Abstract
In Brazil, chikungunya emerged in 2014, and by 2016, co-circulated with other arbovirosis, such as dengue and zika. ELISAs (Enzyme-Linked Immunosorbent Assays) are the most widely used approach for arboviruses diagnosis. However, some limitations include antibody cross reactivities when viruses belong to the same genus, and sensitivity variations in distinct epidemiological scenarios. As chikungunya virus (CHIKV) is an alphavirus, no serological cross reactivity with dengue virus (DENV) should be observed. Here, we evaluated a routinely used chikungunya commercial IgM (Immunoglobulin M) ELISA test (Anti-Chikungunya IgM ELISA, Euroimmun) to assess its performance in confirming chikungunya in a dengue endemic area. Samples (n = 340) representative of all four DENV serotypes, healthy individuals and controls were tested. The Anti-CHIKV IgM ELISA test had a sensitivity of 100% and a specificity of 25.3% due to the cross reactivities observed with dengue. In dengue acute cases, the chikungunya test showed an overall cross-reactivity of 31.6%, with a higher cross-reactivity with DENV-4. In dengue IgM positive cases, the assay showed a cross-reactivity of 46.7%. Serological diagnosis may be challenging and, despite the results observed here, more evaluations shall be performed. Because distinct arboviruses co-circulate in Brazil, reliable diagnostic tools are essential for disease surveillance and patient management.
Highlights
Accepted: 24 January 2021Arboviruses are a major threat to public health in general, especially in tropical and subtropical countries [1,2,3]
A panel of 340 sera was divided into fifteen groups as follows: Groups A to D, acute sera from patients infected with dengue virus (DENV)-1 (n = 33), DENV-2 (n = 12), DENV-3 (n = 20) and DENV-4 (n = 30), respectively, confirmed by molecular detection and/or virus isolation, and Group E, sera from patients with dengue infection serologically confirmed by MAC-enzyme-linked immunosorbent assays (ELISA) with negative virus isolation and room temperature (RT)-PCR (n = 60)
In dengue acute cases (Groups A–D), the anti-chikungunya virus IgM ELISA test showed an overall cross-reactivity of 31.6% (30/95), independently of the infecting serotype, with a higher cross-reactivity observed for DENV-4 cases (Group D; 50.0%), followed by DENV-2 (Group B; 33.3%)
Summary
Accepted: 24 January 2021Arboviruses are a major threat to public health in general, especially in tropical and subtropical countries [1,2,3]. In Brazil, chikungunya was first detected in Bahia and Amapá, in 2014, and, in a short period of time, cases were reported all over the country. Dengue virus (DENV) and chikungunya virus (CHIKV) belong to two different families, Flaviviridae and Togaviridae, respectively, they are mainly transmitted by the same mosquito vector, Aedes aegypti [8]. Those viral infections share many signs and symptoms, such as fever, headache, exanthema, arthralgia, myalgia, nausea, and vomiting, that are, sometimes, clinically indistinguishable [9]. Clinical-based chikungunya diagnosis is usually difficult, especially in areas endemic for dengue [10], such as the one in Brazil
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