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149 Cards in this Set
- Front
- Back
zoonosis
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occurs in animals and can be transmited to humans
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vehicle
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food, water, air,
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vector
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animals that carry pathogens
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what impairs the hosts resistance to infection?
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suppressed immune system, broken skin
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principle sites of NI's
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UTI, surgical site, lower resp, cutaneous infections,
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EID
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Emerging infectious disease.
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EID factors?
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new strains, new serovar, antibiotics, globl warming, animal contro
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epidemiology
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when and where occur, how transmitted in population
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notifiable diease
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infectious
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morbidity
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# infected
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mortality
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# deaths
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reservoir
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continual source of organism; adequate conditions for survival and mult.
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reservoirs are?
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human, animal, non living (soil, water...)
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most common bacterial species
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coagulase negative staphylococci
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chain of transmission for NI's
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direct & indirect contact
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pathogenicity
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ability to cause disease by overcoming defenses of hosts
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virulence
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degree or extent of pethogenicity
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portals of entry
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mucous membranes, skin, parenteral route
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why pathogens have preferred portal of entry
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determines occurence of disease
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id50
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virulence - infectious dose for 50% of sample population
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ld50
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potency of a toxin - lethal dose for 50% of sample population
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adherence
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attachment to host tissues at portal of entry
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adhesins
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surface molecules on pathogens, bind specifically to same surface receptors
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name adhesins
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glococlayx, pili, fimbriae, flagella
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biofilms
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masses of microbes that attach, multiply, 65% cause disease
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how do capsules help cause disease?
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impairs phagocytosis, prevents adhesin
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how do m-protetins help cause disease?
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heat and acid resistantt, resist phagocytosis by white blood cells
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how do fimbriae help cause disease?
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attach, taken into host cell
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waxes help cause disease?
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resists digestion by phagocytes?
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what is antigen variation?
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alters surface antigens, "mutates" before antibodies can respond
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coagulases?
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bact. enzymes coagulate blood - clot the blood
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kinases?
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bact. enzymes digest clots or fibrin
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hyaluronases?
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hydrolyze hyaluronic acids, cause gangrene
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collagenase?
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helps spread gangrene by breaking down collagen
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IgA proteases?
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destroy antibodies
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invasins?
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surface proteins, rearrange actin filamtents of cytoskeleton
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siderophores?
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proteins to obtain free iron
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how else obtain iron?
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receptors, toxins
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toxin?
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poisonous substance produced by certain microorganisms
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exotoxins?
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produced inside some bacteria as part of their growth and metabolism
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toxoid?
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altered exotoxin
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antitoxin?
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provide immunity to exotoxins
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name 4 types of toxins
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A-B = inhibits protein synthesis; membrane disruptin=lysis of host; superantigens=protein response
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source, chemica structure and effects of endotoxins
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outer portion of cell wall in gram-neg
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how bacteria cause hypersensitivity?
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body's intense reaction
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plasmids
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carries information that makes resistance to antibodies
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lysogenic conversion
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host cell takes on new characteristics
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how do virus's evade the host defenses
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mimic useful substances, have attachment sites
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what are cytopathic effects?
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invisible effects of viral infection
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how does fungi cause disease?
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metabolic products, allergic responses
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protozoa and diseases?
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plasmodium -> malaria, multiplication, ruptures. Toxoplasma, prevents normal acidification
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helminths and diseases?
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use host tissues -> parasitic masses; blocks lymph circulation
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algae and diseases?
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neurotoxins?
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portal of exit?
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the specific route a microbe uses to leave. secretion, excretions, discharge, and shedding.
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3 common portals of exit
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respiratory tract, gi tract, genitourinary tract
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infections transmitted from the skin?
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drainage, direct, indirect, nonliving
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3 types of methods used to id viral isolates
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wester blotting, restriction fragment length polymorphisms, polymerase chain reaction
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viral species?
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group of viruses with same genetic info
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3 characteristics that classify into families
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1, nucleic acid type 2, strategy for replication 3, morphology
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4 morphological types of viruses
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helical (long rod), polyhedral (many sides), enveloped (spheres), complex (bacteriophage)
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characteristics of viruses
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single type of nucleic acid, multiply inside living cells using synthesizing machinery, NA is surrounded by a protein coat, cause syntheis to transfer to other cells
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how is host range determined?
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requirements of specific attachment
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virion?
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complete, fully developed, infectious viral particle with NA and protein coats
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nucleic acid
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either DNA or RNA, single OR double
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capsid
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protein coat, determined by nucleic acid
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capsomeres
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protein subunits, arrangement is characteristic
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envelope
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covers capsid, made from protein , lipids, and carbs
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spikes
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carb-protein complex, attach to surface
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outcomes of lysogeny?
