+ ss RNA viruses

• A little bit of history :

• • • Poliovirus : Egyptian stone tablets
    • Yellow fever : flying dutchman ghost ships

• Largest and most diverse subdivision :

• • • >100 viruses in 30 distinct groups
    • VPs divided in 3 groups:
    • • • replication, encapsidation and accessory function
    • Emerging viruses : Dengue, SARS