A mystery respiratory disease sweeping across the world has infected hundreds of people, and is thought to have killed at least nine.
Jessica Nash on her New York trip
Just three months ago Jessica Nash, 25, from Maidenhead, nearly died after falling victim to a similar respiratory illness, which she believes she contracted on a trans-Atlantic flight.
Experts in communicable disease now plan to analyse a sample of Jessica's blood to try to determine the source of her illness.
Here, she tells BBC News Online about her brush with death.
"I flew out to New York for a holiday with my boyfriend on 12 December, and flew back four days later.
"About ten days after I got back I started to develop flu-like symptoms. I felt hot and then cold, had a sore throat and a cough.
"I thought nothing of it, but the symptoms did not get any better, and after Christmas I got a lot worse.
"By mid-January I had developed quite a bad cough, a high temperature and a very bad sore throat.
"I went to see my GP who gave me antibiotics, but they did not make it any better at all.
"On January 16, I collapsed, and was found my by mother. I was admitted to Wexham Park Hospital in Slough.
"They said I had an aggressive unknown virus. I was absolutely delirious, when I spoke I was making no sense at all, and I had trouble breathing, my breaths were really shallow.
I was still on antibiotics, but I was getting worse
"For a couple of days I was kept on a general emergency ward, but on the third day they decided to move me to an isolation unit.
"My mother and father and colleagues who came to visit had to wear full protective suits, plastic shoes and mask to come into the room to see me.
"For two weeks I just could not breathe at all, I was gasping for breath all the time, and I was not aware what was going on around me at all.
"They could not work out what was wrong with me. I was still on antibiotics, but I was getting worse.
"Then they took a chest X-ray, and decided I was developing pneumonia. I also developed septicaemia, and my brain swelled up.
"They began to use a cocktail of antibiotics on me, and thankfully, I finally responded.
"I lost a huge amount of weight and was very sick, but that may have been the drugs they gave me. I could not walk or feed myself unaided, but slowly I began to recover.
"I have only now gone back to work part time, but I am still suffering very badly from memory loss, and I am extremely tired.
"I have been told to take it easy. My immune system is vulnerable because I have been hit so hard by the disease, and by the drugs they had to give me.
"I was quite lucky to survive. They told me it was very unusual for somebody of my age to develop pneumonia.
"I don't know how I got the disease, but I distinctly remember that there was a woman behind me on the plane who kept coughing and spluttering.
"I turned round and asked her if she was alright. I got talking to her, and she told me she had just been in Hong Kong, which is where the latest outbreak is thought to have started.
"It all feels pretty surreal. I feel very lucky, if my mother had not come home and found me after I collapsed it could have had very serious implications.
"But I am also concerned about the people I came into contact with, especially those on the plane, who had to share re-cycled air."