A mother has described the harrowing moment she had to perform CPR on her daughter, who died of sepsis.
Chloe Christopher, 17, from Cwmaman, Rhondda Cynon Taff, had been laughing with friends before being struck by the illness on New Year's Eve 2014.
The condition happens when the body fights infection but causes injury to its own tissue and organs.
Her mother Michelle has made a video with the Welsh Ambulance Service to try and help raise awareness of the signs.
She said the moment her daughter, from Aberdare Community School, collapsed in front of her would "stay with me forever".
Here she tells her story:
Chloe seemed to have what we thought was a cold or maybe the start of a chest infection.
She was a little lethargic with some aches and pains, but it seemed nothing to worry about.
She spent one evening with one of her closest friends laughing and joking and looking forward to New Year's Eve celebrations, as they were going to a fancy dress party.
They were both together as Chloe rapidly deteriorated. It was so sudden; one minute laughing and joking, the next she said she felt unwell and a bit scared.
She then collapsed in front of us. Hearing the words "Mam, I'm frightened, I don't feel very well" will stay with me forever.
I phoned for the emergency services immediately and even though we didn't know what was happening, we knew it was serious.
Chloe suffered a cardiac arrest in front of us, and having to try and perform CPR on your own daughter was indescribable.
The emergency staff were amazing and tried their utmost to save Chloe but to no avail.
What is sepsis?
The life-threatening condition arises when the body's response to infection causes injury to its own tissues and organs.
It can initially look like flu, gastroenteritis or a chest infection.
There are common signs and symptoms including fever, an increased heart, increased breathing rate and confusion.
This can lead to shock, multiple organ failure and death if these are not recognised early.
Source: Welsh Ambulance Service
The first time we heard of sepsis was at Chloe's inquest five months later.
We heard that Chloe had signs of a urine infection which turned to sepsis, led to multi-organ failure and then cardiac arrest.
Since Chloe's passing, it's been my passion to raise awareness and to help educate the public on the signs of sepsis.
It is estimated that sepsis kills around 44,000 people a year; it's bigger than breast, bowel and prostate cancer put together.
If caught early, sepsis can be treatable, so they key message is education, knowledge and awareness and to just ask "could this be sepsis?"
By doing this, it helps keep our beautiful Chloe's memory alive, hoping that maybe we can save a family going through what we have.