Dan Aykroyd leads tributes to Ghostbusters co-star Harold Ramis

Dan Aykroyd has led the tributes to fellow Ghostbusters co-writer and actor Harold Ramis, who has died aged 69.

Director Ramis died of autoimmune inflammatory vasculitis, a rare disease that involves swelling of the blood vessels, his agent told the BBC.

Aykroyd tweeted that he was "deeply saddened to hear of the passing of my brilliant, gifted, funny friend, co-writer/performer and teacher".

Ramis's credits also included Groundhog Day, Animal House and Caddyshack.

Aykroyd added of his friend: "May he now get the answers he was always seeking."

Ramis's family released a statement paying tribute to the actor, which said: "His creativity, compassion, intelligence, humour and spirit will be missed by all who knew and loved him."

Ghostbusters and Groundhog Day star Bill Murray also added: "He earned his keep on this planet."

Ramis found fame as bespectacled ghost-hunter Egon Spengler in the Ghostbusters franchise in 1984, which was a global smash and spawned a sequel in 1989 as well as a long-running cartoon series. A third instalment had been in development for several years.

The film remains one of the most successful comedy movies of all time, with takings of more than $500m (£300m) adjusted for inflation.

Ghostbusters director Ivan Reitman told Entertainment Weekly: "The world has lost a wonderful, truly original, comedy voice with the passing of Harold Ramis.

"He possessed the most agile mind I've ever witnessed. He always had the clearest sense of what was funny and how to create something in a new clever way."

Reitman added he "loved him like a brother" and that Ramis "was very generous about making everyone around him look better and smarter".

Sigourney Weaver, who also starred in Ghostbusters, said that working with him on the film was "one of the happiest experiences of my life".

"He was amazingly talented, kind and generous and always came up with these stealthy and incredibly funny lines. His movies are so brilliant, and Harold was so low key about it all. It's a huge loss."

Born in Chicago, he began his career as a writer for his local newspaper before moving to Playboy magazine.

From there he began working with Chicago's renowned Second City improvised comedy troupe and moved into acting, playing the straight man and sardonic foil to Bill Murray in the army comedy Stripes.

His biggest acting role was as the most straitlaced and scientifically inclined of the Ghostbusters team.

The star had reportedly been quiet about his illness, which dated back to 2010.

But several friends are said to have visited him recently, including Murray, from whom he had been estranged for years, the Chicago Tribune said.

After the Ghostbusters sequel, Ramis developed his career behind the camera, directing Robert De Niro and Billy Crystal in the director's mobster comedies Analyze This and Analyze That. Crystal wrote: "Sad to hear my friend Harold Ramis passed away.

"A brilliant, funny actor and director. A wonderful husband and dad. Big loss to us all."

Chevy Chase, who Ramis directed in Caddyshack and National Lampoon's Vacation, called him "a great man who shunned unnecessary Hollywood-type publicity".

He added: "It was Harold who acted out and gave me the inspiration for the character of Clark Griswold [in National Lampoon's Vacation]. I was really copying Harold's impression of Clark."

Ramis also inspired a new generation of film-makers, including Judd Apatow, who cast the director in his 2007 comedy Knocked Up.

Apatow said: "Harold Ramis made almost every movie which made me want to become a comedy director. Animal House, Stripes, Ghostbusters, Vacation, Groundhog Day. These films are the touchstones of our lives.

"I interviewed him when I was 16 years old for my high school radio station, and he could not have been more gracious and hilarious.

"I looked up to him as a director but even more so as a man. We hired him to play Seth [Rogen's] father in Knocked Up because we all saw him as the dream dad - funny, warm and wise. Harold was one of the nicest people I have ever met and he inspired countless people to go into comedy. His brilliant work will make people happy forever."

Rogen tweeted his own tribute calling Ramis, "one of the coolest, nicest guys".

Ramis wrote, produced and directed Groundhog Day, about an irascible TV weatherman forced to live the same 24 hours over and over

Ramis made a total of six films with Bill Murray, including military comedy Stripes

Ramis's other films included The Ice Harvest, Bedazzled and prehistoric comedy Year One, his final movie, in 2009. More recently, he had directed episodes of NBC television's The Office.

The show's star Steve Carell tweeted: "Funny, gracious, kind hearted. A joy to have known you."

Actor John Cusack, who worked with Ramis on The Ice Harvest, paid tribute to the director, saying: "Harold was a master - a gentle wry subverter and as decent honest and kind a director as I've ever worked with - so sad."

Iron Man director Jon Favreau added: "No, no, not Harold Ramis. Worked for him years ago. He was the real deal. Growing up, his work changed my life. He will be missed."

Family Guy creator Seth McFarlane described Ramis as "a brilliant, shining example for every comedy writer hoping to achieve excellence [in] the field" and actor, comic and musician Steve Martin called him "a comedy master".

Ramis received an American Comedy Award and a Bafta for screenwriting

Oscar-nominated director Jason Reitman - the son of director Ivan, whose films include Juno, had held Ramis in high regard, tweeting: "Egon was my favourite Ghostbuster. Feels like we lost one of the Beatles."

Actress Julianne Moore described Ramis as "exceptionally talented, exceptionally kind" while broadcaster, writer and actor Stephen Fry added that he was "a comedy hero". Happy Days star Henry Winkler simply said: "Rest in peace Harold Ramis: a continued source of everything funny."

He is survived by his wife, Erica, sons Julian and Daniel, daughter Violet and two grandchildren.