Microbio Week 11 - Herpesviruses EBV CMV HHV6 HHV8 and Prions (Exam 3) Flashcards
How is Epstein-Barr virus (EBV) transmitted?
Saliva - mono is known as the kissing disease
By 35-40, almost all people in the US are infected with which disease?
EBV
EBV established latency in ___________ cells
memory B
T/F: People sporadically shed EBV in saliva throughout life after they are infected
True
In infectious mononucleosis, the virus initially divides in the _____________, causing a sore throat through _______ infection. It then infects its main target, B-cells.
oropharynx; lytic
What is known as heterophile antibody-positive mononucleosis?
EBV mononucleosis
What leads to heterophile antibody infection during EBV mononucleosis?
Generalized activation of B cells
Heterophile antibodies are _____________ antibodies that will react with certain animals, horses, and sheep, RBC.
A test for the presence of these antibodies is called the ____________ test
non-specific; monospot
What is the primary cause of all infectious mononucleosis symptoms?
Expansion of CTLs + their cytokines
How long is the incubation time for infectious mononucleosis?
Long, 4-6 weeks
Once the acute infection for infectious mononucleosis is over, some memory B cells have what? (ON EXAM)
Latent EBV genome
Memory B cells maintain their latency of infectious mononucleosis without producing what?
Proteins
When the B cells divide in infectious mononucleosis, they express a _______ ________ to make sure the viral genome goes into both cells.
viral protein
EBV can reactivate from what in order to make new infectious virus?
Memory B cell pool
What are the 3 complications of mononucleosis?
- Ruptured spleen
- Mild hepatitis
- Airway obstruction (enlarged tonsils)
What increases the chance of developing oral hairy leukoplakia?
EBV
Smoking
Benign, non-painful lesion on lateral border of tongue
Oral hairy leukoplakia
Can oral hairy leukoplakia be scraped off the tongue?
NO
Oral hairy leukoplakia can be the first sign that someone has an _______ infection or occurs in people taking immunosuppressive drugs
HIV
T/F: Certain drugs or acyclovir can be taken to clear lesions in oral hairy leukoplakia, and the lesions never come back
FALSE, the lesions usually come back within a few weeks of treatment cessation
When will oral hairy leukoplakia most likely clear up?
When CD4 count increases
T/F: Oral hairy leukoplakia can occur in immunocompetent people, but it is rare
True
What disease is rare in the US, and cases are often found in recent immigrants from certain parts of Africa, some Asian countries, and the native peoples of Alaska and Canada?
Nasopharyngeal Carcinoma
What causes Nasopharyngeal Carcinoma?
EBV
Is there a good chance of survival of Nasopharyngeal Carcinoma with treatment?
Yes, if caught early
In parts of central Africa, what is the causative agent in endemic Burkitt lymphoma and has a high incidence?
EBV
What is a very fast-growing, aggressive cancer?
Burkitt Lymphoma
Endemic Burkitt Lymphoma generally starts as a tumor of the ______ or __________. It is more likely to be in young children
face or jawbone
Burkitt Lymphoma is caused by a chromosomal translocation of the _________ gene to a
chromosome that has an immunoglobulin locus.
What does this cause?
c-myc
Unregulated c-myc expression -> uncontrolled cell growth
Sporadic Burkitt Lymphoma in the US usually starts in the ___________, not the jaw
abdomen
EBV-associated Burkitt Lymphoma is higher in people living with ________
HIV
Immunosuppression can increase the chance that EBV is associated with what?
Sporadic Burkitt Lymphoma
Most Cytomegalovirus (CMV) infections are asymptomatic, except what?
CMV mono-like syndrome
Congenital infections
Immunocompromised
How is CMV transmitted?
Saliva
Urine
Blood
Breast milk
Semen
Cervical secretions
T/F: There are many different strains of CMV, and it is possible to be infected with more than one strain
True
What cells does CMV infect?
Wide range
Where is CMV latency established in the body?
Myeloid precursor cells in bone marrow
In people with AIDS, what is the most frequent problem with CMV?
Retinitis
What disease is a significant problem in transplant recepients?
CMV
In CMV mono like-syndrome, what does CMV activate?
T cells
(not B cells!!!)
