Caden Beggan, six, was diagnosed with meningococcal septicaemia, a type of blood poisoning caused by the same kind of bacteria found in the most common form of bacterial meningitis.
His parents David, 44, and Angela, 39, created a Facebook page to keep friends and family updated, which received over 36,000 "likes".
Followers of the page were told how Caden, of Cleland, North Lanarkshire, had lost both his legs and an arm to the bug, but it had been hoped he would survive his illness.
Last night his father left a heartbreaking update on the site revealing the news that Caden had died in his parents' arms.
He wrote: "Dear friends, Caden Riley Beggan. Born 29th September, 2006. Died 20th November, 2012-in Mummy and Daddy's arms.
"Thank you for all your support. Caden is alive forever more -"
Last night thousands of users began posting tributes on the page.
Sarah Godfrey posted: "I have no words, heartbreaking for us to read the news. I cannot imagine how Caden's loved ones are feeling."
Danielle Jones added: "Can't imagine the pain you must all be feeling, but know that you touched so many people's hearts with your diary of Caden's fight! Every one of them is grieving with you now."
Caden was taken to Wishaw General and transferred to Yorkhill Children's Hospital in Glasgow last month as he battled the infection.
In a post on the site at the weekend, David, a graphic designer, revealed that Caden, who has two brothers, Declan, 12, and Ethan, three, was preparing for surgery on Monday.
But concern for Caden had grown among followers of the page as no post was uploaded on Monday.
Last night the headteacher of Caden's school paid an emotional tribute to the youngster.
Ladywell Primary headteacher Pat Ashworth said: "The whole school is terribly shocked and upset at Caden's tragic death.
"He was an amazing little boy who will be sorely missed by everyone who knew him and the many thousands of people who followed his struggle on Facebook."