A man who complained of headaches found they were caused by an infestation of maggots - which had inadvertently saved him from a deadly infection.

Vietnamese labourer Pham Quang Lanh, 28, had a metal plate inserted over his skull after being struck by an iron bar on a building site.

But the botched operation caused his head to become swollen with a potentially deadly infection.

Fearing he couldn't afford any further medical treatment, Mr Lanh hoped the resulting headaches would eventually subside.

It was only when he asked family to look at the wound that they noticed a dozen maggots crawling under the skin and they took him to the Hanoi's Viet Duc Hospital.

Grim discovery: Vietnamese labourer Pham Quang Lanh shows the wound in his head where a maggot infestation had taken hold following a botched operation to repair an earlier head injury with a metal plate

Dr Nguyen Duc Anh, a neurosurgeon at the hospital, said: 'When his scar swelled a year ago, he did not go to hospital because of financial reasons.

'In fact, the reason that it was swollen was because it was infected and eventually some tissue had died, leaving him with the festering injury.

'When we took him into surgery, we discovered several maggots which were removed.

'We then needed to carry out a full operation to remove the maggots that had managed to go deeper.'

But he said the infestation had actually saved Mr Lanh's life by eating the infected tissue.

He said: 'This sort of fly infestation is extremely rare especially in the skull.

'I found eight references to it in medical literature worldwide and in every case the other patients died.

'In this man's case, however, the maggots had not gone on to eat any of his brain because of the metal plate.

'They actually may have kept him alive by eating the dead tissue that might otherwise have made the infection spread more quickly and killed him.'

Lifesavers: Doctors say the maggots (above) ate diseased tissue that could have caused a fatal infection

The use of maggots to cleanse wounds is well known as they can remove necrotic tissue and also disinfect the wound.

Mr Lanh suffered his initial head injury while working as a labourer in Malaysia.

After surgery to insert a titanium plate, the wound appeared to heal well, although he did suffer headaches occasionally.

He said: 'It was mostly OK until a year ago when I noticed it was swollen and sore to touch.

'I didn't want to go to hospital again because I hoped it would heal on its own and even now three years later I'm still paying the bill back for the last operation.