Introduction to Parasitology Flashcards
A narrower field of parasitology, concerned primarily with the animal parasites of humans and
their medical importance in human communities
Medical Parasitology
Area of biology concerned with the phenomenon of dependence of one living organism on another
Parasitology
Deals with tropical diseases and other special medical problems of tropical regions
Tropical Medicine
An illness which is indigenous to or endemic in a tropical area
→ May also occur in sporadic or epidemic proportions in areas that are non
tropical
→ Many are parasitic diseases
→ E.g. Malaria that is endemic in the Philippines can be present in western
countries due to global transportation of goods
Tropical DIseases
A pathogen that simultaneously injures and derives sustenance
from a host
Parasite
Organisms may develop unique relationships due to
their habitual and long associations with one another
and this relationship is very important for their survival
Biological Relationships
the living together of unlike organisms.
● → May also involve protection or other advantages to
one or both organisms
Symbiosis
Forms of Symbioses
Commensalism
Mutualism
Parasitism
One organisms benefit from
the relationship without
harming or benefitting the
other. give example.
Commensalism
ex: Entamoeba coli - nourished
and protected from harm in the
intestinal lumen without
harming the host tissue
2 organisms mutually benefit
each other and give example
Mutualism
ex: Termites and flagellates in
their digestive system which
synthesize cellulase for
breakdown of ingested wood
One parasite lives in or
another depending on the
latter for its survival and
usually at the expense of the
host and give example
Parasitism
ex: Entamoeba histolytica derives
nutrition from the human host
and causes amoebic dysentery
Classification of Parasites
According to Habitat
TYPE:
Endoparasites
Ectoparasites
Erratic
Lives Inside the host’s body Presence of such parasites is
called INFECTION
E.g. Trichuris trichiura
Endoparasites
live Outside the host’s body, Presence of such parasites is
called infestation
E.g. lice in scalp
Ectoparasites
Found in an organ which is not its
usual habitat
Note: always know the natural
habitat
E.g. Ascaris lumbricoides which is
normally found in the small
intestine → extraintestinal
migration into the lungs and heart
Erratic
Classification of Parasites
According to Dependance of Host
Obligate
Facultative
Needs a host at some stage of their life cycle to complete their development and to propagate their species. They depend entirely upon their host for existence.
Obligate
Example of Obligate
Tapeworm
May exist in a free-living state or may become parasitic when the need arises.
Facultative
Classification of Parasites
According to mode of living
Accidental/incidintal
Permanent
Temporary
Spurious
Establishes in a host where it does not ordinarily live.
Accidental/incidintal
example: ascaris lumbricoides - found in respiratory system
Remains on or in the body of the host for its entire life
Permanent
example: Gut microflora
Lives on or in the host for only a short period of time.
Temporary
Free-living organism that passes through the digestive tract without infecting the host but may cause injury to the host
Spurious
Classification of Host
Type of host:
Definitive/Final
Intermediate
Paratenic
Reservoir
One in which the parasites attain sexual maturity, Doesn’t matter what stage it enters the host as long as it achieves sexual maturity.
Definitive/Final
Example: Taeniasis in human
Harbors the asexual or larval stage of the parasite.
Intermediate
Example: Pigs and cattle in taenia spp.
One in which the parasite does not develop further but remains alive and is able to infect another susceptible host important because they widen the parasite distribution and bridge the ecological gap between the definitive and intermediate hosts.
Paratenic
Allow the parasite’s life cycle to continue and become additional sources of human infection
Reservoir
Example: Pigs in Balantidium coli
responsible for parasite transmission from one host
Vectors
Types of vectors
Biological
Mechanical/Phoretic vector
Transmits the parasite only after it has completes its development within the host. An essential part of the parasite’s life cycle
Biologic
Transports only the parasite No development or multiplication involved in the part of the parasite
Mechanical/Phoretic Vector
Harmful and frequently cause mechanical injury to their hosts
Pathogen or Medically known parasites of humans
Harbors a particular pathogen without manifesting any signs and symptoms.
Carriers
Aedies sp.
Process of inoculating an infective agent
Exposure
Established of the infective agent in the host. Happen once agent has entered the host’s body
Infection
Result when an infected individual becomes his own direct source of infection
Autoinfection
Happen when the already infected individual is further infected with the same species, leading to massive infection with the parasite.
Hyperinfection/Superinfection
Explain incubation period
Clinical
Biological/Pre-patient
Exposure to infection to appearance of first symptoms
Sources of Infection
- Contaminated Solid and Water
- Food
- Arthropods
- Wild or domesticated animals
- Another person, his beddings and clothing and formites
