RNA Viruses - Picornaviridae And Rhabdoviridae Flashcards
Smallest RNA Virus
Picornavirus - 27-30nm
Picornaviridae family includes
Rhinovirus
Enterovirus
Route of transmission of Rhinovirus
Inhalation
Enterovirus family includes
Polio virus
Coxsackie
Enterovirus
Echo virus
Route of transmission of Enterovirus
Feco oral
Antigenic types of Polio virus
Type 1,2 and 3
Immunity is type specific
Which antigenic type of Polio virus is most commonly responsible for epidemics
Type 1
Which antigenic type of Polio virus is most antigenic
Type 2
No case reported since 1999
Vaccine derived
Type 3 Antigenic type of Polio virus is associated with
Vaccine associated Paralytic polio
No case reported since 2013
Dense antigen of Polio virus associated with
A/w whole virion
Type specific
Anti D antibodies are protective
Potency of Injectable polio vaccine is measured using which Antigen
Measured using D antigen units
C antigen of Polio virus is
Non protective
Incubation period and transmission route of Polio virus
IP - 7-14 days (1-2 weeks)
Transmission - Feco oral, inhalation
Reservoir, Carrier and Period of communicability of Polio virus
Reservoir - Humans
Carrier - None
Period of communicability - 1 week before and 2-3 weeks after appearance of signs and symptoms
Phases of Polio virus infection
1) Alimentary phase - enters oropharynx - small intestine - feces
2) Lymphatic phase - Cervical LN or Mesenteric LN
3) Viremic phase - enters blood
4) Neural phase - Crosses BBB - Cerebrum, Spinal Cord
How many percent of Polio infection goes subclinical
90% (via feces)
How many percent of Polio infection reaches to blood causing viremia
8% - Abortive polio
Causes fever, malaise, headache, vomiting
How much percent of Polio infection reaches to brain
1% - causes Non paralytic Poliovirus - Symptoms of meningitis
<1% - Causes paralytic Polio
Final site of Polio virus
Motor neurons
Earliest change in case of Polio virus infection
Nissl body degeneration
Assymetric descending flaccid paralysis (ADFP) clinical Features
Proximal > distal muscles
Bigger muscle of hands > smaller muscle of hands
Leg muscles > Arm muscles
Meningoencephalitis
Resp failure
Samples taken in case of Poliovirus infection
Throat swab
Rectal swab/fecal samples
Cell line used for Polio virus
Rhesus kidney cell line (Primary)
Cytopathic effect seen in case of Poliovirus
Shrinkage and Degeneration of cell lines
Antibody detection in case of Poliovirus infection
Paired sera at 1-2 weeks with increasing titre
Molecular methods used for diagnosis of Poliovirus infection
RT PCR
VP1 protein
Can differentiate between wild and the vaccine strains
Types of Coxsackie virus
Coxsackie A and B
Mode of transmission of Coxsackie virus
Feco oral
Serotypes of Coxsackie A and B
A - 1 to 24
B - 1 to 6
Coxsackie A is known to cause
Herpangina
Hand foot mouth disease
Acute hemorrhagic Conjunctivitis (Coxsackie 24) - Also Enterovirus 70
Coxsackie B is known to cause
Carditis
Bornholms disease/Pleurodynia/Devils grip/Epidemic myalgia
Hand foot mouth disease
Coxsackie Viruses can be isolated on
Brain of suckling mice
Coxsackie A - flaccid paralysis
Coxsackie B - Spastic paralysis
Herpangina Clinical features
Vesicular Pharyngitis - Vesicles in post wall of pharynx
Hand foot mouth disease Clinical features
On Child Hand foot and mouth - Papulovesicular lesions