BERLIN (AFP) - The WHO warned Thursday Europe was seeing the first outbreak of a lethal bacteria, as its death toll climbed to 18, all but one them in Germany. The WHO advisory came as German and Chinese researchers said they cracked the genetic code of the E. coli strain, which they said in a preliminary analysis was resistant to antibiotics and extremely virulent. Russia banned vegetable imports from the European Union in response to the scare, in a move the bloc slammed as "disproportionate", as Britain reported its first cases of the outbreak and Spain demanded a payback for its farmers. There were contradictory accounts as to whether the strain of E. coli was new, or whether Europe was witnessing the first outbreak of a rare but known type of bacteria that officials believe is carried by raw vegetables. The outbreak was initially blamed on Spanish cucumbers by German officials who later admitted that they were in the dark about its origin.