Diagnostic performance of anti-Zika virus IgM, IgAM and IgG ELISAs during co-circulation of Zika, dengue, and chikungunya viruses in Brazil and Venezuela

Abstract

Background Serological diagnosis of Zika virus (ZIKV) infection is challenging because of the antibody cross-reactivity among flaviviruses. At the same time, the role of Nucleic Acid Testing (NAT) is limited by the low proportion of symptomatic infections and the low average viral load. Here, we compared the diagnostic performance of commercially available IgM, IgAM, and IgG ELISAs in sequential samples during the ZIKV and chikungunya (CHIKV) epidemics and co-circulation of dengue virus (DENV) in Brazil and Venezuela. Methodology/Principal findings Acute (day of illness 1–5) and follow-up (day of illness ≥ 6) blood samples were collected from nine hundred and seven symptomatic patients enrolled in a prospective multicenter study of symptomatic patients recruited between June 2012 and August 2016. Acute samples were tested by RT-PCR for ZIKV, DENV, and CHIKV. Acute and follow-up samples were tested for IgM, IgAM, and IgG antibodies to ZIKV using commercially available ELISAs. Among follow-up samples with a RT-PCR confirmed ZIKV infection, anti-ZIKV IgAM sensitivity was 93.5% (43/48), while IgM and IgG exhibited sensitivities of 30.3% (10/35) and 72% (18/25), respectively. An additional 24% (26/109) of ZIKV infections were detected via IgAM seroconversion in ZIKV/DENV/CHIKV RT-PCR negative patients. The specificity of anti-ZIKV IgM was estimated at 93% and that of IgAM at 85%. Conclusions/Significance Our findings exemplify the challenges of the assessment of test performance for ZIKV serological tests in the real-world setting, during co-circulation of DENV, ZIKV, and CHIKV. However, we can also demonstrate that the IgAM immunoassay exhibits superior sensitivity to detect ZIKV RT-PCR confirmed infections compared to IgG and IgM immunoassays. The IgAM assay also proves to be promising for detection of anti-ZIKV seroconversions in sequential samples, both in ZIKV PCR-positive as well as PCR-negative patients, making this a candidate assay for serological monitoring of pregnant women in future ZIKV outbreaks.

Nervous System Manifestations of Arboviral Infections

“…Immunoassay for nonstructural protein 1 can be used as an alternate test for dengue virus infection. IgM for the flaviviruses particularly dengue, Zika, and chikungunya may cross-react causing diagnostic uncertainties [ 7 ]. Plaque reduction neutralization tests (PRNTs) with > fourfold higher titers can sometimes be used for confirmation.…”

“…These can impact the nervous system at any level and lead to a variety of syndromes such as autoimmune encephalitis, acute demyelinating encephalomyelitis (ADEM), acute inflammatory demyelinating polyradiculopathy (AIDP), and its variants [ 6 ]. Antibody cross-reactivity across different arboviruses, particularly flaviviruses, may pose challenges for serological diagnosis and serosurveys to assess prevalence or emergence of arboviruses [ 7 – 12 ]. Further advances in accurate point-of-care diagnostics will help not only with patient care but also surveillance of various co-circulating arboviruses in different regions.…”

Serological Evidence of Widespread Zika Transmission across the Philippines

“…Recent studies have utilized Euroimmun and have reported Zika specificity >90% [ 21 , 22 ], although the test subjects often included small groups of infected travelers who resided outside flavivirus-endemic countries. More recently, however, the accuracy of these commercial tests has been brought into question by studies in flavivirus-endemic regions, including Salvador (Brazil) [ 23 ], Rio de Janerio (Brazil) [ 24 ], and Carabobo (Venezuela) [ 25 ]. Studies have revealed that IgM ELISAs have adequate specificity, yet poor sensitivity for capturing active ZIKV infections.…”

Challenges in Direct Detection of Flaviviruses: A Review

“…Many studies have described homemade protocols that achieve better parameters than commercial tests [ 22 ] and rapid antigen-detection assays [ 24 ]. The vast majority of studies have focused on the diagnosis of dengue, evaluating cross-reactivity with ZIKV, which is especially important for serological discrimination in endemic regions with co-circulation of these viruses [ 25 ]. Therefore, many rapid DENV NS1 detection tests have been developed [ 26 ].…”