Flashcards in Microbiology 3.1 Deck (35):
What are the common viral CNS pathogens which give rise to meningitis?
What are the common viral CNS pathogens which give rise to encephalitis?
What is the difference in symptoms between viral meningitis and viral encephalitis?
viral encephalitis usually associated with more profound
1) mental status abnormalities
2) neurologic findings
What rae the common symptoms of viral encephalitis?
What are the CSF findings of aspetic meningitis?
What are the enterovirus characteristics?
(small, ss linear RNA, virus)
-replicate in cytoplasm
How does picornavirus replication occur?
-release RNA in cytoplasm
-viral protein cap (5') and poly-A tail (3')
-polymerase with its own polymerase [big polyprotein cleaved into smaller proteins]
Where does picornavirus infect the body?
blood stream (meninges, brain, spinal cord)
What are the living conditions and seasonality of the enteroviruses genus?
-low pH, 37o
summer and early fall
Which population is at-risk for enteroviruses?
How is enterovirus infection diagnosed?
RT-PCR using CSF or throat swab
What is the treatment for enteroviruses?
supportive, no treatment
What are the herpesviridae characteristics?
-ds linear DNA
-replicates in nucleus
What is the prevention for enteroviruses?
hand sanitizer with alcohol >70%
What is the primary infection site and latent infection site of alpha herpesviridae (HHV 1-3)?
What are the main differences between HSV-1 and HSV-2?
-"above the waist"
-latent in trigeminal gaglia
-children often infected
-70% adults infected
-"below the waist"
-latent in sacral ganglia
-sexually active people often infected
-25% adults infected
How do herpesviruses produce latent infections?
-after initial infection, infect nerves and "rests" as circular extrachromosomal unit in nucleus
-latency-associated transcripts (LATs) & noncoding regulatory RNAs which maintain latency
-reactivated and dislodges from nucleus
-meningeal branches to reach the brain
How is a herpesvirus infection diagnosed?
-Cowdry type A inclusions
-Tzanck smear (giant cells)
-PCR using CSF [rapid diagnosis for encephalitis or meningitis]
What is the most important anti-viral herpesvirus treatment?
IV *acyclovir* added to cell and becomes phosphorylated with herpes thymidine kinase (from virus)
-triple-phosphorylated with cell's own kinases
-enters nucleus and prevents DNA from being extended
**NOT A CURE**
What is the prevention for herpesviruses?
-cesarean delivery if mother is symptomatic
-acyclovir for reoccurrances
What is the clinical presentaiton of varicella-zoster virus?
-infection (day 0)
-contagious at 11 days
-fever begins at 13 days
-infection of skin/rash at 14 days
What is the at-risk population for varicella-zoster virus?
What is the pathogenesis of varicella-zoster virus?
What is it unsafe to contract a varicella infection as an adult?
-risk for pneumonia
-progressive infection leads to encephalitis
What is the latency and reactivation of varicella-zoster virus?
-latency in nerve ganglia
-when reactivated, expresses at that dermatome/spinal cord level in a "patch"
How is varicella-zoster virus diagnosed?
-Tzanck smear (ginat cells)
-PCR of CSF [encephalitis]
What is the most important anti-viral varicella-zoster virus treatment?
What are the prevention mechanisms for varicella-zoster viral infections?
-zostavax (>60 yo)
How does cytomegalovirus interact with the immune system?
What is the primary infection site and latent infection site of alpha herpesviridae (HHV 5-7)?
primary: leukocytes, lymphocytes, monocytes
latent: monocytes, neutrophils, vascular endothelial cells
latent: T-cells, monocytes, macrophages
latent: CD4+ T-cell
How is cytomegalovirus transmitted?
-children, early adults
-infected body fluids
-oral, sexual, vertical transmission
What is the outcome of a cytomegalovirus infection based on?
immune status of the patient
How is a cytomegalosvirus infection diagnosed?
-cytopathic effect (dense, central "owl's eye" basophilic intranuclear inclusion body)
-serology, shell viral assay
What is the treatment for cytomegalovirus infection?
drug therapy which inhibit DNA replication within the nucleus