Initial infection with HCMV (human cytomegalovirus) generally occurs during ____
childhood
35-90% of adults have been previously infected with HCMV
What the four modes of transmission of HCMV between adults
Saliva and other bodily fluids
Sexual means
Organ transplantation
Blood transfusions
Where does HCMV establish latency? (3)
macrophages/monocytes as well as wells of the kidney
____ represents the most common intrauterine viral infection in the US today
HCMV
____ HCMV diseases can cause damage to the liver, spleen, blood forming organs and the nervous system
Congenital
Why can't you use acyclovir on HCMV?
HCMV doesn't synthesize thymidine kinase (this is needed to start the processes of stopping chain elongation)
Which two viruses have similarities to HCMV (and are in the same herpes subfamily)
HHV 6 and HHV 7
HHV 6 and HHV7 are the causative agent in what disease?
Roseola infantum (rash in infants)
What is the most common clinical syndrome associated with HHV6 infection among aids patients?
encephalitis (brain inflammation)
what virus plays a role in the accelerating the progression from early HIV to AIDS?
HHV6
HHV 8 is also known as
Kaposi sarcome associated herpes virus
What virus is linked to kaposi sarcoma
HHV8--> it has been found in more than 90% of patients with kaposi sarcoma
what was the most common cancer associated with AIDS but declined after the introduction of HAART
Kaposi sarcoma
what does HAART stand for?
Highly active anti-retroviral therapy
How is EBV generally transmitted and what cells does it infect?
saliva
B-lymphocytes
What does the EBV use on the B-lymphocyte
A complement (C3b) receptor (pre-exisiting)
Where does EBV establish latency?
In the B-lymphocyte
EBV induces cell multiplication and immortilization of the B-lymphocyte it infects and this increases the synthesis of what 3 Ig?
IgG
IgM
IgA
IgM contains ____ ___ which are capable of agglutinating sheep and horse RBCs
Heterophile antibodies
what are Heterophile antibodies
antibodies that react with things that are not the designated antigen for them
saw this with cardiolipin and syphillis (cross-reactivity)
What three disease can EBV cause
Infectious mononucleosis (IM)
Burkitt lymphoma
EBV associated nasophayngeal carcinoma
EBV can cause what in immunocompromised individuals
B-cell lymphoma
IM can be identified by detecting heterophillic antibodies using what test?
Paul-Bunnell test
(this is an older version of the mono spot test)
T/F: none of the antiheroes drugs are effective in treating IM due to EBV or preventing development of EBV-related B cell malignancies
True
What can be used to treat oral hairy leukoplakia (white spots on the tongue), in which the EBV is actively replicating int he epithelial cells of the tongue
Acyclovir
malignancy of the JAW that is found in unusually high frequency among children residing in certain regions of equatorial Africa
Caused by EBV
Risk factors: malarial parasites and HIV
Burkitt Lymphoma
What is one of the most common cancers in the southeast asia and north africa regions and among the Inuit population but less common else where
nasopharyngeal carcinoma
A study found that CMV enhanced the immune system in mice...how?
By increasing the T cell response
Hep A, C, D and E contain ____ genomes
Hep B contains a ____ genome
RNA
DNA
portions of asia are endemic for what?
Hep B
The complete viral protein of HBV is called the
Dane particle
the HBV genome is unique because its a circular DNA molecule that is
partly single stranded and partly double stranded
Why can RT inhibitors be used to treat HBV?
because it uses RT in transcription (partly RNA in the genome)
HBV uses what two enzymes during replication?
RT
RNA polymerase
The majority of acute HBV infections result in what?
resolution
What are the 4 (5) proteins encoded by the HBV genome
HBcAg (Hep B nucelocapsid core antigen)
HBeAg (derivative of C--> not considered a separate protein)
In southeast asia, africa, and the middle east the majority of population gets HBV infection _____ but in the western countries people get HBV from ___ or _____
at birth or shortly afterwards (pick it up from mother or infected sibling)
sexual contact
IV drug use
individuals infected with HBV at a very young age have an increased risk of developing
heptaocellular cancer
What is the primary cell type infected by HBV?
Fully differentiated hepatocytes
the titer of infectious HBV (and antibodies to HBV) can be as high as _____ viral particles per mL of blood
100 million
What is used as a marker of disease progression in HBV patients?
levels antigen and antibodies in the titers
What would rise concurrently with HBcAg (nucelocapsid core antigen)
Things like liver enzymes and other collateral processes
what three factors can play a role in the development of fulminant (explosive) hepatitis
more virulent strain of virus
coinfection with other viruses
uncontrolled cytokine activity
_____ HBV greatly increases the risk of developing heptocellular carcinoma
Chronic
What is used to prepare the vaccine for HBV?
HbsAg (surface antigen)
A healthcare worker is exposed to HBV through a needle stick accident. What would be the immediate treatment?
give the person antibodies against HBV (hepatitis B immunoglobulin-->HBiG)
What is found in nature as a co-infection with HBV?
HDV (hepatitis D)
HDV is found in nature as a co-infection with HBV but what is different about the two?
