Introduction Flashcards
(109 cards)
1
Q
The relationship or interaction between two unlike organisms. Type of symbiosis depends on the positivity or negativity of the interaction between the organisms (symbionts).
A
Symbiosis
2
Q
TYPES OF SYMBIOSIS
A
Commensalism
Mutualism
Parasitism
Phoresis
3
Q
Two species live together and one species benefits from the relationship without harming or benefiting the other.
A
Commensalism (+/o)
4
Q
Two organisms mutually benefit from each other.
A
Mutualism (+/+)
5
Q
One organism, the parasite, lives off and benefits from a host, while causing it some harm.
A
Parasitism (+/-)
6
Q
The smaller organism (phoront) is carried by the larger organism (host) but there is almost no/no interaction between the two.
A
*Phoresis (o/o)
7
Q
derived from the phrase “to carry,” and that’s what the larger organism basically does.
A
*Phoresis (o/o)
8
Q
Ex. of symbiotic relationship:
− Ex. Entamoeba coli in the intestinal lumen
A
Commensalism (+/o)
9
Q
− Ex. of symbiotic relationship:
Termites and Flagellates (protozoa that inhabit the gastrointestinal tract) Flagellates help the termites
digest the wood through their cellulase.
A
Mutualism
10
Q
− Ex. of symbiotic relationship:
The protozoan parasite Entamoeba histolytica,
which derives nutrition from the human host and causes amebic dysentery.
A
Parasitism
11
Q
An area of biology concerned with the phenomenon of
dependence of one living organism on another.
A
Parasitology
12
Q
Concerned primarily with parasites of humans and their
medical significance, as well as their importance in human
communities
A
Medical Parasitology
13
Q
The study of parasites, their hosts, and their relationships
A
Parasitology
14
Q
A public health concern, problem of developing societies
A
Medical Parasitology
15
Q
Classification and Types of Parasites
A
Forms
Location
Behaviour?
16
Q
Classification according to form
A
Protozoa (Single-celled)
Helminth (Multi-celled worms)
17
Q
Classification according to location
A
Intestinal (Giardia)
Urogenital (Trichominas)
Blood (Plasmodium)
Tissue (Toxoplasma)
18
Q
Classification according to Behavior
A
Endoparasite Ectoparasite Eratic Obligate Facultative Accidental Permanent Temporary/Transient Spurious Oviparous
19
Q
A parasite which lives inside the host.
The presence of
such a parasite inside the host is also known as an
infection.
A
Endoparasite
Examples: tapeworms, hookworms, whipworms,
roundworms, giardia, coccidia, etc.
20
Q
A parasite which lives outside the host. The presence of
such a parasite inside the host is also known as an
infestation.
*Have humans as their only host
A
Ectoparasite
Examples: head lice, ticks, fleas, etc.
21
Q
A parasite which lives outside its usual habitat.
A
Erratic
22
Q
Examples of Erratic parasites
A
Entamoeba histolytica (found usually in the intestines) which can move up to the patient’s liver or lungs
Ascaris lumbricoides, a roundworm, from the small intestines to other parts of the body
Paragonimus westermani, a lung fluke, which can reach the brain.
23
Q
A parasite which requires a host for survival
A
Obligate
Examples: hookworms, Ascaris, and Trichuris.
24
Q
splits time between being a parasite
and an environment-dwelling organism (free-dwelling
state). May become parasitic in nature when needed.
A
Facultative
Examples:
− threadworms (Strongyloides)
− Acanthamoeba sp.
− free-living Naegleria fowleri
25
A parasite which lives in a place where it doesn’t
| usually live.
Accidental
▪ Examples include parasites that are usually found in
animals that made their way into humans.
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A parasite that resides inside the host for the rest of its
| life.
Permanent
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Temporary/Transient
A parasite that uses the host for feeding or egg-laying
purposes only then leaves after a short amount of
time.
Examples: mosquitoes and bedbugs.
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Spurious
A free-living parasite which passes through human
| hosts without infection.
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Oviparous
A parasite which can produce or lay immature eggs. These immature eggs lack larvae.
Examples: hookworms, Ascaris, and Trichuris.
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Ovoviviparous
A parasite which can produce or lay mature / segmented / embryonated eggs.
Examples : Schistosoma sp, Clonorchis, Heterophyes.
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Larviparous
A parasite which produces larvae in place of eggs.
Example: Trichinella spiralis.
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Parthenogenetic
A female parasite which can self-fertilize.
