6.4.1 : Intro to Parasites Flashcards
What does commensalism mean?
Two species living together, but no metabolic dependence (egg hermit crab and sea anemone).
What does symbiosis mean?
Two species living together, each dependent on the other (egg ruminants and ruminal flora).
What is parasitism?
Two species living together, one (the parasite) at the expense of the other (the host).
What are arthropods?
Insects (fleas, lice, flies)
Acarina (mites, ticks)
What are protozoa?
Single celled organisms
What are helminths?
(Worms)
Cestodes (tapeworms)
Trematodes (flukes)
Nematodes (round worms)
What is a parasite?
Parasitism is the intimate relationship between two organisms in which one (the parasite) lives at the expense of the other (the host).
The relationship involves:
Nutritional dependence
Immunological defence
Integration of life-cycles
How do Protozoa (micro - parasites) multiply?
Inside the host
The host releases cysts or oocysts after replication.
How do helminths (macro-parasites) replicate?
They no not multiply inside the host
What is an overt clinical disease
When an animal is showing clinical signs
What is a sub-clinical disease?
The animal has the disease but does not show any clinical signs
How do parasites like fleas and ticks locate a susceptible host?
Heat
Light
Vibration
CO2 sensors - cows produce lots of CO2 so ticks detect this
Detecting heat helps locate blood vessels, as they are warmer.
How long can parasites survive without a host?
Months or even years
eggs up to 5 years
larvae up to a year
pupa a few months
Can all parasites survive outside of the host?
No, some are transferred by another animal eating the host. It is not fecal oral
How do parasites invade another host
Ingestion
Inoculation
Skin penetration
