AT first glance, three-year-old Oscar McCulloch seems like any other bright and lively little boy, playing happily with his brother and sister.

But Oscar’s life is anything but ordinary: at three weeks old, a heel prick test revealed the little boy had cystic fibrosis, a diagnosis which affects every aspect of his life, and the lives of all his family members. Oscar is used to a regimen of medications, he can’t play in the mud or in fallen leaves, and his parents have to be constantly vigilant to try and protect him from the infections and illnesses which would have little impact on most of us but could cause him to become seriously ill.

Despite the challenges, Oscar’s mum, beauty therapist June, and dad, Jason, a pharmacy dispenser, are evidently proud of their son and the way he responds to the difficulties he faces.

“He’s a real trooper,” said Jason. “He just gets on with it and takes it all in his stride.”

June said: “It was a massive blow when he was diagnosed. It was not long before Christmas, and we were told when we first met the consultant the implications and the impact, the medication and treatment, and that the life expectancy for Oscar was 41.

“By the time of his early to mid-teens, he will need a double lung transplant – it depends how fast the damage sets in to his lungs. Everyone’s different and it affects everyone differently.”

According to the NHS, cystic fibrosis is an inherited condition that causes sticky mucus to build up in the lungs and digestive system, which causes lung infections and problems with digesting food. The condition gets slowly worse over time, with the lungs and digestive system becoming increasingly damaged. Treatments can help reduce the problems it causes, but life expectancy is shortened. Mucus in the lungs can cause breathing problems and, in the pancreas, can stop people with cystic fibrosis absorbing nutrients properly.

“To have a child with cystic fibrosis, both parents need to have the defective gene,” Jason said. “We were completely unaware that we did. It was a complete shock. I can remember the day and the time we found out – it was 4.30pm on December 10 2014.”

The parents, from north Swindon, had a steep learning curve, from knowing nothing about the condition.

“I’d never heard of it. The consultant gave us a brief outline of what it was – and advised us not to google it.,” Jason said.

The following day, they had an appointment with a child paediatrician at the Great Western Hospital, and the process of understanding Oscar’s medical care began. Oscar has pancreatic insufficiency, which means he has to take a medication called Creon when he eats, to help him digest food and gain the nutrients he needs. Without the enzymes in the medication, he would become malnourished.

“In the past, cystic fibrosis killed a lot of children, because they would fail to thrive. Then they discovered this enzyme was the issue,” Jason described.

Every day, Oscar’s parents implement a programme of pills and physiotherapy. The little boy has ten tablets to take at breakfast, including vitamin supplements. He has a special breathing mask he uses twice a day to help exercise his lungs. When he was little he had to be patted to break up the mucus in his lungs. He is more vulnerable to bugs, so coughs and colds affect him for longer and have the potential for complications, so he uses a nebuliser to absorb antibiotics. Even so, Oscar has had four hospital admissions in his three years. At six months, he spent two weeks in hospital being treated for an infection with intravenous antibiotics because of a persistent cough, which could have damaged his lungs. In August, he was admitted to Southampton Children’s Hospital, and had to have a PICC line (a small plastic tube) through his foot, because of difficulties using the veins in his arms.

“It has been a tough journey,” said June. “We have to be so careful about what he plays with, even in the garden. There are bacteria in stagnant water – even if it’s rainwater sat in a bucket. We have to empty out the sandpit if it gets wet.

“He can’t play with fallen leaves. If they’re green that’s okay, but when they are turning brown, that’s when it becomes a problem.”

She said: “It’s so many normal things kids take for granted, like playing in the mud, that he can’t do.”

The parents say they try not to let Oscar’s illness affect the lives of his brother Alfie, aged five, and two-year-old sister Millie, but inevitably it has an impact.

“We think how can we not let it rule their daily lives, accommodating him? But we have to pick activities carefully. We were honest with Alfie from day one and referred to it as Oscar having bugs in his tummy,” Jason said.

“Oscar knows he has cystic fibrosis, and that he has to go to hospital. He’s quite clued up. Alfie and Millie want to get involved and to help.”

Oscar goes to Barn Owl Preschool, which he loves.

“We had meetings with staff and a care plan put in place for him. They had to be aware that he can’t play with wet stuff, and we have to go through that with them. The staff have been amazing.”

It isn’t just at preschool that Oscar needs extra thought from those around him: when family and friends come to visit, they need to make sure they have no coughs or colds they could pass on to Oscar. Events like birthday parties need some thought too, in case guests have infections they might pass on. His parents avoid taking him out in the cold and the wet, in case it makes him susceptible to illness. Outings require pre-planning as Oscar tired easily so cannot walk too far. Even holidays prove complicated – they have to avoid humid destinations, or accommodation with air conditioning, as humidity is tricky for his lungs and air conditioning can harbour bacteria. Oscar’s hospital appointments can also make planning a holiday very difficult.

“Our family is very understanding, but we have lost contact with some friends because of the situation,” Jason said.

Despite all the demands on their time, June and Jason are committed to raising money for research and for helping others in the same situation as themselves. They support the charities Flutterby FUNdraisers for cystic fibrosis, and the Cystic Fibrosis Holiday Fund, which offers much-needed holidays to families affected by the condition. They aim to raise £5000 and have organised a series of events, such as a recent 50km treadmill walk in the Brunel Centre, to reach their target.

For the future, Oscar’s parents want for their son exactly what all parents want – that he is healthy and happy.

“We hope he lives as long and healthy a life as possible, and for one day there to be a cure,” June said.

“Currently it is a life-limiting condition,” Jason added. “It’s early in his journey. We want him to have as long and happy a life as we can give him. I want him to outlive me. We don’t know how things will turn out for him. He may flourish, or it may be the other side of that coin.”

To support Jason and June's fundraising, visit gofundme.com/livehopecure-for-cf.