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