d. Present Ideology. Modern medicine has recognized the pathogenic effects
of parasites and is searching for drugs useful in the treatment of parasitic infections.
Prevention is the best method to attack the problem of parasites. Therefore, to prevent
and to treat parasitic infections, the life cycles of the parasites must be known. To this
end, much time and money have been invested in the eradication of vectors (carriers)
that spread parasites. In fact, the fauna (animal life) and flora (plant life) of entire
regions have been changed in an attempt to disrupt the reproduction of Schistosoma in
TYPES OF ORGANISM RELATIONSHIPS
a. Normal Flora. Normal flora consists of microorganisms that are normally and
consistently found in or on the body in the absence of disease.
b. Symbiosis. This is the close association or living together of two organisms
of different species; each party involved in this relationship is called a symbiont.
c. Mutualism. This is a type of symbiosis in which both organisms (host and
parasite) benefit from the association.
d. Commensalism. This is also a type of symbiosis, but in this case, the
parasite (commensal) is benefited and the host is neither benefited nor harmed by the
e. Parasitism. Parasitism is an obligatory relationship in which one organism,
the parasite, is metabolically dependent on another organism, the host. The host may
be harmed by such a relationship.
TERMS IMPORTANT IN PARASITOLOGY
a. Facultative Parasite. A parasite which normally has a free-living existence,
but that will establish a parasitic relationship with a host only if the opportunity presents
itself, is called a facultative parasite.
b. Obligate Parasite. This parasite cannot survive a free living state.
c. Pathogenic Parasite. The main concern of the medical parasitologist is the
identification, treatment, and prevention of parasites that harm man, his crops, and his
d. Ectoparasite. This parasite lives on the outer surface of the host.
e. Endoparasite. This is a parasite that lives inside the host.