?
Can be free-living or parasitic, they usually feed on decaying meat but can infect live hosts by mistake
What is a permanent ectoparasite?
Spends its entire life cycle on the host and can only spread via close-contact
What is a semi-permanent ectoparasite?
It spends part of its life cycle off of the host, e.g fleas
it actively seeks a host
During what stage of an ectoparasites life is it most prone to environmental stress?
The stages where it is off the host
Where do the majority of ectoparasites live?
Mostly on or in the skin
Name three ways ectoparsites can cause damage
- Blood feeding which can cause fatal anemia
- Damage to the skin/ the underlying tissue
- Inducing an inflammatory reaction
What are 5 types of Pruritus (itching) ?
- Rubbing and scratching (often excessive)
- Scab lesions (allergic reaction)
- Traumatic wounds (excessive scratching)
- Hairballs (excessive grooming – especially calves)
- Structural damage to objects (excessive rubbing)
What are three clinical signs of an ectoparasite?
- Anaemia
- Pruritus
- Loss of Body Condition
What are the two mechanisms that Pruritus can be induced?
- Mechanical stimuli, e.g sensation via free nerve endings in the skin
- Allergic reaction, e.g bites/stings
Give some examples of things that can influence the specificty of an ectoparasite
- Skin characteristics
- Bacterial flora
- Blood components
- hair coat characteristics
- host availabilty
What are some characteristics of astimgmatic mites?
Free-living fungivorous mites (skin and respiratory allergies)
Ecto or endoparasites (under skin); often found in stale animal feed
What are some characteristics of Prostigmatic mites?
Free-Living and parasitic
What are some characteristics of Oribatidae mites?
Free-Living soil dwellers
Intermediate hosts of mammalian tapeworms
What are some characteristics of Mesostigmata parasites?
Free-living ectoparasites
They often move quickly
What are some characteristics of Ixodida ticks
Highly specialised blood feeders
What is teh difference between Mesostigmatid and Prostigmatid?
Mesostigmatid have openings in the body and prostigmatid have openings at the head
How long does moulting take in Mites?
Moulting can take hours to days depending on the species
they do not feed whilst moulting (which means they will be insensitive to treatment during this time
What are some non-burrowing mites?
- Octodectes
- Chorioptes
- Psoroptes
- Cheyletiella
What are some Burrowing mites?
- Sarcoptes
- Notoedres
- Trixacarus
- Cnemidocoptes
- Demodex
- Psorobia
What are some things that mites can do to cause allergic dermatitis?
- Salivary secretions
- Sloughed skin
- Excreta
- Peritrophic mange
What type of mite causes sarcoptic mange?
Sarcoptes scabiei (burrowing mite)
What type of mite causes Psoroptic mange?
Psoroptes spp. (non-burrowing mite)
How do ticks actively seek hosts?
Use ‘questing’ using carbon dioxide
What is the name of the disease that lice cause?
Pediculosis
What kind of parasites are lice?
Permanent parasites, they spend their whole life cycle on the host
What two kinds of lice are there?
- Blood sucking (longer heads)
- Chewing (flatter heads and less prone to systemic insecticide)
Name 5 adaptations lice have to ‘parasitic life’
- Dorso-ventral flattening
- Head and mouthparts are directed forward
- reduced number of antennal segments
- thoracic and abdominal spiracles
- specialised legs and claws
they are also adapted to cling to hair and are therefore hard to remove
Name 3 mechanisms of spread for lice
- Close penning of animals together
- Mother to offspring
- Shared combs and brushes
What disease can fleas cause in rabbits?
- Myxamatosis
Give 5 ways fleas are adapted to parasitic life
- Laterally flattened
- Antennae recessed in fossae
- Head sessile on pro-thorax
- Body covered in backwards-pointing hairs
- Allow for easy movement through fur or feathers
What effects do fleas have on the host?
- Can cause flea allergy dermatitis
- Aneamia
- vectors for tapeworms, bubonic plague, typhus
What kind of parasites are flies?
Semi-Permanent parasites
Blood sucking, secretophagous
Give some examples of obligate flies
- Warble flies
- Horse bots
- Sheep nasal bots
Give some examples of Faculative flies
- Sheep blowfly strike
Give some examples of Accidental flies
- Hover fly
- Crane fly larvae
Where are the respiratory openings found on protsigmata, astigmata and mesostigmata respectively?
- Anterior (around the head)
- Do not have respiratory openings
- On the body
Why are mites insensitive to treatment during moulting?
Because they do not feed
What type of lice are sensitive to systemic insecticide?
Blood sucking lice
Describe the life cycle of a flea
- Adults (must feed on blood to become capable of reproduction)
- After 48 hours the adult females can then lay eggs (40-50 per day)
- After 2-10 days they grow into larvae
- after 7-21 days they form pupae (have a cocoon so they are camouflaged and blend into the environment)
- after 7-200 days the pupae become adults
What is the meaning of Nidicolous?
associated with nest-dwelling animals, means that they stay in the same area for a long time after birth (e.g fleas)
What percentage of fleas are in the immature stage?
95%
(50% of eggs drop off into the environment)
(35% larvae in the environment)
(10% are pupae in their resistant stage in the environment)
What do pupae hatch in response to?
In response to vibrations from passing hosts, adult fleas jump in the direction of warmth
What is Myiasis?
Infestation with fly larvaea
What two flies cause sheep blowfly strike?
- Lucilia sericata (green bottle)
- Calliphora erythrocephala (blue bottle)
