cold and flu Flashcards
what are the steps of viral replication
1: Attachment: the virus attach itself to its host cell
2: Penetration: the virus or its genetic information penetrates the cell.
3: Uncoating: the nucleic acid is uncoated which frees the DNA or RNA from its capsomeresor lipid envelope and permits the host cell to read out ( express ) the genetic functions of the virus.
4: Translation: At this stage in the life cycle if many viruses, only a portion of the viral genetic information is expressed, resulting in the synthesis of only the subset of viral-encoded proteins collectively called the early viral gene functions ( proteins )
5. Replication: The viral nucleic acid is then synthesized to produce hundreds or thousands of copies of viral chromosome.
5 B: Replication: At this time, a second subset of the viral genetic information, commonly termed the late proteins, is expressed. These are the structural proteins including the capsomeres of the virus
Step 6: Assembly: The capsomeresare assembled to form a new shell around the nucleic acid of the virus.
Step 7: The mature virus having duplicated its new copies, is released from the infected cell to attack a new cell and repeat this process.
what is viruses
- intracellular parasite cannot replicate on their own
- recruit the host cell to replicate viral DNA and new cell contain the virus
- or recruit the cell to replicate viral RNA where the cell creates viruses that are released through budding and the cell lyses
what are the s & s of viral infection
- fever,
- headache
- cough
- malaise
- myalgia
- nausea
- vomiting
- diarrhea
- insomnia
- photophobia
*WBC count remains normal
what is antigenic drift
- a genetic change (mutation of a gene for the anitbody binding sites) of the virus that is minimal
- the effect of genetic change is managable
e. g. small variation in the protein of influenza virus: hemagglutinin & neuraminidase
what is antigenic shift
- a process where 2 or more different strains of virus combine to form a new subtype of the original virus
–> the result of the combination is a REASSORTMENT of a gene segment that code for the surface protein
–>occurs only in influenza A (as it affects more than just human)
signs and symptoms of adenovirus
- ->asymptomatic
1. fever>39 degree for >5 days, especially in pediatrics - ->sore throat, cough, rhinorrhea may occur
2. may cause conjunctivits, pharygitis
what is the treatment of adenovirus
supportive
What is Respiratory Syncytial Virus (RSV)?
pneumovirus
- ubiquitious: all infant/child infect by age 4
- doesn’t confer immunity
- Cause lower respiratory tract infection in baby
what is the S & S of RSV?
- brochioloitis
- pneumonia
what is the treatment of RSV
supportive
-o2, hydration, rest
maybe use ribavirin
what is Common Cold
50% caused by one of >100 rhinoviruses
–>common in the fall and spring…less common in the winter
what is the sign and symptoms of common cold
- sore throat
- sneeze
- rhinorrhea
- malaise
- nasal obstruction
- Latent infection: takes 24-72 hours to develop
how does common cold spread
Direct contact via
- -> droplet
- ->aerosolized liquids
what are the Treatment of common cold?
-Decongestant •Antihistamine (1stgeneration) •Antipyretic •Analgesic •Anticholinergic
What is the Sequale of common cold
- body immune system resolves the infection
or
- Bacterial infection
- ->sinusitus - pneumonia
- otitis media
what is influenza
viral respiratory infection
what is the epidemiology of influenza
Widespread in fall and winter months
Influenza virus A, B, C
Viruses usually sequential but may be simultaneous
what are some exmaple of influenza
H5N1 avian flu
H1N1 swine flu
what are the types of influenza
Influenza A
- Most common viral serotype
- May cause severe disease
Influenza B
- Produces mild disease
- cause moderate –severe disease
Influenza C
- Rarely causes infection
How is influenza spread?
- Droplet
- Direct contact
- Contaminated items
- ->Virus can live on surfaces for 2 –48 hours, some longer
what is the S&S of influenza
- affect upper respiratory tract
- malaise
- Nasal congestion.
- Sore throat
- Aching muscles
- Chills and sweats
- cough
how to diagnosis influenza
- nasal swab
- blood test
- allergy test
what are the treatment for influenza
medication
- Antiviral medications (for severe infection and those at risk for serious complication)
- Antipyretic
- Analgesic
- decongestent
supportive treatment
what are some antivirals
inhibit viral replication
- zanamivir(Relenza®)
- oseltamivir(Tamiflu®)
what are the Side Effects/Contraindications of antivirals
- GI
- Relenza : exacerbate asthma, COPD
what is epidemic
occurs when an infectious disease spreads rapidly to many people.
what is pandemic
a global disease outbreak.
Influenza pandemics have occurred more than once.
e. g.
- ->spanish influenza
- ->Asian influenza
- ->Hong Kong influenza
what are the sequale of influenza?
usual outcome
–>resolved
What are the possible complication of influenza
- Decreased lung function and ventilation for weeks
- Pneumonia
- Respiratory failure
Who should NOT get the flu vaccine or contraindication to flu vaccine?
- Infants under six months of age
- Anyone with a serious allergy (anaphylaxis) to eggs or egg products
- Anyone who is acutely ill with a fever should usually wait until the fever goes down before being vaccinated.
- Anyone who has developed Guillain-Barre within 6 to 8 weeks of a previous influenza vaccination.
