DNA Viruses Flashcards
this virus:
- interacts with the “CAR” receptor
- uses its own DDDP for replication
- egresses by cell destruction
- is spread by fecal-oral or respiratory route, most commonly causing URIs
adenovirus
this viral family:
- has small, naked circular dsDNA
- spread through respiratory
- causes urinary tract disease (BK virus) and progressive multifocal leukoencephalopathy (JC virus)
polyomavirus
Which virus:
- is a common childhood illness that has respiratory spread and replicates in macrophages and pneumocytes
- travels through the lung to other organs and spreads to dermal epithelium
- establishes latency in sensory ganglia from the skin
Varicella Zoster Virus (VZV)
this group of diseases is slow, progressive and lethal, is spread by sheep and other related species, and makes holes in the brain of infected individuals via mutations in their PrP proteins
TSEs (AKA transmissible spongiform encephalopathies, AKA prion diseases)
this virus:
- is the largest human virus
- is enveloped with complex structure
- replicates in cytoplasm
poxvirus
this is the most common infectious cause of birth defects, and resembles Mono syndrome but with more visceral adenopathy and negative heterophile antibody
CMV
*heterophile = antibodies that are induced by external antigen
Name the 6 childhood exanthems. Which ones have vaccines?
- Measles (Rubeola) vaccine
- Scarlet fever (Strep)
- VZV vaccine
- German measles vaccine
- Parvovirus B19
- Roseola - HHV6
this virus:
- infects RBC precurors
- causes fifth disease (B19, slapped cheek syndrome)
- is the smallest DNA virus
- may cause congenital infection or aplastic anemia crisis in persons wth shortened RBC survival or a compromised immune system
parvovirus
virus that drives squamous cell division by inhibiting p53 and Rb; pathology shows large swollen cells with distorted pyknotic nuclei
HPV
Which of the following statements about Herpesvirus is FALSE?
A. It mostly causes mild infections, but some strains may cause more severe disease
B. It uses receptor-mediated fusion of its envelope via multiple glycoproteins to enter host cells
C. It transcribes its genes to make proteins in 3 stages, which are important for transcription, replication and particle synthesis
D. It replicates in the nucleus after cirularizing its DNA and integrating into the host genome
E. It uses viral specific thymidine kinase and DNA polymerase for replication
D. It does circularize its DNA, but does this episomally and replicates independently of the host genome inside the nucleus.
infects and establishes latency in B cells, causing lymphomas and Castleman’s disease
HHV-8
this herpesvirus reactivation disease is asssociated with age-related immune suppression
Zoster (Shingles)
*vaccine recommended for adults >60, but effective >50
this virus is found living latently in a different population of cells than the cells in which active replication is occurring
herpesvirus
Which herpes virus is usually spread sexually, more often in women, and establishes latency in the spinal ganglia?
HSV-2
*recent studies show that HSV-1 was a more frequent cause of genital infection than HSV-2
virus whose initial lytic replication occurs in oropharyngeal cells, spreading to secondary immmune sites (lymph nodes, spleen) and establshing latency in B cells
EBV
this virus’s particles assemble in the nucleus, bud from the nuclear membrane and Golgi, and lyse the plasma membrane on their way out of the host cell
herpesvirus
these highly active enzymes of HPV lead to high risk of cancer; when they are poorly active they cause genital warts
E6 and E7
Which of the following statements about Hepatitis B infections is TRUE?
A. It is not transmitted as easily as HCV.
B. Antibody to HBsAg is protective and enhanced by vaccine.
C. The more severe an acute infection is, the less likely it is to be cleared by the immune system.
D. Hep B infections are more severe in children and young adults.
E. Acute Hep B infections tend to be fulminant with a short incubation prior to symptoms
B.
Hep B is transmitted more easily than HCV, and the more severe an infection the more likely it is to be cleared by the immune response. This is why A and C are false. Acute Hep B infections are more severe with aging and they have long incubation periods prior to symptoms (2-6 months). This is why D and E are false.
herpesvirus associated with Kaposi’s sarcoma and is probably spread through sexual transmission
HHV-8
Which of the following statements about HDV is FALSE?
A. Infection with HDV elevates cancer risk
B. HDV requires HBV for envelope formation
C. The HDV genome is negative, circular strand RNA
D. Occurs worldwide and is not highly prevalent in US
E. There is no treatment or vaccine available but it can be prevented with prevention of HBV
A
HDV does not specifically elevate a person’s risk of cancer. HBV does, however, and a person with HBV may also become co-infected with HDV if exposed.
Which herpes virus:
- is latent in the trigeminal ganglion after infecting oral mucosa
- is common, and may be shed asymptomatically
- is cytopathic during primary infection, and killed by T cells when reactivated (at the same site)
- is characterized by multinucleated giant cells and inclusion cells
HSV-1
*cannot be cleared with antivirals (acyclovir) during latency
herpesvirus that causes roseola in early childhood, is spread by saliva, and is latent in T cells, monoctyes and macrophages
HHV-6
*reactivations are generally asymptomatic and there is no vaccine or treatment available; HHV-7 is like HHV-6 but is rarely associated with disease
With a positive monospot, serology may be performed to determine the time course of the mononucleosis infection. What antigen may provide this information?
EBV nuclear-associated antigen
EBNA+ means infection began at least 6 months ago
EBNA- means it is still early in the infection
EBV-associated tumors contain latent virus, and are associated with what 3 malignancies?
- Burkett’s lymphoma
- B cell lymphoma
- Nasopharyngeal carcinoma
Which of the following statements is FALSE about hepatitis B infections?
A. An insufficient immune response leads to chronic infection.
B. Vaccinated individuals will be positive for anti-HBsAg antibodies
C. When cirrhosis is also present, there is a high risk for hepatocellular carcinoma.
D. Surface antigen correlates with the amount of virus in the blood while surface antibody correlates with protection
E. A person who presents with jaundice, nausea, vomiting and has surface antigen and core antibody but no IgM in their blood is acutely infected with HBV.
E. Core antibody in the blood suggests that this person has been exposed to HBV at some point, and the lack of IgM during a symptomatic presentation suggests an acute exacerbation of a chronic HBV infection.
Virus that:
- has an infectious virion called a Dane particle
- is most often spread maternal-fetal
- has RDDP packaged in virion
- makes 2 RNA products: a full-length genome that is packaged in the virion and a pregenome RNA for translation
HBV
*spread more easily than HCV
