Medical Virology

genome, capsid, envelope

all viruses are made up of 2 parts: ________ and ________.

Some also have an __________

7-10

anti-virus antibodies are formed in host in about __________ days

attachment

uncoating

synthesis of viral particles (transcription/translation)

assembly

release

The basic steps of the viral life cycle are:

1)

2)

3)

4)

5)

random

A virus interacts with a host cell through a _____________ collision with the host cell.

non-specific

Viral attachment to the host cell occurs through ______________ interactions between spikes and proteins on the surface of both the virus and host cell

DNA, RNA, retrovirus

The three types of viruses based on genetic material

immediately

(+) ssRNA viruses use the host ribosome to _______________ translate the viral RNA into one long polyprotein.

viral protease

enzyme that cleaves long protein into the individual viral proteins in (+) ssRNA virus

RNA polymerase (RdRp)

(-) ssRNA viruses cannot be translated immediately once inside the host cell;

require ______________ to transcribe the RNA

RNA

DNA viruses must first be transcribed into _______ after entering host cell

DNA polymerase/RT

Some DNA viruses bring along their own _________________ which can be a target of antiviral therapies

reverse transcriptase

enzyme retroviruses use to transcribe RNA --> ssDNA --> dsDNA

drug therapy

Any viral process that differs from normal host cellular processes is a potential target for _____________

outside

Your immune system "sees" what part of a virus?

host

Viruses cannot move without the _________ spreading them

cancer

Viruses can interfere with your DNA and cellular replication machinery leading to different types of _____________

reactivate

Some viruses hide in your body to _____________ at a later time

antigens/proteins

Viruses typically cause an infected cell to express _____________ --> tells host immune system that cell is infected

immune system

Most of the damage caused by many viruses is produced by the ______________, NOT the virus itself

IgM

first type of antibody produced

IgG

long lasting antibodies

lungs (superficial mucosa of upper resp. tract)

primary target organ of influenza virus

airborne particles/direct contact with infected surfaces

influenza transmission

influenza A

subtype of influenza virus that has more antigenic changes over a period of time and can experience recombination of genomes from different species

HA, NA

the important spikes on the outer surface of the influenza virus

HA

the protein on the surface of influenza virus that attaches to the host cell

HA

protein on the surface of influenza virus that elicits the most effective immune response

NA

protein on influenza surface that allows new viral particles to release from the infected host cell

NA

protein on influenza surface that is a target for our influenza drug therapy

antigenic shift

abrupt genetic change where different strains of Influenza A virus mix genetic material to create foreign surface proteins that the host immune system won't recognize

antigenic drift

When an influenza virus genome experiences multiple point mutations over time making the surface proteins unrecognizable to immune system

proofreading

antigenic drift point mutations occur due to lack of _____________ by the viral RNA polymerase

bacterial pneumonia

A potential complication of influenza infection is _________________ due to the destruction of the epithelial lining in the lungs

vaccine, infection

two ways to acquire immunity to influenza virus

long

immunity to influenza virus from either vaccine or infection is _________-lived

lungs

primary target organ for COVID-19

Other host targets of COVID-19 = endothelial lining of several organs and vasculature

blood clots

COVID-19 infection in endothelial lining of organs and vasculature can lead to a hypercoagulable state causing the patient to develop ______________ throughout their body

(can cause stroke, pulmonary embolism, etc.)

spike

The most important surface protein on the COVID-19 viral particle is the ___________ protein

attachment, immune response

the COVID-19 spike protein is important in the _____________ to the host cell and in eliciting an ________________ by the host

viral protease

COVID-19 is a (+) ssRNA virus, so it uses ________________ to cleave the long proteins made inside the host cell

day 0

The day of a positive test or the first day of symptoms from COVID-19

infectious

stage in which viral replication of COVID-19 occurs

inflammatory response phase

occurs after ~Day 7 of illness with COVID-19

viral replication phase

occurs from days 0-7 of illness with COVID-19

spike protein

The vaccines for COVID-19 have focused on creating antibodies to which viral protein?

obesity, high viral load

two key risk factors for severe COVID-19 infection

liver

target organ for viruses that cause hepatitis

fecal oral

route of transmission for hepatitis A

lifelong

Immunity to Hepatitis A is __________ and can be achieved from a infection or vaccine

supportive care

treatment of hepatitis A

Hep A

hepatitis virus that does NOT cause chronic disease

Hep C

type of hepatitis virus that does NOT have a vaccine

DNA polymerase/Reverse transcriptase

Hepatitis B brings along its own enzyme called _______________

lifelong

Immunity to Hepatitis B is _____________ and can be achieved from a vaccine or infection

chronic, neonates

Unlike Hepatitis A, Hep B can become a ___________ infection in up to 10% of adults and in up to 95% of ______________

HBsAg, HBcAg, HBeAg

The envelope of Hep B contains surface antigen __________ while the core of the virus contains __________ and ___________

HBcAg

Hep B protein that forms core but is not secreted outside of cell

HBeAg

Hep B protein that is secreted from infected cell during replication, indicating active replication

HBsAg

The Hep B vaccine contains which antigen?

