Viral Pathogenesis II Flashcards
example of viral exanthem
HPV
what are some low risk and high risk HPV
low risk - genital warts
high risk - premalignant lesions
genome of HPV and what they infect
circular 8kB dsDNA
infect epithelial cells
what is Epidermodysplasia verruciformis (EV)?
rare inherited disorder that exposes pt to widespread HPV infection and cutaneous squamous cell carcinomas
symptoms from viral disease arise from what
tissue damage or inflammatory responses
in the CNS, what does viral infection lead to
most do not cause disease but some can be serious
how do you identify the viral agent in CNS viral infections
CSF fluid or biopsy
major route for some viruses to spread
sex
don’t forget oral and GI are the common site for most viral infections
what is of particular concern in STIs
asymptomatic shedding – so people can unknowingly pass it to their partners because they do not show any symptoms
CNS and STI viral examples
HHV-1 and 2
what does HHV-1 and 2 share
DNA homology, antigenic determinants, tissue tropism and disease symptoms
type of virus that can stay in the body indefinitely
Ubiquitous, large, ds DNA, enveloped icosahedral virus aka HHV-1 and 2
importance of the enzymes that HHV-1 and 2 encode
encode enzyme that are good antiviral targets
what types of cells do HHV-1 and 2 infect and replicate
mucoepithelial cells
resultant phase of HHV-1 and 2 infections
– lytic (most cells: Cowdry type A inclusion bodies, syncytia)
– persistent (lymphocytes and macrophages)
– latent infections (neurons)
pathogenesis of HHV-1 and 2
Virus blocks effects of interferon, prevents CD8 T-cell recognition of infected cells, escapes antibody neutralization and clearance by going into “hiding” during latent infection
how does recurrence of HHV-1 and 2 occur
in response to various stimuli
eyes are another site of viral diseases – how is it transmitted
direct contact or viremic spread
example of viral eye infection
HHV-5 (CMV)
most prevalent cause of congenital diseases
HHV-5 (CMV)
what is associated with CMV in newborns
chorioretinitis
10% of affected newborns show clinical evidence of disease
what are some evidence of CMV in newborns
small size, thrombocytopenia, microcephaly, intracerebral calcification, jaundice, hepatosplenomegaly, and rash
examples of viruses transmitted in blood
– Hepatitis B, C, G, D – HIV – HTVL-1 – HHV-5 (CMV) – HHV-4 (EBV) – West Nile encephalitis virus
in hematological diseases of viral infections, lymphocytes and macrophages are targets for what type of viruses
those that establish persistent infections
transient viral expression of some viruses elicit large T cell responses
some additional modes of transmission for viral diseases
– congenital, neonatal, perinatal infections
– transfusion, transplantation
– arthropods, other animals
some properties of chronic viral infections
– immune system has trouble resolving infections
– most DNA viruses and retroviruses cause latent infections recurrence
some properties of oncogenic viruses
– viruses can carry copies of genes in which altered expression results in loss of growth control
– viruses can modulate the cell’s regulatory factors
consequences of viral infections in immunocompromised people
- Atypical and more severe presentation
- Deficient cell-mediated immunity
- Severe T-cell deficiencies
- Immunoglobulin A deficiency or hypogammaglobulinemia
what are host cell changes in response to viral infection
cytopathic effects – Rounding – Inclusion bodies – Cell lysis, Necrosis, Apoptosis, etc. – Syncytia formation – Transformation
difference between visualizing a virus and its effects
you need an electron microscope to see viruses but you can visualize its effects without it
