According to Sofie Ivarsson, epidemiologist at the Swedish Institute for Communicable Disease Control (Smitskyddsinstitutet), it is the complication haemolytic-uremic syndrome (HUS) that causes patients serious trouble.
“It is the kidneys that are hit by HUS, but other systems are also affected,” she said to news agency TT.
Ivarsson also told TT that those who were not sick enough to require hospitalisation still suffer from a serious gastric illness with diarrhoea and bloody stools.
What is extraordinary with this outbreak is that it is only adults that have suffered complications.
“Usually these kind of complications tend to strike against children,” Ivarsson said to TT.
So far the disease have been identified in several southern Swedish counties and tests are showing that it is probably the same bacteria as the recent outbreak in Germany.
The institute was informed of the first Swedish case during the second week in May. More Swedes are expected to fall ill because it takes a while before a person who has contracted the disease first starts showing symptoms.
The institute is taking the situation seriously and has urged hospitals to be take extra care with patients seeking care for EHEC-like symptoms such as bloody diarrhoea or abdominal pain and to quickly test them for E.coli infection.
Since the end of April there have been 214 reported cases of HUS in Germany and several hundred cases of E.coli–infection, an unusually high number of cases in such short period of time.
German health officials have announced that the bacteria has been found in three Spanish cucumbers.
“We believe that cucumbers are the most probable source of the disease,” said Cornerlia Pruefer-Storcks, state health minister for Hamburg to the AFP news agency.
A fourth cucumber has tested positive for the bacteria but authotirties are not sure of it origins.
The Swedish National Food Administration (Livsmedelsverket) have said that they will be in contact with the German authorities.
“We hope to get more detailed information from Germany regarding the origins of these vegetables, so that we can work out if any of these have ended up in Sweden,” microbiologist Mats Lindblad of the food administration told TT.
But according to Lindblad it can be rather difficult to track a vegetable's journey through Europe.
The institute is now urging Swedes to be careful when traveling to Germany. Apart from Sweden and Germany, cases have been reported in Britain, the Netherlands and Denmark.
EHEC is a very contagious disease and can pass from person to person.
“We have a few of these cases as well, where family members have passed the disease among each other,” Per Follin, a specialist on infectious disease from western Sweden, told TT.
Outbreaks of EHEC are not that common in Sweden. Smaller outbreaks are sometimes connected to farms, wells, day care centres and restaurants.
The largest outbreak to date in Sweden was in 2005 when 135 cases, of which 11 developed the complication HUS, occurred in southern Sweden.
That time the source of the disease was iceberg lettuce, which had been irrigated with water that had been in contact with EHEC carrying manure.