The most famous one is the bacteria that causes the Bubonic Plague.
Dipylidium sp.
The cat with fleas is a host
Cow: Intermediate host to the larval stages of beef tapeworm (Taenia saginata)
It is a parasite - host relationship. The fleas as parasites living off of the dog as a host.
Fleas jump from host to host, so a flea can jump from one cat to another if bitten, but the bite itself will not cause the fleas.
a free-swimming larval stage in which a parasitic fluke passes from an intermediate host (typically a snail) to another intermediate host or to the final vertebrate host
Dogs/fleas is an example of a Host/parasite relationship.
http://tinyurl.com/gdhosting
vector
Intermediate host - snail definitive host - cattle/sheep
An intermediate host is an animal that is needed for a parasite to develop through one or more stages of life before being transferred to a definitive host in which the parasite will develop into sexual maturity. A reservoir host is a host that may be an intermediate or definitive host but provides a place where a parasite may "hang out" while enviromental conditions are less than optimal.
Cats and dogs
reproduces asexually.