Enterovirus Laboratory Testing
Lab Update No. 39 – April 2023
Introduction
Enteroviruses are common human pathogens, transmitted mainly via the faecal-oral route, and less commonly through the respiratory route.
They cause a wide range of clinical symptoms, from mild to severe.
Enteroviruses are classified into:
- Polio viruses
- Non-polio enteroviruses: Coxsackie A & B, Echoviruses, Enterovirus A71, Enterovirus D68
Clinical Manifestations
Central Nervous System
- Acute flaccid paralysis (AFP) & brain stem encephalitis: Polio virus, EV71, EVD68
- Aseptic meningitis or encephalitis: Coxsackie A9, B2, B5; Echovirus 6, 9
Ocular
- Acute haemorrhagic conjunctivitis: Coxsackie A24, EV70
Skin & Mucosa
- Herpangina: Coxsackie A
- Hand, foot & mouth disease: Coxsackie A16, EV71
- Maculopapular rash with fever
Heart
- Myopericarditis: Coxsackie B viruses
Respiratory
- URTI/LRTI: Various, including EV68
- Pleurodynia: Coxsackie B viruses
Neonates
- Myocarditis: Coxsackie B viruses
- Fulminant hepatitis: Echoviruses
Immunocompromised
- Chronic meningitis
- Disseminated infection
Note: AFP cases require two stool samples collected 24–48 hours apart within 14 days of onset. Serology is not useful for polio diagnosis.
Available Tests for Enterovirus Detection
Molecular Testing
- Enterovirus PCR: Can be ordered alone or as part of a multiplex panel
- Viremic phase is short → may miss infection
- Stool shedding lasts longer → may detect past infection (up to 3 months)
Antibody Testing
- Enterovirus ELISA: Detects IgA, IgM, IgG for Coxsackie & Echoviruses
- Cannot differentiate between enterovirus types
- Coxsackie B IFA: Detects IgM & IgG for B1–B6
- Replaces older neutralisation test
- Improved sensitivity & reduced cross-reactivity
Specimen Types for Testing
PCR Tests
- Enterovirus PCR (Mnemonic: ENTPCR):
- Blood (serum/plasma)
- Eye swab
- Vesicle swab (blister fluid)
- Fluid (e.g. pleural fluid)
- Tissue (e.g. biopsy for myocarditis)
- Stool
- Viral Meningitis PCR (Mnemonic: VMPCR):
- CSF
- Comprehensive Respiratory Panel (Mnemonic: RPCOMPCR):
- BAL, NP swab/aspirate, throat swab, sputum, tracheal aspirate, pleural fluid, tissue
- Biofire Respiratory Panel (Mnemonic: RESPMPCR):
- NP swab
- Does not differentiate between rhinovirus and enterovirus
Antibody Tests
- Enterovirus ELISA (Mnemonic: ENTERO):
- Serum (SST tube)
- Acute infection: Positive IgM/IgA or rising IgG over 2 weeks
- Batched weekly
- Coxsackie B IFA (Mnemonic: COXB):
- Serum (SST tube)
- Acute infection: Positive IgM or >2× rise in IgG over 2 weeks
- Batched twice weekly