Elite athletes are disproportionately affected by MND, with a study of Italian footballers suggesting the rate of the disease is up to six times higher than in the general population.
It is thought that by limiting the oxygen available and causing damage to motor neurone cells, regular, strenuous exercise can trigger the disease in those already genetically susceptible.
Moody, who won 71 England caps and toured with the British and Irish Lions in New Zealand in 2005, was nicknamed ‘Mad Dog’ during his playing career, in honour of his fearless, relentless approach to the game.
He played through a stress fracture of his leg for a time with Leicester and once sparked a training-ground scuffle with team-mate and friend Martin Johnson when, frustrated, he abandoned a tackle pad and started throwing himself into tackles.
After coming on as a replacement in the Rugby World Cup final win over Australia in 2003, he claimed a ball at the back of the line-out in the decisive passage of play, setting a platform for scrum-half Matt Dawson to snipe and Jonny Wilkinson to kick the match-winning drop-goal.
Moody has already told Johnson, who captained England to that title, and a couple of other former England team-mates about his diagnosis.
Geordan Murphy and Leon Lloyd, who Moody played alongside at Leicester, have set up a fundraising page to help support him and his family.
But many of Moody’s former team-mates will be learning his news with the rest of the public.
“There will be a time when we’ll need to lean on their support but, at the minute, just having that sort of love and acknowledgment that people are there is all that matters,” he said.
“Rugby is such a great community.
“I said to the kids the other day, I’ve had an incredible life.
“Even if it ended now, I’ve enjoyed all of it and embraced all of it and got to do it with unbelievable people.
“When you get to call your passion your career, it’s one of the greatest privileges.
“To have done it for so long with the teams that I did it with was a pleasure. And I know they will want to support in whatever way they can and I look forward to having those conversations.”