We characterized the clinical, virological, and epidemiological features of acute dengue-like cases at two primary healthcare facilities in the Caribbean region of Costa Rica and compared the clinical data with laboratory confirmatory RT-qPCR for DENV, ZIKV and CHIKV to determine the cause of the febrile disease and for those negative samples with more than 6 days of symptom onset, DENV IgM was tested. The gene discussed is CD40LG; the disease is dengue disease.