A man, 26 years-old, presented fever, mental confusion and a progressively worsening headache 6 days prior to admission. The CSF study was suggestive of meningoencephalitis, the PCR study revealed presence of HSV-1 and ZIKV, while other immunology tests were negative. ZIKV was also identified in serum. The MRI showed temporal lobe hyper-intensity in FLAIR-weight sequence with areas of contrast enhancement and the electroencephalogram showed slow wave activity in such region. Patient was treated with acyclovir and supportive measures and had good clinical outcome at evaluation after 6 months. Neurological spectrum of ZIKV manifestations is wide, but meningoencephalitis is not frequent. Co-infection HSV-1 plus ZIKV was not yet related in humans, but there is increased cellular damage caused by association of ZIKV and herpes virus family infection. ZIKV may facilitate infection or recrudescence by other viruses or cause concurrently neuronal injury by direct or indirect mechanisms. We suggest that clinicians attempt new manifestations related to ZIKV and include this agent in differential diagnosis of neurological diseases even when other agents were identified. Keywords: Zika virus, Human herpesvirus 1, Meningoencephalitis, Case report
