2017 Microbiology - Prions, DNA Viruses and Diseases Flashcards
Understand the PrP gene, PrPc protein and what changes take place in protein structure to cause disease
PrP found on chromosome 20
creates the protein PrPc which undergoes gylcosylation to become PrPsc -> structural change from a-helix to b-sheet.
B-sheet forms peptide aggregates to make amyloid fibrils
What is the difference between horizontal and vertical transmission?
Horizontal - one person to another via contact (ingestion, transplant, etc.)
Vertical - familial cases, prior gene
What are some examples of acquired prion diseases and examples of inherited prion diseases?
Acquired:
- Kuru
- Crutzfeldt-Jakob Disease
- Variant CJD
Inherited:
- Gerstmann-Straussler-Scheinker disease (GSS)
- Fatal familial insomina
Characteristics of PARVOVIRUS and example disease
Linear ssDNA
icosahedral
naked
smallest DNA virus
Erythrovirus B19
Erythrovirus B19 (Parvoviridae) Transmission, Pathology, Disease, Dx.
TRANS: respiratory droplets or transplacental, Nasopharynx -> bone marrow, kills erythroid precursors
PATH: 1. Viremia and anemia, 2. Immune response (rash and arthralgia)
DISEASE: late winter/spring
-fifth disease (slapped face rash)
-aplasitc crisis in chronic hemolytic anemia pts
-acute polyarthritis
-spontaneous abortion
DX: clinical presentation, ELISA, PCR
Characteristics of PAPILLOMAVIRUS and example disease
DNA, naked, icosahedral, dsDNA
Prickled appearing virus
HPV
Which types of HPV cause warts and which are associated with cancers?
Type 1-4 cause warts
Types 16, 18 (31,45 less common) associated w/ cancer
What is the pathology of HPV?
warts appear in keratinized skin which stimulates hyperplasia
Koilocytes develop = enlarged keratinocytes with clear halos around condensed nuclei.
What are diseases of HPV?
Papillomas (warts) - children/young adults
Laryngopapillomas: infant to 50 yo., single, peduculated, can block airways in infants
Anogenital (condylomata acuminata)
Cervical dysplasia, CIN & carcinoma
Characteristics of POLYOMAVIRUSES and example disease
Naked, DNA virus
2 diseases: BK & JC
typically only symptomatic in IC patients
POLYOMAVIRUS (JC & BK) epidemiology key points, what CNS cell is targeted by injection?
enters via respiratory droplets, goes to epithelia cells then lymphocytes -> travels to kidneys
in lytic infectious there is demyelination of oligodendrocytes.
Which Polyomavarius causes the following:
Hemorrhagic cystitis, nephritis and/or urethritis?
Progrssive multifocal leukoencephalopathy?
BK virus
JC virus
Characteristics of ADENOVIRUSES? What does it do to MHC 1 Receptors, and why is that important?
linear dsDNA, icosahedral, naked
has a characteristic long fiber extending from capsomer at corners which are hemagglutinators
Can down regulate MHC Class 1 receptors thus helping the infection avoid Tc cells.
Examples of diseases/conditions caused by ADENOVIRUS
acute febrile pharyngitis and pharyngoconjunctival fever acute respiratory tract disease Colds conjunctivitis and keratoconjunctivitis gastroenteritis and diarrhea Intussesception sepsis in IC patients acute hermorrhagic cystitis
How is Adenovirus dx? What are some cytological clues?
ADV produces nuclear inclusion bodies.
ADV is cultured in epithelium derived cells