London, Nov 21 (IANS): For the first time, the genome of a rarely seen tapeworm - residing in a British man's brain for four years - has been sequenced, offering new opportunities to diagnose and treat this invasive parasite.

The tapeworm, called Spirometra erinaceieuropaei, has been reported only 300 times worldwide since 1953 and has never been seen before in Britain.

The worm causes sparganosis - inflammation of the body's tissues in response to the parasite.

When this occurs in the brain, it can cause seizures, memory loss and headaches.

Before the one-cm-long parasite was diagnosed and successfully removed by surgery, it had travelled five cm from the right side of the brain to the left.

The tapeworm was placed on a histology slide by the hospital to confirm the clinical diagnosis.

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

Fortunately for the patient, the gene's DNA sequence revealed that the parasite was the more benign of the two sparganosis-causing worm species.

Remarkably, the team also were able to generate sufficient DNA sequence data to piece together a draft genome.

This is now being used to investigate known and potential treatment targets which may help patients in the future.

It is believed that people may be infected by this tapeworm by consuming tiny infected crustaceans from lakes, eating raw meat from reptiles and amphibians or by using a raw frog poultice - a Chinese remedy to calm sore eyes.