Coronavirus survivor Jim Groo first sensed he was in trouble when he started struggling to breathe - and his body told him this wasn't just a case of regular flu.
"You can expect fever, cough, laboured breathing, light-headedness, and potentially changes in taste and smell," he explains.
"You may also feel, as I did, like you breathed in a bunch of broken glass."
The Swiss-based American is one of more than 1.2 million patients worldwide diagnosed with COVID-19 over the past couple of months.
Luckily, he's also one of 260,000 to recover from the pandemic that has claimed 70,000 lives so far.
Groo, 50, posted about his experience on Facebook, lending graphic detail to an illness that has relied on statistics and the odd celebrity sufferer for its profile.
Living in the Montreux district, near Geneva, he works as managing director for a marketing tech company located squarely in the European red zone of Italy, France, Germany and Spain, where the virus has wreaked carnage.
"We border Italy and there is a direct train line from Milan to Geneva, which was left open during the escalation in Italy," he told Newshub.
Switzerland has a population of eight million - about twice that of New Zealand - and is one of the worst-hit nations, both numerically (21,000 cases, 715 deaths) and per capita (2400 cases per 1m people).
Groo isn't sure how he caught COVID-19 - it could have been during a recent trip to London or off his teenage son, who probably picked it up from school.
But he quickly realised something was wrong when he began feeling asthma-like symptoms he hadn't seen in 20 years, along with debilitating fever and dizziness.
"I'm not a doctor, so this is just my personal experience, perspective and thoughts in hindsight," he posted. "Things are changing daily.
"I sincerely hope none of you will experience this."
Groo breaks the process into four phases:
The Infection (5-7 days)
"At this stage, you are infected, but asymptomatic. You probably caught the virus innocently from a friend, colleague or passerby, and are now innocently passing on the virus to others.
"The spread of infection is so fast and is one reason you see the numbers increasing so rapidly."
The Sucker Punch (5-7 days)
"At this stage, the virus sneaks up on you and hits you hard, without you expecting it... the virus knocks you off your feet.
"My lungs were burning and super irritated. For me, I immediately felt this was different from the flu.
"Outside of all the aches and pains and tiredness of the fever, something fundamentally felt different. Listen to your body - it knows.
"My muscles were in a lot of pain from the coughing at this point. Every exhale, I had to cough... I felt my body was filled with a cold toxic gel.
"You can also think about it like you've been pushed underwater and you need to swim to the surface in order to catch some air. The further down you were pushed or the harder you were hit, the longer it takes to catch your breath.
"Oxygen is key. I spent a lot of time trying to relax and not panic in order to maintain control over my breathing.
"For me, I get freaked out when I can't breathe well.
"I was getting frustrated not to see any progress day after day. I slept a lot, could not concentrate, had to manage anxiety… but my body was slowly getting ready for the fight."
The Fight (5-7 days)
"Once your body gets above water and/or you are able to get on your feet again, you are able to start fighting the virus, as you would the flu.
"It still takes time, but slowly and surely you start to make progress. Breathing becomes easier.
"There are pockets of feeling good and days when you feel like you regressed.
"At this point, I would say it's critical to stay on oxygen, until you are really better. I took it off early and it was a big mistake.
"I also got a big rash on my back, almost like a light version of chickenpox.
"It could also have been me lying in bed for several days, managing between chills, fever and sweating.
"As with the flu, eventually you break your fever and feel inside that something has changed. Don't get overly excited, because it is fragile... still need rest."
Recovery (2-3 weeks)
"At this point, you are done with the virus, you're at home and recovering. It is really two steps forward and one backwards.
"I've found I need to pace myself, because once you feel better, you feel so much better and want to do stuff. Then, when you overdo it... bam, you take a step backwards.
"I can't do the things like I used to... still don’t have full breathing capacity and get out of breath easier.”
Groo isn't sure what the future holds, as he continues to recover, while watching COVID-19 take a terrible toll across Europe and the United States.
"My advice is to adhere to the guidelines to stop the spread," he told Newshub. "Do everything possible to stay healthy, because you will need all your strength to fight this, if you get a serious case."
Watch the video for more on Groo's battle against coronavirus.
