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39 Cards in this Set
- Front
- Back
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D SYMBIOSIS
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LIVING TOGETHER
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D COMMENSALISM
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ONE PARTNER BENEFITS AND THE OTHER IS NEITHER HELPED NOR HARMED
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D MUTUALISM
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BOTH PARTNERS BENEFIT. USUALLY OBLIGATORY.
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D PARASITISM
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ONE PARTNER EITHER HARMS ITS HOST OR LIVES AT THE EXPENSE OF THE HOST
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3 GROUPS OF PARASITES
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Protozoans - single celled organisms
Helminths - worm-like animals - showing differentiated tissues (multicellular) Arthropods - insects and arachnids |
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WHAT INCREASES PARASITE PREVALANCE
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POOR SANITATION AND NUTRITION, CUSTOMS, CLIMATE, OPPORUTNISTIC PARASITES, LACK OF CDC AND EDUCATION
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YOU CAN DIVIDE PARASITES INTO
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MACROPARSITES AND MICROPARASITES
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MICROPRASTIES EXAMPLES
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PROTOZOANS, BACTERIA, VIRUSES
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MICROPRASTIES GENERATION TIME
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SHORT
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MICROPRASTIES REPRODUCTIVE RATE
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HIGH
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MICROPRASTIES INFECTION TYPES. ACUTE OR CHRONIC?
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ACUTE...SOMETIMES CHRONIC
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MACROPARASITE EXAMPLES
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HELMINTHS ARTHROPODS
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MACROPARASITE REPRODUCTION
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proudce eggs, RELEASE PROGENY, RARELY MULTIPLY IN HOST
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MACROPARASITE GENERATION TI ME
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LONG
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MACROPARASITE INFECTION TYPE. ACUTE/CHRONIC?
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USUALLY CHRONIC INFECTION. BUT ACUTE INFECTIONS CAN BE SEEN. Recovery from acute infections does not necessarily confer immune protection on the host.
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TOXOCARA CANIS WORM INFECTS
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INTESTINES OF PUPPIES
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PROTOZOAN GIARDIA CAUSES
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DIARRHEA IN HUMANS AND DOMESTIC ANIMALS
TROPHOZOAITE STAGE ATTACHES TO SMALL INTESTINE |
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D. FASCIOLA HEPATICA
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LIVER FLUKE. USES SNAIL AS INTERMEDIATE HOST. PROMOTES SEVERE INFLMMATION AND LIVER DAMAGE.
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WHAT IS THE MOST COMMON PARASITE? (INFECTS THE MOST PEOPLE)
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INTESTINAL ROUNDWORM
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D OBLIGATIVE PARASITE
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Obligatory Parasite: Cannot complete their life cycle without spending at least part of the time in a parasitic relationship.
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D FACULTATIVE PARASTIE
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Facultative: when it can live both in a host as well as in free form normally free-living:but can become parasitic when eaten, enters a wound or other body orifice.
CAN BE LETHAL. |
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The organism that harbors the parasite and suffers a loss caused by the parasite is a_______.
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HOST
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D DEFINITIVE HOST
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-The host in which the parasite lives its adult stage
-The host in which the parasite reaches sexual maturity. EX. MOSQUITO IS DEFINITIVE HOST FOR MALARIA |
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D INTERMEDIATE HOST
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Intermediate host:
The host in which a parasite lives as the larval stage The host in which a parasite lives asexual stage Required for parasite development but parasite does not reach adulthood or sexual maturity. EX. HUMANS ARE INTERMDIATE HOST FOR MALARIA |
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D RESERVOIR HOSTS
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The host in which the parasite does not undergo any development but remains alive and infective to another host.
EX. SUSHI WORM IN FISH |
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D Accidental or incidental parasite:
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When a parasite enters or attaches to the body of a host species different from its normal one.
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D DIRECT LIFE CYCLE
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NO INTERMEDIATE HOST
EX. TRICHOMONAS VAGINALIS IS ONLY PARASITE WITH THIS LIFE CYCLE |
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D INDIRECT LIFE CYCLE
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USES ONE OR MORE INTERMEDIATE HOST
MOST PARASITES USE THIS LIFE CYCLE |
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D VECTOR
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An organism (usually an insect) or object (water or food) that is responsible for transmitting the parasitic infection is known as the vector.
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TYPES OF VECTORS
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Types of vectors:
Mechanical Biological |
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D MECHANICAL VECTOR
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Mechanical vector:
Vector which transmits the parasite unchanged (parasite is unchanged); usually an environmentally resistant stage EX. FOOD, WATER |
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D BIOLOGICAL VECTOR
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Biological Vector:
Vector in which the parasite multiples or develops ex. instects |
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D ECTOPARASITE
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Ectoparasite
Lives on the outside of the host Causes infestation Possible biological vector EX. LICE |
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D ENDOPARASITE
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Endoparasite
Lives within the host Causes infection |
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METHODS ENTRY OF PARASITE
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Ingestion
Arthropod bite Direct penetration of the skin by the parasite |
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HOW DO PARASITES DAMAGE HOST?
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Mechanical tissue damage
Toxic Parasite Products Immunopathology Interference with the immune function |
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MECHANICAL TISSUE DAMAGE MECHS
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Blockage of internal organs & vessels:
Pressure atrophy: Migration through tissues: |
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IMMUNOPATHALOGY MECHS
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Anaphylactic: Antigen + IgE, histamine, seen in helminthic infections
Cytotoxic: Antigen on host cells, complement or ADCC, seen in Trypanosoma cruzi infection Immune complex: Antibody complexes with extracelluar antigen, seen in malaria, schistosomiasis Cell mediated: Sensitized T cells kill host cells or release cytokines, seen in Leishmania, schistosomiasis, trypanosomiasis |
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HOW DO PARASITES EVADE IMMUNE SYS?
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ANTIGENIC VARIATION
INTRACELLULAR INFECTION Encystation Camouflage Cleavage of antibodies or complement components Suppression or redirection of the cellular immune response |
