Objective: to confirm Zika virus circulation and discard other etiological agents in an outbreak occurred in the states of Rio Grande do Norte, Maranhão and Paraíba, in May, 2015.
Methods: this is a case series descriptive study with residents in Natal-RN, Barra do Corda-MA, São Luis-MA and João Pessoa-PB, with 20 cases in each state, presenting rash, absent or mild fever and one of the following signs/symptoms: conjunctival hyperemia, arthralgia or limb edema; RT-PCR/isolation tests for Zika, enterovirus and respiratory viruses, and serology tests (dengue, rubella and parvovirus B19) were performed.
Results: the main symptoms were rash (n=60), pruritus (n=54), and arthralgia (n=47); 51 individuals did not present fever; Zika virus was identified in 18 cases (12 in Paraíba, four in Maranhão and two in Rio Grande do Norte), and antibodies to dengue, in 14 cases.
Conclusion: the symptoms were consistent with Zika virus fever; there was laboratory confirmation for Zika and dengue.