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3# Enteroviruses
1. A CSF picture showing negative culture with increased mononuclear cells is MOST consistent with:
Acute bacterial meningitis
Aseptic (viral) meningitis
Subarachnoid hemorrhage
Fungal meningitis
Explanation:
Aseptic meningitis is characterized by lymphocytic (mononuclear) CSF with negative cultures.
2. A child with meningitis symptoms lasting more than one week should raise suspicion of:
Enteroviral meningitis
HSV encephalitis
Tuberculous meningitis
Drug-induced meningitis
Explanation:
Prolonged illness (>1 week) with meningitic symptoms suggests MTB rather than viral causes.
3. Which property explains why enteroviruses survive gastric acidity?
Acid stability at pH 3–9
Presence of lipid envelope
Replication in macrophages
Integration into host genome
Explanation:
Enteroviruses are acid-stable, allowing survival through the stomach.
4. Which feature of enteroviruses explains resistance to ether and detergents?
Double-stranded RNA
Capsid symmetry
Small genome size
Absence of envelope
Explanation:
Naked (non-enveloped) viruses are resistant to ether and detergents.
5. The MOST common enteroviral infection outcome is:
Paralytic poliomyelitis
Asymptomatic infection
Aseptic meningitis
Myocarditis
Explanation:
Over 90% of enteroviral infections are asymptomatic and self-limited.
6. Paralytic poliomyelitis is MOST commonly caused by which poliovirus serotype?
Type 2
Type 3
Type 1
Type 4
Explanation:
Poliovirus type 1 accounts for about 85% of paralytic cases.
7. A key distinguishing feature of paralytic poliomyelitis is:
Flaccid paralysis without sensory loss
Spastic paralysis
Early cranial nerve involvement
Ascending paralysis
Explanation:
Poliomyelitis causes lower motor neuron weakness without sensory deficits.
8. Bulbar poliomyelitis is particularly dangerous because it affects:
Spinal reflex arcs
Sensory cortex
Basal ganglia
Brainstem respiratory centers
Explanation:
Brainstem involvement leads to respiratory failure and high mortality.
9. Post-polio syndrome occurs due to:
Reactivation of poliovirus
Loss of compensatory motor neurons
Persistent viral replication
Autoimmune demyelination
Explanation:
It results from degeneration of neurons that compensated after initial infection.
10. The MOST sensitive and specific test for diagnosing enteroviral meningitis is:
Serology
Stool culture
RT-PCR on CSF
Electron microscopy
Explanation:
RT-PCR on CSF is highly sensitive and specific for enteroviruses.
11. Herpangina is MOST commonly caused by:
Coxsackievirus A
Coxsackievirus B
Echovirus
Enterovirus 71
Explanation:
Coxsackievirus A causes herpangina with painful oral vesicles.
12. Hand-Foot-Mouth disease typically occurs in:
Winter only
Elderly patients
Immunocompromised adults
Summer and autumn in young children
Explanation:
HFMD occurs in epidemics among children, mainly in summer and autumn.
13. Which echovirus-related condition is also known as Boston fever?
Echovirus 6
Parechovirus type 16
Coxsackievirus B3
Enterovirus 70
Explanation:
Parechovirus (echovirus type 16) is associated with Boston fever.
14. The MOST common complication of mumps involving the nervous system is:
SSPE
Transverse myelitis
Aseptic meningitis
Brain abscess
Explanation:
Mumps frequently causes aseptic meningitis, especially in older children.
15. Koplik spots are pathognomonic for:
Measles
Rubella
Mumps
Scarlet fever
Explanation:
Koplik spots precede the measles rash and are diagnostic.
16. Which late complication of measles occurs years after infection?
Giant cell pneumonia
Otitis media
Post-measles encephalitis
SSPE
Explanation:
Subacute sclerosing panencephalitis is a late, fatal complication.
17. Rabies virus reaches the CNS primarily by:
Hematogenous spread
Retrograde axonal transport
Lymphatic spread
CSF dissemination
Explanation:
Rabies spreads via retrograde axonal transport along peripheral nerves.
18. Hydrophobia in rabies is due to:
Esophageal obstruction
Salivary gland destruction
Painful pharyngeal muscle spasms
Laryngeal edema
Explanation:
Attempted swallowing triggers painful spasms, causing fear of water.
19. Negri bodies are BEST described as:
Eosinophilic cytoplasmic inclusions in neurons
Intranuclear viral inclusions
Clusters of inflammatory cells
Demyelinated plaques
Explanation:
Negri bodies are cytoplasmic aggregates of rabies viral proteins.
20. The MOST critical immediate step after a suspected rabid animal bite is:
Immediate vaccination only
Primary wound suturing
Administration of antibiotics
Thorough wound washing with soap and water
Explanation:
Prompt and thorough wound washing significantly reduces viral load and transmission.