The official numbers reported this morning by Germany’s Robert Koch Institut are worthy of a Hollywood thriller. Nine people dead, and 470 notified cases of hemolytic uremic syndrome (HUS) – a life-threatening complication of enterohemorrhagic E. coli infections.

The German outbreak data reported by BBC and others are even worse. Sixteen deaths, including one in Sweden; 1,534 infected with the outbreak strain known as E. coli O104:H4 – 470 of them suffering from HUS.

The outbreak began in Northern Germany; the heaviest concentration of confirmed cases – and of HUS – can be found in the states of Hamburg and Bremen. As of May 26th, thirteen German states had reported 214 cases of HUS – Hamburg (59), Bremen (11), Schleswig-Holstein (21), Mecklenburg-Vorpommern (10), Hesse (31), Saarland (5), Lower Saxony (28), North Rhine-Westphalia (31), Berlin (3), Baden-Württemberg (8), Bavaria (5), Thuringia (1) and Rhineland-Palatinate (1). These numbers already are far out of date, as the total number of cases has more than doubled since that report was issued.

Thanks to the ease of international travel – especially within the European Union, where most borders are invisible and undefended – the outbreak has not been confined to Germany. Eight other countries have reported confirmed or suspect cases of enterohemorrhagic E. coli in German nationals visiting their country or in individuals who reported having traveled to Germany:

  • Austria: 2 cases
  • Denmark: 14 cases, 6 with HUS
  • France: 6 cases
  • Netherlands: 7 cases, 3 with HUS
  • Spain: 1 case
  • Sweden: 41 cases, 15 with HUS and one death
  • Switzerland: 2 cases 
  • United Kingdom: 3 cases, 2 with HUS

Despite the best efforts of Germany’s epidemiologists, the source of this outbreak is unknown – except that it appears to be associated with consumption of raw tomatoes, cucumber and leaf salad.

For a time, suspicion fell on raw cucumbers imported from Spain – especially after lab analysis of two cucumber samples yielded enterohemorrhagic E. coli. But the cucumber contaminant did not match the outbreak strain.

The most frightening aspect of this outbreak, other than the lack of success in finding its cause, is the unusually high percentage of victims who have developed HUS – more than 30% of victims, as compared to the 5-10% HUS rate experienced in most other outbreaks.

HUS is a life-threatening complication, usually beginning with kidney failure and often progressing to failure of other organs and systems. Some 5-10% of HUS patients die, and most others suffer life-long consequences of their fight for survival – even with treatment. Conventional treatment consists of dialysis and, where necessary, plasma exchange.

The massive and deadly Canadian E. coli O157:H7 outbreak that was centered in Walkerton, Ontario in 2000 spurred Canadian researchers to study ways of preventing HUS – by preventing the bacterial toxins from binding to its target cells in the body. Researchers at the University of Maryland and in Argentina independently explored similar approaches – using monoclonal antibodies against the toxin in order to block its activity.

Just a few days ago, researchers in Canada, France and Germany reported that they used yet another antibody to treat successfully three 3-year-old children who were suffering from severe cases of HUS. But this new development might be too late to help many of the German outbreak victims.

The German outbreak has many unknowns:

  • What is the source?
  • What is the true number of illnesses?
  • Why is the incidence of HUS so high?
  • Why have adult women been disproportionately stricken?

And, most importantly, when will it end?