David Marks began playing music with his neighbours, the Wilson brothers, in 1958 when he was 10 years old and helped create the now famous California surf sound of the Beach Boys.
David was diagnosed with hepatitis C
He left the band - for the second time - in 1999 after being diagnosed with hepatitis C.
He finally beat the virus in 2004, but still remains the spokesman for a number of awareness campaigns.
HOW DID YOU FIRST REALISE SOMETHING WAS WRONG?
I didn't actually know I had anything wrong with me because I didn't have any obvious symptoms.
This is why hepatitis C is such an insidious disease.
People don't always have any symptoms until their livers are severely damaged.
I don't know exactly how I got hepatitis C.
I have been exposed to multiple risk factors, including indiscriminate experimentation with drugs in the early 1970s.
I really want to break the stereotype, though. Drug use is not the only way of getting hepatitis C. In most cases people can't pinpoint how they got it.
I know soccer mums who have hepatitis C, and can't remember ever being exposed to any risk factors.
HOW DID YOU GET DIAGNOSED?
I was diagnosed by accident, actually.
I went to the hospital because I had a pain in my side that turned out to be a cracked rib, but before the doctor figured out where the pain was coming from, he drew some blood that revealed my liver enzymes were elevated.
They did a test for hepatitis C that came back positive.
I tell people a broken rib saved my life, otherwise I might not have found out I had hepatitis C until it was too late.
WHAT WAS YOUR REACTION TO THE DIAGNOSIS?
My initial reaction was that I didn't even know what hepatitis C was, so I wasn't scared until my wife looked it up on the internet and read that I could die from this virus.
At that point, I immediately began to take it seriously, quit drinking alcohol and went on a strict regime of diet and herbs that would reduce inflammation in my liver and increase my immune system and energy.
WHAT WAS YOUR TREATMENT?
My treatment consisted of two antiviral drugs called Pegalayted Interferon and Ribavirin.
I took six pills a day and injected the interferon once a week for a year.
I was virus-free after six months, but I continued for an additional six months just to make sure every last virus was killed.
HOW DID YOU FEEL DURING TREATMENT?
The treatment was not easy, but the side effects are manageable. I was still able to tour and record and I also travelled all over raising awareness for hepatitis C while on treatment.
Improvements in treatment keep happening.
David was a founder member of the Beach Boys
For example, time released interferon means that you can now have an injection once a week, instead of once a day, which makes it easier.
With my own treatment, I didn't experience any excruciating discomfort. I was able to function in my daily life.
Side effects often include fatigue, nausea and sometimes flu-like symptoms. It's different for everyone though.
HOW DO YOU FEEL NOW?
Before I was diagnosed with hepatitis C my general health was OK.
I suppose I could have been taking better care of myself. I was drinking quite a lot of alcohol, not getting much sleep and sometimes forgetting to eat.
When I found out I had hepatitis C I started eating right, I quit smoking cigarettes and drinking alcohol completely.
I think that hepatitis C for me was almost a blessing in disguise.
I've cleared the virus and now lead a healthy lifestyle. It's become a habit for me.
I am healthier than I've been in 30 years. I feel really lucky that I was able to benefit from treatment and am now living a virus-free life. I'm a perfect example of how you can beat the virus, but you have to know you have it first.
If you think you might be affected, consult your doctor and get tested - it could save your life.
WHAT IS YOUR MESSAGE TO OTHER PEOPLE WITH THE SAME CONDITION?
My message to other people with hepatitis C is to take it seriously.
Just because you don't feel sick doesn't mean you can ignore that you might have this virus eating away at your liver, and that you could be putting other people at risk. Anyone may have put themselves at risk and not realise it.
For those who have risk factors, I suggest getting tested...a simple blood test saved my life and it could save yours as well!