A new mum has spoken about the terrifying moment she took her two-week-old baby to doctors with a chest infection to be told the youngster had whooping cough.
Worried Aimee Webber, 26, took her daughter Poppy to Kent Elms Health Centre, in Southend, Essex three times, but incredibly the symptoms went undetected.
The youngster's clear chest meant medics never even considered she might be suffering from whooping cough.
It wasn't until Aimee stayed in the surgery chatting to the doctor after her third examination that the medic picked up on the youngster's distinctive cough.
Alarmed the doctor told Aimee and her husband, policeman Rob, 26, to take their little girl to Southend University Hospital.
Hospital staff hurriedly ran tests after hearing the recognisable "whooping" sound and discovered to her parents dismay that one of her little lungs had collapsed.
Struggling and fighting for her life the little youngster was unable to feed causing shocking water retention - making her tiny body double in size.
[Related: Pregnant and the offered whooping cough jab]
Anxious Aimee yesterday warned all parents to be on guard against the killer virus as the outbreak of a new whooping cough epidemic was confirmed.
She said: "We brought her home from the hospital after she was born and the whole family had colds and coughs.
"So when Poppy started to develop a little cough and became a little groggy we didn't think anything of it we just thought she had caught our cold.
"I took to her the doctors for the first time when she had just turned two-weeks-old because she still sounded chesty.
"When doctors checked her chest they said it was all clear, I went back a week later because nothing had improved but once again the doctor said her chest was completely clear.
"While we were chatting in the doctors surgery Poppy started to cough and the doctor just looked so alarmed - she said "I think it's whooping cough" and I just burst into tears.
"In the hospital me and my husband were sat beside her and she started to make the unusual coughing noise - which we were used to by now.
"And suddenly we were surrounded by doctors and nurses who were frantic that she wasn't going to be able to breathe.
"It was terrifying because she was just under four-weeks-old and I wanted to cuddle her and tell her she's going to be OK. I was helpless.
[Related: Sharp rise in whooping cough in infants]
"It was unsettling because whooping cough has only recently started reoccurring again.
"One member of staff said it was only the second case they had ever seen.
"We worried because Poppy is so precious and tiny and she was brand new.
"The injection for whooping cough was released the day Poppy was submitted into hospital, if I was pregnant now I wouldn't even question having the jab.
"If you see your daughter struggling to breathe, covered in tubes, fighting for a life she's barely lived yet there is no doubt that you would want to stop that from happening.
"You never think it will be your child."
Poppy, who was born on September 5, developed cold-like symptoms shortly after Aimee gave birth.
Unaware of the deadly symptoms, mum Aimee, from Southend, Essex, continued to monitor the "cold" taking her back and forth to the doctors.
Little Poppy caught what is known as the "100 day cough" which lays undetected in the chest but can be picked up on early cold-like symptoms.
The baby, now three-months-old, is still suffering from the illness but doctors hope she will make a full recovery.
Aimee, a care assistant who is currently on maternity leave, added: "Me and Rob looked back over the video of Poppy coughing last night and you forget just how poorly she was.
"At one point her whole body was retaining so much water that it had collected to a point on her head.
"I panicked, I was inconsolable, I thought the worst - that she was going to be brain damaged.
"As the doctors moved her the water which had collected spread back through the body.
"Now she is slowly getting better, she is still coughing but she is out of the worst of it. We can only pray that she doesn't pick up any infections because her immune system is so weak.
"We just hope she'll get better and not have any long term effects."