14 - RNA VIRUS

Reoviridae

RNA Virus in General

All are single-stranded RNA except

Picornaviridae, Reoviridae, Caliciviridae (PCR)

RNA Virus in General

All are enveloped except (3)

Bunyaviridae, Orthomyxovirus, Arenavirus, Retrovirus (BOAR)

RNA Virus in General

Envelope-segmented (4)

Envelope-segmented viruses

RNA Virus in General

Allows for easier reassortment of genome which is a potential for causing pandemics

Coronavirus, Rhabdovirus, Flavivirus, Togavirus, Filovirus, Paramyxovirus (CRaFT For Princess)

RNA Virus in General

Envelope non-segmented (6)

Orthomyxoviridae & Retroviridae

RNA Virus in General

All replicated in nucleus except (2)

Caliciviridae, Picornaviridae, Flaviviridae, Togaviridae, Reoviridae, Retroviridae

RNA Virus in General

All replicated in nucleus except (6) (icosahedral)

Arbovirus (Bunyaviridae, Flaviviridae, Togaviridae)

RNA Virus in General

Arthropodborne (3)

Paramyxoviridae

RNA Virus in General

Largest RNA virus

Picornaviridae

RNA Virus in General

Smallest RNA virus

Influenza virus A, B, C

RNA VIRUSES
Virus Family	Disease Associated
Orthomyxoviridae	(1)

Mumps virus, measles virus, RSV, hMPV

RNA VIRUSES
Virus Family	Disease Associated
Paramyxoviridae	(4)

Poliovirus, Coxsackievirus A & B, Hepatitis A virus, ECHO virus, Parechovirus

RNA VIRUSES
Virus Family	Disease Associated
Picornaviridae	(5)

Rabies

RNA VIRUSES
Virus Family	Disease Associated
Rhabdoviridae	(1)

Dengue virus, Hepatitis C virus, yellow fever, St. Louis encephalitis, west nile virus, zika virus, hepatitis G

RNA VIRUSES
Virus Family	Disease Associated
Flaviviridae	(7)

Marburg virus, ebola virus

RNA VIRUSES
Virus Family	Disease Associated
Filoviridae	(2)

SARS-COV-1, SARS-COV-2, MERS-COV

RNA VIRUSES
Virus Family	Disease Associated
Coronaviridae	(3)

Rubella virus, Chikungunya virus

RNA VIRUSES
Virus Family	Disease Associated
Togaviridae	(2)

Hepatitis E virus

RNA VIRUSES
Virus Family	Disease Associated
Hepeviridae	(1)

Rotavirus, Colorado Tick Fever

RNA VIRUSES
Virus Family	Disease Associated
Reoviridae	(2)

Sapporo Virus, Norwalk Virus, Rabbit Hemorrhagic Disease Virus, Feline Calicivirus

RNA VIRUSES
Virus Family	Disease Associated
Caliciviridae	(4)

Hantavirus, arboviruses

RNA VIRUSES
Virus Family	Disease Associated
Bunyaviridae	(2)

Astrovirus

RNA VIRUSES
Virus Family	Disease Associated
Astroviridae	(1)

HIV, oncoviruses

RNA VIRUSES
Virus Family	Disease Associated
Retroviridae	(2)

Orthomyxoviridae

SS (-) RNA, helical, enveloped

2 important antigens

HemAgglutinin (HA)

NeurAminidase (NA)

Orthomyxoviridae

2 important antigens

_: 15 subtypes H1, H2,H3

_: 9 subtypes N1, N2

Antigenic shift

Antigenic drift

Orthomyxoviridae

Antigenic Variation

_ _: Major mutation/causes pandemic

_ _: Minor mutation/causes local outbreaks

H1 H2 H3 N1 N2

Orthomyxoviridae

Only (5) are found in human population

Spanish Flu pandemic

H1N1

Orthomyxoviridae

Deadliest pandemic in recorded history

Caused by _ strain

H1N1

H2N2

H3N2

H5N1

ORTHOMYXOVIRIDAE
Virus Family	Disease Associated
_	Spanish flu
_	Asian flu
_	Hongkong flu
_	Avian flu