Example: Strongyloides stercoralis.
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Types of Host
Definitive or Final Host
Intermediate Host
Paratenic Host
Reservoir Host
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A host which carries the mature parasite.
Stage at which
sexual reproduction of the parasite happens.
Definitive or Final Host
Humans are usually the final hosts. (they can be intermediate hosts too. see Plasmodium life span.)
35
A host that harbors or carries the immature, larval stage
of the parasite.
Also where asexual reproduction happens. Examples include animals, plants, insects.
Intermediate Host
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Indirect life cycle
life cycle that contains intermediate host
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Stage of the parasite that you would look for in the
| specimen.
Diagnostic stage
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The final host must obtain it in order for the infection
| to happen.
Infective stage
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Also known as the Transfer Host
Paratenic Host
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Host wherein the parasite does not develop to later stages.
carries the larva stage and there will be
no further development stage.
Paratenic Host
Example: Wild Boars are the paratenic hosts of
Paragonimus westermani
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Are primarily animal hosts.
able to continue the life cycle even with the absence of humans.
They can be a source of human infection.
Reservoir Host
Examples:
▪ Pigs are the reservoir hosts of Balantidium coli
▪ Field rats are the reservoir hosts of Paragonimus
westermani
▪ Cats are the reservoir hosts of Brugia malayi
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Types of Vectors
Biological Vector
Mechanical / Phoretic Vector
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Type of vector:
The parasite would be found inside the host
There would be physiologic changes in the parasite if it is
found inside this
Aedes Mosquitoes which are the vectors of Plasmodium. It can also be a vector of other parasites.
▪ Anopheles Mosquitoes are primarily thevectors of Plasmodium.
Biologic Vector
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Would carry parasites but there will be no morphologic changes that would happen.
Mechanical / Phoretic Vector
Example: House flies and cockroaches can serve as Phoretic Vectors to Ascaris Eggs and certain Protozoans.
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Modes of Transmission
```
Oral
Skin penetration
Arthropod Bites
Congenital Transmission
Transmammary Transmission
```
46
Very common method of getting parasitic infection.
You get infected by ingestion of contaminated food or water. The food or water could contain the embryonated eggs or
larva of the parasite.
Usually the larvae are attached to the contaminated food.
Oral transmission (ingestion of contaminated food and water)
47
Examples of orally transmitted parasites
▪ Taenia solium
− can be acquired through the ingestion of undercooked or raw pork.
▪ Taenia saginata
− can be acquired through the ingestion of undercooked
or raw beef.
Dibothriocephalus latus (formerly known as
Diphyllobothrium latum)
− These are actually tapeworms. They can be acquired through the ingestion of undercooked or raw freshwater fish.
Entamoeba histolytica and Giardia duodenalis (G. lamblia).
− These are Protozoans. They can be acquired through the ingestion of the cyst. This cyst can be found in fecally contaminated water.
▪ Clonorchis, Opisthorchis, and Haplorchis
− all are food-borne parasites wherein the larva can be
found in undercooked or raw freshwater fish.
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Larval penetration
Mode of transmission of certain nematodes such as your Hookworms, Strongyloides
Skin Penetration
Examples:
▪ Hookworms, and Strongyloides
− wherein the Filariform larva (L3 larva) penetrates the skin in order for you to get infected.
▪ Schistosoma species
− wherein the Cercariae would penetrate the skin to get
infected.
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type of transmission:
Vector-borne parasites
Usually vectors involving mosquitoes
Arthropod Bites
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Examples of Anthropod bites
Mosquito Bites
▪ Examples:
− Malaria, which is usually transmitted by Anopheles
mosquitoes
− Filariasis, which are usually transmitted by a variety of
Aedes mosquitoes or Mansonia mosquitoes depending on the species of FIlariasis.
Bites of Flies
Leishmaniasis is usually transmitted by Sand flies that belong to genus Phlebotomus.
African trypanosomiasis, also known as your African sleeping sickness, is usually transmitted by TseTse flies.
Onchocerciasis and Loiasis
Tick Bites
▪ Example: Babesiosis are usually transmitted by ticks under the genus Ixodes.
Bug Bites
▪ Example: Chagas’ Disease or American Trypanosomiasis
is usually transmitted by the Triatoma bug.
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Transmission via breast milk / Transmammary Transmission
→ Example: Ancylostama and Strongyloides
Congenital Transmission
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Mode of transmission of Enterobius vermicularis (pinworm)
Almost anybody can become infected with this parasite,
especially children.
