Picornaviruses Flashcards
Picornaviruses General Characteristics (3)
Small
Non-enveloped
ssRNA
Pico = small rna = RNA
Picornaviruses Two Main Groups
1- RHINOVIRUSES —> Replicate only in Respiratory tract —> Common cold
2- ENTEROVIRUSES —> Replicate in GI tract and/or Respiratory tract
Rhinovirus Characteristic
Most common cause of COMMON COLD
Rhinovirus Clinical Manifestations (8)
Fever Sore throat Runny nose and Nasal congestion Sneezing Cough
Sometimes accompanied by:
1- Fatigue, muscle aches, muscle weakness
2- Headache
3- Loss of appetite
Vaccine and Antiviral?
Antiviral —> PLECONARIL
Vaccine—> NO
Enteroviruses Groups (5)
1- Polioviruses
2- Coxsackie A and B
3- Echoviruses
4- Enteroviruses (subtype 68-71)
5- Hepatitis A virus
Can Enteroviruses spread other than fecal-oral route??
YES
Eyes, nose, mouth secretions (e.g. saliva, nasal mucus, or sputum), or blister fluid
Remember- they are in the respiratory tract also!!
Enteroviruses comparison (7)
Asymptomatic infection? All
Meningitis? All
Paralysis? No- Enteroviruses (other)
Febrile Exanthema? No- Poliovirus
Acute Respiratory Disease? No- Poliovirus
Myocarditis? No- Poliovirus and Enteroviruses (other)
Orchitis? No- Poliovirus, Coxsackie A, Enteroviruses (other)
Enteroviruses- Skin (1)
Coxsackievirus A
Enteroviruses- Muscles (3)
Echovirus
Coxsackie A and B
Enteroviruses- Brain/spinal cord (3)
Poliovirus
Coxsackie A and B
Enteroviruses- Meninges (4)
Poliovirus
Echoviruses
Coxsackie A and B
Asymptomatic Polio Infection (3)
When replication of virus restricted to GI tract
Most common
Results in life-long immunity
Abortive poliomyelitis (Mild Illness) (3)
Occurs in infants in undeveloped nations, where poor sanitation
Patient exhibit febrile disease in first week which may be accompanied by general malaise, vomiting, headache, and sore throat
5% of cases
Non-paralytic Poliomyelitis (3)
Three or four days later, patient exhibits stiff neck and vomiting —> similar to aseptic meningitis
Virus now progressed to brain and affected meninges
Recovery in 1 week
Paralytic Poliomyelitis (2)
About 4 days, virus spread from blood to anterior horn cells of spinal cord and to motor cortex of brain
Degree of paralysis depends on which neurons affected and amount of damage they sustain
Types of Paralysis (3)
1- Spinal Paralysis (affects spine) —> One or both limbs may be affected leading to Flaccid paralysis
2- Bulbar Paralysis (affects brain stem) —> Cranial nerves affected leading to muscle paralysis of tongue, lips, palate, pharynx, and larynx
3- Bulbospinal paralysis (affects spine and brain stem)
Poliovirus vaccines
1- Inactivated vaccine (Salk)
- Injection
2- Live attenuated vaccine (Sabin)
- Oral
Enteroviruses Meningitis (4)
Most COMMON type of viral meningitis
Coxsackie A + B and Echoviruses
Summer months
No vaccine- most patients recover on their own
Another name for Viral Meningitis
Aseptic Meningitis
What is the most common cause of Myocarditis?
Viral infections
Which Enteroviruses cause Carditis?
Coxsackie A+B and Echoviruses
Hand, Foot, and Mouth Disease (4)
Caused by Coxsackie A and Echoviruses
Common and highly contagious self-limiting viral infection
Mainly affects infants and children
Begins with Fever followed by Maculopapular Rash that may involve skin of hands, feet, and oral cavity (goes away in a week)
Herpangina (4)
Mouth blisters
In summer, mostly affects children
Mild, self-limiting
Coxsackie A, Coxsackie B, Echoviruses
Treatment (3)
Antibody preparations resulted in stabilization of conditions
PLECONARIL is an ANTIVIRAL DRUG active against ENTEROVIRUSES and RHINOVIRUS
NO VACCINE to prevent ENTEROVIRUSES infections (apart from POLIOVIRUS)