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1. immune to reinfection by same phage 2. phage conversion: host-cell takes on new properties 3. specialized transduction (only certain genes can be transfered)
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how differ in multiplication?
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mechanism of entering, synthesis and assembly, maturation and release
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Animal Viruses: attachment
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attach to proteins and glycoproteins of plasma membrane, many sites bound
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AV: entry
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pinocytosis (fold inward), OR fusion
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AV: uncoating
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separation of nucleic acid in protein coat, capsid is digested
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AV: biosynthesis
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DNA or RNA are transcribed and translated
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location of maturation
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DNA & RNA: nucleus, retro: cytoplasm
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molecular biology fo replication: DNA
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single & (double-> polymerase cell enzyme transcribes DNA)
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MB replication:RNA
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must have reverse trascriptase
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MB replication: retroviruses
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RNA->DNA
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enveloped viruses released from the cell?
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budding
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nonenveloped viruses released from the cells?
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lysis
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why difficult to associate viruses of diseases?
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mechanisms of diease are similar
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oncogene
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part of genome that is affected by cancer causing alterations
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oncogenic virus
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causes tumors in animals
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transformation?
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tumor cells, acquire properties that are distinct from properties of uninfected cells
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Human Papiloma Virus
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cervical cancer
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Epstein-Barr virus
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cancer
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Hepatitis B
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liver cancer
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Herpes Simplex virus
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cold sores
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HTLV
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leukemia
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latent viral infection
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virus that remain inactive until reactived by immunosuppresion
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subacute sclerosing panencephalitis
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measles, mental deterioration
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progressive encephalitis
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rubella, rapid mental deterioration
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AIDS dementia complex
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HIV (lentivirus), brain degeneration
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prion
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PROtetinaceous Infectious particle
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how is a prion able to multiploy without nucleic acid
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interaction between 2 proteins, mutates others
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Creutzfeldt-Jakob disease, kuru, scrapie, bovine spongiform
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large vacuoles in brain
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how do viruses enter plant cells?
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wounds or assisted by plant parasites
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viroid
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short pieces of naked RNA, 300-400 nucleotides, no protein coat
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pathogen
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disease causing microorganisms
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pathology
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scientific study of disease
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etiology
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cause of disease
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pathogenesis
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manner in how a diease develops
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infection
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invasion/colonization of body by pathogenic microorganisms
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disease
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an infection that results in any change from a state of health
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normal microbiota
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organisms that live on us, but don't produce disease under normal cocnditions
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origin of normal microbiota
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birth canal, eating
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normal flora
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present, but dissapear
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locations of normal microbiota
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skin, eyes, nose, mouth, large intestine, urinary tract
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factors that determine distribution and comp of normal microbiota
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nutrients, physical and chemical factors, defenses of hosts
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microbial antagonism
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prevent overgrowth of harmful organisms
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mutualism
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both benefit
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commensalism
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one benefits, the other is unaffected
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parasitism
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one benefits at the expense of others
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probiotics
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live microbial cultures applied to or ingested, exert benefit effect
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opportunistic pathogens
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don't cause disease in normal environment
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synergism
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2 things working together, 2 microbes working together to cause diease, ie gingivitis
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symptoms
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changes in body function, not seen by observer
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signs
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objective changes
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syndrome
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specific group of signs or symptoms
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communicable disease
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spreads indirect or direct
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contagious
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EASILY spread
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noncommunicable
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not spread from one host to another
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incidence
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# of people in a population / time period (see spread of disease)
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prevalence
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# of people in population / specific time, new & old cases (seriousness and length)
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sporadic
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occurs occasionally
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endemic
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constantly present
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epidemic
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many in short period of time
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pandemic
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epidemic gone world wide
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acute
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develops fast, lasts short
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chronic
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develops slowly, continual, recurrent for long time
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subacute
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intermediate, between acute and chronic
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latent
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remains inactive til triggered
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herd immunity
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many immunne people in a community
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local
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invading microorganisms, small area
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systemic or general
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spread throughout body by blood or lymph
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focal
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systemic, specific area
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bacteremia
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presence of bacteria in blood
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sepsis
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toxic inflammatory condition from spread of microbes
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toxemia
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presence of toxins in blood
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viremia
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presence of viruses in blood
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primary
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acute infection that causes initial illness
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secondary
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caused by opportunistic pathogen
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subclinical
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no noticeable illness
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predisposing factors
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makes body more susceptable to disease, may alter course...gender, genetics, climate, nutrition, fatigue, age
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incubation
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1. initial infection until first appearence of signs and symptoms
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prodromal
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2. sometimes present, early mild symptoms
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illness
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3. most severe, death
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decline
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4. s&s subside, vulnerable to 2nd infections
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convalesence
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5. regains strength, recovery
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