Absolutely! It's very, very similar to COPD! Would anyone today be dumb enough to pick up a cigarette knowing anything about COPD or having a family member suffering from it? Ok, maybe a dumb question as some of the younger crowd doesn't seem to learn very easily but if you are diagnosed with COPD and you smoke the first thing you're going to do is quite smoking. just like COPD, PHS never goes away or gets better...you treat it the best you can until it kills you (or the bird) and dying from COPD is like drowning in your own bodily fluids...I'm guessing the same is true for PHS.
As someone who has had a family member die from both COPD and lung cancer (different people, both smokers), I can unfortunately say that people can be very illogical creatures and slow to change their ways or admit mistakes.
My maternal grandmother smoked most of her adult life. Tried quiting a few times, mostly due to pressure from her adult children, but it never stuck. She was diagnosed with COPD and kept smoking. She was put on supplemental oxygen and kept smoking. She was diagnosed with emphysema and kept smoking. She started a small house fire by falling asleep while smoking AND using an O2 tank ... kept smoking. She literally kept smoking until she was physically incapable of getting out of bed long enough to light a cigarette. And she would have kept smoking even then if she was could have convinced someone to light it for her. She was a very determined and stubborn woman.
Then there was my step grandmother. She was a smoker for decades before she successfully quit. She stayed smoke free for almost ten years. Then she was diagnosed with lung cancer. She was gone a few months later. It was a shock to everyone, because she was still quite young, relatively-speaking, and a generally healthy person, especially compared to my grandfather who was ten years older than her, also a smoker, and had a laundry list of health problems. He tried quitting, both before and after her death, but he always went back to smoking cigars. He outlived her by almost fourteen years and was smoking until he died of heart failure.
Anyways, I don't know that much about PHS in birds, but if it is anything like COPD, it is a really miserable way to die. I would not wish it on my worst enemy, let alone one of my birds.
But in regards to the debate about lethality, there is a huge difference between getting diagnosed with COPD and getting diagnosed with small cell lung cancer, for example. COPD is a chronic, debilitating condition. It shortens your natural lifespan by as much as ten years and it can significantly compromise your quality of life and physical wellness. But it isn't a terminal diagnosis. If you get diagnosed with COPD in your sixties, you will probably live another ten or fifteen years. In contrast, small cell lung cancer is a deadly and aggressive disease. The five year survival rate is as low as 6%, depending on type and severity. Most people who get diagnosed with small cell lung cancer will not be alive in two years, although recent treatment advances are hopefully improving that number. If it is caught in the later stages, your life expectancy can be less than six months. It kills very fast. Other types of lung cancer are less severe, but still more immediately and faster killing, compared with a slow, dragged out death from COPD.
My point is not that being diagnosed with COPD is somehow "better" than getting diagnosed with lung cancer, but rather that the expected disease trajectory are dramatically different between these two lung diseases. They both can (probably will) kill you, given the chance, but one is much slower and less of a "sure thing".
I think at the core of the original argument in this thread, there lies a question about lethality - is PHS more like lung cancer or is it more like COPD (or maybe something else entirely)? Unfortunately, bird diseases lack the medical research and population studies that human diseases receive so it is hard to judge. I am no expert, but it sounds like it can kill very swiftly at times, but sometimes it takes many years to strike. It is difficult to say if it is really "100% lethal", but lung disease is nothing to mess around with, regardless of type. I am glad this thread was created because more people need to be aware of the danger.
It is also worth mentioning that powder-down birds can trigger respiratory hypersensitivity in some people also. Bird fancier's lung is a serious lung condition that can lead to chronic breathing problems that may persist even after the birds are removed from the person's environment. People with existing lung disease or asthma are at greater risk, but even completely healthy people can develop a sensitivity to bird dust. This condition is relatively rare, but it is also probably under diagnosed, due to the slow onset and non-specific symptoms. If you have persistent breathing problems that seem to improve when you spend time away from your birds, you should probably get checked out, just in case.
Stay healthy folks!
