MVIP Flashcards
What are the three patterns of viral infections?
→acute infection
→latent, reactivating infection
→persistent infection
Give examples of acute infections
→common cold
→measles
→ebola
→small pox
How many human herpes viruses are there?
→8
What is HHV8?
→Kaposi sarcoma
What is HHV3?
→chicken pox
What is HHV4?
→EBV
What is HHV5?
→cytomegalovirus
What is HHV1 in infants?
→Primary Gingivostomatitis
What is HHV1 brought under control?
→cold sore
Describe the primary infection of herpes simplex and VZV
→ herpes infection causes mild pharyngitis fever
→VZV infection causes chicken pox
→virus transits up to peripheral nerve using microtubules to neuronal nucleus
→lies latent
→amplification using cells mcachinery
Describe the recurrence of VZV and herpes
→age and X-irradiation or local injury activates VZ virus in neuron
→fever, sunlight to face, menstruation activates herpes
→virus transits down peripheral nerve
→causes shingles in VZV
→ causes cold sore
Which viruses are persistent in presence of active immune response?
→HIV- retrovirus
→HCV-flavivirus
→measles
What is flavivirus
→positive,
→single-stranded,
→enveloped RNA viruses
What can be caused by measles shed virus years after acute infection?
→encephalitis
What is congenital rubella?
→if infected in utero, virus is seen as self, baby is born immunotolerant and virus continues to replicate (and cause damage) in neonatal tissues
How does rubella infect pregnant women?
→infect the placenta
→viral replication can infect all foetal organs
What is a hallmark of rubella in foetal rubella infection?
→infection that persists throughout foetal life
→shedding of virus up to 2 years after birth
What percentage of poliovirus infections are asymptomatic?
→90%
What is a requirement of inapparent infections?
→viruses be non-cytopathic
What are zoonotic infections?
→virus from one species to another
What does Ebola virus target?
→Vascular Endothelial Cells
What damage does Influenza A virus cause?
→targets lung epithelia
What does RSV(Respiratory syncytial virus) induce?
→syncytia in lung epithelia
→Nuclei are inactive as a result
Describe the course of illness of Hep C
→acute infection
→chronic infection
→fibrosis
→cancer or cirrhosis
How can you differentiate between Hep C infected hepatocytes and healthy cells?
→by staining
Describe the immunopathology response to Hep C
→extensive liver infiltration of leukocytes
→infiltration of CD8+ cells
→Liver has a lot of CD8+
What is HCV persistence associated with?
→generation of HCV variants that are not recognised by CD8+ cells
What type of viral infection is Dengue fever?
→mosquito-borne infection
How many serotypes of Dengue are there?
→4
→have the same clinical manifestations
What are the symptoms of dengue virus?
→acute fever →severe abdominal pain →headache →plasma leakage skin rash vomiting
What can happen as a result of severe dengue?
→dengue shock syndrome (DSS),
→hemorrhage
What is the greatest risk of severe dengue?
→previous infection with a different serotype
→Antibodies formed in response to a dengue infection are not cross-protective against other subtypes of the virus
What is antibody dependent enhancement in dengue?
→preexisting antibodies from a primary dengue virus infection bind to an infecting DENV particle during a subsequent infection with a different dengue serotype.
→The antibodies from the primary infection cannot neutralize the virus
→ Ab–virus complex attaches to receptors called Fcγ receptors (FcγR) on circulating monocytes
→ antibodies help the virus infect monocytes more efficiently.
Describe RSV immunopathology
→RSV infections in early life show unbalanced Th1/Th2 responses
→depresses inflammatory cytokine production, CD8+ responses and IgG production
→clearance is slow
→enhances IgE production, leading to allergy/asthma on re-exposure by activating eosinophils
What are the symptoms of influenza?
→Fever, often prolonged
→Neurological (headache, malaise)
→Myalgia- sore muscles
Why are there different vaccines for influenza?
→Influenza changes its amino acids on H1N1 which are required for binding to receptors
→antibodies against those amino acids
What is pandemic flu?
→strain of influenza virus that causes much more morbidity and mortality
→every 20-40 years
Why can be pandemic flu?
virus has changed it’s surface proteins (H and N)
→there is no widespread immunity
What is antigenic shift?
→major change in a flu A virus, resulting in new HA and/or new HA and NA proteins in flu viruses that infect humans
→eg swine flu
What does outcome of infection depend on?
→what you are you infected by,
→whether you’ve seen it (or anything like it) before,
→the state of your immune system
What is antigenic dift?
→small changes (or mutations) in the genes of influenza viruses that can lead to changes in the surface proteins of the virus, HA (hemagglutinin) and NA (neuraminidase)
