Since 2013, the arthropod-borne Chikungunya virus (CHIKV) has cocirculated with the autochthonous Mayaro virus (MAYV) in Latin America. Both belong to the same alphavirus serocomplex, termed the Semliki Forest serocomplex. The extent of antibody cross-reactivity due to the antigenic relatedness of CHIKV and MAYV in commonly used serologic tests remains unclear. By testing 64 CHIKV- and 37 MAYV-specific sera from cohort studies conducted in Peru and Brazil, we demonstrate about 50% false-positive test results using commercially available enzyme-linked immunosorbent assays (ELISAs) based on structural antigens. In contrast, combining ELISAs for CHIKV and MAYV significantly increased positive predictive values (PPV) among all cohorts from 35.3% to 88.2% for IgM and from 61.3% to 96.8% for IgG (P < 0.0001). Testing of longitudinally collected CHIKV-specific patient sera indicated that ELISA specificity is highest for IgM testing at 5 to 9 days post-onset of symptoms (dpo) and for IgG testing at 10 to 14 dpo. IgG cross-reactivity in ELISA was asymmetric, occurring in 57.9% of MAYV-specific sera compared to 29.5% of CHIKV-specific sera. Parallel plaque reduction neutralization testing (PRNT) for CHIKV and MAYV increased the PPV from 80.0% to 100% (P = 0.0053). However, labor-intense procedures and delayed seroconversion limit PRNT for patient diagnostics. In sum, individual testing for CHIKV or MAYV only is prone to misclassifications that dramatically impact patient diagnostics and sero-epidemiologic investigation. Parallel ELISAs for both CHIKV and MAYV provide an easy and efficient solution to differentiate CHIKV from MAYV infections. This approach may provide a template globally for settings in which alphavirus coemergence imposes similar problems.IMPORTANCE Geographically overlapping transmission of Chikungunya virus (CHIKV) and Mayaro virus (MAYV) in Latin America challenges serologic diagnostics and epidemiologic surveillance, as antibodies against the antigenically related viruses can be cross-reactive, potentially causing false-positive test results. We examined whether widely used ELISAs and plaque reduction neutralization testing allow specific antibody detection in the scenario of CHIKV and MAYV coemergence. For this purpose, we used 37 patient-derived MAYV-specific sera from Peru and 64 patient-derived CHIKV-specific sera from Brazil, including longitudinally collected samples. Extensive testing of those samples revealed strong antibody cross-reactivity in ELISAs, particularly for IgM, which is commonly used for patient diagnostics. Cross-neutralization was also observed, albeit at lower frequencies. Parallel testing for both viruses and comparison of ELISA reactivities and neutralizing antibody titers significantly increased diagnostic specificity. Our data provide a convenient and practicable solution to ensure robust differentiation of CHIKV- and MAYV-specific antibodies.

中文翻译：

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共同出现后，基孔肯雅热和玛雅罗病毒血清学检查的稳健性。

自2013年以来，节肢动物传播的基孔肯雅热病毒（CHIKV）与拉美当地的马雅洛病毒（MAYV）一起流行。两者都属于同一个alpha病毒血清复合体，称为Semliki Forest血清复合体。在常用的血清学检测中，由于CHIKV和MAYV的抗原相关性，导致抗体交叉反应的程度尚不清楚。通过在秘鲁和巴西进行的队列研究中测试64种CHIKV特异性血清和37种MAYV特异性血清，我们证明了使用基于结构抗原的市售酶联免疫吸附测定（ELISA），约有50％的假阳性结果。相比之下，CHIGV和MAYV的ELISA组合在所有队列中将IgM的阳性预测值（PPV）分别从35.3％提高到88.2％，将IgG的阳性预测值从61.3％提高到96.8％（P <0.0001）。纵向收集的CHIKV特异性患者血清的测试表明，对于症状发作（dpo）后5至9天的IgM测试和对于10至14 dpo的IgG测试，ELISA特异性最高。ELISA中的IgG交叉反应是不对称的，在57.9％的MAYV特异性血清中发生，而在29.5％的CHIKV特异性血清中发生。CHIKV和MAYV的并行牙斑减少中和测试（PRNT）将PPV从80.0％提高到100％（P = 0.0053）。但是，劳动强度大的程序和延迟的血清转换限制了PRNT的诊断能力。总而言之，仅针对CHIKV或MAYV的单独测试很容易出现错误分类，从而极大地影响患者的诊断和血清流行病学调查。CHIKV和MAYV的平行ELISA提供了一种简便有效的解决方案，可将CHIKV与MAYV感染区分开。这种方法可能会为全球范围内的模板提供模板，在这种情况下，甲型病毒共生会带来类似的问题。重要事项拉丁美洲的基孔肯雅病毒（CHIKV）和马亚罗病毒（MAYV）在地理上重叠传播，作为针对抗原相关病毒的抗体，挑战了血清学诊断和流行病学监测可能是交叉反应的，可能导致假阳性的测试结果。我们检查了广泛使用的ELISA和斑块减少中和测试是否允许在CHIKV和MAYV共存的情况下进行特异性抗体检测。为此，我们使用了秘鲁的37种患者来源的MAYV特异性血清和巴西的64种患者来源的CHIKV特异性血清，包括纵向采集的样本。对这些样品进行的广泛测试表明，ELISA中存在很强的抗体交叉反应性，特别是对于IgM（通常用于患者诊断）。尽管频率较低，但也观察到交叉中和现象。两种病毒的并行测试以及ELISA反应性和中和抗体效价的比较显着提高了诊断特异性。我们的数据为确保CHIKV和MAYV特异性抗体的强大区分提供了方便实用的解决方案。