sciencetech-blog

comments

This series of brain scans shows the path a tiny parasitic tapeworm takes as it burrows its way through a man's brain 

In the first case of its kind in Britain, the one centimetre long worm is seen travelling 5cm from the right side of the brain to the left over the space of four years. 

Known as Spirometra erinaceieuropaei, the worm which originates in the Far East, is extremely rare, with just 300 cases recorded worldwide since 1953.

It causes inflammation of the body's tissues known as sparganosis, triggering seizures, memory loss and severe headaches.

Very little is known about the worm, though it is thought people may be infected by accidentally consuming tiny infected crustaceans from lakes, eating raw meat from reptiles and amphibians, or by using a raw frog poultice as a Chinese remedy to calm sore eyes. 

This series of brain scans shows a tiny parasitic worm burrowing its way through a man's brain

The case is the first of its kind in the UK. The images show the one centimetre long worm travelling 5cm from the right side of the brain to the left

Surgeons managed to successfully remove the worm, which they found was a benign version.

Had it been a more aggressive type, it could have laid eggs, which then feed off the brain as they grow. 

To identify the exact species of worm, surgeons at Addenbrooke's NHS Trust in Cambridge, sequenced one particular gene.

The so-called 'barcode of life' revealed the parasite was the more benign of the two sparganosis-causing creature.

But their research found the worm was resistant to current anti-tapeworm drugs and as more people travel to exotic destinations, the risk of becoming infected increases. 

In response British scientists examined its DNA to spot weaknesses that can be targeted with other existing drugs.

Dr Effrossyni Gkrania-Klotsas from Addenbrooke's, said: 'We did not expect to see an infection of this kind in the UK, but global travel means that unfamiliar parasites do sometimes appear.

'We can now diagnose sparganosis using MRI scans, but this does not give us the information we need to identify the exact tapeworm species and its vulnerabilities.

'Our work shows that, even with only tiny amounts of DNA from clinical samples, we can find out all we need to identify and characterise the parasite.

'This emphasises just how important a global database of worm genomes is to allow us to identify the parasite and determine the best course of treatment.

 'Additionally, this information can be paired with our work in global travellers' infection to give additional insights in what infections other patients can get in specific destinations.'

The study looked at discovering targets in the genome for existing licensed drugs which could prove to be the best way to treat this rare disease.

This data could contribute to the growing global database for identifying parasites and identifying new treatments, according to the report, published Genome Biology. 

Known as Spirometra erinaceieuropaei, the worm which originates in the Far East, is extremely rare, with just 300 cases recorded worldwide since 1953

Surgeons at Addenbrooke's Hospital in Cambridge successfully removed the worm 

They identified it as the less aggressive of the species of worm. Had it been the more aggressive type it could have laid eggs, which feed of the brain

Dr Hayley Bennett, of Wellcome Trust Sanger Institute, said: 'The clinical histology slide offered us a great opportunity to generate the first genome sequence of this elusive class of tapeworms.

'However, we only had a minute amount of DNA available to work with - just 40 billionths of a gram.

'So we had to make difficult decisions as to what we wanted to find out from the DNA we had.'

The researchers used the draft sequence to look for similarities and differences from other, previously sequenced, tapeworm species in the GeneDB pathogen database.

This has revealed more about Spirometra erinaceieuropaei's biology than ever before, for example, the worm has a large selection of molecular motors for moving proteins around the cell, which could underpin the large changes in body shape and environmental adaptions that the worm undergoes during its complicated life cycle.

Dr Matt Berriman of Faculty of the Sanger Institute said: 'For this uncharted group of tapeworms, this is the first genome to be sequenced and has allowed us to make some predictions about the likely activity of known drugs.

'The genome sequence suggests that the parasite is naturally resistant to albendazole - an existing anti-tapeworm drug.

'However, many new drug targets that are being explored for other tapeworms are present in this parasite and could offer future clinical possibilities.'