micro Flashcards
HBsAG
- is a noninfective glycoprotein that forms spheres and tubules 22nm in diameter, it is part of the virus enveloppe
- it can be produced in enormous quantities so it is not considered a measure of viral reproductivitym unlike the HBcAg core antigen.
HbcAg
-nucleocapis core protein that resides within hepatocytes and aseembles virion it would be a measure of replication
Hep B has DNA polymerase that uses revere trascriptase
to replicated genome and produce an intermediate RNA template
Hep B is a hepadna virus it is partially DS, Circular and has an envelope
HBeAg
is a nuceleocapsis core and precore protein and a marker of high infectivity!
-the core component resides within hepatocytes and assembles virion, while the precore component directs secretion into blood.
hypopigmented, hyperpigmented skin patches or papules, in the setting of a hot and humid climate like the beach!
- pityriasis versicolor/tinea versicolor
- caused by fungus malassezia fur fur
- localized to stratum corneum
- does not tan, so becomes visible on suntanned skin
- diagnosis made by KOH treatment of skin scrappings –> spaghettic ameatballs appearance
streat: topical antifuncals or selenium-containing shampoo
transmission of meningococci usually occurs by exposure to respiratory droplets or direct contact with respiratory secretions
- adheres to mucosal epithelium via pillus in the pharynx then gains access to circulation
- IgA protease that facilitates the survival of the organism
- an antibody coating these pili would prevent pious-mediated attachment
IgA protease
step pneumo
neisseria
h influenzae
herpesviruses
HSV, CMV, EBV etc
are envelloped, linear, DS DNA
circular DNA
hepadnavirus (HBV)
pappilomavirus
polyomavirus (JC, BK)
the only ss DNA virus?
poor pervy single parvovirus B19
Which RNA viruses have no envellope?
Reovirus (colitvirus ROTAVIRUS)
Picornavirus (Hep A, polio, echovirus, rhino virus, coxsackievirus)
Hepevirus (HEV)
Calcivirus (norovirus)
they are ss (+) linear except reovirus which is DS linear
note all the SS (-) sense viruses have what kind of capsid?
helical
except HDV
The majority of ss (+) sense viruses have what kind of capsid?
icosahedral
retroviruses are
envelopped, ss (+) linear, icosahedral
HTLV and HIV
Some important envelopped, ss (-) linear viruses are
orthomyxovirus (segemented, flu)
paramyzovirues (non segmented, Mumps, RSV, parainfluenze virus/croup and rubeola/measles)
Rubella seams simliar to rubeola and mumps and friends but its not a parmyxovirus, what virus family is it?
togavirus
envelopped, ss (+) linear, icosahedral
EEE and WEE encephalitis are toga too
what are some arboviruses (mosquito and tick vector)?
EEE, WEE (toga)
Yellow fever, dengue, St. louis ecephalitis, WNV (flavi flava flav)
the above are enveloped, ss (+) linear
the below are helical, enveloped, ss (-) circular
california E, snadfly/rift valley fever, congo hemorrhagic fever, hanta virus-hemorrhagic fever
HDV alone is considered replication defective until?
it needs HBsAg of hep B to coat the HDAg of heptatitis D
The most common clinical manifestations of C. botulinum is?
diplopia (blurred vision), dysphagia (difficulty swallowing) and dysphonia
What does mycobacteria have that prevents the fusion of lysosome to phagosomes? perimitting it to persist ad a facultative intracellular organism within phagocytes?
sulfatides
Cord factor of mycobacteria
-establish virulence through neutrophil inhibition, mitochondiral destruction, and the induced release of TNF
aspergillus fumigatus and asthma
- generally only infects immunocompromied or deblillitated patients
- but it can colonize bronchial mucosa and complicated asthma and CF via hypersensitivitt rxn
-high serum IgE levels, eosinophilia, IgE and IgG serum antibodies to aspergillus.
Listeria is a facultative intracellular, gram-positive rod
-beta hemolytic
-tumbling mitility at 22 C
-multiple in as low at 4C
has listeriolysin O which can lyse vacuolar membranes which is selectively activated within acidified phagosomes. This allows it to escape the phagosome into the cytosol!
-need cell-mediated immune responses leading to macriphage activation to kill it
Asperigillus 45 (V branching), spores are normally cleared by the mucus and ciliated epithelium of respiratory tract Colonizing aspergillosis
- occurs in OLD lung CAVITIES (form tuberculosis, emphysema or sarcoidosis)
- it does not invade in this case, but grows to form a fungus ball or aspergilloma
Invasive aspergillosis
develps in immunisuppressed patients, especially those with neutropenia –> necrotizing pneumonia and granulomas
it can become disseminated and spreads hematogenously to an organ
Allergic bronchopulmonary aspergillosis
patients with asthma
-titers of IgE antibodies to aspergillus are diagnostic
without preexisting endothelial damage leading to fibrin and platelt deposition at the cusps of valve leaflets, the viridins streptococci are unable to adhere to the valve and estabish an infection leading to endocarditis
-they bind by extracellular polysaccharides (dextran) to fibrin
BK virus is a DNA virus in the polyomavirus family
DS DNA circular no envellop
-in the immunocompromised:
nephropathy (typically post transplant when latent infection is reactivated)
-hemorrhagic cystitis
Which DNA viruses have no envelop?
