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52 Cards in this Set
- Front
- Back
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Definition of Symbiosis
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The living together or close association of two dissimilar organims without consideration of harm or benefit in the relationship.
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Definition of Symbiont
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An organism that spends part or all of its life intimately associated with another dissimilar living organism
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Types of Symbiosis
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+/+ Mutually beneficial
+/0 Beneficial to 1, no effect to other +/- Beneficial to 1, detrimental to other -/0 Detrimental to 1, no effect to other -/- Detrimental to both |
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Definition of Commensalism
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Spatial proximity allows commensal to feed on substances captured/ingested by host...."eating at same table". Neither organism is dependent on the other and relationship benefits one organism (commensal) but neither benefits nor harms the other
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Definition of Phoresis: a type of Commensalism
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"To Carry". One organism (phoront) is carried by another. No physiologic dependency involved and usually involves a smaller organism being carried by a larger organism.
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Definition of Mutualism
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Both participants ("mutuals") gain from the association
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Obligatory Mutualism
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Organisms physiologically interdependent and CANNOT survive without each other
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Facultative Mutualism
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Organisms are not interdependent and CAN survive without each other
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Definition of Parasitism
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One organism ("parasite") lives in or on the other organism ("host"). Parasite benefits, host is harmed.
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Obligate parasite
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Physiologically dependent on the host and CANNOT survive without it.
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Facultative parasite
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Opportunistic parasites CAN survive without the host
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Categories of Parasites
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Macroparasites vs. Microparasites
Ectoparasites vs. Endoparasites Temporary vs. Permanent Facultative vs. Obligatory Accidental vs. Aberrant |
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Differences between Macroparasites (worms, arthropods) and Microparasites (protozoa)
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Macro: multicellular, most do not multiple in host, long generation time, and moderate stimulation of immunity.
Micro: single celled, do multiple in host, short generation time, very good for stimulation of immunity. |
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Definition of Endoparasite
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Any parasite which lives in the internal organs of animals.
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Definition of Infection
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The entry and development or multiplication of an infectious agent within the body of an animal.
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Definition of Ectoparasite
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Any parasite which lives on the exterior of animals.
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Definition of Infestation
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The lodgment, development or reproduction of parasites ON THE SURFACE of the body or superficial tissues.
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Differences between Temporary vs. Permanent parasites.
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Permanent = Individual parasite: lives it's entire life in/on the body of the host
Temporary Lair parasite: lives in lair (resting place) of host when not directly on the host. Range parasite: occurs throughout a large area occupied by the host when not on the host. |
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Differences between Facultative vs. Obligate parasites
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Facultative: Parasitism is optional and can live under different conditions
Obligate: physiologically dependent on host and live as a parasite or dies. It cannot survive under different conditions. |
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Differences between Accidental and Aberrant parasites
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Accidental: infects an animal that is not the natural host and usually develops in a matter similar to that in its natural host.
Aberrant: parasite wanders to wrong site within host and cannot complete life cycle. Can occur in natural host but occurs more commonly in animal that is not the natural host. |
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Definition of Pseudoparasite
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Any object or organism that resembles or is mistaken for a parasite. Ex. pollen grains, fungal spores, blood vessels in muscle, etc...
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Definition of Spurious parasite
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Parasites that pass through the GI tract of a non-host species and are mistaken as parasites of the non-host.
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Categories of hosts
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Definitive, primary or final host
Intermediate or secondary host Paratenic or transport host Reservoir host |
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Definition of Definitive Host
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Primary host/final host. The host in which a parasite reaches maturity (become an adult) and, if applicable, reproduces sexually. The host in or on which a parasite spends the sexual stage of its life cycle. Usually a vertebrate.
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Definition of Intermediate Host
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Secondary host. A host in which a parasite goes through its larval or developmental stages. An animal, usually an invertebrate, that hosts an immature parasite which then moves on to a definitive host where it becomes an adult and reproduces sexually, if applicable.
