During the third quarter of 2000, an outbreak of echovirus 16 meningoencephalitis was firstly occurred in Cuba and produced vomiting, headache, fever and exanthem that differentiate it from other enterovirus epidemies.To describe the intrathecal immunoglobulin synthesis pattern of the epidemie from the reibergram.Diagnostic serum and cerebrospinal fluid from 18 children during the acute phase by nephelometrie assay, besides cytochemical and virological study.A predominant absence of intrathecal immunoglobulin synthesis and two patients with IgA and IgM synthesis was produced. 66% of cerebrospinal blood barrier dysfunction, 6.26 10 3 mean albumin ratio, lactate below 2.1 mmol/L and glucose concentration in cerebrospinal fluid was 50% over glucose blood content and 168 cells 10 6 L mainly lymphocytes were observed.The intratecal immunoglobulin synthesis pattern differs from other enterovirus outbreaks that have affected this population and it seems the one found for the diagnostic period in adults. This finding alerts the possibility of genetic changes in echovirus 16 strain, interesting from the neuroimmunoepidemiological point of view.