Adenovirus
parvovirus
papillomavirus
polyomavirus
Which DNA viruses have circular DNA?
hepadnavirus (HBV)
pappilomavirus - no envellope
polyomavirus (JC, BK) -no envellope
Hepevirus is Hep E of HEV
non envelopped ss (+) linear
- spread through the fecal-oral route
- high mortality in infected pregnant women
What two drugs do we use to treat toxoplama gondii?
pyrimethamine and sulfadiazine
coccidioides immitis
- you will see a large spherule much larger than a RBC filled with little balls called endospores
- dimophic fungus
- SW USA
- can cause lung disease in immunocompitent and diseminated disease in immuno compromised
- KOH or silver stain
Most envelopped nucleocapsid viruese acquire their lipid bilaer envelop by budding though the plasma membrane of the host cell.
but?
Some actually acquire their membrane though the nuclear host cell membrane:
herepesvirus
HSV1,2, CMV, EBV, HSV 6, HSV 8
remember these are enveloped, DS linear DNA
How to prevent recurrences of genital herpes
-daily oral treatments of valacyclovir, acyclovir or famciclovir
Corynebacterium diphtheriae
non motile, gram negative rod
-found in clumbs resembling chines letters or in joined V and Y shaped chains
their cytoplasm contains metachromatic granules that stain with ANILINE dyes like METHLYENE BLUE
-tonsillar excudates!
Diptheria AB exotoxin that cataylyzes ADP ribosylation of protein elongation factor 2 EF 2.
EF2 is necessary for tRNA to insert a new amino acid into the growing protein chain during translation.
Hep C envelop proteins
note Hep C is envelloped ss (+) linear RNA virus, icosahedral (flaviviruses)
think flavi flav and his wild party of drugs and booze –> hep C
Envelop proteins (two glycloproteins):
- highly immunogenic
- not lost after recurrent replications
- not sequestered in hepatocytes but are present on the outermost surface of the virus and facilitate entrance into hepatocytes
- antigenic variety –> laging host antibodies
the glycoprotein is prone to frequent mutation, example is there is no 3’-4’ exonuclease proofreading activity in its vision-encoded RNA polymerase
Treatment for pinworm enterobius vermicularis? (the one with the scotch tape test)
albendzole or mebendazole
-pyrantel pamoate is an alternate agent and is preffered in pregnant patients
How to treat loa loa and wuchereria bancrofti (lymphatic filariasis) infections?
diethylcarbanazine
How to treat strongyloided stercoralis and ochocerca volvulus?
ivermectin
How to treat schistosoma, clonorchis siensis and paragonium westermani?
praziquantel
parasite hints
biliary tract disease, cholangiocarcinoma
clonorchis sinensis
parasite hints
brain cyts and seizures
taenia solieum cysticercosis
parasite hints
hematuria, bladder cancer
schistosome haematobium
liver (hyatid) cyst
echinococcus granulosus
parasite hints:
microcytic anemia
ancylostoma, necator
parasite hints: portal HTN
shistosoma mansoni, schistosoma japonicum
parasite hints perianal pruitis
enterobius
parasite hints vitamin B12 deficiency
diphyllobothrium datum
Rheumatic fever is autoimmune following step pyogenes pharyngitis
- the antigenic similarity (epitopes) between bacterial antigens and normal self antigens in heart and CNS are believed to cause formation of anti-self antibodies resulting in rheumatic fever
- fever, arthritis, subcutanous nodules, erythema marginatum, involuntary rhthmic movements (sydeham chorea)
suspect legionella when
- recent exposude to contaminated water (cruise trip, hotel)
- radiographic evidence of pneumonia
- high fever
- neurological symptoms
- GI symptoms
pateints who smoke or have chronic lung disease are at higher risk.
hyponatremia lab finding!
dimorphic fungi
grow at molds at 25-30C
yeast at body temp 35-37C
Blastomycese dermatitidis
ohio and Mississippi river valleys, GREAT LAKES region, found in soil
causes: pneumonia sometimes disseminated
at 25C see branching hyphae
Biopsy large round yeasts with doubly refractile wall and single board based bud
secondary bacterial pneumonia after influenza infection
- elderly patients prone
- step pneumo, staph A, H. influenza common pathogens
- due to virally induced damage to the mucociliary clearence mechanisms in respiratory epitheliem leaves at risk for bacterial infection
Parvovirus B19 ss linear DNA
- slapped cheek
- the blood group P antigen, globoside is a parvovirus B19 receptor expressed on mature erythrocytes and erythroid progenitors.
- thus B19 often replicates in the BONE MARROW
child: febrile respiratory illness then followed by sudden appearance of red, flushed cheeks 2-5 day later
Picornaviruses are non envelopped ss (+) linear, icosahedral
their RNA is translated into one large peptide that is cleaved by proteases into functional viral proteins
