Parasitology 1 - Ticks & Mites Flashcards
What is a parasite?
An organism which lives on or in another organism (host) by deriving nutrients at the other’s expense
What is the final host?
Where the parasite reaches sexual maturity and reproduces sexually = production of eggs which are passed in the faeces.
What is an intermediate host?
Harbors immature stages of the parasite, required for completion of the life cycle.
What is a paratenic host?
Harbors immature stages of the parasite also but is not essential for the life cycle of the parasite
What is the pre patent period?
The period of time before the parasite becomes sexually mature (and the host starts to shed parasitic eggs)
Explain the term ‘prevalence’
The % of infected animals in a population
Which group do ticks and mites belong to?
To the arachnids which belong to the arthropods.
Ticks are obligate, blood feeding ectoparasites. How would differ between male/female (hard) ticks?
Males have a large scutum where as the female has a small scutum.
Describe the life cycle of a tick. How long is the life span?
- The male and female mate, resulting in an engorged female laying eggs
- A larva (6 legs) moults and feeds once
- They then turn into a nymph (8 legs), feed once, and reach sexual maturation. The cycle repeats
- Their life span is from 3-5 years.
What is Ixodes Ricinus? Give some characteristics about it
Commonly known as the sheep tick.
- Widespread through out Europe and Ireland
- Requires >80/85% humidity, good vegetation cover and a temp of around 7-10 degrees
- Very broad host range but deer are preferable
What are some characteristics of mites?
- Mange/scabs
- Spends entire life on host
- Transmission by direct contact
- Burrowing and non burrowing mites
What are sarcoptes and demodex spp.?
They are types of burrowing mites. They tunnel into the skin. Sarcoptes have round bodies and short legs. Demodex have elongated bodies and no legs.
Describe sarcoptes mites
- Type of burrowing mite that causes sarcoptic mange (scabies)
- Disease is linked to hypersensitivty
- Causes secondary bacterial infections
- Highly contagious
- Can cause pseudo scabies in humans.
Describe demodex spp.
- Type of burrowing mite, causes demodectic mange
- Inhabits hair follicles and sebaceous gland
- Part of ‘normal skin flora’
- Not contagious
- Occasionally cause disease, esp in dogs.
Describe demodectic mange
- Disease linked to immunodeficiency
- Early stages exhibit hair loss, skin thickening
- Late stages exhibit dry squamous and pustular form (bad odour)
- **NOT A PRURITIC DISEASE!
