Consuming raw or undercooked frogs may increase your risk of getting a rare tapeworm in your brain

Don’t eat me, bro. (photo from Wikipedia)

A 50-year-old UK resident had been living with an unwelcome visitor for the past 4 years and it was such a headache. Surgeons from Addenbrooke’s Hospital in Cambridge removed the tapeworm during a biopsy after noticing a small circular lesion migrating across his brain in a series of MRIs taken across the years:

Image from New Scientist / Nagui Antoun

The tapeworm turned out to be an rare find:Spirometra erinaceieuropaei. It is typically found in the intestines of their definitive hosts – cats and dogs. However, this time, it was found in what is known as an “aberrant host” – a dead-end for the tapeworm. But before it dies off, it can cause some issues in the aberrant host, such as seizures, headaches, and memory loss.
Fortunately for us, researchers at the Wellcome Trust Sanger Institute did what we all wanted to do: sequence it’s genome! What they found was pretty cool:

The 1.26Gb draft genome of S. erinaceieuropaei is currently the largest reported for any flatworm.

That’s a gigantic tapeworm genome. It’s 10x the size of any published tapeworm genome and over 1/3 the size of the human genome. The scientists went on to try and figure out why it didn’t die when the patient received antibiotics:

Through investigation of β-tubulin genes, we predict that S. erinaceieuropaeilarvae are insensitive to the tapeworm drug albendazole.

Fortunately, for us they also found targets for other known tapeworm drugs, which means that next time they might be able to stop the worm in its tracks… in your brain.
Bennett et al. (2014). The genome of the sparganosis tapewormSpirometra erinaceieuropaei isolated fromthe biopsy of a migrating brain lesion. Genome Biology. 15:510. doi:10.1186/s13059-014-0510-3

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