Influenza A

Orthomyxoviridae

Three Serotypes

Naturally infects birds, swine, seals, felines, and horses

Influenza B

Orthomyxoviridae

Three Serotypes

Distribution: Human

Epidemiology: Less serious infection than Type A

Influenza virus C

Orthomyxoviridae

Three Serotypes

Distribution: Humans, swine

Epidemiology: Rarely causes diseases, ubiquitous

Influenza Virus

Orthomyxoviridae

Distribution: Humans, aquatic birds, swine, horses, seals, whales

Epidemiology: Flu epidemic, highly contagious

aerosol inhalation

Orthomyxoviridae

Influenza Virus

MOT: Inhalation of respiratory droplets, _ _

1-4

3-7

1-2

Orthomyxoviridae

Influenza Virus

Manifestation: Sore throat, fever, chills, myalgia, headache

Incubation period: _-_ days

Self-limiting infection: _-_ days, cough (_-_ weeks)

Nasopharyngeal swab, washes, aspirates

Orthomyxoviridae

Influenza Virus

Sample for diagnosis: (3)

Enzyme immunoassays

embryonated chicken eggs

RT-PCR

Orthomyxoviridae

Influenza Virus

Diagnosis: _ _ (detection of antigens), immunoassays, grows in amniotic cavity of _ _ _ and various mammalian cell, _-_

Vaccine

Orthomyxoviridae

Influenza Virus

Most effective tool against influenza

fall

Orthomyxoviridae

Influenza Virus

Vaccine

Usually administered during _ (before the onset of winter epidemics) “flu shot”

inactivated whole virus

Orthomyxoviridae

Influenza Virus

Vaccine

Uses _ _ _

Trivalent

Type-A H1N1, H3N2, Type-B antigen

Orthomyxoviridae

Influenza Virus

Vaccine

_ subunit vaccine

Purified HA antigen: (3)

Paramyxoviridae

SS (-) RNA, enveloped

Hemagglutinin-Neuraminidase (HN)

Paramyxoviridae

Glycoprotein responsible for attachment to host cells and viral release

Fusion protein (F-protein/F Ag)

Paramyxoviridae

Syncytia formation

Multiple host cells will fuse into one large multinucleated cell

respiratory tract

Paramyxoviridae

Pathogenesis: Infection by the _ _

respiratory disease

Paramyxoviridae

All members cause _ _

Mumps Virus/Rubulavirus

Paramyxoviridae

“Beke”

droplets

Paramyxoviridae

Mumps Virus/Rubulavirus

MOT: Inhalation of _

1-3

Paramyxoviridae

Mumps Virus/Rubulavirus

Manifestations: Generalized infection (_-_ weeks)

Parotitis

Orchitis

Paramyxoviridae

Mumps Virus/Rubulavirus

Hallmark: _ – inflammation of the parotid gland

_ – causes testicular inflammation and rarely infertility

Viral meningitis, pancreatitis, encephalitis

Paramyxoviridae

Mumps Virus/Rubulavirus

Complications: (3)

Multinucleated cell

Saliva, urine, CSF

Paramyxoviridae

Mumps Virus/Rubulavirus

Diagnosis:

Cytopathic effect (CPE): _ _

Specimens: (3)

MMR vaccine

Live attenuated, 12-15

Paramyxoviridae

Mumps Virus/Rubulavirus

Prevention: ?

