Junín virus and Argentine haemorrhagic fever: Virology, pathogenesis, diagnosis, and prevention strategies

Table 2 Laboratory diagnostic methods for Junín virus infection

Diagnostic method	Principle	Specimen	Optimal timing	Advantages	Limitations	Ref.
RT-PCR	Detection and amplification of Junín viral RNA after reverse transcription	Whole blood, serum, plasma, occasionally tissue samples	Early acute phase (first 7-10 days during viremia)	Highly sensitive and specific; rapid confirmation of active infection; widely used in reference laboratories	Requires specialized molecular equipment and trained personnel; contamination risk; limited availability in rural endemic settings	[2,4]
Real-time RT-PCR (qRT-PCR)	Quantitative detection of viral RNA using fluorescent probes during amplification	Whole blood, serum, plasma	Early acute phase	Rapid and highly sensitive; allows quantification of viral load and monitoring of disease progression	Expensive instrumentation; requires advanced molecular laboratory infrastructure	[2,4]
Virus isolation	Cultivation of infectious virus in susceptible cell cultures (e.g., Vero cells)	Blood, serum, tissue samples	Early stage of infection when viremia is present	Gold standard for confirmation; enables viral characterization, sequencing, and research studies	Requires biosafety level-4 containment; slow and labor-intensive; high biohazard risk; rarely used for routine diagnosis	[2,3,13]
IgM ELISA	Detection of virus-specific IgM antibodies generated during the early immune response	Serum or plasma	From end of first week of illness onward	Indicates recent infection; relatively simple, cost-effective, and widely used for screening	Not suitable for very early infection; possible cross-reactivity with other arenaviruses	[2,4,8,9]
IgG ELISA	Detection of virus-specific IgG antibodies indicating immune response or past exposure	Serum or plasma	Late acute phase or convalescent stage	Useful for seroepidemiological studies, vaccine evaluation, and confirmation of seroconversion	Cannot diagnose early infection; often requires paired sera samples	[1,2,4,10]
Antigen detection assays	Detection of viral proteins using specific monoclonal or polyclonal antibodies	Blood, serum, plasma	Early phase of infection	Faster than serological tests; useful when molecular testing is unavailable	Lower sensitivity compared with PCR; limited commercial availability	[2,4,9]
Neutralization test (PRNT)	Measurement of virus-neutralizing antibodies capable of inhibiting viral infectivity	Serum	Convalescent phase	Highly specific; considered reference method for assessing protective immunity and vaccine response	Requires live virus and high-containment laboratory; technically demanding and time-consuming	[1,10,18,22,23]
Routine laboratory tests (supportive)	Detection of hematological and biochemical abnormalities associated with infection	Whole blood, urine	Any stage of illness	Supports clinical suspicion (e.g., thrombocytopenia, leukopenia, elevated liver enzymes, proteinuria)	Nonspecific; cannot confirm Junín virus infection	[4,8,9]

RT-PCR: Reverse transcription polymerase chain reaction; qRT-PCR: Quantitative reverse transcription polymerase chain reaction; RNA: Ribonucleic acid; IgM ELISA: Immunoglobulin M enzyme-linked immunosorbent assay; IgG ELISA: Immunoglobulin G enzyme-linked immunosorbent assay; PRNT: Plaque reduction neutralization test.