*2.4.2. Indirect methods*

### *2.4.2.1. IgM ELISA*

IgM can be detected on 50% infected people within 3–5 days and after the symptoms onset, and it reaches approximately to 80% infected people on day 5 and to 99% infected people on day 10 reaching maximum levels in humans at the 2 weeks to falter until they are not detected on 2–3 months. An indirect capture ELISA is usually used for detecting IgM, and it allows increasing sensitivity of the test in detecting antibodies. However, IgM antibodies are not specific, and they could present a cross-reaction with other flavivirus like YFV, ZIKV, etc. Besides, some particular test characteristics could alter the result of the test as the rheumatoid factor depending on IgM ELISA type causes false positives [5, 7–9].
