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Flashcards in Infection Deck (68)
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what are the 6 chains of infection

infectious agent
portal of entry
portal of exit
susceptible host


give an example of an endotoxin and exotoxin

endotoxin - lipopolysaccharide wall
exotoxin - proteases


what is a fomite

an area that a microbe can survive between reservoirs - keyboards, worktops


what is the incubation period and what is the relevance

where a person is infected but not showing clinical symptoms - dont realise they are. a long incubation period allows for more transmission


what is colonisation

where a patient has high levels of the microbe but is showing no signs of infection. no symptoms or clinical onset - staph aureus in nose


what is the difference between an endogenous and exogenous infection

endogenous - infectious agent comes from within, just in a different place - mutans in pulp
exogenous - infectious agent comes from an external source


what is the RO

risk of transmission, if 1 case can cause 1 case - high risk of transmission, likely to cause an outbreak


describe hepatitis A

RNA virus, lives in contaminated water, transmission via faecal-oral route - seafood can be contaminated. causes an acute infection, more common in developing countries


how can hepatitis A be detected

serology - antibodies (if enough time has passed since infection) or antigens
or antigens detected in faeces


what is the viral load

number of viral particles per ml of blood - high suggests highly transmissible


what is the viral structure of hepatitis B

double stranded DNA genome, protein coat with surface antigens, a core antigen beneath the surface


what are the 3 main routes of transmission of hepatitis B

blood borne - intravenous drug user, healthcare worker
sexual - homo and hetero
mother to baby


why is hepatitis b concerning in a baby

more likely to cause chronic disease - cirrhosis or liver cancer


what is the difference in disease in hepatitis b in endemic and non-endemic areas

endemic - acute disease mainly, with recovery - only 5% of chronic disease
non-endemic - common in children and 95% have chronic disease


describe hepatitis C

RNA virus, blood borne from human flavivirus, no vaccine available but effective treatments, subclinical infection can result in chronic disease - 60%


how is hepatitis D a defective virus

can only replicate protein coat if hepatitis B is present


what is the difference between co infection and super infection

co-infection - infection of hepatitis b and d at same time
super infection - hepatitis b infection, then get d infection


explain the virology of HIV

RNA virus, enters cells and converts to DNA. Then everytime the cell replicates, DNA replicates and proteins made. these can be released to then infect more cells. infects CD4 cells - reduces numbers, less able to fight infections


describe the primary infection of HIV

virus enters CD4 cells and reduces numbers - may have flu like symptoms


describe the latent infection of HIV

body is managing to control the virus, dont realise you have it for 2-15 years. control is lost, allows CD4 numbers to drop and patient to develop more infections


what infections are indictive of HIV

kaposi's sarcoma, candidiasis, hairy leukoplakia, non-hodgkin lymphoma


what does HIV cause

acquired immunodeficiency syndrome


how is HIV transmitted

blood transfusion, IV drug user, unprotected sex


what is HIV PrEp

pre-exposure prophylaxis, given to HIV negative patients who are high risk for catching HIV, keeps virus from establishing a permanent infection


what is the aim of treatment of HIV

reduce viral load to stop developing AID


who are high risk individuals for HIV

sex workers, IV drug users, gay men


define sepsis

organ dysfunction due to excessive inflammatory response to infection


what differentiates sepsis from an infection

organ dysfunction


what is SIRS

systemic inflammatory response syndrome - high or low body temperature, increased respiratory rate, increased heart rate, increased white blood cell count


why can SIRS not be used alone to diagnose sepsis

it doesnt account for organ dysfunction, just systemic inflammation and at risk for sepsis