He didn't take antimalarial medication, believing the course he had taken for a previous trip to the West African country still protected him.
But he fell ill soon after returning to the UK and spent two weeks fighting for his life in hospital.
A chaplain was even called to give Mo his last rites after doctors feared he would not survive.
“I was told I could have died,” says Mo. “Compared to what I went through, the potential mild discomfort of taking antimalarial pills is nothing.”
Immunity to malaria
In 2010, 61% of the 1,700 cases of malaria reported in the UK were in people who had travelled to a malaria region in their country of origin.
Many people mistakenly think they are immune to diseases such as malaria because they have previously lived in a malaria region.
However, immunity is quickly lost when someone moves to a malaria-free country like the UK.
Mo thought the antimalarial pills he had taken on his previous trip to Sierra Leone 10 months earlier would give him immunity.
He also thought that his genes provided some protection against the mosquito-borne parasite.
Both his brother and grandmother, who live in Sierra Leone, had had malaria and made a full recovery after developing only mild symptoms.
Mo flew out on April 11 2013 to join the rest of his family for the funeral of his mother, who had died unexpectedly from a heart attack.
“Her death was such a shock,” he says. “In the rush of making last minute travel arrangements, antimalarials were low down on my to-do list.”
He spent a week in the country travelling between Freetown and his ancestral home attending ceremonial events in honour of his mother.
“I didn’t take any precautions at all,” says Mo, an online marketing manager from east London. “No mosquito net, no mosquito repellent.
“I remember being bitten a few times but we had so many things to deal with that malaria was the last thing on my mind.”
Back in the UK
On his return to the UK, Mo says he felt “absolutely fine”, apart from a complete loss of appetite, which he put down to grieving.
“In a week, I probably managed to eat one banana and a couple of bowls of soup,” he says.
By the end of his first week back, Mo quickly began experiencing symptoms including sweats, muscle ache, severe headaches and breathing difficulties.
“It dawned on me that it might be malaria but I wasn’t too worried,” he says. “I thought it would be cured easily with a few tablets.”
As his breathing worsened, he called for an ambulance and was taken to Homerton University Hospital, in east London, on April 24.
A blood test confirmed malaria. However, it was not just any malaria. Mo had been infected with plasmodium falciparum, the most deadly form of malaria.
Found mainly in Africa, almost all deaths from malaria are due to the plasmodium falciparum parasite.
Mo was placed in intensive care. “A doctor said he was going to put me to sleep for a few hours to insert a tube to help me breathe,” he says.
The next thing Mo remembers is waking up nine days later in St Thomas’ Hospital, in central London, hooked up to life-support equipment.
“It was a complete shock,” he says. “I had tubes and needles going in and out of me. I couldn’t speak because there was a large tube in my mouth.”
The drama of the previous nine days – his family’s distress, the chaplain’s prayers, moving hospital – were revealed to him over the following days.
“When I woke up, the medical staff, family and friends helped me piece together the past nine days.
"It was very upsetting to be told that I had come close to dying.
"The malaria parasite had been attacking my lungs and they were filling up with fluid.
"Pint after pint of brown fluid was being pumped out. The doctors feared I was going to drown in this fluid.”
In falciparum malaria, fluid can accumulate in the lungs and cause severe breathing problems.
“My family was told that the outlook wasn’t good and that they should be prepared for the possibility that I wasn’t going to make it.
“We had only just buried our mother and now they were being told I was probably going to die.”
In case Mo didn’t make it through the night, a hospital chaplain was called to administer his last rites.
Transfer to St Thomas'
With his condition deteriorating by the day, a medical team from St Thomas’ came to Homerton to assess his condition.
It was decided that Mo should be transferred to St Thomas’ where they would try to beat the malaria parasite using different drugs.
By the time Mo woke up after his nine-day blackout, the parasite level had dropped significantly, his lungs had cleared and he was able to breathe unaided.
He remained at St Thomas’ under close supervision for another five days until the parasite had virtually disappeared from his blood.
“The staff at St Thomas’ saved my life, for which I will forever be grateful,” says Mo. “They were fantastic.”
After two weeks in hospital, Mo was discharged on May 8 and spent the following two weeks recovering at home.
“I had lost about two stone and I still felt weak,” he says. “I still had difficulty breathing. Even going to the bathroom was a struggle."
He has since made a full recovery and a subsequent blood test showed that the malaria parasite was no longer present in his system.
"A near-death experience makes you realise life can be taken away from you at a moment's notice," says Mo.
"If I've taken anything away from this experience, it's to never take your health for granted."