Inhalation of airborne eggs
Example: Eggs of Enterobius vermicularis
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Mode of transmission of Trichomonas vaginalis
sexual intercourse or intimate contact.
54
```
Symptoms include:
Offensive frothy discharge
Vulvitis / Vaginitis
Skin irritation
May be asymptomatic
Strawberry cervix
```
Trichomonas vaginalis
STI - co-exist with chlamydia
55
Group of parasite that:
→ Source of infection: soil
→ Can be transmitted through the ingestion of eggs in the
soil.
SOIL TRANSMITTED HELMINTHS (STH)
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What are the SOIL TRANSMITTED HELMINTHS (STH)
```
H.A.T.S.
▪ Hookworms
− Ancylostoma duodenale
− Necator americanus
▪ Ascaris Lumbricoides
▪ Trichuris trichiura
▪ Strongyloides stercoralis
```
57
Dealing with the study of pattern, distribution, and occurrence of disease.
Epidemiology
58
Focuses on answering these questions
▪ Where are the parasites present in the area/country?
▪ During what season is the parasite more common?
▪ Which group is affected by the parasite?
Epidemiology
Example: Epidemiology of Malaria
▪ Malaria would be more common and frequent in Palawan.
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Dealing with the risk or chance of the infection to happen.
The number of new cases.
Incidence
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The higher the incidence the higher the chance of infection.
True
61
Always correlate the ___ with the risk of infection
incidence
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Dealing with the number of cases in a particular point of time.
Can change in time
Example: There are 40 students in your class and five have acquired the Ascaris infection. As of today, 5 out of 40
students are positive of Ascaris infection.
▪ Answer: ( 5 divided by 40 ) multiplied by 100 = 12.5% is
your prevalence of Ascaris within that group.
Prevalence
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Measure of how severe the infection is, especially when you are dealing with certain nematodes such as Ascaris and Trichuris.
The more worms present or recovered from the patient the more intense or severe the infection.
Intensity of Infection / Worm Burden
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Morbidity
Number of diseased individuals.
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Mortality
Number of patients who died of the disease.
66
A process or program of the government wherein the individual or group of persons would receive anthelmintic drugs.
Deworming
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Public Health Program of DOH
Usually done every year to school-aged children because they
are at higher risk of getting parasitic infection.
Deworming
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Keywords: No more reported cases of that infection.
No more transmission of the infection.
Disease Eradication
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Permanent reduction to zero of the worldwide incidence of
infection caused by a specific agent, as a result of deliberate
efforts.
Disease Eradication
Example: A virus that was completely eradicated or extinct is Smallpox.
70
Keywords: No more cases reported in humans but there is still transmission.
The parasites or the organism is still being transmitted, usually in animals.
Disease Elimination
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A reduction to zero of the incidence of a specified disease in a defined geographic area as a result of deliberate efforts.
Disease Elimination
Example: A parasite nearing extinction / elimination is Malaria.
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→ These are diseases that occur infrequently and irregularly.
→ These are not common or few cases of infection.
Sporadic
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There is constant presence or ongoing transmission of the infection in a particular area or part of the country.
Endemic
→ Example: The Malarial disease is endemic in Palawan.
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A sudden increase in the number of cases.
Epidemic
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An epidemic that has already spread to other countries or worldwide.
Pandemic
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Effects of Parasites on Hosts : Mechanisms by which parasites cause injury
Creation or Release of Enzymes
▪ Example: Cysteine proteinases by Entamoeba histolytica
Invasion and Destruction of Host Tissue
▪ Example: Formation of flask shaped ulcers in your large intestine by Entamoeba histolytica
Deprivation of Nutrients
▪ Example: Diphyllobothrium latum can lead to deficiency in Vitamin B12
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Effects of Hosts on Parasites :
Genetic Make-up of the Host
Nutritional Status of the Host
Immunity of the Host
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Host-Parasite Interactions
Physical Barriers
Host Immune Response
→ Innate Immune Response
→ Acquired Immune Response
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1st line of defense against pathogens
Physical Barriers
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what are the physical barriers
Skin
Mucous membranes (antibodies like IgA)
Components of body fluids
Physiologic Functions of the Body (There are certain physiologic actions in your body that would also protect you from the parasite like the flushing action of urine and tears.)
81
Natural type of immunity
▪ The body would eliminate organisms by nonspecific mechanisms.
Innate Immune Response
Example: Phagocytosis or engulfing those parasites or infectious agents.