_ _ vaccine (_-_ months)

Measles Virus or Morbillivirus Fever

Paramyxoviridae

Clinical features: 3Cs – Coryza (runny nose), Cough, Conjunctivitis

Koplik’s Spot

Paramyxoviridae

Measles Virus or Morbillivirus Fever

Highly contagious accompanied by maculopapular rash and fever called _ _

Airborne

Giant cells

Paramyxoviridae

Measles Virus or Morbillivirus Fever

MOT: _

CPE: _ _

Cough, coryza (colds), conjunctivitis

Maculopapular rash

Paramyxoviridae

Measles Virus or Morbillivirus Fever

Manifestations:

Early symptoms: (3)

Late symptoms: _ _

Otitis media, viral pneumonia

Post-infectious Encephalomyelitis

Subacute Sclerosing Panencephalitis (SSE)

Paramyxoviridae

Measles Virus or Morbillivirus Fever

Severe complications: (3)

_-_ _: 1:1000 (15% fatality rate)

_ _ _: 1:1 million cases

Pneumonia

Koplik’s Spot

Vitamin A

MMR

Paramyxoviridae

Measles Virus or Morbillivirus Fever

Diagnosis: _ _

• Small, white lesions found on the buccal mucosa near the molars

Treatment: _ _ (for infants)

Vaccine: ?

• Highly effective if 2 doses are administered

Respiratory Syncytial Virus (RSV)/Pneumovirus

Paramyxoviridae

Causes: Croup, bronchitis (infants), pneumonia

Pneumovirus

Syncytia

Paramyxoviridae

Respiratory Syncytial VIrus (RSV)/Pneumovirus

SS (-) RNA

Specific virus: _

CPE: _

Fusion protein (F)

Paramyxoviridae

Respiratory Syncytial VIrus (RSV)/Pneumovirus

responsible for syncytia formation

Nucleoprotein (N)

Paramyxoviridae

Respiratory Syncytial VIrus (RSV)/Pneumovirus

protects and organizes the viral RNA

Matrix protein (M)

Paramyxoviridae

Respiratory Syncytial VIrus (RSV)/Pneumovirus

helps assemble and shape the virus

Attachment protein (G)

Paramyxoviridae

Respiratory Syncytial VIrus (RSV)/Pneumovirus

attachment of the virus

Small hydrophobic protein (SH)

Paramyxoviridae

Respiratory Syncytial VIrus (RSV)/Pneumovirus

acts as an ion channel which helps in immune evasion

Human Metapneumovirus (hMPV)

Paramyxoviridae

Associated with winter epidemics of bronchiolitis and pneumonia which is common in children

Indistinguishable from RSV infections

Affects slightly older children and adults

No specific antiviral treatment exists yet so supportive care remains the mainstay of management

phosphoprotein

polymerase

Paramyxoviridae

Human Metapneumovirus (hMPV)

Additional _ (P) and _ (L) proteins

Picornaviridae

SS (+) RNA, naked/non-enveloped

Simplest of RNA viruses with highly structured capsid but limited surface elaboration

Poliovirus, Coxsackievirus A/B, Enteric Cytopathogenic Human Orphan Virus (ECHO virus)

Picornaviridae

Enteroviruses (3)

Rectal swab, stool, throat swab or washings or CSF

Picornaviridae

Sample preference: (4)

resistant

Picornaviridae

Acid _

Poliovirus (1-3)

Coxsackie A (1-23)

Coxsackie B (1-6)

ECHO Virus (1-32) Enterocytopathogenic orphan virus

Enterovirus 72/Hepatitis A virus

Others: Parechovirus (1-4)

Picornaviridae

Specific enteroviruses (7)

Brunheldi Virus

Lansing Virus

Leon Virus

Picornaviridae

Poliovirus

• Types:

  • Asymptomatic/Type 1 – _ _

    • Most cases of paralytic polio

  • Abortional/Type 2 – _ _

    • Abortive or minor illnesses

  • Paralytic Poliomyelitis/Type 3 – _ _

    • Neurovirulent

    • <1%: Acute flaccid paralysis

Fecal-oral

Picornaviridae

Poliovirus

MOT: ?

