Owners of exotic pets such as snakes and lizards are at risk from salmonella, the chief medical officer has warned.

The warning comes after a three-week-old baby died from contracting the disease from the family's pet lizard. Five other children have contracted salmonella from pet reptiles in the past six months.

Children under five, pregnant women, the elderly and people whose immune systems are low are particularly at risk and were advised to avoid contact.

The latest figures show a rise in cases - 13 people have contracted salmonella from reptiles in the past two years.

The three-week-old baby is thought to have contracted a rare strain of salmonella - called salmonella rubislaw - from the family's pet water dragon.

Traces of the disease were found in the animal's drinking water.

Nine out of ten reptiles shed salmonella in their faeces and attempts to eliminate the disease have proved ineffective.

Increase in sales

There has been a dramatic increase in sales of exotic pets in the UK over the past ten years and it is estimated that tens of thousands are now kept as pets.

Professor Liam Donaldson, chief medical officer for England, said: "Thousands of reptiles are now kept as pets and it is important that their owners are made aware of the potential health risks associated with these animals.

"It is estimated that nine out of ten reptiles carry salmonella and people must take precautions if they own these exotic pets.

"There have been a number of recent cases of people contracting salmonella from their pet reptiles, one of which resulted in the tragic death of a three-week-old baby. The advice I am issuing today will alert the public to the dangers of keeping reptiles and I am also considering what further steps need to be taken."

He advised that people should wash hands with warm, soapy water after contact with reptiles and children should be supervised while handling the pets to prevent hand to mouth contact.

Reptiles should be kept away from food preparation areas.