Bayesian skyline plot inference of the Toscana virus epidemic: a decline in the effective number of infections over the last 30 years

Infect Genet Evol. 2009 Jul;9(4):562-6. doi: 10.1016/j.meegid.2009.02.007. Epub 2009 Feb 27.

Abstract

Toscana virus (TosV), a sandfly fever virus, is one of the main causes of the aseptic meningitis that occurs during the summer in some Mediterranean regions, and whose epidemiology is largely unknown. We used a Bayesian Markov Chain Monte Carlo approach and a relaxed molecular clock to estimate the demographic history of the TosV infection in a series of isolates sampled between 1980 and 2003. The estimated mean evolutionary rate was 2.5 x 10(-4) substitutions per site per year (95% HPD: 0.31-5.44 x 10(-4)subs/site/year). Bayesian skyline plot revealed a sharp decline in the effective number of infections over the last 30 years. In conclusion, our data suggest that continuous and prolonged perturbations of vector/phlebovirus interactions due to the relatively recent climate changes may have contributed to gradually reducing the viral population in endemic areas.

MeSH terms

  • Animals
  • Bayes Theorem
  • Evolution, Molecular*
  • Genome, Viral*
  • Humans
  • Markov Chains
  • Meningitis, Aseptic / epidemiology*
  • Meningitis, Aseptic / virology
  • Monte Carlo Method
  • Phlebotomus
  • Phlebotomus Fever / epidemiology*
  • Phlebotomus Fever / virology
  • Phylogeny
  • Sandfly fever Naples virus / genetics*
  • Sequence Alignment
  • Sequence Analysis, RNA