Introduction to Parasitology

Parasitology: is the science dealing with the study of protozoa & pathogenic effects.
Parasite: an organism that lives in or on anther organisms (host) and obtains its food from host.
Host: an organism which harbors parasite.
The parasites of medical importance fall into kingdom: Protista and animalia.
The parasites are classified as three phyla into
1. phylum: protozoa
2. phylum: platyhelminthus
3. phylum: nematoda
Protozoa is single organism microscopic (belong to Protista ). In contrast, Helminthes are multicellular organism or worm, macroscopic (belong to animalia). It possessing well differentiated tissues &organ system. The length of worm vary from less than millimeter to more than meter.
Classes of Protozoa:
Types of locomotion of organelle have been used to divide these into four major classes:
1. Rhizopods (amoebae): organelle of locomotion are pseudopodia and the mode of reproduce by binary fission. Such as E. histolytica
2. Ciliaphora: Organelles of locomotion are cilia and the mode of reproduce by binary fission. Such as Blantidium coli
3. Mastigophora or flagellated: organelle of locomotion are flagella and the mode of reproduce by binary fission.
4. Sporozoa: is non motile and reproduce by sporogony\schizogony.

The types of relationships between parasites and host
1. Phoresis: the parasite transport through the host with mechanism. E. histolytica
2. Commensalism: this relation positive for parasite while neutralized for host.
3. Mutalism: positive for parasite and host.
4. Parasitism: positive for parasite and negative for host.