Influenza, Respiratory Syncytial Virus (RSV) and Ebola Flashcards
What age group has the highest attack rates?
Children, but infants experience the highest mortality and hospitalizations rates.
During what seasons does influenza peak?
winter/spring
What does the genome of influenza look like?
Eight different pieces of single-stranded RNA.
What two surface proteins are found on the lipid envelope of influenza viruses?
Hemagglutinin (H) and Neuraminidase (N)
What are the three types of influenza viruses?
- Type A
- Type B
- Type C (clinically insignificant)
Which type of influenza causes epidemics, pandemics and can infect other animal?
Type A
Define antigenic drift.
Refers to a gradual change in the virus through a slow series of mutations, substitutions, or deletions of amino acids
Define antigenic shift.
When a type A influenza virus with a completely novel hemagglutinin or neuraminidase gene. More dramatic impact.
True or False: Influenza type B viruses are subject to antigenic shift as they infect only humans.
False: They are not subject to antigenic shift and thus they only infect humans
Name four influenza pandemics .
- 1918-1919- Spanish Flu killed 550,000
- 1957-1958- Asian Flu killed 70,000
- 1968-1969- Hong Kong Flu killed 34,000
- 2009-2010- Swine Flu
What are the symptoms of influenza?
Acute fever, chills, myalgias, headache, and cough. Infants can also have gastrointestinal symptoms, apnea, and anorexia.
What are the two forms of treatment for influenza?
- Matrix protein inhibitors
2. Neuraminidase Inhibitors
What are two types of matrix protein inhibitors and what type of influenza do they treat?
- Amantadine
- Rimantadine
Type A
What are three types of neuraminidase inhibitors and what type of influenza do they treat?
- Oseltamivir (tamiflu)- Oral
- Zanamivir (Relenza)- Inhalation
- Peramivir (Rapivab)- IV only
Subtype A and B
To which antiviral is H1N1 resistant?
Oseltamivir
Can you use Zanamivir in children less than 7 years of age?
No.
What are the two types of seasonal influenza vaccines?
- Inactivated influenza vaccines- injectable,killed vaccine for all individuals 6 months and over.
- Live attenuated influenza vaccine- Intranasally, ages 2-49yo
What is in a trivalent vaccine?
Two “A” strains and one “B” strain
What is a quadrivalent vaccine?
Two “A” strains and two “B” strain
What is coccooning?
Everyone in a household with an infant younger than 6 months are vaccinated against influenza.
Name some high-risk individuals who should be targeted for vaccination for influenza.
- Children younger than 2
- Adult over 65
- Pregnant women
- Immunosuppressed
- Morbidly obese
- People who have been on long-term aspirin
What age group did the H1N1 pandemic affect the most?
Highest among children and young adults.
What is the primary risk factor for Avian flu (H5N1)?
Living close to birds.
Direct contact with infected birds
Direct contact with humans with avian influenza
What three conditions must be met to define when an influenza pandemic is occurring?
- Emergence of a new influenza subtype
- Must infect humans and cause serious illness
- Sustained human-to-human transmission and spread easily among humans
What are the symptoms of respiratory syncytial viral infection?
Significant lower respiratory infection in all ages and most common cause of bronchiolitis.
What is the structure of RSV?
Single stranded, non-segmented RNA virus, two important proteins: F protein and G protein.
What is the function of F protein in RSV?
Function: Fusion of viral envelope to host cell
What is the function of G protein?
Function: Initial binding of virus to the host cell
What are the two types of RSV? And which is more severe?
Subtypes: A and B
A is more serious
What are the three ways to test for RSV?
- PCR- Quick and accurate
- Direct Antigen (Rapid Test)- Quick not accurate
- Cell Culture- not quick
What is Palivizumal (Respigam)?
Human pooled antibody against RSV
What are the five species of Ebola?
- Zaire
- Sudan
- Bundibugyo
- Tai Forest
- Reston
What is the structure of ebola?
Enveloped, negative-strand RNA, replicates in the cytoplasm. It has 7 structural proteins and 2 non-structural proteins.
What is the role of glycoproteins in ebola viral envelopes?
Attachment/entry and important in pathogenicity
What are the two types of matrix proteins in ebola?
- VP40- important for structure, stability, assembly, budding
- VP24- assembly budidng, necleocapsid assembly, immune defense
What is Ebola’s target cell?
Phagocytic cells and then induces a massive cytokine storm and destroys endothelial cells.
And parenchymal cells leading to cell destruction and necrosis
How is immunity acquired for Ebola?
Antibodies to glycoproteins.
How can Ebola evade the human immune system?
Glycoproteins mask antibody binding sites and physically blocks the MHC.
Glycoproteins can also act as decoys when they are soluble by binding up antibodies.
What are the roles of VP35 and VP24 in Ebola ?
They interfer with the cell’s interferon production with plays a role in signaling for “help” and also inhibits the cell from apoptosis.
What are the symptoms of Ebola?
GI, fever, fatigue/weakness, loss of fluids, vomiting and diarrhea.
What is the treatment in Ebola?
Management is symptomatic. Treatment- Zmapp- monoclonal antibody agains 3 targets on the GP.
What do patients with Ebola usually die from?
Hypovolemia and/or organ failure
