The strain of E coli that has caused deaths in Germany has never before been seen in an outbreak of illness, according to the WHO.
‘This strain has never been seen in an outbreak situation before,’ spokesperson Aphaluck Bhatiasevi said, adding that the World Health Organisation was waiting for more information from laboratories.
Chinese scientists at the Beijing Genomics Institute in Shenzhen city, who have analysed the genes of the strain, said it carried genes which made it resistant to some classes of antibiotics and was highly toxic: 'This E coli is a new strain of bacteria that is highly infectious and toxic.'
Earlier, Russia banned the import of fresh vegetables from European Union countries because of a bacteria scare, as Germany kept up the search for the source of the bug that has killed 17 people.
Announcing the ban, Russia's top consumer protection official took the opportunity to criticise EU food safety standards.
'The fresh vegetable import ban affecting all EU countries went into effect this morning,' consumer protection agency chief Gennady Onishchenko said, Interfax reported.
Vegetables already shipped in from the EU 'will be seized across Russia', Mr Onishchenko said.
Enterohaemorrhagic E coli can result in full-blown haemolytic uraemic syndrome - a disease that causes bloody diarrhoea and serious liver damage.
The move came as officials in Germany, which has suffered all but one of the 17 fatalities, kept up the hunt for the cause of the deaths. Hundreds more people have fallen sick.
On Monday, Russia banned fresh vegetable shipments from Spain and Germany, warning the sanction could soon be applied to all EU countries if it failed to receive a proper explanation as to how the fatal disease was being spread.
But German and EU officials have been unable to find the cause of the outbreak.
After initially blaming it on organic cucumbers imported from Spain, they backed off from that position yesterday.
Mr Onishchenko said orders to stop all incoming European vegetable shipments had already been issued to Russian customs authorities.
Mr Onishchenko, one of Russia's most outspoken health officials, has in the past thrown himself into the centre of political and diplomatic disputes.
He said the latest outbreak proved that Russia's food safety standards were being more professionally observed than those in Europe.
‘This shows that Europe's lauded health legislation - one which Russia is being urged to adopt - does not work,’ he said.
‘I am far from believing that my colleagues in Germany and other European countries lack professional skills,’ he said.
‘But their hands are tied by an overly-politicised atmosphere.’
Mr Onishchenko added that 'it was obvious' that Spanish cucumbers could not have been the true cause of the problem.
Russia has been quick in the past to ban the import of products that are also produced locally.
While this has ostensibly been on health grounds, some critics have accused the authorities of using this as a pretext to unfairly back Russian producers.
Spain has threatened to file a suit on behalf of its farmers against German authorities because of their initial claims and may seek financial compensation.
Germany's national disease centre has also admitted that the outbreak started nearly two weeks before the first infections were reported in mid-May.
The European Commission has lifted its warning over the Spanish cucumbers after saying it could 'not confirm the presence of the specific serotype (O104), which is responsible for the outbreak affecting humans.'
