Respiratory Viruses Flashcards

Question

Serious RSV illness

Answer 1

Very young infants, premature infants Children <2 - 3 yo Elderly Children and adults with chronic illness and compromised immune systems Mortality = .5-1% but > 15% in impaired host

Answer 2

Leading viral cause of mortality in infancy 10x morality of influenza in infants < 1 yr 500 deaths per year - 80% in infants < 1 yo

Answer 3

Bronchiolitis (most common) Pneumonia Tracheobronchitis Croup Asymptomatic (Ascending--> descending, most common--> leas common)

Answer 4

URI = cough, rhinitis pharyngitis, fever LRI = expiration wheezing, air trapping, tachpnea, dyspnea, rales (clicking rattling in lungs), rhonchi (snoring sound in lungs), retractions (sinking in of the chest wall above collarbone, between ribs and below rib cage), nasal flaring, grunting hypoxemia (low oxygenation of blood), irritability, dehydration, respiratory distress Clinical findings: Hyperexpansion of lungs and hypercapnia (carbon dioxide retention- especially bad when young) Other; otitis media, vomiting, conjunctivitis Duration: 10 - 14 days

Answer 5

Look at pic slide 26 of respiratory lecture - see child with suprasternal and intercostal retractions and nasal flaring--> child cant breathe

Answer 6

Slide 27 of respiratory lecture Hyperinflation of lungs (due to airtrapping tachypnea) with flattened diaphragm, horizontal ribs and increased hilar bronchial markings See pulmonary insterstitial infiltrates with areas of pulmonary collapse RSV pathogenesis: infx in respiratory tract - no viremia, respiratory epithelial cells killed by virus and cellular immune response--> necrosis of epithelium in medium to small airways--> mucus/fibrin plugs impeding airflow gas exchange and leading to pulmonary infiltrates

Answer 7

Healthy adults frequent, mild influenza like In elderly and immunocompromised (CHF, immune suppression, bronchiopulmonary insuffiency) it can the serious 2- 4% pneumonia deaths among elderly Suspect RSV in all adults who present with fever and pulmonary infiltrates

Answer 8

Concern in pediatric wards, nurseries, nursing homes, adult medical wards Controlling spread can be difficult Recovered rom counter tops for 3 - 30 h Cloth gowns, gloves, paper tissue for 1 h Skin 30 min Max period of viral shedding is 3 - 8 days for immune competent and 3 - 4 weeks in young infants WASH HANDS

Answer 9

Supportive, maintain hydration and oxygenation and keep airways clear of mucus and debris No vaccine Palivizumab(synagogue) - humanized mouse monoclonal Ab for HIGH RISK children - IM injections 1x/mo during RSV season, 5 doses given Aersolized - Ribavirin - drug to treat RSV lower respiratory tract, cost and risk of aersolized administration, used selectively - generic antiviral for lower respiratory tract, not suggested for routine use

Answer 10

Family: paramyxovirus Not a new virus All age groups all over the world Pleomorphic particles, spherical, filamentous SsRNA, single stranded negative sense RNA virus Enveloped No hemagglutin 4 genotypes of the virus that can be found in two major groups (A and B)

Answer 11

Mid January -- mid June

Answer 12

Symptoms similar to RSV Acute respiratory illness in children, elderly, those with underlying immune compromise and cardiopulmonary disease Virtually all children infected by 5 to 10 yo, new infections throughout life Clinical presentation from URI to severe bronchiolitis and pneumonia

Answer 13

Paramyxovirus family (with RSV, HMPV, mumps and measles) 120-300 mm Enveloped Nonsegments, ssRNA genome Paramyxoviruses have hemagglutinin and neuraminidase activity (HN protein) and fusion (F protein) - positive hemagglutination tests are parainfluenza and negative are HMPV

Answer 14

Parainfluenza virus

Answer 15

Four serotypes: 1, 2, 3, 4 (A&B) Individual types are antigenically stable - unlike influenza, no antigenic shift or drift Differ in frequency of occurrence, disease spectrum, and epidemic patterns Cause disease in larger airways of LRT Important cause of LRI in infants and children (15-20%( of all non bacterial respiratory disease causing hospitalization