Sabin

Salk

Picornaviridae

Poliovirus

• Vaccine: All 3 strains must be included in the vaccine

  • _ (live attenuated PV): Oral

    • Provides mucosal immunity but carries the small risk of vaccine-derived polio

  • _ (killed PV): Parenteral

    • Safer for immunocompromised individuals

Coxsackievirus A (1-23)

Picornaviridae

Manifestations: Mild respiratory disease

Herpangina

Coxsackie A24

Coxsackie A9, & A16

Picornaviridae

Coxsackievirus A (1-23)

Aseptic meningitis (80-90% of viral meningitis)

_ (severe febrile, vesicular pharyngitis)

Acute hemorrhagic conjunctivitis (_ _)

Hand, foot, and mouth disease (HFMD) (_ _ & _)

Hemolytic uremic syndrome (HUS)

Onychomadesis

Coxsackievirus B (1-6)

Picornaviridae

Manifestations: Leading viral cause of myocarditis & pericarditis

Aseptic meningitis

Pleurodynia/Devil’s Grip

Bornholm Disease

Picornaviridae

Coxsackievirus B (1-6)

Other manifestations (3)

ECHO Virus (1-32) Entrocytopathogenic Orphan Virus

Picornaviridae

Infantile diarrhea & aseptic meningitis, cough, rash, and influenza-like

Enterovirus 72/Hepatitis A Virus

Picornaviridae

Causes infectious/epidemic hepatitis

No chronic state

Fecal-oral route

Parechovirus (1-4)

Picornaviridae

Emerging cause of Summer diarrhea in infants

Rabies Virus/Lyssa Virus

Rhabdoviridae

SS (-) RNA, helical, enveloped, “bullet-shaped”

Cytoplasm

Rhabdoviridae

Rabies Virus/Lyssa Virus

Replication: ?

Raccoons

dogs

Rhabdoviridae

Rabies Virus/Lyssa Virus

Epidemiology:

_ (most common animal carrier)

Unvaccinated domestic animals (_)

Skunks, wild mammals, bats (US)

Humans are accidental hosts

Negri bodies

Rhabdoviridae

Rabies Virus/Lyssa Virus

Diagnosis: _ _ in the neurons

Bite of animal

Rhabdoviridae

Rabies Virus/Lyssa Virus

MOT: ?

Fatal encephalitis

Rhabdoviridae

Rabies Virus/Lyssa Virus

Symptoms:

_ _, hypertonic muscle contraction, convulsions, coma, death

Hydrophobia, photophobia, arophobia

Human rabies immune globulin

Human diploid cell vaccine, 6

Rhabdoviridae

Rabies Virus/Lyssa Virus

Treatment:

_ _ _ _ (HRIG)

_ _ _ _ (HDCV-) (_ doses)

Flaviviridae

SS (+) RNA, icosahedral, enveloped

golgi

Flaviviridae

Bud into internal membranous structures (_)

Yellow Fever Virus

Dengue Fever Virus

St. Louis Encephalitis Virus

Zika Virus

West Nile Virus

Hepatitis C Virus

Hepatitis G Virus

Flaviviridae

Specific viruses (7)

Hepatitis C and Hepatitis G

Flaviviridae

Arthropod borne except: (2)

Plaque Reduction Neutralization Test

Flaviviridae

Most specific serology test for Flaviviridae

E Protein

Flaviviridae

critical for viral attachment and fusion with host cells and serve as major antigenic targets

Yellow Fever Virus

Flaviviridae

Transmitted by Aedes aegypti

Causes hemorrhagic fever

Causes biphasic illness

Initial

Toxic

Flaviviridae

Yellow Fever Virus

_ phase

Fever, muscle pain, headache, nausea

_ phase

Recurrence of fever, jaundice, bleeding, multi-organ failure

Live attenuated yellow fever vaccine

Flaviviridae

Yellow Fever Virus

Prevention: ?