Parasitology: By: Jahre Mark Toledo, RMT, Maed Bio
Parasitology: By: Jahre Mark Toledo, RMT, Maed Bio
Parasitology: By: Jahre Mark Toledo, RMT, Maed Bio
LECTURE 1
BY: JAHRE MARK TOLEDO, RMT, MAED BIO
O Parasitology is the area of biology concerned with the
phenomenon INTRODUCTION
of dependence of one livingTO organism on
another. PARASITOLOGY
O Medical Parasitology is concerned primarily with
parasites of humans and their medical significance, as
well as their importance in human communities.
O Tropical Medicine is a branch of medicine that deals
with tropical diseases and other special medical
problems of tropical regions.
O tropical disease is an illness, which is indigenous to or
endemic in a tropical area but may also occur in sporadic
or epidemic proportions in areas that are not. tropical.
O Symbiosis is the living together of unlike organisms.
O Commensalism is a symbiotic relationship in which two
species live together and one species benefits from the
relationship without harming or benefiting the other.
O Entamoeba coli in the intestinal lumen are supplied with
nourishment and are protected from harm, while it does
not cause any damage to the tissues of its host.
O Mutualism is a symbiosis in which two organisms
mutually benefit from each other
O like termites and the flagellates in their digestive system,
which cellulase to aid in the breakdown of ingested wood.
O Parasitism is a symbiotic relationship where one organism, the
parasite, lives in or on another, depending on the latter for its
survival and usually at the expense of the host.
O One example of a parasite is Entamoeba histolytica, which
derives nutrition from the human host and causes amebic
dysentery.
O Endoparasite- living inside the host
O Ectoparasite- living outside the host
O Infection- presence of endoparasite
O Infestation- presence of ectoparasite
O Obligate parasites- they need host to complete their life cycle
(ex. Tapeworms)
O Facultative parasite- may exist in a free living state. (ex.
Acanthameoba)
O Accidental/incidental parasites- parasites that
establish itself but it is not originally living in that
organism.
O Permanent parasites- parasites that remains on the
body of the host for its entire life cycle(ex.
Dientameoba fragilis)
O Temporary parasites- parasites that temporary
lives in the host
O Spurious parasites- parasites that passes the
digestive tract without infecting the host
O definitive or final host is one in which the parasite
attains sexual maturity. In taeniasis, for example,
humans are considered the definitive host.
O intermediate host harbors the asexual or larval stage
of the parasite. Pigs or cattle serve as intermediate
hosts of Taenia spp.,while snails are hosts of
Schistosoma spp.
O paratenic host is one in which the parasite does not
develop further to later stages.
O Reservoir host animals that harbor the parasite other
than definitive, intermediate, and paratenic hosts.
O Vectors are responsible for transmitting the parasite
from one host to another.
O Biologic vector transmits the parasite only after the
latter has completed its development within the host.
O mechanical or phoretic vector, on the other hand, only
transports the parasite.
O A carrier harbors a particular pathogen without
manifesting any signs and symptoms.
O Exposure is the process of inoculating an infective
agent, while infection connotes the establishment of
the infective agent in the host.
O The incubation period is the period between infection
and evidence of symptoms. Also known as clinical
incubation period.
O The pre-patent period, also known as the biologic
incubation period, is the period between infection or
acquisition of the parasite and evidence or
demonstration of infection.
O Autoinfection results when an infected individual
becomes his own direct source of infection.
O Superinfection or hyperinfection happens when the
already infected individual is further infected with the
same species leading to massive infection of the
parasite.
O SOURCES OF INFECTION
O infective cyst
O invasive trophozoite form.