11

Influenza A, B, C viruses● Classification, Composition, Genome, Biology - Family Orthomyxoviridae Influenza A subtypes : 16 distinct HA & 9 distinct NA ( ~ outbreaks in humans : H1-3 & N1-2 )

- Virion (spherical) : a. Segmented, minus strand RNA b. Helically coiled nucleocapsid c. Enveloped (hemagglutinin & neuraminidase glycoprotein

spikes)

2

Zuckerman et al, 2009. Principles & Practice of Clin Virol. Wiley-Blackwell

33

- Genome :13000-15000 nt, 7-8 segments (reassortment !); which code 10-11 different proteins. Influenza C virus : NA gene Ө

Example : A/Johannesburg/33/94(H3N2)

4

5

- Primary cell cultures including monkey kidney cells - Host : Influenza A virus : wild avian, humans, swine, horses

(note : all known HA & NA subtypes) Influenza B & C viruses : humans : swine, dogs, cats, horse- Inactivated by : ionizing radiation, pH <5 / >9, >50C, ionic & non ionic detergents, organic solvents, drying

666

● Epidemiology - Worldwide (all age groups); outbreak : unpredictable 9 pandemik : Influenza A virus H1N1 (swine) 1918, H2N2 (Asian) 1957, H3N2 (Hongkong) 1968, H5N1 (chicken/bird) 1997 1947 : WHO surveillance program

7

- New strain ~ outbreak/pandemic (>>Influenza A virus) Changing antigenecity : antigenic shift (HA ± NA) &

antigenic drift (HA/NA)

- Influenza A virus : > avian; ~ epidemic (swine as an intermediate host)

: non human & human (reassortment!) Influenza B & C viruses : ~ milder disease; winter outbreaks

- Seasonal : (~ humidity) winter / spring (temperate) & year round : rainy season (tropics).

(Influenza C virus : non seasonal)

88

- Low mortality (~ lower respiratory/ cardiovascular disease) - Transmission : by airborne droplets (person-to-person,

zoonotic infection) - Reinfection >> - Nosocomial infection (~ Influenza A virus)

● Clinical Manifestation - Incubation period : 1-5 days Influenza syndrome (all age groups) - Complication : common (otitis media/sinusitis, bronchitis, croup, pneumonia, CNS, myocarditis, acute renal failure)

9

● Lab Diagnosis - Virus isolation from sputum, nose/throat swabs, nasal aspirate/washing (cell culture) & CPE detection and hemadsorption - Nucleic acid detection (RT-PCR) - Serology tests : to detect ag & ab (IF, EIA, HAI)

● Prevention (vaccine, patient isolation : in hospital, antiviral)

● Treatment (symptomatic dan antiviral : Amantadine, Rimantadine, Oseltamivir ~ H5N1 resistant !!)

1010

Parainfluenza virus● Classification, Structure, Genome, Biology - Genus : Respirovirus & Rubulavirus,

Family :Paramyxoviridae Types of HPIV : 1, 2, 3, 4 (subtypes A & B)

- Virion : pleomorphic (spherical/filamentous) : a. Single stranded of negative sense RNA b. Helical nucleocapsid c. Envelope (spike-like glycoproteins & lipid from host cell)

11

1212

- Genome : 15500 nt which code : 6 VP (HN = Hemaglutinin-Neuraminidase,

M = Matrix F = Fusion)

& 1 NSP - Primary cell cultures : i.e Hep-2 cells , monkey kidney cells

1313

● Epidemiology (~ age, seasonality, clinical manifestation) - Worldwide (early childhood) mortality : ~ pneumonia (children <5 y.o)

in developing countries - HPIV type 1 : croup epidemics (~ autumn) 2 : ~ PIV type 1 (milder) 3 : sporadic, least predictable (late winter &spring) in tropics : rainy season - Transmission : droplet (port d’entry : nose & eyes) close-contact transmission &

surface contamination

14

- Host range : humans. - Host factors : age & immunodeficiency - Immunity : not long lasting - Reinfections : common (HPIV type 3) - Nosocomial infections (HPIV type 3)

● Clinical Manifestation : - Upper resp. tract infection: “croup”

(laringotrakheobronchitis) Lower resp. tract infection (bronchiolitis & pneumonia) - Complications : otitis media, bacterial pneumonia

15

MANDELL, DOUGLAS, BENNETT’S. 2010. PRINCIPLES & PRACTICE OF INFECTIOUS DISEASES 7th ed Churchill Livingstone

16

1717

● Lab Diagnosis - Specimens : nasal wash/ nasal aspirate, nasopharyngeal swabs, BAL - Virus isolation, CPE detection and hemadsorption - Serology tests : ag (IF) & ab (CFT, HI) - Nucleic acid detection (RT-PCR)

● Prevention (vaccine ~ HPIV tipe 3, handwashing, glove-goggle-masker-gown)

● Treatment (supportive, no licensed antiviral)