(XVI) Viruses (1)Enteroviruses" Flashcards
Coxsackievirus strain […] is the most common cause of HFMD. […] is the second-most common cause. Many other strains of coxsackievirus and enterovirus can also be responsible.
Coxsackievirus strain A16 is the most common cause of HFMD. 71 (EV-71) is the second-most common cause. Many other strains of coxsackievirus and enterovirus can also be responsible.
They are part of Coxsackie A virus
Came out for MEQ
Diseases caused by
Coxsackie A virus
Mainly […] infections:
- […]
- […]
Coxsackie B virus
Mainly […] infection
- […]
- […]
Diseases caused by
Coxsackie A virus
Mainly mucosal infections:
- Herpangina (fever, sore throat, vesicles in oropharynx)
- HFMD (ulcer in mouth, vesicular rash on hands and feet)
Coxsackie B virus
Mainly muscular infection
- Burnholm’s disease (pleuritic-type chest pain, infecting intercostal muscles. Can be mistaken for appendicitis)
- Myocarditis (fever, chest pain, signs of congestive heart failure)
Both types can cause encephalitis
Enterovirus infection symptoms
- mostly asymptomatic
- Undifferentiated febrile illness
Viral Exanthema
- Generalized rash.
- […]
- […]
Enterovirus infection symptoms
- mostly asymptomatic
- Undifferentiated febrile illness
Viral Exanthema
- Generalized rash.
- Hand,foot and mouth disease(HFMD)
- Herpangina (mouth blisters)
Severe complications arerare.
- Encephalitis.
- Myelitis/Lower motor neuron dysfunction –paralysis.
- Myocarditis.
- Asepticmeningitis.
Enteroviruses transmit by […] route
Enteroviruses transmit by faecal oral route
They are quite stable. cannot be destroyed by detergent (can be destroyed by 70% alcohol). Therefore very easy to get it if you don’t wash hands thoroughly.
Prefer warm, moist places.
General features of Enteroviruses
- […]
- Insensitive to detergents
- Survives even at 4 or 60 degree celcius
- but prefers warm moist environments - Replicates in […]
General features of Enteroviruses
-
Stable
- Insensitive to detergents
- Survives even at 4 or 60 degree celcius
- but prefers warm moist environments - Replicates in GI tract
Intramuscular Poliovirus Vaccine(IPV) VS Oral Poliovirus Vaccine(OPV) (IMPT)
Oral (Sabin vaccine) (OPV): […] virus (from engineering it to live in monkey livers)
Advantage
- adminstered […]
- prevents […]
- […] immunity (mimics natural infection, produce large antigenic stimulus)
- cheap, can be given to poor countries
- Secondary vaccination (“freebie” vaccine from feacal oral transmission)
Disadvantage
- risk of […] and hence […]
- may retain some […], not safe enough to vaccinate […] subjects
- require […] (hence stringent storage and transportation requirements)
IM (Salk vaccine) (IPV): virus inactivated by formalin
Advantage:
- no risk of […]
- Can be combined with other vaccines (less clinic visits, more convenient)
Disadvantage:
- Does not prevent […]
- Administered […]
- only vaccinates subject
- 5 times more expensive
TLDR, OPV better for population with low herd immunity, IPV better for population with high herd immunity
Intramuscular Poliovirus Vaccine(IPV) VS Oral Poliovirus Vaccine(OPV) (IMPT)
Oral (Sabin vaccine) (OPV): Live attenuated virus (from engineering it to live in monkey livers)
Advantage
- adminstered orally (no medical training required)
- prevents carriage cuz taken orally, passes through the gut (gut immunity, IgA) before going into systemic circulation (IgG)
- life long immunity (mimics natural infection, produce large antigenic stimulus)
- cheap, can be given to poor countries
- Secondary vaccination (“freebie” vaccine from feacal oral transmission)
Disadvantage
- risk of reverting to wildtype and hence vaccine associated paralytic poliomyelitis (VAPP)
- may retain some pathogenicity, not safe enough to vaccinate immuno-compromised subjects
- require “cold chain” (hence stringent storage and transportation requirements)
IM (Salk vaccine) (IPV): virus inactivated by formalin
Advantage:
- no risk of VAPP
- Can be combined with other vaccines (less clinic visits, more convenient)
Disadvantage:
- Does not prevent carriage (bypass gut cuz IM) (therefore low herd immunity)
- Administered IM (requires trained medical personnel)
- only vaccinates subject
- 5 times more expensive
TLDR, OPV better for population with low herd immunity, IPV better for population with high herd immunity
IPV is killed virus: Antigenic components and adjuvants (basically counterfeit PAMPs and DAMPs that will never cause tissue damage as much as live viruses)
OPV is LIVE attenuated virus: live virus that is less virulent, but still generates tissue damage and all the necessary pathways to elicit immune response
Disease = paralysis disease due to systemic polio virus infection
Infection = infection of the gut due to localized gut polio virus infection
FYI:
- Actually in SG, only initial doses has been replaced by IPV
- But the last jab is still OPV
- Ensure target population is immune to disease first, then give mucosal protection
- Smart sia
Pathophysiology of Poliovirus
1. infects […] tissue associated with […]
2. in minority of cases, viremia crosses […] or travel […] along axons to grey matter of CNS
Pathophysiology of Poliovirus
1. infects lymphoid tissue associated with oropharynx/gut
2. in minority of cases, viremia crosses blood-brain barrier or travel retrograde along axons to grey matter of CNS
Serology is rarely used for enteroviruses due to […]
Serology is rarely used for enteroviruses due to cross-reactivity
but serology useful for sero-epidemiological studies
RT PCR still best la hor
Symptoms of Poliovirus:
Mostly asymptomatic (95%)
[…] infection (4-8%):
Flu-like symptoms with quick recovery in few days. may be accompanied by […]
major illness (1-2%):
- 2-3 days after minor illness
- […]
- flaccid paralysis (rare), usually affecting lower motor neuron, causing muscle atrophy (affected limb will be shorter since bone grows less if its childhood infection)
- involvement in medulla can lead to fatal […]
Symptoms of Poliovirus:
Mostly asymptomatic (95%)
Abortive infection (4-8%):
Flu-like symptoms with quick recovery in few days. may be accompanied by asceptic meningitis
major illness (1-2%):
- 2-3 days after minor illness
- Asceptic meningitis
- flaccid paralysis (rare), usually affecting lower motor neuron, causing muscle atrophy (affected limb will be shorter since bone grows less if its childhood infection)
- involvement in medulla can lead to fatal respiratory paralysis
The main enteroviruses are
[…].
They belong to the picornavirus family (et. Pico = small RNA Virus)
The main enteroviruses are
Poliovirus and Coxsackievirus (A and B).
They belong to the picornavirus family (et. Pico = small RNA Virus)
And echovirus (not that impt)
Polio means gray. affecting gray matter of CNS
