A descriptive retrospective study was carried out to describe an epidemic 
outbreak of enteroviral meningitis in Misiones. We reviewed records of 143 
children from 1 month to 14 years of age who were hospitalized with aseptic 
meningitis in the Pediatric Hospital of Posadas from August to December 2005. 
Increased number of cases was observed between weeks 33 to 50 which reached a 
maximum peak in weeks 47 and 48, confirming an outbreak. The median of age was 8 
years old, 55.2% were males. Eighty percent of cases were in 5 to 14 years old 
children. The average length of time spent in the hospital was 4.5+/-1.7 days, 
no deaths were reported. We performed cell counts, chemical and bacterial 
studies of CSF, and culture or RT-Nested/PCR for enteroviruses. Isolates were 
serotyped by RT-PCR amplification and genetic sequencing. Cell counts were from 
6 to 5040 cells/mm3. Ninety two percent had less than 500 cells/mm3 and 43.5% 
had lymphocyte predominance. Glucose levels were normal with slightly elevated 
protein counts in 56% of cases. Of the cultured samples, 28% (17/60) showed 
cytopathic effect compatible with enterovirus. RT-n-PCR detected enterovirus in 
73% (43/59) of the analyzed CSF. Echovirus type 4 was identified in 6 of them. 
The positive indicator obtained by combining both techniques was 83% (58/70).