T/F: Because CMV mono-like syndrome does not infect B cells, there will be no generalized activation of antibodies and no production of heterophile antibodies
True!
Will CMV mono-like syndrome be monospot positive or monospot negative?
Monospot negative, since it does not activate B cells nor cause production of heterophile antibodies
Will CMV mono-like syndrome be heterophile AB positive or heterophile AB negative?
Heterophile AB negative, since it does not activate B cells nor cause production of heterophile antibodies
What is the #1 congenital infection in the US?
Congenital CMV
During pregnancy, what primary infection has a high risk of being transferred to the fetus?
CMV
The risk of congenital CMV from an already CMV-positive woman is (high/low)
Low
Babies born with asymptomatic CMV infections have a 10% risk of some __________ ________, which can be delayed and progressive
hearing loss
Babies born with symptomatic CMV infection can develop what?
Motor and cognitive defects
Hearing loss
Vision loss
Babies born with symptomatic CMV infection have (more/less) sequelae than babies born with asymptomatic infection
More
T/F: Unless a baby is a very low birth weight or is immunosuppressed, CMV infections that are acquired at birth or through breastfeeding are not a problem
True
What is a very common childhood infection?
HHV6
What is the cause of Roseola and can cause febrile seizures?
HHV6
What virus is present in large numbers in MSM, but much lower in the general population of the US?
HHV8
HHV8 usually causes no symptoms unless co-infected with _______.
People with co-infections have a risk of developing what?
HIV
Kaposi sarcoma
The risk of developing Kaposi sarcoma increases with what?
However, with an aging population infected with HIV, Kaposi’s sarcoma can also be seen with what?
Lower CD4 count
Higher CD4 count
How is HHV8 spread?
Sex
Saliva
What is often seen with Kaposi sarcoma?
Violet or brown oral lesions
What was coined to highlight the fact that it was a proteinaceous infectious particle?
A prion
What is a prion made of?
Protein
The prion protein is a normal protein that is highly expressed where?
The brain
What does the infectious prion look like?
Misfolded prion protein
Normal prion protein
PrPc
Misfolded infectious prion protein
PrPsc
The PrPsc has a high number of what compared to PrPc?
Beta sheets
The infectious PrPsc converts the cells PrPc into an altered form, causing what?
Aggregates that form amyloid plaques
What do the aggregates that form amyloid plaques with the misfolded proteins cause?
Cell death -> releases the infectious misfolded prion
PrPsc goes on to other cells and converts their PrPc protein to the misfolded form. What does this lead to?
Spongiform appearance in the brain
There are lots of different kinds of prion disease. What are they all caused by?
Misfolded prions
What is the most common prion disease?
Spontaneous Creutzfeldt-Jacob disease (CJD)
What prion disease is a spontaneous mutation in the prion gene or a spontaneously misfolded protein that becomes ‘infectious’ to the normal prion proteins in the brain?
Spontaneous Creutzfeldt-Jacob disease (CJD)
Is Spontaneous Creutzfeldt-Jacob disease (CJD) genetic?
No
T/F: After symptoms of Spontaneous Creutzfeldt-Jacob disease (CJD) appear, life expectancy is rarely over a year. It is a fatal condition.
True
T/F: It is easy to kill prions
FALSE!! It is very hard to kill prions! They are resistant to many disinfectants, proteases, and normal autoclaving
A small sliver of Spontaneous Creutzfeldt-Jacob disease (CJD) is from “infectious” causes, meaning obtained from a source outside of the body. Name one potential source
Contaminated surgical instruments
What disease is caused by eating beef contaminated with prion proteins?
Variant Creutzfeldt-Jacob disease (vCJD)
T/F: Cases of Variant Creutzfeldt-Jacob disease (vCJD) from the UK were due to cows that had bovine spongiform encephalitis (Mad Cow Disease) entering the food chain
True
Is Variant Creutzfeldt-Jacob disease (vCJD) fatal?
Yes, it is 100% fatal
What is the incubation time for Variant Creutzfeldt-Jacob disease (vCJD)?
As short as 5 years
What are most cases of Iatrogenic Creutzfeldt-Jacob disease (iCJD) from?
Material harvested from cadavers
Dental instruments that come in contact with nerve tissue could potentially be contaminated with ___________ if not cleaned properly
prions