Data mining from a 27-years rotavirus surveillance in Palermo, Italy

- Genetic diversity of the HRVs over 27 years in the pre-vaccine era in Palermo, Sicily.
- Emergence of different intra-genotype lineages and sublineages over the time.
- Punctate mutations in the VP7 and VP4 antigenic residues have been observed.

Uninterrupted surveillance conducted in Palermo, Sicily, for 27 years (1985-2012) detected rotavirus infection in 32.7% of 6522 children <5 years of age, hospitalised at the “G. Di Cristina” Children's Hospital of Palermo. Increased rotavirus activity usually occurred from the beginning of winter to mid-spring. G1P[8] rotaviruses were the prevalent strains in most of the years and were only occasionally overcome by G9P[8], G4P[8] or G2P[4]. The circulation of non-G1P[8] strains was discontinuous and fluctuating. Phylogenetic analyses revealed an heterogeneous population of viruses within each genotype, with different lineages and sublineages emerging over the time. Amino acid substitutions in both VP7 and VP8∗ antigenic epitopes were generally associated with different lineages/sublineages, emerging sequentially and replacing partially or completely the former strains. The present study summarises one of the longest surveillance activities conducted in the European continent, offering a useful temporal observatory of rotavirus epidemiology and strains variation and evolution in a settled population.