INTRO TO PARASITOLOGY Flashcards
It concerns primarily the animal parasites of humans
and their medical significance?
Medical or Clinical Parasitology
Parasitology deals with the
Phenomenon of dependence of oneliving organism to another.
True or False:
Parasites are said to be zoonotic
True, means they exist in animals.
It is an infectious disease that is transmitted between species from animals to humans
Zoonosis
An organism that depends on the host for shelter and
food.
Parasites
An organism that supports or harbors parasites.
Host
Responsible for transmitting the organism from one
place to another
Vector
The number of cases of infection in a population in
any given time.
Incidence
Living together also known as
Symbiosis
3 forms of symbiotic relationship
■ Commensalism
■ Mutualism
■ Parasitism
Association of two different species of organisms that
is beneficial to one and neutral to the other.
Commensalism
What form of symbiotic relationship is Entamoeba Coli?
Commensalism
Association of two different species of organisms that
is beneficial to both.
Mutualism
What form of symbiotic relationship is Shark and remora fish & Corals and fishes?
Mutualism
Association of two different species of organisms that
is beneficial to one at the other’s expense
Parasitism
4 Types of Parasites
- Obligate Parasite
- Facultative Parasite
- Incidental or Accidental Parasite
- Spurious Parasite
Depends on the host for their existence.
Obligate Parasite
Exists in a free-living state or may become parasitic
when the need arises.
Facultative Parasite
Example:
■ Acanthamoeba and Naegleria species
What type of Parasite?
Facultative Parasite
also known as the brain-eating amoeba.
Naegleria fowleri
Attacks on unusual hosts.
Incidental or Accidental Parasite
Examples:
■ Ascaris Lumbricoides (Giant Intestinal
Roundworm)
What type of Parasite?
Incidental or Accidental Parasite
Example:
■ Filarial Worms
What type of Parasite?
Obligate Parasite
Free living organisms in nature that are parasitic to
others but not in humans
Spurious Parasite
TYPES OF HOST
Intermediate Host
Definitive Host
Reservoir Host
Accidental or Incidental Host
Transport Host
Carrier
Host in which the larval asexual phase of parasite
development occurs.
○ Where the asexual phase happens.
Intermediate Host
Host in which the adult sexual phase of parasite
development occurs.
Definitive Host
Host harboring parasites that are parasitic for humans
and from which humans may become infected
(animal).
Reservoir Host
Host other than the normal one that is harboring a
parasite.
Accidental or Incidental Host
Host responsible for transferring a parasite from one
location to another.
Transport Host
Parasite-harboring host that is not exhibiting any
clinical symptoms but can infect others.
Carrier
Parasite that is only seen on the surface of the
organism.
Mechanical (Phoretic Vector)
Parasite that is seen inside the body of the organism
or parasite needs this organism for its development.
Biological Vector
What type of transport host?
Examples:
■ Sandfly
■ Mosquito
■ Kissing bug
Biological Vector
What type of transport host?
Examples:
■ Fly
■ Cockroach
Mechanical vector
TYPES OF PARASITE
(ACCORDING TO THE HABITAT)
-Parasite that is established in or on the exterior surface of a host.
Ectoparasite
Parasite that is established inside of a host
Endoparasite
Lives in organic substances in a state of
decomposition.
○ Lives on dead or decaying organic matter.
Saprophytes
TYPES OF PARASITE
(ACCORDING TO THE HABITAT)
Example: Head Lice
Ectoparasite
The act or process of Inoculation
Exposure
Animal parasites which are harmful causing local and systemic damage.
Pathogen
Period between infection of evidence of symptoms
Incubation Period
Two types of Incubation Period
Prepatent period and Clinical Incubation period
From the time the organism enters the body up to the point that you can recover it from human excreta, urine, or other bodily fluids.
Prepatent Period
From the time the organism enters the body up to the time that the human already is manifesting symptoms.
