By Kirsten Grieshaber and Maria Cheng
June 2, 2011
LONDON — The E. coli strain responsible for the deadly outbreak in Europe is a new bacteria that has never been seen before, the World Health Organization said Thursday.
The agency said that preliminary genetic sequencing suggests the strain is a mutant form of two different E.coli bacterium, with lethal genes that could explain why the Europe-wide outbreak appears to be so massive and dangerous. "This is a unique strain that has never been isolated from patients before," Hilde Kruse, a food safety expert at the World Health Organization, said.
She added that the new strain has "various characteristics that make it more virulent and toxin-producing."
So far, the mutant E. coli strain has killed 17 people in Germany and one in Sweden, and sickened more than1,500 others, including 470 who have developed a rare kidney failure complication. On Thursday Britain's Health Protection Agency says 7 people in the U.K. have been confirmed with the new strain. All of the infected had recently visited Germany.
Kruse said it was not uncommon for bacteria to continually evolve and swap genes. "There's a lot of mobility in the microbial world," she said.
Kruse said it was difficult to explain where the new strain came from but said strains of bacteria from both humans and animals easily trade genes, similar to how animal viruses like Ebola sometimes jump into humans. "One should think of an animal source," Kruse said. "Many animals are hosts of various types of toxin-producing E. coli."
Kruse said the new bacteria strain had traits that made it more dangerous than other types of E. coli, which might explain why the outbreak is mainly striking adults, and women in particular. Normally, severe E. coli cases are seen in children and the elderly.
But she cautioned that since people with milder cases probably weren't seeking medical help, officials don't know just how big the outbreak is. "It's hard to say how virulent (this new E. coli strain) is because we just don't know the real number of people affected," she said.
The outbreak is already considered the third-largest involving E. coli in recent world history, and it may be the deadliest. Twelve people died in a 1996 Japanese outbreak that reportedly sickened more than 12,000, and seven died in a 2000 Canadian outbreak.
In a statement on WHO's website Thursday, it said 10 countries in Europe had now reported patients with two diseases related to the bacteria: haemolytic uraemic syndrome (HUS) and enterohemorrhagic E. coli (EHEC).
It said that as of May 31, nine of the patients in Germany had died of HUS and six of EHEC. "There are many hospitalized patients, several of them requiring intensive care, including dialysis," the statement said.
NBC News reported that according to doctors, two-thirds of patients in Hamburg, Germany, were suffering from severe neurological problems such as language difficulties and seizures.
Cause 'still unclear
In addition to Germany and Sweden, Austria, Denmark, France, Netherlands, Norway, Spain, Switzerland and the United Kingdom have all reported cases.
"All these cases except two are in people who had recently visited northern Germany or in one case, had contact with a visitor from northern Germany," the WHO statement said.
"Numerous investigations are continuing into the cause of the outbreak, which is still unclear," it added.
Two U.S. residents who recently traveled in northern Germany are also thought to become ill because of the outbreak, federal health officials said Tuesday.
WHO said it was keeping countries informed and added that it was not recommending any trade restrictions relating to the outbreak.
The statement came shortly after Russia announced it was banning imports of raw vegetables from the European Union because of the E. coli outbreak.
"A ban on the import of fresh vegetables from EU countries takes effect from this morning," the head of the consumer protection agency Gennady Onishchenko said, according to the Interfax news agency.
"How many more lives of European citizens does it take for European officials to tackle this problem?" he told the state-owned RIA Novosti news agency.
Russia had already banned imports of vegetables from Germany and Spain. No fatalities or infections have yet been reported in Russia.
The European Union argued the Russian ban was disproportionate.
Frederic Vincent, a spokesman for the EU's Health and Consumer Policy Commissioner John Dalli, said Thursday that the European Commission would write to the Russian Agency for the Supervision of Consumer Rights to demand further clarification of the ban.
Meanwhile, Spain's prime minister slammed the European Commission and Germany for singling out the country's produce as a possible source of a deadly bacterial outbreak in Europe, and said the government would demand explanations and reparations.
Jose Luis Rodriguez Zapatero told Spanish National Radio that the German federal government was ultimately responsible for the allegations, adding that Spain would seek "conclusive explanations and sufficient reparations."
The Associated Press, Reuters and msnbc.com staff contributed to this report.