Lecture - 5 (1st DDS program)|
PREZENTATION (pdf - password)
BEHAVIOURAL ADAPTATIONS OF PARASITESA. What is the main aim of parasites?
• to survive;
• to produce many offspring stages (dispersive stages);
• to complete the life cycle.
B. What is most important for the parasite strategy?
• Place (where the parasite can find its host?);
• Time (when the parasite can find its host?);
• Host (how to overcome barriers of the host defence?):
a) ecological-etiological barriers;
b) metabolic-immune barriers.
C. How does the presence of a parasite alter host behaviour?
• host’s nervous system
... Toxoplasma gondii and
Dicrocoelium dendriticum (fluke)
Ligula intestinalis (tapeworm)
• host’s muscle
... Trichinella sp.
• by affecting host tissues other than neurons and muscles parasite has influence on host organism (for example on development, metabolism, immunity).
... Giardia intestinalis and the other intestinal parasites - the watery diarrhea that often accompanies Giardia infection can be seen as a host attempt to expel the parasite, or a dissemination that benefits the parasite;
... Echinococcus sp. (example with caribou and wolves);
... Enterobius vermicularis;
... Dipylidium caninum
It is a tapeworm; fleas are intermediate hosts - infected with the tapeworm fleas are slower at escaping and jump on shorter distances; therefore infected insects (fleas) can be easily caught by the dogs or cats and swallowed.