Clinical Incubation Period
Types of Infection
-Infected person is their own direct source of re-exposure.
-reinfected with
some organism coming from them.
Autoinfection
Examples of Autoinfection
■ Enterobius vermicularis (Pinworm)
■ Taenia Species (Tapeworms)
When an individual harboring parasite is re-infected with the same species of parasite
Superinfection
Example of superinfection
Person A has Amoeba histolytica (she is
diagnosed with Amoebiasis)
Acquired at the same time, Infection.
Coinfection
Enters the body where the parasite prefers to enter
Portal of Entry
Portal of exit in
Anus and mouth
Life Cycle of the Organisms
Simple– ideally in the free-living organisms
Complex-trematodes needs two intermediate hosts
Mode of Transmission
■ Inhalation
■ Ingestion
■ Skin Penetration
■ One definitive host
Monoxenous
■ Two or more definitive hosts
Heteroxenous
The process by which an infection leads to disease
Pathogenesis
PATHOGENESIS OF PARASITIC INFECTION
- Trauma or Physical Damage
- Lytic (liquefaction) Necrosis
- Stimulation of host’s tissue reaction (cellular or
immunologic) - Toxic and/or allergic response
TREATMENT
PARASITE GROUP
-Protozoan
Drugs-Metronidazole
PARASITE GROUP
-Nematode
Drugs-Mebendazole
PARASITE GROUP
-Platyhelminthes:
Drug-Praziquantel
○ Unicellular organisms
○ Organelles
○ Under the kingdom of Protista.
○ All of these organisms have an infective stage but not
all of them are capable of pathogenicity, the disease.
Protozoa
○ Multicellular organisms
○ Organ System
○ Under the kingdom of Animalia.
● Metazoa
The subkingdom Protozoa has three phyla (singular: phylum):
- Sarcomastigophora
2.Apicomplexa
3.Ciliophora
Sarcomastigophora
■ Divided into two subphylum:
-Provided with pseudopodia (a finger-like structure that is being used as an organ of locomotion)
➢ Sarcodina
Sarcomastigophora
■ Divided into two subphylum
-Usually flagellates are provided with
flagella (a leaf-like structure) as a mode
of locomotion.
➢ Mastigophora
■ These are the Malaria.
■ No organs of locomotion because these are cells.
Apicomplexa
Balantidium coli is the only organism under the protozoa na may cilia
Ciliophora
○ Is the dormant or non-motile form.
○ Responsible for transfer of infection.
○ More resistant.
○ Can be found in semi or formed stools pero pwede rin
watery.
○ Can only be found in the intestine
● Cyst
○ Motile stage
○ Has an organ of locomotion
○ Responsible for pathogenesis.
○ Can be easily destroyed.
● Trophozoite
○ Formation of the trophozoite from cyst.
○ The conversion of trophozoites to cysts, a process
known as encystation.
○ Occurs in the intestine when the environment
becomes unacceptable for continued trophozoite
multiplication.
● Encystation
○ Formation of the cyst from the trophozoite
Excystation
Common between Encystation and Excystation is the
pH
STRUCTURES INSIDE THE PROTOZOA
○ Usually can be found in Entamoeba species.
○ Centrically located karyosome (similar to nucleolus).
○ Scanty cytoplasm
○ Chromatid granules which surround the cyst wall.
Vesicular Nucleus
○ Can be found in Balantidium species.
○ Usually bean-like shaped.
○ Compact and no cytoplasm can be found
○ When stained, the color is bluish or almost black.
○ Cyst wall comes from the ectoplasm and adjacent to
that is endoplasm.
Compact Nucleus
The subkingdom Metazoa has two phyla:
-Nematodes
-Platyhelminthes
Platyhelminthes
Divided into 2 classes
➢ Cestodes (tapeworms)
★ Can grow as long as 10 meters.
➢ Trematodes (flukes/flatworms)
