Viral Transmission
What is the transmission of RSV
Transmitted via direct contact with respiratory droplets and indirect contact with contaminated surfaces
Describe the basic structure of a virus. What are the main differentiating factors of viruses?
Nucleic acid, capsid, envelope made up of a lipid bilayer and surface proteins.
RNA versus DNA, single versus double, positive versus negative, enveloped or not.
What is a nasopharyngeal swab test and what does it look for ?
Its a type of nasal swab test that is used to look for bacteria or viruses that cause respiratory infections.
To perform a swab test, clinicians take a small sample of cells from your nasopharynx, the top part of your nose and throat.
The test looks for
COVID-19.
The flu.
Whooping cough.
Meningitis.
Respiratory syncytial virus (RSV).
MRSA (methicillin-resistant Staphylococcus aureus).
Define antimicrobial stewardship.
The effort to measure and improve how antibiotics are prescribed by clinicians and used by patients.
1)What is Environmental determiants on viral transmission?
Environmental determinants affect transmissibility by influencing the survival and persistence of respiratory viruses in respiratory droplets or fomites after their release to the environment.
What is the enzyme needed for RSV transmission? Why?
RSV is a negative-strand RNA virus, it needs to be transcribed into mRNA through an RNA-dependent RNA polymerase.
What kind of virus does Joseph have? Describe its structure.
Joseph has RSV, a negative sense single-stranded RNA virus. It is enveloped and has G and F proteins on the surface which facilitate binding and fusing to cell-surface receptors.
What are some examples of pathogens that dictate a Upper Respiratory Tract Infection vs that of a Lower Respiratory Tract Infection
URTI - Haemophilus influenzae, Streptococcus pyogenes
LRTI - Streptococcus pneumoniae, Chlamydia spp, Legionella, Coxiella burnetti, Respiratory Syncitial Virus
Name one negative outcome of unnecessary antibiotic use.
Superinfections caused by killing of the good bacteria.
2)What is Virulence factor?
Virulence can be defined as the quality of being poisonous or injurious to life (i.e., virulent). For an organism to be virulent, it must be able to infect its human host, reproduce, and/or cause a disease. Virulence is the severity of the disease produced after exposure and infection.
What is RSV replication life cycle after transmission?
Show photo
Can you name another negative sense single-stranded RNA virus that we learned about this week? What about a positive sense single-stranded RNA virus?
Influenza is another negative sense single-stranded RNA virus. Coronavirus is a positive sense single-stranded RNA virus.
What are some of the symptoms that are present in a URTI and LRTI - try and elaborate more to elaborate with patient
URTI - breathing, muffled speech, drooling and stridor
LRTI - cough, fever, chest pain, tachypnea (rapid breathing), wheezing, and sputum production
URTI - Joeseph first had what was seemingly a URTI, which follows the symptoms presented (No fever, although it is slight, no fast breathing, no abnormal HR, and finally, normal oxygen)
LRTI - When Jason was seen at the ER, he was shown the signs that are expected of an LRTI (high RR, O2, Fever, and HR) as well as mucus secretion and the associated wheezing
Name another negative outcome of unnecessary antibiotic use.
Development of antibiotic resistance.
3) What are risk factors for severe RSV infection in Children?
Chronological age < 6 months (single most important risk factor) [10]
Comorbidities [10]
Preterm birth, especially if associated with chronic lung disease of prematurity
Congenital heart disease
Immunocompromised state
Neuromuscular disorders that affect the ability to clear airway secretions
Environmental factors
What is DNA viral replication cycle after transmission ?
Attachment,penetration> uncoating> nuclear entry> replication> assembly>release
Show photo
What is a key difference between influenza and RSV?
Influenza replicates in the nucleus, whereas RSV replicates in the cytoplasm like most other viruses.
What is the general difference between Bronchitis and Bronchiolitis ? What is the main difference between the 2 and the types of infections that produce each issue.
Bronchitis affects the bronchi or the larger airways.
Caused by an upper respiratory tract infection or forms part of a clinical syndrome in diseases such as influenza, rubeola, rubella, pertussis, scarlet fever and typhoid fever.
Bronchiolitis affects your smaller airways (bronchioles)
Caused normally by more lower respiratory tract infections, Cough and sputum production appears to be caused by a combination of environmental factors, such as smoking, and bacterial infection with pathogen, such as H influenzae and S pneumonia, and Respiratory Syncitial Virus.
Explain to Joseph’s mother why he does not need and should not receive an antibiotic. Act this out with your partner.
Joseph’s positive RSV RNA swab confirmed that this is more likely an infection of viral origin rather than bacterial. Antibiotics only work on bacteria and thus would not affect the virus that has invaded Joseph’s cells.
4) What are the general principles for RSV prevention?
Recommend the RSV vaccine in older adults.
To decrease the risk of infection in children, encourage:
a.RSV vaccination during each pregnancy
b.Exclusive breastfeeding for infants ( Breast milk contains antibodies, particular IgA. Breast milk has anti-bacterial, anti-viral, and anti inflammatory properties that boost infants’ own immune response to RSV.
c.RSV prophylaxis for eligible young children
d. Avoidance of tobacco smoke exposure
Why do RNA viruses have easier adaptation?
RNA virus genomes such as those of influenza virus have higher mutation rates, giving rise to diverse viral genomic variants in infected individuals. which may allow faster host adaptation of a virus strain that is efficiently transmitted via respiratory droplets.
Describe the mechanism by which RSV spreads its genetic material to surrounding cells.
RSV has F proteins that allow for fusion with neighboring, unaffected cells. This forms multinucleated giant cells known as syncytia.
How does Bronchilitis affect the imagery on an x-ray. What is that special condition called in an x-ray that causes this change?
Brionchiolitis leads to what is known as Peribronchial cuffing
Peribronchial cuffing essentially causes the thickening of the bronchioles.
Show image
Describe a common scenario in which an antibiotic may be mistakenly prescribed (hint: think about another virus we learned this week).
Mononucleosis can cause pharyngitis which appears like strep A. Often this can be treated inappropriately with an antibiotic (penicillin) and a side effect of this is a maculopapular rash.
5) Palivizumab( monoclonal antibody) is sometimes given to prevent severe diseases in infant at high risk for RSV infection, why?
Palivizumab is a humanized monoclonal antibody against RSV F protein used to prevent severe disease in infants at high risk for RSV infection, including those with a history of premature delivery and/or hemodynamically unstable heart disease, such as this patient. Palivizumab provides passive immunizationby neutralization and inhibition of the fusion activity of RSV, which decreases virus replication. Prophylactic IM administration should be performed monthly during RSV season for the first year of life. Treatment of present RSV bronchiolitis is primarily supportive, but ribavirin may be used in severely affected immunosuppressed children.
Targeting the F Protein: The F protein on the surface of the RSV is crucial for the virus's ability to enter and infect human cells. It facilitates the fusion of the viral membrane with the host cell membrane, allowing the virus to inject its genetic material into the cell.
Neutralizing Fusion Activity: Palivizumab binds to a specific site on the F protein, preventing it from undergoing the conformational changes necessary for membrane fusion. By blocking this process, palivizumab stops the virus from entering the host cells and replicating.