A toddler was forced to have the lower part of all four of his limbs surgically removed after being struck by a mystery infection.

Jeremiah Cox, two, started to develop a fever on September 29 – shortly after his pregnant mother Ashley, 19, went on maternity leave.

After being rushed to Riley Children’s Hospital, Indianapolis, Jeremiah’s health took a rapid turn for the worse when purple marks began to cover his body.

Doctors diagnosed him with septic shock and the condition purpura, which they believe came about from an unknown bacterial infection.

Although antibiotics managed to control the infection, the blood supply to Jeremiah’s limbs had already shut down and the condition threatened to spread.

To save his life, medics were therefore forced to remove parts of his limbs below the knees and elbows.

More than a month later, Jeremiah is still in hospital, where he is relearning how to crawl and even eat.

Jeremiah had been happily playing in the park just the day before bruise-like marks covered his entire body.

His father Nicholas Thompson, 21, said: ‘It’s kind of like blood vessels that’s ruptured really in the body.’

When the youngster developed a fever and started vomiting uncontrollably, his parents rushed him to the emergency room, where things took a dramatic turn.

‘Just to watch your child lay there and watch everything shutting down, and then basically watching your son fading in front of you – it’s overwhelming,’ Ms Cox said.

Due to doctors being unable to determine the cause of his purpura, they gave him an antibiotic in the hope it would treat any underlying bacterial infection.

‘If they didn’t give it to him my boy wouldn’t be here,’ Ms Cox said.

Purpura occurs when small blood vessels burst, causing blood to pool beneath the skin and appear as purple-coloured spots.

Despite the youngster’s treatment being a success, his dangerously low blood pressure had already cut off the blood supply to his limbs, leaving doctors with no choice but to carry out the procedure.

Although Jeremiah is out of intensive care, his recovery is far from over, with medics hoping to move him to a rehabilitation unit later this week.

While there, the youngster will have to relearn how to crawl and even eat, as well as how to walk in the hope he will one day be given prosthetics.

Doctors have told Jeremiah’s parents they may never know the cause of his life-threatening illness.

While her son fought for his life, Ms Cox was forced to give birth to the couple’s fourth child.

Although the pair are grateful their son managed to pull through against the odds, they worry about the day Jeremiah realizes he is different.

‘I think he’s really recognizing that everything’s changed,’ Mr Thompson told WTHR. ‘At this point, now he’s realizing his life has changed.’

Ms Cox is still on maternity leave and is struggling to care for hospitalised Jeremiah, who is her eldest, as well as a newborn and her two other children.

The family, who currently rely on Mr Thompson’s income, have set up a fundraising page to help make ends meet.

Jeremiah’s story comes as another mysterious illness, which has been likened to polio, is affecting parts of the US.