Wendy Vuong Joseph Martin del Campo Reza Parhizkar Micro 401

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.

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 nm, 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

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, Access: Oct. 18, Krilov, Leonard R. Respiratory Syncytial Virus Infection. “Background.” Updated: Sep 20, Access: Oct. 18, MedlinePlus. “Respiratory syncytial virus (RSV).” Updated: Feb 17, Access: Oct. 18, Meridian Bioscience. Testing for Respiratory Syncytial (RSV). Access: Oct. 18, information/rsv/testing.aspx 5. National Institute of Allergy and Infectioious Diseases. “Respriatory Syncytial Virus (RSV).” Updated: Sept 27, Access: Oct. 18,