1. Respiratory Syncytial Virus Sonia Leng Heather Leonard
RSV
Respiratory Syncytial Virus
Sonia Leng
Heather Leonard

2. Taxonomy Order Mononegavirales Family Paramyzoviridae
Subfamily Pneumovirinae
Genus Pneumovirus

3. Background Information of the Virus
Enveloped virus
nm diameter
Helical nucleocapsid
(-) ssRNA
Most prevalent during winter months

4. Diseases Bronchiolitis Asthma Pneumonia COPD
droplet inhalation through the nose
Asthma
Pneumonia
COPD
Chronic Obstructive
Pulmonary Disease
Spread through respiratory secretions
- coughing, sneezing

5. Infection Process
RSV envelope fuses to cell membrane and injects viral genome into the cell’s cytoplasm where translation will occur and the virion will be replicated
Genome is transcribed from 3’ end into monocistronic mRNA molecules
Each species only encodes a single protein
New viruses released via budding
Clumping may occur when new synthesized RSV surrounded by other infected cells
New viruses spread from cell to cell
produces a characteristic fusion of human cells in tissue culture
the syncytial effect

6. Symptoms Occurs within either days or hours of exposure
vary from person to person
symptoms most severe in children under the age of two
symptoms in adults and children are mild
Stuffy Nose
Nose flaring
Low-grade fever
Wheezing
Rapid Breathing
Ear Infection

7. Diagnostic Tests
For confirmation of RSV, proper testing of the patient's respiratory secretions will:
Positively identify RSV 
Rule out bacterial infection 
Nasopharyngeal secretions containing epithelial cells are necessary for positive diagnosis of severe RSV infections
There are two strains, A and B
A causes severe cases
B is asymptomatic and is transmitted to most people

8. Treatment Currently no RSV vaccine available
No treatment given in mild
disease
just medication to reduce fever
Oxygen therapy and mechanical ventilation (severe disease)
Ribavirin aerosol (severe disease)
Sometimes used---IGIV (immune globulin intravenous) with RSV-IGIV (neutralizing RSV antibody) and Ribavirin. [severe disease]

9. Treatment (cont.) Drug Therapies
1. HRSV IV immune globulin (RSV-IVIG)
First approved immunoprophylactic
released as Respigam (1996)
made by high titre Sera (protective and neutralizing antibodies)
administered monthly to prevent infection over 4-5 month period. (during peak season)
2. Palvizumab (Synagis)
next generation prophylactic
(MAb) humanized monoclonal antibody
IM injection, not IV
admin. During peak season
1960’s- Formalin-inactivated whole-virus hRSV vaccine
given to infants (no previous exposure)
later infected by hRSV, suffered severe symptoms of hRSV.

10. Prevention Frequent hand washing
At-Risk children can be given an injection of RSV antibodies monthly during peak season.
Keeping school-age children away from younger siblings (anyone under 2 years of age) if cold symptoms are present
Minimize number of visitors with the infant
Avoid any crowded places
mall, grocery store
If possible, don’t take child to daycare during
RSV season
Partake in influenza vaccinations

11. Epidemiology Transmission Prevalence Global Distribution
RSV is easily transmitted via large, aerosolized respiratory particles, or through contact with nasal secretions, and may even be transmitted indirectly by contact with contaminated objects, such as bathroom fixtures or even clothing. The most common sites of innoculation are the eyes and nose
Prevalence
Winter months
Most frequently transmitted between family members and hospitals
The incubation period is three to five days for most patients
Strain A more prevalent than Strain B
Global Distribution
Warmer climates tend to have longer periods of outbreaks without any peak times
USA is generally November til May

12. Latest reports on morbidity and mortality
Preventing Respiratory Syncytial Virus Bronchiolitis
mortality rate in the United States is at 0.13%
Viral Lower Respiratory Tract Infections in infants and Young Children
mortality rate is increased when the child is immunocompromised.
Prospective study of healthcare utilization and respiratory morbidity due to RSV infection in prematurely born infants
RSV infection is associated with increased healthcare utilization and respiratory morbidity in premature babies
study was performed on infants born before 32 weeks gestation and during the RSV season of February through September. Thereafter, they were followed until the corrected age of one.

13. Latest research on pathogenicity and prevention
During the course of RSV infection, predominant T helper cell (TH) 2 response is associated with disease progression, whereas predominant TH1 reaction provides response to physical sickness. Interleukin (IL)-18 plays an important role in adjusting the TH1/TH2 immune response to viral infections. The have tested the hypothesis that polymorphisms in IL-18 were associated with severe RSV-associated diseases.
This study indicates possible involvement of IL-18 in the determination of severe RSV-associated diseases. Defining the genetic basis of RSV bronchiolitis might help us in identifying new drug targets for a more specific therapy.
Prevention
Palivizumab is approved for prevention of RSV disease, and ribavirin is approved for treatment of RSV infections but its efficacy in high-risk patients has not been conclusively established
31 (20 male and 11 female) patients hospitalized for RSV infection were treated with intravenous palivizumab
from October 2001 through July 2005
25 patients (80%) also received ribavirin
29 (93.6%) patients survived and 2 died
No adverse events attributed to palivizumab or ribavirin administration were observed.
Treatment of RSV-infected high-risk children with palivizumab alone or in combination with ribavirin was well tolerated and associated with decreased mortality compared with previous reports

14. References
Respiratory Syncytial Virus. National Center for Infectious Diseases. Respiratory and Enteric Viruses Branch. 2005
Respiratory Syncytial Virus. KidsHealth. 2006
Prospective study of healthcare utilisation and respiratory morbidity due to RSV infection in prematurely born infants. S Broughton, A Roberts, G Fox, E Pollina, M Zuckerman, S Chaudhry, and A Greenough. Thorax, Dec 2005; 60:
Diminished lung function, RSV infection, and respiratory morbidity in prematurely born infants. S Broughton, R Bhat, A Roberts, M Zuckerman, G Rafferty, and A Greenough. Arch. Dis. Child. 2006; 91;26-30; 27 Sept 2005
Human Respiratory Syncytial Virus (HRSV). Virology Down Under. Virus, Disease, Diagnosis. 2005
Signs and Symptoms of Human Respiratory Syncytial Virus. About.com-Lung Diseases. 2006
Respiratory Syncytial Virus Prevention. About.com-Lung Diseases. 2006
Preventing Respiratory Syncytial Virus Bronchiolitis. Mike Sharland and Alison Bedford-Russell BMJ 2001;322:62-63
RSV. The RSV Info Center.
Principle and Practices of Clinical Virology. Arie J. Zuckerman. John Wiley and Son Ltd
Viral Lower Respiratory Tract Infections in infants and Young Children. JBM van Woensel, WMC van Aalderen and JLL Kimpen. BMJ 2003;327;36-40
Interleukin (IL)-18 polymorphism 133C/G is associated with severe respiratory syncytial virus infection. Puthothu B., et al. Center for Pediatrics and Adolescent Medicine, University of Freiburg, Freiburg, Germany. Pediatric Infectious Disease Journal Dec;26(12):
Intravenous palivizumab and ribavirin combination for respiratory syncytial virus disease in high-risk pediatric patients. Chávez-Bueno S., et al. Department of Pediatrics, Division of Infectious Diseases, The University of Texas Southwestern Medical Center at Dallas, TX. Pediatric Infectious Disease Journal Dec;26(12): ttp://

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