| Ribavarin + Interferon alpha 2a, Adefovir, and lamivudine are
antivirals used to treat what virus? |
HBV (note the "ine"--a reverse transcriptase inhibitor) |
| What interferon is licensed for tx of chronic hep b and c infections?
|
INF-alpha-2b |
| T or F: Interferons are viral specific |
False; they are HOST specific, not viral specific |
| What definition? Host encoded proteins produced in response to
viruses, synthetic nucleotides, and foreign cells |
Interferons |
| T or F: Hepatitis B encodes a reverse transcriptase. |
TRUE |
| What is responsible for effecting resolution of HBV infection by
elimination infected hepatocyte? |
Cell-mediated immunity and inflammation |
| What is responsible for causing the symptoms in HBV infections? |
Cell-mediated immunity and inflammation |
| ____ of patients w/ chronic HBV infection have continued liver
destruction, cirrhosis, liver failure or primary hepatocellular carcinoma;
_____ of patients have chronic passsive hepatitis and don't have as many
problems. |
1/3; 2/3; Basically know that MOST pts w/ chronic HBV have a passive
chronic infection. |
| (Acute/Chronic) infection of HBV occurs in about 5-10% of the
population. |
Chronic |
| Fulminant hepatitis occurs in ___% of patients and may be ______. |
1; fatal |
| T or F: HBV is characterized by a short incubation period. |
False; long incubation |
| Symptoms of HBV infection appear in about _____% of the patients |
twenty five |
| T or F: HBV can be asymptomatic (chronic) |
TRUE |
| Where does HBV virus replicate? |
in the liver (w/in 3 days of infection) |
| What is the major source of the infectious virus HBV? |
blood (ie needlesticks, injections); other sources: semen, saliva,
milk, vaginal and menstrual secretions, amniotic fluid: **VIA SEX OR
BIRTH** |
| A chronic infection (of HBV) can be distinguished by the continued
finding of __________, ___________, or both and a lack of detectable
___________ to these antigens. |
HbeAg, HbsAg, antibody |
| (HBsAG/HBeAg) is the best correlate to the presence of infectious
virus (HBV). |
HBeAg |
| Detection of both HBsAg and HBeAg in the blood indicates
_____________. |
Active infection |
| What is HbcAG? |
hepatitis b core antigen |
| What common antigen to the particles produced by HBV-infected cells
have on the envelope? |
Hepatitis B surface antigen (HbsAg) |
| How many particles does an HBV-infected cell produce? |
three |
| Which particles produced by HBV-infected cells are the infectious
particles? |
Dane particles |
| What are the largest particles produced by the infected cells (from
HBV)? |
Dane particles |
| What is the virion of HBV called? (national board question) |
Dane Particle |
| What virus? Genome in a relaxed circular partially duplexed DNA (3.2
kb), replicates in the nucleus, has an RNA intermediate, enveloped, tissue
tropism in the liver. |
Hepadnavirus B (HBV) |
| Why was there a sudden peak in influenza resistance to rimantadine and
amantadine in 2003 (mainly in China)? |
Because of the SARS scare, everyone took tons of these drugs over the
counter (even though it doesn't help with SARS….idiots!! Gosh!!) |
| What does neuraminidase (NA) on influenza do? |
Helps viruses "break apart" (important, because two viruses stuck
together aren't infectious--important for drug therapy) |
| What do the new drugs Zanamivir and Oseltavivir (tamiflu) do? |
inhibit neuraminidase |
| How does influenza develop resistance to antivirals? |
mutations in the M2 protein |
| How do antivirals work to inhibit flu infection? |
Block M2 protein FOLLOWING penetration, and PRIOR to RNA replication
|
| What antivirals are used for influenza? |
Amantadine and Rimantadine (tolerated at high dose) |
| T or F: Bird virus and Human virus can mix genes (undergo
reassortment) |
True; this is the bird flu scare |
| Why is the flu vaccine an educated guess? |
Because you can't predict the exact reassortment the virus will
undergo. |
| T or F: Flu vaccine is perfect every time |
false; educated guess |
| What is the definition of epidemic? Pandemic? |
local dissemination; worldwide dissemination |
| Reassortment is a _______ shift, while mutational drift is a _________
shift. (occurs in influenza) |
Major; minor |
| T or F: enzymes (HA and NA) in flu virus can undergo mutation. |
TRUE |
| T or F: antivirals are effective against influenza even after the RNA
has been released into the cell. |
False; have to take w/in 24-48 hrs, before this happens |
| What are the steps (4) of infection and replication for influenza? |
1) synthesis of mRNAs from each segment by a viral specific RNA
dependent RNA polymerase; 2) Synthesis of viral proteins from these mRNAs.
3) Synthesis of positive strand RNA segments that serve as template for
negative strand progeny RNAs; 4) Packaging of progeny virus |
| What is the part of the flu virus that makes it very distinct from
other viruses? |
M2 protein, which forms an ion channel (important for
antivirals--target) |
| T or F: bacterial pneumonia can develop secondary to the flu |
TRUE |
| What causes the systemic symptoms of the flu? |
inteferon and lymphokine response |
| Flu symptoms usually resolve within ___ to ____ days. |
4 to 7 |
| What is the incubation period for flu virus? |
24-48 hours (important, because this is the period if you want to use
an antiviral) |
| where does flu infection begin? |
URT, can spread to LRT |
| How is influenza transmitted? |
airborne respiratory droplets |
| In an average year about ____ to _____% of the population get the flu
|
5 to 20 |
| What is the target for influenza antivirals? |
M2 that forms an ion channel (which is required for uncoating of
virus) |
| Which glycoproteins are present on the surface of Influenza virus? |
Hemagglutinin (HA), Nueraminidase (NA) |
| What virus? Segmented negative strand RNA, Helical Symmetry, Enveloped
|
Influenza |