82
Specific type of immunity
There is immunologic memory
Acquired Immune Response
immunologic memory:
initially if you get the infection the Innate response would be activated, the T
cells and B cell will be activated.
− T Cells - will produce certain chemicals known as cytokines.
− B Cells - will produce antibodies.
▪ After the initial infection the body will remember that particular organism. The next time your body gets the same infection it will easily recall how to deal with it.
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How the parasites hide from the human host.
Parasite Evasion Mechanism
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What are the Parasite Evasion Mechanism
Resistance to infection
Immune Suppression
Antigenic Variation
Host Mimicry
Intracellular Sequestration
85
→ Permits survival of parasites upon entering blood and tissues.
→ Parasites actually hide inside certain organs in order for them
not to get detected by the immune system.
→ Parasites who have resistant cuticles and integument which is
the covering of the parasite that prevents the phagocytosis of macrophage.
Resistance to infection
86
Reducing the immune function of antibodies and less effective antigen processing.
modify or modulate your immune response.
Immune Suppression
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Changes in the antigen
| → Antigens would serve as the markers of the parasites.
Antigenic Variation
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Copy or mimic the HOST
| TISSUE so that it cannot be noticed by the immune system
Host Mimicry
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Parasite would hide INSIDE THE CELL so that immune system would not detect it
Inside separation or isolation
Intracellular Sequestration
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Adverse Effects of Immune Response to the Host
The body would tend to overreact with a certain infection or parasite because of this overreaction of the body it would do more harm than good to the body.
91
There is an overreaction in a particular infection in the body.
Hypersensitivity
92
TYPES OF REACTION (of immune response of the host)
Type 1 (Immediate type hypersensitivity)
Type 2 (Immune complex formation)
```
Type 3 (Cytotoxic reactions of antibody)
- damage or destruction of cells
```
```
Type 4 (Delayed-type hypersensitivity)
- You would only see the effect after a few days or weeks.
```
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unicellular eukaryotic organisms
four traditional groups based on their means of locomotion and
mode of reproduction: flagellates, amebae, sporozoa, and ciliates
Protozoans
94
4 classifications of Protozoans
Flagellates
Amebae
Sporozoa
Ciliates
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one or more whip-like flagella and, in some cases, an undulating membrane (eg, trypanosomes)
▪ intestinal and genitourinary
Flagellates
96
use pseudopodia or protoplasmic flow to move
Amebae
97
undergo a complex life cycle with alternating sexual and asexual reproductive phases
Sporozoa
98
type of protozoan include:
Cryptosporidium, Cyclospora, and Toxoplasma, and the malarial parasites (Plasmodium species) are all intracellular parasites.
Sporozoa
99
type of protozoan include
Examples:
▪ Entamoeba, Naegleria, and Acanthamoeba
Amebae
100
complex protozoa bearing cilia distributed in rows or patches, with two kinds of nuclei in each individual.
Ciliates
101
parasite representative of this group: Balantidium coli, a giant intestinal __ of humans and pigs, is the only human
Ciliates
102
Formerly listed with the sporozoa, because they possess polar
filaments within a spore,
include more than 1000 species of intracellular parasites that infect invertebrates (mostly insects)
Fungi -- MICROSPORA
103
In humans, these are opportunistic parasites of immunocompromised patients, including those undergoing chemotherapy and organ transplants.
Fungi - MICROSPORA
104
“Worms”; metazoan parasites
Helminths
105
Types of Helminths
Nematodes (Roundworms)
Cestode (Tapeworm)
Trematodes (Flukes)
106
type of helminth: elongated and tapered at both ends, round in cross-section, and unsegmented
Nematode (Roundworm)
A. lumbricoides
Trichinella Spiralis
107
type of helminth:
flat and have a ribbon-like chain of segments (proglottids) containing male and female reproductive structures
Usually involved in indirect life cycle
Cestodes (Tapeworms)
108
Found At the anterior end of an adult tapeworm
often elaborated with muscular suckers, hooks, or structures that aid in its ability to attach to the intestinal wall
SCOLEX OF CESTODES (TAPEWORMS)
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type of helminth:
flattened and leaf shaped with two muscular suckers (oral and ventral)
hermaphroditic, with the exception of the schistosomes (blood flukes), which have male and female worms that exist coupled together within small blood vessels of their hosts.
acquired by ingestion of the metacercariae. The cercariae of schistosomes, however, directly penetrate the skin of their hosts and do not encyst as metacercariae.
Trematodes (Flukes)