Answer 16

PIV1 - major cause of acute viral croup, mostly in the fall and early winter, 6 - 12 mo yo PIV3 and 2 (second and 3rd most frequent cases) PIV2 - fall and early winter but not concurrent with PIV1 - less significant, 6 - 12 mo yo PIV3 - mostly in the spring and summer- common cause of pneumonia and bronchiolitis , all throughout the year - highest attack rates in 3 - 6 mo PIV4 is least common and infrequent cause of acute LRtract disease and associated with mild URI Viruses 1 & 2: Croup, 6 mo - 12 yr, Autumn 3: Bronchiolitis, Pnejmonia, < 6 mo, Endemic (spring) 4: URI, children, endemic

Answer 17

Virus infects epithelial cells of upper airways Begins as URI with thin nasal discharge, sore throat, mild cough Within 1 - 2 d, inspiration stridor, retractions, worsening barking cough (hoarseness due to narrowing in region of larynx and subglottic trachea) Symptoms exacerbated at nigh, children wake up gasping for breath Self limited, last 3 - 7 days in most and up to 7 - 14 days STEEPLE SIGN - see pic on slide 42

Answer 18

Supportive care for mild disease Oxygen, nebulized epinephrine and corticosteroids for severe infection Immunity short lived so reinfections throughout life are common though less severe

Answer 19

Symptoms from inflamed larynx and subglottic airway, may close the airway in severe case Dry barking seal life cough 6mo - 12 yrs, peak incidence at 2, more common in boys Fall or early winter 10pm - 4 am ED visits, worst ending symptoms at night Self-limited condition - last 3 - 7 days, up to 7 - 14 days in some See treatment slide for treatment

Answer 20

Nonenveloped viruses 80 - 90 mm in size Icosahedral capsid of. Hexon and Peyton capsomers DsDNA (encodes 30 - 40 genes) Fibers project from capsid at Peyton base and are major attachment for proteins (knobbed viruses--> classic shape) Peyton base and fiber proteins determine serotypes, tissue tropism and disease

Answer 21

~ 100 types, 57 affect humans Species A to G (varied tissue tropism) - mainly b and C, some E: infect respiratory tract - B and D: ocular - primarily F, some a and G--> GI disease Ubiquity and persistence in host tissues for days to years (prolonged infx without disease!) Only 45% of infx result in disease Serotypes 1-5, 7, 8, 21 important respiratory agents, 14 associated with sever pneumonia in civilian and military communities

Answer 22

Endemic in US, sporadic outbreaks Children: 6 mo - 5 yrs and grade school and junior high Epidemics occur in military recruits (primarily AdV types 4 & 7) Spread by respiratory and fecal route - resist drying, detergents, GI secretion - aerosols, fingers, fomites (including medical instruments), poorly chlorinated swimming pools - in day care, hospitals, clinics, children's homes, physicians offices, industrial settings

Answer 23

Many common diseases including multiple respiratory and GI syndromes, significant cause of conjunctivitis (pink eye) Cause disseminated disease and high morbidity and mortality in immunocompromised patients, transplant reciepients and are a significant cause of nonstreptococcal exudative pharyngitis < 3 yo Infants, young children, - acute febrile pharyngitis - **pneumonia - pertussis like syndromes School age children - pharyngoconjunctivial fever - pic on slide 49 Military recruits - acute respiratory disease Transplant recipients, AIDS patients, other immunocompromised - disseminated diseas - acute hemorrhagic cystitis

Answer 24

Slide 49 - foreign body sensation in right eye Conjunctiva was injected and red with clear discharge No foreign body--> give anti-inflammatories for possible allergic reaction--> next day eye was swollen and appearance of pale real conjunctiva was intensely red and granular Patient complained of severe eye pain and burning, photophobia, and eye was constantly tearing Over the next 2 - 3 days, develop: - sore throat, cough, Coryza, stiff neck, malaise aches and pains, fever, vomiting, diarrhea, anorexia, lymphadenopathy, left eye conjunctivitis - adenovirus from respiratory tract, persisted for 14 days infected from children

