Background: Enteroviruses (EV) circulate worldwide and are a major cause for annual epidemics of meningitis in humans. During the last two decades, echovirus type 30 (E-30) has revealed to be one of the most prevalent enteroviruses at the origin of epidemics of EV meningitis.
Objectives: To design an approach to timely investigate epidemics due to EV. To apply this strategy to the outbreak of meningitis due to E-30 that occurred at the end of year 2000 in Marseilles, France.
Study design: The approach consisted to (i) determine whether the epidemic was caused by a dominant strain; (ii) identify the dominant strain by sequencing the first isolates during the outbreak; (iii) identify a restriction enzyme, capable to produce an Restriction fragment length polymorphism (RFLP) profile characteristic for the dominant strain, for rapid identification based on RFLP analysis of PCR products.
Results and conclusions: A total of 394 samples were tested; 258 (corresponding to 177 patients) were positive for the presence of EV by cell culture and/or RT-PCR. Sequence analysis of a 785-bp PCR product (including the 5' end of the VP1 gene) performed for the 30 first isolates permitted to identify a RFLP profile that was specific of the dominant strain after enzymatic cleavage by Bst X1. This RFLP profile was observed in 246 out of 258 PCR products. This method of typing is rapid, simple and inexpensive, and may be applied for the epidemiological typing of EV in epidemic situations.