Introduction to Parasitology Flashcards
area of biology concerned with the phenomenon of dependence of one living organism on another
Parasitology
is concerned primarily with parasites of humans and their medical significance, as well as their importance in human communities
Medical Parasitology
is a branch of medicine that deals with tropical diseases and other special medical problems of tropical regions
Tropical Medicine
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
Tropical Disease
study of diseases at the population and community level
Epidemiology
is the living together of unlike organisms. It may also involve protection or other advantages to one or both organisms
Symbiosis
Types of Symbiosis:
- Commensalism
- Mutualism
- Parasitism
is a symbiotic relationship in which two species live together and one species benefits from the relationship without harming or benefiting the other
Commensalism (Ex: Entamoeba coli)
is a symbiosis in which two organisms mutually benefit from each other
Mutualism (Ex: Termites and flagellates)
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
Parasitism (Ex: Entamoeba histolytica)
a parasite living outside the body of a host
Ectoparasite
Its presence is called an infestation
Ectoparasite
a parasite living inside the body of a host
Endoparasite
Its presence is called an infection
Endoparasite
found at the surface of skin
Ectoparasite
found beyond the skin
Endoparasite
Type of Parasite According to Host Requirement:
- Obligate Parasite
- Facultative Parasite
they need a host at some stage of their life cycle to complete their development and to propagate their species
Obligate Parasite
It cannot exist without a host.
Obligate Parasite
may exist in a free-living state or may become parasitic when the need arises
Facultative Parasite
Type of Parasite According to Duration:
- Temporary Parasite
- Permanent Parasite
- Periodic Parasite
- Transitory Parasite
lives on the host only for a short period of time
Temporary Parasite
remains on or in the body of the host for its entire life
Permanent Parasite
the parasite affects you, but the stage of the parasite is only in the “larval stage” or “baby stage”
Periodic Parasite
it is like a periodic parasite, it is in its “larval stage” in a host, but when it becomes an “adult,” it will NOT become a parasite
Transitory Parasite
Parasite according to duration:
talks about duration of time
Temporary vs. Permanent
Parasite according to duration:
talks about the stages
Periodic vs. Transitory
Parasite according to duration:
parasite in its “larval stage”
Periodic
Parasite according to duration:
when it becomes an “adult” –> not anymore a parasite (becomes free-living and independent)
Transitory
parasite that causes disease
Pathogenic Parasite
parasite that causes disease only on an immunocompromised host
Opportunistic Parasite
a parasite, which establishes itself in a host where it does not ordinarily live
Accidental or Incidental Parasite
organisms that attack a host where they cannot live or develop further
Aberrant Parasite
a parasite where it is found in an organ which is not its usual habitat
Erratic Parasite
is a free-living organism that passes through the digestive tract without infecting the host
Spurious Parasite
Defined as an organism which harbors the parasite and provides nourishment
HOST
It is usually larger, when compared to parasite
HOST
Types of Hosts:
- Definitive or Final Host
- Intermediate Host
- Paratenic Host
- Reservoir Host
is one in which the parasite attains sexual maturity (infective stage)
Definitive or Final Host
harbors the asexual or larval stage of the parasite
Intermediate Host
is one in which the parasite does not develop further to later stages. However, the parasite remains alive and is able to infect another susceptible host
Paratenic Host
they allow the parasite’s life cycle to continue and become additional sources of human infection
Reservoir Host
Life Cycles:
- Simple
- Complicated or Complex
life cycle is completed inside one host (give ex)
Simple (Life Cycle)
Ex: Entamoeba histolytica and Ascaris lumbricoides
parasite requiring two different host, one definitive and one or more intermediate host (give ex)
Complicated or Complex (Life Cycle)
Ex: Schistosoma (human & snail) and Leishmania donavani (human & sandfly)
are responsible for transmitting the parasite from one host to another
Vectors
transmits the parasite only after the latter has completed its development within the host. Therefore, it is an essential part of the parasite’s life cycle.
Biologic Vector
non-essential; only transports the parasite
Mechanical or Phoretic Vector
Two types of Vector:
- Biologic Vector
- Mechanical or Phoretic Vector
is the natural abode of parasite species
Habitat
Where is the habitat of E. histolytica?
Large Intestine (Cecum)
Where is the habitat of Trichomonas tenax
Gingival crevices
Attacks and kills to attain food
PREDATOR
Portal of Entry:
Mouth
Skin
Sexual Contact
Kissing
Congenital
Inhalation
Iatrogenic
Ingestional
from mother to fetus
Congenital
Factors that Determine Intensity of Parasitic Infection:
- Topography or locality
- Faulty sanitary and hygienic measures
- Social condition
- Poverty
- Age
- Presence of intermediate host
- Custom of people
HOW PARASITES DAMAGE HOST:
- Toxic or Lytic
- Traumatic
- Mechanical
- Migration to delicate organs
- Complicating factor
- Obstruction of food
- Irritative or inflammatory
- Excessive reproduction
- Specific pathogenicity
refers to the resistance offered by the host towards injury caused by parasite
Immunity
Types of Immunity:
Innate Immunity
Acquired Immunity
Concomitant Immunity
refers to the resistance offered by the host towards injury caused by parasite
Immunity
Type of immunity where it is inherited
Innate Immunity
both AMI (antibody-mediated immunity) and CMI (cell-mediated immunity) plays a role in prevention
Acquired Immunity
a host infected with a Schistosome resist reinfection with fresh cercariae at the same time maintains adult Schistosome
Concomitant Immunity
