Introduction Flashcards
Parasite
Organism that lives ON (external) or IN (internal) and at the expense of another organism (the HOST)
Definitive (Final) Host:
The host in which the parasite adults undergo sexual reproduction.
Intermediate Host:
Usually the host in which only immature (asexual) stages of the parasite occur.
Paratenic (Transport) Host
A potential intermediate host in which there is no development of the immature parasite; the host does not favor nor hinder the parasite in the completion of its life cycle.
Reservoir Host:
An infected definitive host (animal) serving as a source from which other animals or man can become infected.
Direct transmission
transfer does not require an intermediate host
Indirect transmission:
requires an intermediate host in which development occurs
parasitism
Type of symbiosis
Host is usually injured to some degree
Protozoa: in Kingdom Protista
Single celled organisms – usually microscopic, complex.
flagellates
move by flagella(e)
Amoebas
move by cytoplasmic protrusions called pseudopodia
(many free living, many parasitic)
Sporozoa
All intracellular parasites
Ciliates
cell surface covered with rows of cilia
Trematoda flatworms – Flukes
Thick oval, leaf shape is most common
All except Schistosoma contain both ovaries and testes
Cestoidea – Tapeworms
Most common form is elongated, ribbon-like
Growth of worm begins from segments being budded off anterior end, called scolex
Larval forms called metacestodes develop in intermediate hosts