Answer 25

Picornaviridae: small RNA virus Genus: enterovirus Naked, nucleocapsid, Capsid has 4 viral proteins: VP1, VP2, VP3, VP4 Attach to intracellular adhesion molecule 1(ICAM-1) on cells (member of Ig super family( SsRNA genome (single stranded negative sense RNA) > 100 sero/genotypes in three groups (A-C); 3 - 4 circulate at a time Common cold virus Acid labile (unlike enteroviruses) so they cannot replicate in GI tract

Answer 26

Rhinovirus

Answer 27

Antigenic diversity! 3 - 4 serotypes circulate at one time Infection with one type appears to confer lasting type specific immunity but offers no protection against other types By adulthood, we have Ab to about half the serotypes Infections throughout the year but peak in the fall/ spring

Answer 28

All ages, especially older children and adults All throughout the year, peak activity in fall and spring

Answer 29

Most viral replication is in nose; release of bradykinin and histamine causes "runny nose"

Answer 30

Flu like illness - significant cause of lower respiratory tract disease, more common than expected Indirectly or directly cause many cases of acute sinusitis and otitis media Important role of rhinoviruses as a cause of - bronchiolitis in infancy, - childhood pneumonia - exacerbation of asthma, COPD, cystic fibrosis, Enterovirus respiratory infections - associated with respiratory illness, seen in late summer/early fall

Answer 31

Enveloped virus Petal or club shaped spikes (solar corona) created by spike protein peplomers SsRNA genome, positive sense single stranded RNA Phenotypically and genotypically diverse Infect respiratory and GI tracts of mammals and birds 4 respiratory serotypes in man SARS coV in 2003; MERs coV in 2012

Answer 32

In the winter corona virus is more common the cause In the summer rhinovirus more commonly causes the common cold

Answer 33

Two non structural replicate polyproteins and four structural proteins structural proteins - spike (S): responsible for receptor binding - envelop (E): virus assembly - membrane (M) glycoproteins : virus assembly - nucleocapsid (N) protein: internal protein binds to viral RNA to form ribonucleoprotein complexes Replicate polyproteins directly translated from viral genome and used in viral transcription and replication

Answer 34

Common viruses, people get in their life time 10-30% common colds Can cause more serious LRTI Can also cause enteric, hepatic, or neurological diseases Can be found in other species, birds cats dogs pigs mice, horses whales and are widespread in bats!

Answer 35

Excellent for healthy individuals Increased risk: young children, elderly, ill chornically ill, immunocompromised Complications - exacerbation of underlying respiratory disease - development of chronic lung disease - possible secondary bacterial infections - apnea, respiratory failure - acute otitis media - sudden infant death syndrome in immunocompromised children

Answer 36

Infection induces immunity only partially protective and of short duration Ab acquired early in life but reinfection is common Cell mediated immunity is likely to be pivotal in clearance of RVs and in recovery - resistance to infection of upper respiratory tract due to secretory antibody - resistance of lower respiratory tract due to circulating antibody Illness is. Milder with reinfection Ag variants may exist for which immunity is not completely cross protective Only vaccines for influenza

Answer 37

No vaccines or therapeutics for most respiratory viruses Good supportive care Treatment - aersolized ribavirin (RSV) for select patients, - amantadine, rimantadine (influenza A) - Zane I IR, oseltamivir (influenza A and B) RSV: treat with aersolized ribavirin and prevent with palivizumab (humanized monoclonal ab) Parainfluenza: ribavirin (limited studies) Adenovirus: ribavirin, cidofovir - anecdotal Rhinovirus: limited, pleconaril an dother canyon inhibitors

Answer 38

Immunoglobulin: Palivizumab (synagogue) humanized monoclonal antibody against RSV Vaccine and antivirals (influenza)

Answer 39

Interrupt transmission: contact isolation, cohorting, gowns and gloves, HANDWASHING

Answer 40

Certain bacteria and fungi but at lesser frequency than viruses discussed today Bacterial infections may result of secondary infection following viral illness - symptoms may persist longer than expected 10-14 days of viral illness and fever worse and get worse after a few days Secondary infections: sinusitis, ear infections, pneumonia (productive cough for bacterial infections with more discrete foci unlike the diffuse interstitial infiltrates of viruses)