HBV is a DNA virus and HDV is a ssRNA virus
What is the difference between positive strand and negative strand RNA?
positive means it can be readily translated into protein
negative means it needs to be converted to positive before it is made
all enteroviruses can cause ___ including ____
CNS disease
viral meningitis
_____ meningitis is generally milder than ___ meningitis
Viral
Bacterial
What enterovirus is associated with type 1 diabetes?
coxsackievirus
A disease where the gray matter of the brain is inflamed, aka "infantile paralysis"
Poliomyelitis
poliovirus selective destroys what?
the lower motor neurons of the spinal cord and brain stem, resulting in flaccid paralysis
Polio virus binds to a specific receptor that is a member of the ____ ___ family of proteins
Immunoglobulin supergene
Polio virus has the following courses:
95%:
4%:
1%:
95%: no illness-->asymptomatic infection
4%: minor illness--> abortive infection, minor nonspecific symptoms
1%: major illness
____ ___ of poliovirus is when the symptoms are indistinguishable from meningitis caused by other viruses
nonparalytic infection
____ ___ of poliovirus is characterized by muscle paralysis and sometimes respiratory paralysis
Paralytic poliomyelitis
what is post-poliomyelitis syndrome (PPS)
when you have had the disease and you get over it and then get muscle weakness, pain, atrophy, and fatigue later on in life
what are the two different explanations for PPS
fatigue of overworked motor units (new motor units form after polio and they aren't as strong as the original ones)
possible brain damage from viral infection
what are the two polio vaccines and what is the difference between them?
Salk vaccine-- inactivated virus
Sabin vaccine-- live, attenuated virus
Why did they switch from the Sabin to the Salk vaccine?
Since sabin was live they were worried about reversion to virulence of the virus
Three countries where polio is endemic
Afghanistan, Pakistan, Nigeria
Rhinovirus differes from enterovirus because...
enterovirus survives better in acid and rhinovirus survives better in cold environments
How is Hep A transmitted?
Fecal oral route--> consuming contaminated shellfish that have come in contact with sewage
HAV infection is common in countries with ____ ____
poor sanitation
T/F: prognosis of hep A is generally favorable as the development of persistent infection and chronic hepatitis is uncommon
True
immunoglobulins directed against HAV has been used for ___ ____ (passive immunization)
post-exposure prophylaxis
this is passive immunization!
Rubella causes ____ but rubeola causes____
these are NOT the same thing
german measles
measles
Why is it important for pregnant women and children should be vaccinated for rubella?
because it can cross the placenta and spread to the fetus without protective antibodies
it is ~teratogenic~
Class triad of rubella symptoms in the affected neonates (think CDCA)
Cataracts
Deafness
Cardiac abnormalities
T/F: rubella can cause a rash
True
The majority of infections with HCV are _____
subclinical
____ used to be a major cause of post transfusion hepatitis before blood was testing for disease
HCV
Vaccines available?
HAV
HBV
HCV
HAV: yes
HBC: yes
HCV: no
Modes of transmission
HAV
HBV
HCV
HAV:fecal-oral route, contaminated food
HBV: in the USA (IV drug use, sexual means), in other parts of the world (mother to fetus)
HCV: IV drug users
HCV if linked to what?
IV drug use
Most chronic hepatitis infections are :
US:
World:
Us: hep C > hep B
World: hep B> hep C
A not chronic
Order of most common new hepatitis viruses per year in the US
B> A> C
How is the mumps spread?
Respiratory droplets
what does the mumps affect? (2)
The salivary glands, particularly the parotid
can also cause orchitis which can lead to sterility
T/F: measles is more virulent than mumps
True
What is the MMR vaccine?
A live attenuated vaccine for measles, mumps and rubella
The receptor for measles virus is found on most or all nucleated cells and is function is an inhibitory complement receptor, what is it?
CD46
the measles starts with a prodromal fever and the three Cs...what are they
Coryza (a nose cold)
Cough
Conjunctivitis
What is a diagnostic sign associated with measles?
Koplik spots
small white spots on red mucous membranes of the mouth and throat
T/F: koplik spots and the skin rash you get from measles are the same thing
FALSE!!!!
Influenza is what type of virus?
an orthomyxovirus
The flu virus consists of ____ separate and different ____ ____
8
RNA molecules
What is neuramindiase involved in?
Exit from the host cell
What is hemagluttin involved in
entry into the host cell
both attachment and fusion functions
The influenza virus attaches to ____ ___ on host respirtory cell glycoproteins or glycolipids to get into the cell and cleaves it to bud out of the cell
sialic acid (aka neuraminic acid)
replication of the flu virus involves synthesis of ____ positive strand mRNA molecules
8
When do infections from influenza peak?
from october to may
What the two processes that cause the antigenic variability of the influenza viruses?
Antigenic drift
Antigenic shift
caused by random mutations in the viral RNA of the flu virus and does NOT involve change in the viral subtype
antigenic drift
example: H1N1 stays H1N1 there is just a small/conservative change that doesn't affect the phenotype
A more dramatic change in the antigenic properties of the H and/or N proteins of the flu virus and occurs every 10-20 years
antigenic shift
example: H1N1 to H2N2
antiviral agent used to TREAT influenza A and B
tamiflu
How does tamiflu work?
it inhibits neuraminidase and therefore blocks exit of the virus from the cell
the flu vaccine consists of
a formalin-inactivated influenza virus
a live, attenuated influenza virus vaccine which is administered intranasally
