Berlin: Racing to curb the spread of a killer food bug, Germany set up a task force on Friday to hunt down the source of a highly toxic strain of E coli that has killed 19 people and sounded alarms around the world.
Russian Prime Minister Vladimir Putin, locked in a trade row with the European Union after banning imports of its raw fruit and vegetables, struck a dramatic note by saying he would not "poison" Russians by lifting the embargo.
Health authorities repeated warnings to avoid some raw vegetables in northern Germany rattling farmers and stores in the high season for salad and said 199 new cases of the rare strain of the bacteria had been reported in the past two days.
The total of those infected in Germany since the outbreak was detected in early May rose to 1,733 and Germany's death toll rose by two on Friday to 18, added to one death reported in Sweden, in possibly the deadliest ever such outbreak recorded.
Scientists struggled to find the source of contamination which was assumed to have been caused by poor hygiene at a farm, in transit, or in a shop or food outlet.
After days of warnings against eating potentially toxic raw vegetables, one German expert said there were faint signs the spread of the illness had peaked, though he was still cautious.
"We have a little bit the impression it's fading but numbers are not yet demonstrating this clearly," said kidney specialist Reinhardt Brunkhorst in Hamburg, the centre of the outbreak.
European health institutes have tried to reassure the public that the spread of E.coli, a frequent cause of food poisoning, can be contained by washing vegetables and hands before eating or preparing food to avoid bacteria being passed on from the faeces of an infected person.
The failure to find the source of the outbreak, complicated by the fact that salads include a variety of ingredients from different producers and often different countries, has becoming increasingly worrying for health authorities and consumers.
The north German city of Hamburg is at the centre of the outbreak and people who have become ill in 10 other European countries and the United States, probably ate lettuce, tomatoes, cucumbers or other raw salad vegetables in Germany.
The World Health Organisation said the strain was a rare one, seen in humans before, but never in this kind of outbreak.
People have also become ill in Austria, the Czech Republic, Denmark, France, Netherlands, Norway, Spain, Sweden, Switzerland, Britain and the United States.
"All these cases except two are in people who reside in or had recently visited northern Germany during the incubation period for the infection -- typically 3 to 4 days post-exposure -- or in one case, had contact with a visitor from northern Germany," the WHO said in a statement.
E coli bacteria themselves are harmless but the strain making people sick in Europe has the ability to stick to intestinal walls where it pumps out toxins, sometimes causing severe bloody diarrhoea and kidney problems.
"Wash and Wash"
Robert Tauxe of the US Centers for Disease Control and Prevention, which has been working with German health officials since last week, said the strain was likely the most deadly yet in terms of the number of deaths recorded.
"I believe it is," he told. He said it was unclear how the bacteria became so resistant.
The outbreak is causing bad infections and in a number of cases, complications affecting blood and kidneys. Haemolytic uraemic syndrome (HUS), which often leads to kidney failure and can kill, has been diagnosed in hundreds of the cases.
Many patients have gone into hospital, and several needed intensive care, including dialysis due to kidney complications.
The outbreak has triggered a sharp rise in demand for blood plasma, but the Red Cross denied media reports that supplies were running low.
"Our national inventory of blood (plasma) stocks amounts to about 100,000 bags that can be used immediately," German Red Cross Blood Donation Service spokesman Friedrich-Ernst Dueppe said.
HUS patients require plasma to flush out the Shiga toxins that build up in the circulatory system through infection and need about 13-17 bags a day for five to seven days.
E coli infections can spread from person to person but only by what is known as the faecal-oral route.
"I wash and wash and wash my vegetables. You can't stop eating them but I have children and so I'm buying only safe produce and cooking them," said Max Fehrer, a 43-year-old computer programmer shopping in Berlin's Kreuzberg neighbourhood on his way to work on Friday.
The strain is part of a class of bacteria known as Shiga toxin-producing Escherichia coli or STEC that produces a poison known as the shiga toxin.
"The immediate public health problem is the identification of the source of infection so that it can be controlled," said Robert Hall, an expert on communicable disease control in Victoria, Australia.
He said this is done with a combination of epidemiological, microbiological and environmental investigations: "These are all highly skilled tasks that need to be done rapidly and are nearly always done in a glare of publicity."
Trade ties tainted
A German government spokesman said Chancellor Angela Merkel had set up an E coli task force and spoken to Spain's Jose Luis Rodriguez Zapatero about the impact on farmers there.
The outbreak has put strains on trade relations. German state officials initially accused Spain of exporting contaminated cucumbers, but later withdrew the allegationn.
Spain said the allegations had cost its farmers hundreds of millions of euros in lost sales and it was considering a compensation claim.
Responding to EU calls that Russia lift its import ban and respect free-trade rules of the World Trade Organisation, Putin said: "We cannot poison our people for the sake of some spirit."
EU countries exported 594 million euros ($853 million) worth of vegetables to Russia last year and imported just 29 million euros of Russian vegetables, EU data show.
In Moscow, consumers expressed a mixture of scorn and pride at the ban. Some said the threat was exaggerated.
"I am not afraid of buying vegetables from any country here," said pensioner Vyacheslav Yegorov, carrying a shopping basket filled with grapes and fresh vegetables.