Chapter 4 Flashcards
microflora
microorganisms normally living in or on body
are microflora useful
some are, particularly bacteria (some give vitamins)
many microflora give no effect
pathogens
cause disease
are microflora capable of causing disease
yes if health and immune system are weakened
opportunistic pathogens
pathogen background
-vary in where they live and replicate
-how they damage host cells
-ability to persist outside body
virulence
ability to cause damage and disease in host
why are some pathogens more virulent than others
secrete toxins, adhesion factors, evasive factors, host factors
endotoxins
component of bacteria’s cell wall; must consume bacteria in order to have effect on body
exotoxins
bacteria secretes exotoxins that damage host outside of the cell
adhesion factors
help infective organism colonize
evasive factors
help keep immune system from killing infective agent
host factors
genetics
malnutrition
age
does immune system increase or decrease w/age
decrease
contagion
how easily spread from one organism to another is the infection
modes of transmission
direct contact, congestion, indirect contact (fomites), droplets, vectors
indirect contact
sneeze into hand, touch door, another person touches door after
fomite
inanimate object that holds bacteria for certain amount of time
direct contact
bodily fluids
droplets
airborne
vectors
anything that bites
agents of infectious diseases
prions, virus, bacteria, fungus, parasites
prions
small infectious misfolded proteins (prions can spread)
what do prions affect
primarily the nervous system
transmission of prions
genetics/consuming infected tissue
genetic prion disease
creutzfeldt jakob disease
30-40yrs
consuming prion disease
mad cow disease
eating brain tissue
are prions digested
no
virus
protein coat surrounding nucleic acid core (DNA or RNA)
do viruses have their own metabolic enzymes
no
how do viruses attack host
insert genome into host’s DNA and uses that cell’s metabolic machinery to make new viruses
viral-induced cell injury
alters cell physiology (ion movement and messengers)
inhibits synthesis of host cell macromolecules
genotoxic
inflammation
alters cell’s antigenic properties
genotoxic cell injury
toxic to genome
alters host cell and becomes cancerous
antigenic properties
MHC I proteins on cell, cytoplasm not present to cytotoxic T cells
virus changes cell proteins
types of viral infections
acute or latent
acute viral infections
body eliminates (transient)
examples of acute viral infections
rhinovirus, norovirus, measles, influenza
latent viral infections
causes persistent infections (virus stays and hangs out)
example of latent viral infections
HIV
how do antiviral agents kill viruses
they inhibit some stage of viral replication cycle w/o toxicity to cell
examples of anti-viral agents
blocking viral RNA or DNA synthesis (acyclovir blocking HSV)
blocking viral binding to cells (entry inhibitors)
blocking production of protein coats of new viruses (protease inhibitors for HIV)
bacteria
prokaryotes that can live independently and use infected organism for food and shelter
are bacterial infections acute or latent
acute
what are bacterial infections based on
shape and gram stain
shape of bacteria
bacilli, cocci, spirochetes
gram stains
gram positive or negative
gram positive
found on skin, takes up stain
staphylococci and streptococci
gram negative
does not take up stain
causes intestinal and respiratory infections
HB pylori, ecoli, salmonella
mycobacterium
chronic infections
sepsis
blood-borne bacterial infection
gram negative bacteria
what kind of inflammation is sepsis
whole body
what does sepsis lead to
septic shock
septic shock
high mortality (40-50%)
secondary infection and organs shut down
antibiotics
kill bacteria by targeting cell wall, protein, and nucleic acid synthesis, bacterial metabolism
how do bacteria fight antibiotics
inactivating antibiotics, changing binding sites, using different metabolic pathways, and changing walls to keep antibiotics out
can antibiotics treat viral infections
no
fungi
requires cooler temp than human core body temp so most infections are on surface of body (toes, scrotum, scalp)
examples of fungal infections
cadidiasis (yeast), thrush, tinea pedis (athlete’s foot)
examples of vector borne infections
malaria (mosquitos), rocky mountain spotted fever (ticks, lice, chiggers), lyme disease (deer ticks), plague (rodent fleas)
what is an emerging disease
infections that were previously unknown or undetected that have recently appeared
examples of emerging diseases
SARS, Zika, swine flu
why do most emerging diseases come from china
