Utility of neutralization test for laboratory diagnosis of suspected mumps

Area of Science:

• Virology
• Immunology
• Infectious Diseases

Background:

• Mumps virus (MuV), a Paramyxoviridae family member, causes mumps, characterized by fever and parotid gland swelling, though it can be asymptomatic.
• Current diagnostic methods for mumps include molecular (PCR) and serological assays like Enzyme Immunoassay (EIA), each with limitations.

Purpose of the Study:

• To compare the diagnostic performance of the focus reduction neutralization test (FRNT) against commercial MuV-specific IgM and IgG antibody EIAs.
• To evaluate the utility of FRNT for mumps diagnosis, particularly in non-immunized populations.

Main Methods:

• Serological analysis of 186 patient samples collected during a 2012-16 mumps outbreak.
• Testing of 80 samples using IgM EIA, IgG EIA, and FRNT.
• Comparison of serological results with mumps RT-PCR data based on time post-onset.

Main Results:

• Positivity rates were 70.4% for IgM EIA, 83% for IgG EIA, and 92.5% for FRNT among the 80 tested samples.
• Concordance between mumps RT-PCR and IgM EIA was highest within 2-5 days post-onset, decreasing over time.
• FRNT results showed agreement with RT-PCR/IgM EIA from the second week onwards; IgG EIA results agreed from post-onset days 3-10.

Conclusions:

• The focus reduction neutralization test (FRNT) demonstrates significant diagnostic utility for mumps virus.
• FRNT offers a reliable method for mumps diagnosis, especially in populations without prior immunization against the infection.