Micro 401
Wendy Vuong
Joseph Martin del Campo
Reza Parhizkar
What is RSV?
 Common name:
cold
 Specific name:
RSV Infection
Targets
 Everyone
 Mostly, infants (by 2 years
of age)
Dangerous for…
 Premature infants,
 children with heart/lung
problems,
 elderly,
 those with weak immune
system.
History
 First isolated from a chimpanzee
(1956)
 localized to respiratory tract
 Virus has large enveloped virion
that is easily inactivated by
dryness and acid
 Host range is limited to humans
CASE STUDY
A 13-month-old child had a runny nose, mild
cough, and low-grade fever for several days.
The cough got worse and sounded like
"barking." The child made a wheezing sound
when agitated. The child appeared well except
for the cough. A lateral radiograph of the neck
showed a subglottic narrowing.
Virology
 Negative sense, single-stranded RNA




virus
Belong to the Paramyxoviridae which
which consist of three genera:
 Paramyxovirus: Parainfluenza and
Mumps viruses.
 Pneumovirus: Respiratory syncytial
virus.
• Morbillivirus: Measles
virus.
RSV has the average size of 150-300nm,
encodes at least 10 proteins (7-8
structural and 2 nonstructural proteins).
The RNA is surrounded by a helical
nucleocapsid.
Account for a large percentage of
pediatric respiratory infections.
 Global annual infection rates of 64
million and mortality of 160,000 for
children under the age of two.
Case study Questions
 1. What is the specific and common name for these symptoms?
 2. What other agents would cause a similar clinical presentation?
 Coryza
 Symptoms of a common head cold
nasal congestion
 Rhinorrhea (runny nose)
 Sore throat
 Mild cough
 Inflammation of nasal cavity mucous membrane, affecting upper
respiratory tract ( larynx, nasal cavity, Trachea).
 Croup (Laryngotracheobronchitis)
 Inflammation of the larynx and upper airway
 Results in narrowing of the airway
 Characterized by a barking cough, inspiratory stridor, and a
variable amount of respiratory distress that develops over a brief
period.
 Stridor
 A high pitched, breathing sound caused by turbulent flow of air,
usually caused by a blockage in breathing

 Intercostal retractions



Are the inward movements of the muscles between the ribs as a
result of reduced pressure in the chest cavity.
The movement is usually a sign of difficulty breathing.
Common causes: Bronchiolitis is swelling and mucus buildup in
the smallest air passages in the lower respiratory system
(bronchioles), usually due to infection by RSV.
 Subglottic Stenosis: Subglottic stenosis (SGS) is a narrowing of the
subglottic airway, subglottic airway is the narrowest area of the airway
and small amount of edema will significantly restrict airflow.
Other Agents
 Viruses from the Paramyxoviridae family
 Mumps, measles, Parainfluenza Can also cause sporadic
cases of croup
 Adenovirus
 Infection of the respiratory tract, as well as eyes, intestines,
and urinary tract
 Pneumonia
 Inflammation of the lungs caused by bacteria, viruses, or
other microorganisms
 Leading cause of death in children worldwide
 Influenza A and B
 Both caused by viruses in the family Orthomyxoviridae
Testing
• Rapid antigen test
•By nasal aspirate
•By nasopharyngeal
(NP) swab
• Detected by RT-PCR
techniques
Treatment
•
•
•
•
•
Antibiotics? Vaccines? NO!
No treatment, self cured
Plenty of Liquids
Plenty of Rest
Make sure to breathe
Unless it’s a severe case…
then go to the hospital
>>>> 1%
Treatment
• Ribavirin, a guanosine analogue,
– severe course (e.g., premature or
immunocompromised infants)
– administered by inhalation
• Passive immunization with anti-RSV
immunoglobulin
– premature infants. Infected children
• Infected children must be isolated. Control
measures are required for hospital
– To avoid transmitting
– measures include hand washing, wearing gowns,
goggles, and masks
Transmission
●
●
●
RSV is easily transmitted
through aerosols, fomites
or direct contact
Inhalation of large droplet
aerosols that contain RSV
Direct contact from
touching contaminated
surfaces
Transmitted From What?
•
•
•
•
•
•
•
RSV is most likely introduced into families by
children in school undergoing reinfection.
Also can be introduced in hospitals or urban
centers where adults also spread the infection.
Depends on the opportunity of exposure.
Severity of illness relies on the age and
immune status of the host.
More severe in young infants due to immune
system underdeveloped.
Initially the infection is contracted to by
mucosal epithelial cells of the nose, eyes, and
mouth.
Infection can then either be confined to the
upper respiratory tract or move to lower
respiratory tract meaning more severe
symptoms.
Contagion Period
●
●
●
●
●
●
RSV is highly contagious from the point of infection and is
shed in respiratory secretions such as breathing, sneezing,
or coughing.
Incubation period is about 4 – 5 days.
Contagion period precedes symptoms and may occur in
absence of symptoms.
Within 10 to 24h after infection, projections of viral proteins
appear on the cell surface and bud off the cell membrane.
Greatest virus shedding in the first 4 to 5 days after onset of
symptoms.
Infectious respiratory secretions can last from 5 days to up to
3 weeks.
CS Questions
• What is the specific and common name for these
symptoms?
• What other agents would cause a similar clinical
presentation (differential diagnosis)?
• Are there readily available laboratory tests to
confirm this diagnosis? If so, what are they?
• Was there a possible treatment for this child?
• When was this child contagious, and how was the
virus transmitted?
References
1. Centers for Disease Control and Prevention. “Respiratory Syncytial Virus
Infection (RSV).” Updated: Mar. 31, 2010. Access: Oct. 18, 2012.
<http://www.cdc.gov/rsv/about/index.html>
2. Krilov, Leonard R. Respiratory Syncytial Virus Infection. “Background.” Updated:
Sep 20,
2012.
Access: Oct. 18,
2012.<http://emedicine.medscape.com/article/971488-overview>
3. MedlinePlus. “Respiratory syncytial virus (RSV).” Updated: Feb 17, 2011.
Access: Oct. 18,
2012.<http://www.nlm.nih.gov/medlineplus/ency/article/001564.htm>
4. Meridian Bioscience. Testing for Respiratory Syncytial (RSV). Access: Oct. 18,
2012.<http://www.meridianbioscience.com/diseaseinformation/rsv/testing.aspx>
5. National Institute of Allergy and Infectioious Diseases. “Respriatory Syncytial
Virus (RSV).”
Updated: Sept 27, 2012. Access: Oct. 18, 2012.
<http://www.niaid.nih.gov/topics/rsv/understanding/Pages/cause.aspx>