MICRO Flashcards
what are the 4 reasons that smallpox was able to be eradicated?
- humans are the only reservoir
- no healthy carriers
- no sub-clinical infections
- effective vaccine available
what causes molluscum contagiosum?
pox virus
what is molluscum contagiosum?
Childhood form --lesions on the face, trunk and limbs --spread from skin to skin --mostly tropical Young adult form (mostly lower abd. lesions, sexually transmitted)
how do you diagnose molluscum contagiosum?
by appearance, confirmed by presence of cytoplasmic inclusions in eosinophils of the affected area
when does a person with smallpox stop being contagious?
when the last scab has fallen off
when does a pt with parvoB19 stop being contagious?
once the rash appears
where does smallpox virus replicate?
in the cytoplasm of infected cells
E. chaffeensis (HME) replicates in which kind of cells?
monocytes
A. phagocytophilia (HGA) replicates in which kind of cells?
granulocytes
which bug causes cat scratch disease?
bortonella henselae
which bug causes lyme disase?
borrelia burgdorferi
what is the classic skin finding with lyme disease?
bullseye lesion
what is the classic skin finding in cat scratch disease?
swollen gland near site of scratch
which bug causes epidemic typhus?
R. prowazekii
which bug causes rocky mountain spotted fever?
R. rickettsia
describe the rash in Rocky mountain spotted fever
spreads from ankles and wrists to soles, palms, trunk
most measles mortality is due to what?
secondary bacterial infections and pneumonia
what disease was the leading cause of aseptic meningitis prior to development of vaccine?
mumps
orchitis in post-pubertal men is the major complication of what diseaes?
mumps
which virus causes a mild disease but is a serious threat to the fetus?
rubella
why was the MMR vaccine so successful?
all 3 viruses are monotypic (only 1 serotype)
humans are the only known reservoir
which highly contagious pathogen causes significant immune suppression and has associated neurological complications?
measles
This pathogen has the H protein rather than the HN and also forms inclusion bodies:
measles virus
what are the contraindications to the MMR and the varicella vaccine?
severe allergic rxn
pregnancy
immunodeficiencey
what is the downside to taking the MMRV instead of MMR and varicella vaccines separately?
taking the MMRV has an increased risk of fever and febrile seizures
which virus causes the roseola rash?
HHV6 & HHV7
what types of pts get the roseola rash?
children 3months - 6 yrs
what kind of genome does the herpes viruses have?
linar, ds DNA genome, icosahedral capsid, enveloped
is VZV neurotropic or lymphotropic?
neurotropic
is HHV6 & HHV7 neurotropic or lymphotropic?
lymphotropic
where do you usually see leprosy affecting the pt (antomically)?
face, butt, limbs
you might get lepromatous leprosy if you lack what type of immune response?
Th1 mediators
how do you diagnose leprosy?
clinical w/ confirmation from skin biopsies and detection of AFB (can’t be grown in culture)
other than humans, who gets leprosy?
armadillos
how do you treat tuberculoid leprosy?
dapsone & rifampin for 6 months
how do you treat lepromatous leprosy?
dapsone & rifampin + clofazime (for 2 yrs)
what type of genome does the parvovirus B19 have?
ss DNA icosahedral no envelope
what causes erythema infectiosum?
ParvoB19
which pathogen causes the slapped cheek rash and lacy rash (on trunk and limbs)?
ParvoB19
what kind of genome does smallpox have?
large dsDNA that is enveloped
what would be the cause of death in a pt who had smallpox?
due to toxic effects on vascular endothelium
when is a patient with smallpox the most contagious?
when the small red spots in the mouth and tongue rupture
how do you distinguish between smallpox and chickenpox?
smallpox has febrile prodrome (chickenpox doesnt)
smallpox are firm and well defined, (chickenpox are superficial)
smallpox lesions will all be at the same stage (chickenpox won’t)
where is relapsing fever endemic?
high, dry areas of western US
what accounts for the relapsing fever in borrelia?
antigenic variation
how might a pt acquired leptospirosis?
contact w/ water contaminated with animal urine, usually through a break in the skin
why are the symptoms assoicated w/ leptospirosis?
DOESN’T CAUSE SKIN LESIONS
Flu-like symptoms
Jaundice & renal damage (Weil’s disease)
Meningitis
how do you diagnose leptospirosis?
serology
how do you treat leptospirosis?
penicillin
how do you diagnose E. chafeensis?
blood smear
confirm w/ serology
how do you diagnose A. phagocytophilia?
blood smear (look for morulae in granulocytes)
how do you treat the Rickettsial diseases?
DOXY
how do you diagnose relapsing fever?
blood smear w/ serology to confirm
Measles virus uses which 2 notable receptors?
CD46 & SLAM
what is the measles clinical case definition?
gen. rash lasting>3 days
Temp. > 38.3
Cough, rhinorhea, and/or conjunctivitis (light sensitivity)
where does the MV replicate?
most lymphatic tissues and organs throughout the body (epithelial, endothelial, mphages, monocytes)
describe the classic measles rash?
starts on the back of the neck or forehead and spreads to extremities
The neurological measles virus complications are the result of an autoimmune response to what protein?
myelin basic protein
what is acute disseminated encephalomyelitis or postinfectious encephalomyelitis?
neurological Measles complication resulting in convulsions, deafness, mental retardations
describe the classic rubella rash?
morbilliform and starts on the face and spreads to the rest of the body
how is measles different than the other paramyxoviridae?
Has H protein instead of HN
forms intracellular inclusion bodies
