Human to human spread of the new E coli, superspreader events and the start of a pandemic

In my previous blog, I wrote about a cluster of cases in Poland that indicated human to human spread of the new E coli bacteria. The cluster indicated at least three and maybe four passages of the bacteria through different individuals. That was alarming because it indicated that the E coli was spreading through the human population sustainably.

Unfortunately, more recent reports support this idea.

The Local, June 29, 2011 [hat-tip Pixie]

For the first time, a Swede with no connections to Germany has been infected with the virulent enterohaemorrhagic E. coli (EHEC) bacteria that has claimed dozens of lives across Europe, Swedish health authorities reported on Tuesday.

[snip]

The infected Swede comes from Skåne, in southern Sweden, and has not been traveling in Germany. Neither does he have any other known connections to anyone else who have been taken ill after visiting Germany.

“All previous Swedish cases had a connection to Germany, but not this. This is a completely new case, which we identified this morning. We have not left any stones unturned and yet we have not been able to find any connection,” Ivarsson told TT.

So how did this Swedish man become infected? Authorities are still looking for “smoking sprouts”, but have not found them.

A recent large outbreak of the new E coli was reported in France. Although some of the individuals infected remember eating sprouts at an event at a childcare institution, at least one of the patients is not known to have attended this event (Le Nouvel Observer, June 26, 2011 [hat-tip, Pixie]). Although it is possible that the seeds which were used to produce sprouts in France are the source of this outbreak, there are other possibilities.

For example, in Germany one person is known to have infected a large number of other people.

From Monsters and Critics, June 17, 2011

German scientists have discovered a second cause of the outbreak of E coli bacteria that has killed 39 people in recent weeks: a kitchen employee at a catering company was unwittingly spreading the germ on food.

[snip]

Hesse state consumer protection officials said that a woman who had caught Type O104:H4 enterohaemorrhagic Escherichia coli (EHEC) from the sprouts, but had not yet fallen ill, passed it to 20 other people via food she handled.

A person who spreads a pathogen to a large number of other individuals is known as a superspreader. The kitchen worker apparently did not wash her hands after using the bathroom and thus spread her feces on the food which was then delivered to unsuspecting clients of the caterer. We’ve all seen warnings to kitchen staff to wash their hands before returning work. Unfortunately, the compliance rate with this request is not what we would hope. Hence, we can expect other events like this. Indeed, the outbreak in France may represent just such a case.

As bad as these outbreaks have been, there could be worse to come.

From The Local, June 18, 2011

The Environment Ministry of the state of Hesse announced that the deadly O 104:H 4 strain of the bacteria had been found in the Erlenbach stream in the north-east of the city.

[snip]

The ministries said there were various theories on how the E. coli got into the stream, though they added that the test sample was taken from near a sewage plant. While such plants generally have very high hygiene standards, authorities said this could not be ruled out as a possible source.

This is a very disturbing finding because it suggests that the new E coli could enter drinking water. Although water treatment plants should eliminate this threat, such plants do not always work as they should, even in first world countries. And in third world countries, water treatment may not exist at all. If the new E coli currently attacking Europe gets into untreated drinking water, we will see the mother of all superspreading events.

Public health authorities are pushing the “bad seed” hypothesis as an explanation for the many of the outbreaks in Europe, even though they currently have no evidence for this. We do have strong, irrefutable evidence that the bacteria is spreading human to human in multiple countries.

It’s time to acknowledge the obvious, that a pandemic has started, so we can focus on stopping it. While there is still time.

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2 thoughts on “Human to human spread of the new E coli, superspreader events and the start of a pandemic

  1. It’s true that a few thousand infections does not make a pandemic. But spread of a pathogen to 20 countries and sustained human to human spread does.

    The initial outbreak in Germany was caused by one mass infection. The cause of this initial bolus of bacteria is still unknown. Although all the people who were infected in this first superpreading event have now likely died or been treated, the number of untraced new outbreaks is going up, not down. None of these have equaled the first outbreak in the number of people infected, yet. But I’m afraid that may just be a matter of time.

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