HBeAg

A patient who has actively replicating Hep B virus will be positive for which antigen?

anti-HbsAg, anti-HBcAg

If a patient with Hep B has resolution of their disease within 6 months, they should test positive for __________ and __________

Anti-HBsAg

A patient will test positive for _____________ after a Hepatitis B vaccine series

Anti-HBsAg

Which Hep B antibody confers immunity?

chronic

If a patient with Hep B continues to have elevated AST/ALT after 6 months, they are now considered to have __________ hepatitis B

acute

Resolution of ___________Hep B: normal AST/ALT within 4-6 months; positive for anti-HBsAg and anti-HBcAg

immune tolerant, immune clearance, immune control

three main phases of chronic Hep B

immune tolerant

phase of chronic Hep B in which there is minimal hepatic injury; high HBV DNA, normal ALT, postive for HBeAg; contageous

clearance (active)

phase of chronic Hep B in which there are flares --> inflammation and injury; clearance of HBeAg; have anti-HBeAg, HBV DNA decreases, elevated ALT; seroconversion may occur

control (inactive carrier)

phase of chronic Hep B in which a person has anti-HBeAg, low HBV DNA, normal ALT; classified after 1 year of normal ALT and low DNA levels

cirrhosis, fibrosis, HCC (hepatocellular carcinoma)

Patients who are classified as having chronic Hep B are at higher risk of developing __________, ____________, and ___________

immune clearance (active)

A patient with chronic Hep B who is experiencing flares would be considered to be in the _______________ phase and will have intermittent elevations in ALT

RdRp, viral protease

Hepatitis C virus brings along 2 enzymes: __________ and _________

parenteral (IV drug abuse)

most common transmission of Hep C

antibodies

___________ to Hep C do not correlate to active, chronic or resolved infection because Hep C lacks a proofreading polymerase which increases its genetic variability

<200, opportunistic infection

AIDS is a result of HIV infection and is defined as a CD4+ count of ___________ cells/mL or when the patient has an ________________

retrovirus

HIV is what type of virus?

gp120

envelope protein that are found on the HIV virus which binds to the CD4 receptor

gp41

envelope proteins that are found on the HIV virus which penetrates the cell membrane.

reverse transcriptase, integrase, protease

enzymes that HIV virus brings along that are important for its life cycle

reverse transcriptase

converts (+) ssRNA genome to dsDNA (very error prone)

integrase

incorporates HIV dsDNA genome into host genome (randomly)

protease

cleaves polypeptide chain into viral proteins

GALT (gut associated lymphoid tissue)

After initial infection, the infected CD4+ T cells hide out in the _________

mononucleosis

After the eclipse phase of HIV infection, patients will experience a ______________-like illness and will mount an immune response that will not completely eliminate the virus.

Fusion inhibitors

Reverse transcriptase inhibitors

Integrase inhibitors

CCR5 (chemokine receptor) antagonists

Protease inhibitors

potential drug therapies using HIV targets

viral load

What is the #1 factor in determining risk of transmission of HIV?

lymphoid tissue (GALT and lymph nodes)

cellular reservoirs (resting T-cells, macrophages, etc.)

What are the 2 types of reservoirs for HIV in the human host?

cancer and/or opportunistic infection

What ultimately causes death in AIDS patients?

within 72 hours of exposure

For a person who has been potentially exposed to HIV+ blood, when should combination anti-retroviral therapy start?

Prevents establishment of lymphoid tissue reservoir

why is it important to start HIV anti-retroviral therapy within 72 hours of exposure?

viral load

it is important for an HIV+ mom to be treated for HIV prior to delivering baby because if ____________ is low, there is a low rate of transmission to the baby

HSV, VZV, CMV

three main herpes viruses

latent

HSV, VZV, and CMV all cause lifelong ____________ infections in the host

cold sores

The HSV-1 primary infection can cause systemic symptoms, while the reactivation commonly causes _____________

peripheral nervous system

The herpes simplex virus can migrate to other areas of the body through the ________________

meningitis

HSV ____________ requires prompt antiviral treatment to prevent neurological sequelae

neonates

_____________ are at high risk of CNS infection due to HSV infection

varicella (chickenpox), zoster (shingles)

The 2 different clinical presentations of varicella zoster virus

chicken pox

The first time a patient is infected with VZV, they will develop a contagious rash called _____________

herpes zoster

Reactivation of latent VZV causes a dermatomal rash called ______________