An outbreak of killer E. coli that has spread to 12 countries and killed 19 people may be linked to a Hamburg festival in May and could have claimed a 20th victim, reports said on Saturday.
German weekly newspaper Focus said authorities were looking closely at a harbour festival that took place in Hamburg on May 6-8 and that drew 1.5 million visitors from Germany and abroad.
The newspaper noted that the first reported case of E. coli infection followed just a week later in the city's university hospital.
Germany's national disease institute The Robert-Koch Institute, however, said there did not appear to be a connection. "Press information regarding a link between the E. coli infections and large gatherings does not correspond with the institute's knowledge," German news agency DPA quoted it as saying.
Local media also said Saturday a man in his 50s who died in Brandenberg may be the 20th victim in Europe but the cause of death was uncertain because he had several other infections as well as E. coli.
The latest confirmed death was of an 80-year-old woman in the northern German state of Mecklenburg-Western Pomerania on Friday.
The European Commission on Saturday said it was preparing to send a team of experts to Germany to help speed up efforts to locate the source of the outbreak, a statement said.
So far, scientific tests have failed to support a link to the epidemic, the European Union's Reference Laboratory for E. coli in Rome has said.
Faced with the mystery, German reports said police were investigating a possible deliberate act and were also checking two restaurants in the northern town of Lubeck, one in which 17 diners fell ill and another in which eight women were affected, one of whom died.
Christian Seyfert, a spokesman for the regional consumer protection ministry told AFP speculation over the eateries' link to the outbreak was unfounded. But he added: "There are different elements in different regional states.
Germany is facing its biggest epidemic caused by bacteria in recent decades. All but one of the fatalities since the outbreak of enterohaemorrhagic E. coli (EHEC) poisoning began last month have occurred in Germany. A patient who died in Sweden had recently returned from Germany.
Federal Health Minister Daniel Bahr will on Sunday visit the Hamburg hospital where several of the victims died, the government announced Saturday.
Cases of E. coli poisoning have also been reported in Austria, Britain, the Czech Republic, Denmark, France, The Netherlands, Norway, Spain, Sweden, Switzerland and the United States. Each is related to German travel.
Regional German health authorities have reported more than 2,000 cases of people falling ill, with symptoms including stomach cramps, diarrhoea, fever and vomiting.
A large majority are female, suggesting the source is "probably something that women prefer more than men," Andrea Ellis, an epidemiologist at the World Health Organisation's (WHO) department of food safety, said in Geneva.
In some cases the infection can lead to the potentially life-threatening condition haemolytic uraemic syndrome (HUS), a kidney disease.
At least 552 people, 520 of them in Germany, have HUS, according to the WHO, with 10 other European countries plus the United States reporting HUS or EHEC infections.
The WHO has identified the bacteria as a rare E. coli strain never before connected to an outbreak of food poisoning. But researchers in Hamburg said earlier they and Chinese colleagues had found the strain was a "new type" which is extremely aggressive and resistant to antibiotics.
The health crisis has also triggered trade tensions in Europe.
Berlin pointed the blame for the outbreak at cucumbers imported from Spain, provoking a backlash from Madrid which said it plans to demand damages from Europe for slander.
Tens of thousands of tonnes of Spanish produce have been unsold, costing Spanish growers an estimated 200 million euros ($290 million) a week.
And some countries such as Russia and Lebanon banned vegetables from the EU, in moves criticised by the 27-member bloc.
To ease tension over the heavy losses, European agriculture ministers are scheduled to meet in Luxembourg for talks after June 17, according to diplomats.
Explore further: Cucumbers blamed for deadly German E. coli outbreak