As Lowri Denman holidayed in India, she was thankful she hadn’t contracted ‘Delhi belly’… but in reality, she had picked up something much worse, a metre-long tapeworm that would later nearly kill her. 

In 2007, Ms Denman, now 42, spent two months travelling through the South Asian country but it wasn’t until four years after getting home she discovered she’d brought home a writhing souvenir. 

Up until she passed the huge tapeworm as she went to the toilet at her home in Cardiff, she had had no clue that anything was wrong, and after seeing her GP she was assured that there was nothing else to worry about. 

It was around this time she started experiencing crippling headaches and in 2011 she suffered a tonic-clonic (grand mal) seizure – which is characterised by stiffness, loss of consciousness, and jerking movements.

She immediately sought medical advice and, after waiting three months for a brain scan, Ms Denman learned she had neurocysticercosis, a parasitic infection of the brain caused by the larvae of the pork tapeworm.

There were 38 parasites in her brain, the offspring of the tapeworm she had carried inside her for four years. 

She said: ‘It was just so disgusting to think that these things were in my head.’ 

Neurocysticercosis is developed when a tapeworm infection is left untreated, as larvae build up in the central nervous system, causing cysts to form deep in bodily tissue. It is the most severe form of the disease, and a common cause of seizures.

Lowri Denman travelled through India for two months in 2007 – she’s still recovering now

Neurocysticercosis strikes about 4,000 people a year in the US, making it the most common way that parasites infect the central nervous system. 

The tapeworm Taenia Solium often infects pigs, laying larvae in them. If pork isn’t properly cooked, humans can wind up eating these larvae, which hatch in the intestines. 

If people don’t pass the worms, their life cycle will continue: Taenia Solium will lay its eggs in the person’s body. 

These larvae develop in sacs or cysts, that can travel around the body, in rare cases, reaching the brain.

The irony is that Ms Denman had made a conscious decision to stick to a vegetarian diet to reduce the risk of picking up foodborne illnesses. However, tapeworms and neurocysticercosis can be caused by water contaminated with tapeworm eggs or poor hygiene practices – you don’t have to eat meat to be affected. 

But it wasn’t only seizures that would define this period of Ms Denman’s life; the stress led to her developing psychosis. 

After receiving her diagnosis, Ms Denman was treated for epilepsy while doctors consulted tropical disease experts across the globe to decide on a course of action for eliminating the parasites.

Ms Denman lost her driving licence due to the risks of having a seizure behind the wheel, and her independence took a hit: she was advised not to do certain things, like having a bath while at home alone in case she had a seizure, and since she lived alone she found it particularly difficult.

Ms Denman’s seizures continued as the correct dosage of epilepsy medication was ascertained, and she began to experience anxiety about leaving the house.

She passed a metre-long tapeworm while on the toilet (file photo)

 A brain scan revealed that there were 38 tapeworm larvae in her brain, causing headaches and seizures 

‘There was one, it was lunchtime, and I was just walking around Cardiff on my own,’ she said.

‘Luckily I was on the phone to my mate, and I said, “I don’t feel well”, then I passed my phone to a stranger on the street. Then the next thing, I come around and my mate who I was on the phone to was there, and she was like, “You’ve had a fit again”.

‘Obviously, I was really cautious then, just scared of being anywhere, and that happening.’

Meanwhile, Ms Denman was given steroids and albendazole, which is used to treat a wide variety of parasitic worm infections. For a time, things calmed down and her seizures reduced, but in 2015 the parasites caused a serious flare up as they ‘weren’t dying off as they’d expected’.

Doctors then tried her on another anti-worm medication, praziquantel, as well as the albendazole and steroids, and while she said the medication would initially start killing the parasites and taking the swelling down in her brain, when she weaned off the medication the swelling would return in a different part of her brain.

‘This went on for at least a year, where I was getting more and more ill, more anxious,’ Ms Denman said.

‘I had to give up work, had to move home to be taken care of, and then it got to a point where I went on Personal Independence Payments (PIP), and I wasn’t capable of filling out the forms on my own.

‘For someone that’s extremely independent and capable and lived on my own most of my life, I was like, what the hell is going on here?’

Ms Denman then started experiencing more severe paranoia, worrying about getting enough sleep, struggling with how the medication made her look and feel – the steroids made her face swell, and she didn’t feel like herself.

‘It was just getting worse and worse and worse,’ she said.

‘I just wanted to go back to work. I just wanted a normal life, and I didn’t feel comfortable being in social settings. I didn’t want to leave the house, really.’

Ms Denman at the peak of her illnesses in 2016 (left); and today

‘The swelling was coming back and forth all the time, so they were trying to figure out what medication to put me on,’ she added.

‘They put me on methotrexate, then, which is a chemotherapy drug, so I was worried my hair was going to fall out. It made me really tired, but then steroids would make me really energetic, so there was loads going on, on top of the worries of not getting better.’

In September 2016, Lowri was admitted to a neuropsychiatric ward for three months due to her declining mental health, and was prescribed mood stabilisers and anti-psychotics on top of her other medication.

‘I was having panic attacks, I thought I was going to die, I think, and then that turned into paranoia, and then the psychosis came out,’ she said.

‘I wasn’t stable at all, all these thoughts and crazy things were going on in my head.’

Ms Denman explained that it is difficult to ascertain whether the symptoms were because of the parasites directly, or due to the stress and trauma of her prolonged treatment.

‘It just built into this huge thing at that point, nobody could tell me when I was going to get better,’ she said.

Eventually, in January 2017 Lowri was able to leave hospital and move back in with her dad. By then, she was 34, and desperately wanted her life back.

‘I didn’t look myself, and I was also really paranoid,’ she said.

‘I kept asking my friends, anyone that could come and visit me in hospital, to ask, what did I do?

‘Because I thought I was going to be on the news for doing something terrible.

‘I thought I’d done this mad stuff, and I didn’t know what I’d done.’

Now, Ms Denman is fit and healthy, and her seizures are managed by her medication so she has not experienced a fit for 10 years.

During her recovery, Lowri was desperate to find more information about her illness and to connect with others who had been through the same, but found there was very little information available to her beyond what she learned from her doctors.

Now that she’s feeling stronger, she wants to share her story with the world. She plans to do so with a 12-part podcast, called 38 Parasites, which will delve into her personal journey along with interviews with consultants and experts in tropical diseases, insights on neurology, and more.

‘I spent my whole thirties being ill and anxious and worried, and now I’ve moved into my 40s, I want to do something positive with that negative thing – help other people, and not just feel like I’ve lost all of this time.’

Through Crowdfunder, Lowri and her friend of 20 years, producer Nicola Brown, are raising £25,000 to fund the project, which was shortlisted for 2025’s The Whickers Podcast Pitch Award.