highly populated (transmission is easy)
daily wildlife trade (transfer from animals to humans)
zoonoses
zoonoses
microbe jumps from one species to another
coronavirus
novel - haven’t been exposed before
origin - China, bats
large group of viruses causing disease in humans
naming of coronavirus
SARS CoV2 (actual virus)
COVID19 (illness)
how does SARS CoV2 enter body
via ACE2 receptors in lung (associated w/respiratory symptoms)
what does infection cause
injury
what is the response to infection
inflammation
natural course of infection
inoculation, incubation, prodromal, illness, convalescence, recovery
inoculation
first exposure
incubation
infection multiplies
prodromal
nonspecific bodily changes
malaise
illness
typical symptoms of disease
convalescence
symptoms fade
immune system fights illness
recovery
back to normal
tuberculosis
caused by mycobacterium living inside host cell, macrophages
VERY CONTAGIOUS
what organs/tissues does TB typically affect
lungs, but can affect any part
transmission of TB
airborne droplets
common symptoms of TB
cough (2-3+weeks)
coughing up blood
chest pains
fever
night sweats
feeling weak or tired
weight loss
decreased/no appetite
tuberculosis incidence
highest incidence in Southeast Asia and Africa
developing countries due to poor sanitation, crowded living conditions
course of tuberculosis
immune system forms tubercules (granulomas)
granulomas
macrophages that are infected
what type of necrosis is tuberculosis
caseous
diagnosis of TB
symptoms, medical history, TB test, blood test, chest xray, diagnostic microbiology (sputum smear)
TB exposure
majority of people don’t develop TB after first exposure
latent TB
you don’t know you have it, but can be activated
why does latent tuberculosis infection (LTBI) become active
predisposing factors (HIV, other illnesses, weak immune system, stress, being homeless)
latent TB treatment
long term
isoniazid for 6-12 months
infectious TB treatment
treated in phases w/various drugs
must be isolated until non-infectious
long term
STI
general term for any disease that can be spread by intimate and/or sexual contact
common signs/symptoms of STI
hematuria, urinary frequency, incontinence, purulent discharge, burning, itching, pelvic/genital pain, skin ulcerations, fever, malaise
hematuria
blood in urine
incontinence
leaking out urine
purulent discharge
pus-like discharge
types of STIs
bacterial, viral, protozoal, parasitic, fungal
gonorrhea
bacterial infection (neisseria gonorrhoeae)
transmission of gonorrhea
contact of epithelial surfaces
symptoms of gonorrhea
pain, discharge, asymptomatic
gonorrhea treatment
antibiotics
syphilis
bacterial infection (treponema pallidum)
systemic disease
more deadly
congenital syphilis
maternal-fetal transmission
deadly for baby
stages of syphilis
primary, secondary, latent, tertiary
primary syphilis
chancre, painless
resolves spontaneously
HIGHLY CONTAGIOUS
chancre
bump on genitals, not painful or itchy
secondary syphilis
bacteria has got into blood and traveled to other tissues
HIGHLY CONTAGIOUS
latent syphilis
medical evidence that syphilis is there but patient is asymptomatic
tertiary syphilis
can emerge 5-20yrs after latency
most severe stage
gummas
neurosyphilis
destructive systemic manifestation
gummas
destruction of skin, bone, and soft tissue lesions
treatment for syphilis
antibiotics
chlamydia
bacterial infection (chlamydia trachomatis)
intracellular bacterium
HIGHLY PREVALENT
symptoms of chlamydia
urinary frequency, abdominal pelvic discomfort, discharge, burning and itching, swollen scrotum
chlamydia prognosis
good w/early treatment
what if chlamydia is left untreated
pelvic inflammatory disease, infertility, sterility, epididymitis
genital herpes
VIRUS and HIGHLY CONTAGIOUS
once you have it you can’t get rid of it
stages of genital herpes
active w/skin lesions
latent w/o symptoms but still contagious
types of genital herpes
herpes simplex virus type 1 and 2 (HSV1 and HSV2)
are most cases HSV1 or HSV2
HSV2
genital herpes transmission
through contact w/person shedding virus
symptoms of genital herpes
multiple shallow ulcerations, pustules on genitals, mouth, anus
vesicles rupturing causing pain and itching
genital herpes treatment
managed but not cured
anti-viral medications
human papillomavirus (HPV)
most common
easily spread
120 types
HPV genital warts
found on genitals, very contagious
may go away w/o treatment
transmission of HPV
intimate sexual contact, mother-fetal transfer
what is incubation of HPV
1-6 months
what is HPV a risk factor for
cervical cancer
throat/oral cancers
HPV prevention
vaccine
how to prevent STI
vaccines, safe sex
