Invasive worm now in 75% of France, study shows

The invasive flatworm the Obama Nungara has now spread into two thirds of departments in France, according to a new study, with researchers saying it may threaten biodiversity and soil health.

10 February 2020
The Obama Nungara flatworm is now in 75% of departments in France, researchers have said
By Connexion journalist

The report was published this month by Jean-Lou Justine, professor at the Paris natural history museum, le Muséum National d’Histoire Naturelle (MNHN). It estimated that there are “billions” of these flatworms across France.

Also known as a “plathelminthe”, the worm tends to be a dark brown colour, and measures between 5-10 centimetres in length. It has no known predators, breeds rapidly, and eats ground animals such as earthworms and snails.

The name “Obama Nungara” (no relation to the former US President...) translates as “flat as a leaf” in a Brazilian indigenous language, in reference to the worm’s flat appearance. It has no visible feet, mouth or eyes.

The worm has spread rapidly in recent months, with 72 departments affected in April last year, up from 60 departments just six months before that. Now, a new study has estimated that it has spread to 75% of departments across the country.

It is mainly found in the west of France, although parts of the north-east and south-east are starting to become affected.

In a recent article on the subject, Mr Justine and co-researcher Leigh Winsor (James Cook University, Australia) wrote: “The two major enemies of mainland plathelminthes are drought, and very cold winters. [And] something we have noticed in our work, is that there have been no reports from places that are higher than 500 metres.”

Last year, researchers at the MNHN, led by Mr Justine, asked members of the public to help collect the worms and send them through the post using special kits.

At the time, Mr Justine said: “If a predator is diminishing the earthworm population, the soil is in danger [as earthworms] are the only animals capable of permanently rejuvenating our ground. Right now, we do not think any earthworm species are at risk of disappearing [completely]. But the number of species may drop. We need to do more studies.”

The researcher added: “There is no chemical product authorised to kill flatworms and the Obama Nungara. And there are no plants that allow us to repel them. The only possible solution for a gardener is to squash [and kill] the worm [and to burn them].”

The worm cannot fly and moves slowly, so is most likely to travel between places in plant pots and soil.

Originally from South America, it is estimated to have arrived in France in 2013, and is now present in several nearby countries too, including the UK, Spain, Portugal, Belgium, Italy, and Switzerland.

If you see any Obama Nungara flatworms in your garden, you can submit your sighting to Mr Justine - full instructions on this page (in French) - including photos and precise geographical information.

You are then advised to collect the worm in a secure container and contact Mr Justine directly (

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