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Definition of a Paratenic Host.
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Transport or Transfer host. A host in which the parasite remains viable, but does not undergo any further growth or development.
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Definition of a Paratenic Host
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"Transport or transfer host". A host in which the parasite remains viable, but does not undergo any further growth or development. Not essential to completion of life cycle.
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Definition of a Reservoir host.
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An animals (or species) that is infected by a parasite and serves as a source of infection for humans or another species. An animal host in which the parasite resides. The reservoir host serves as a source of infection and potential reinfection of other host species and as a meanas of sustaining a parasite when it is not infecting the other species.
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Definition of a Direct Life Cycle
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Requires a definitive host but not an intermediate host. Parasite infects new definitive host via the environment.
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Definition of Indirect Life Cycle
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Requires more than/equal to 1 intermediate host(s) in addition to a definitive host to complete its cycle. Environmental stage(s) may or may not be included in the life cycle depending upon the parasite species.
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Definition of Incubation period for parasites
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The time interval between entry of an infectious organism into a host and the first appearance of clinical signs of disease in the host. Usually shorter than the pre-patent period, but can be longer.
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Stages of Infection
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Pre-patent period and Patent period
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Definition of Pre-patent Period for infection
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"Before becoming apparent or manifest". The time interval between entry of an infectious organism into a host and the first time we can detect the organism in the host.
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Definition of Paten period for infection
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The period when infection is apparent as indicated by detection or demonstration of the infectious agent.
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Definition of Host Specificity
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The degree to which a parasite is able to mature in more than one host species.
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Presumptive diagnosis of Parasitism
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Infection is presumed based on factors other than actual detection of parasite.
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Definitive Diagnosis of Parasitism
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Presence of the parasite in the host has been demonstrated directly or indirectly.
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Ante-mortem vs. Post-mortem
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Ante-mortem requires demonstration of a parasite in host tissues accessible in the LIVE animal.
Post-mortem requires demonstration of a parasite in host tissues accessible in DEAD animal |
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Definition of Sub-Clinical Parasitism
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Parasites cause infection without causing overt clinical signs, but reduce host productivity.
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Definition of Clinical Parasitism
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Parasites cause overt clinical disease
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Definition of Parasitism
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Animal is infected/infested and it may or may not have overt disease. Only requires detection of some stage of the parasite.
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Definition of Parasitic Disease
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Animals is infected/infested AND HAS clinical disease as a result. Requires detection of parasite, presence of clinical signs AND interpretation of these findings.
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Parasite Factors in Host Damage
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1) Virulence and Strain of parasite
2) Numbers Route of infection Rate of acquisition 3) Ability to multiply in host 4) Predilection site in host 5) Self-limitation |
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Mechanisms of Parasite damage
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1) Competition for ingesta
2) Feed on blood, lymph, organ parenchyma 3) Produce/release toxic or inflammatory substances 4) Destroy host tissues 5) Obstruct vessels, ducts, intestine 6) Serve as vectors for other pathogens; facilitate entry or proliferation of other pathogens 7) Annoyance |
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Host Resistance to Parasites
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1) Inflammation
2) Immunity - Premunition: a state of resistance to re-infection that develops after an acute infection becomes chronic (persists only as long as the infecting organisms remain in body) |
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Definition of Hyperplasia.
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Increase in cell number
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Definition of Hypertrophy
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Increase in cell/organ size.
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Definition of Metaplasia
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Conversion of one type of tissue to another.
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Definition of Neoplasia
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Abnormal cell growth forming a new entity ("tumor")
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Parasite Life-Style Adaptations
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Host seeking activity
Attachment to host Penetration of host cells, tissues Prehension of food Resistance to host enzymes, immunity Inapparent presence Loss of organs |
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Parasite Life Cycle Features
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Environmentally resistant stages
Copious reproduction "Telescoping" life cycle |
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Taxonomy Top to Bottom
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Kingdom
Phylum Class Order Family Genus species |
