A HEALTH board is investigating two probable cases of botulism poisoning in drug injecting heroin users.

Officials said both patients are from the Greater Glasgow area and are receiving treatment in city hospitals.

Their condition is described as serious.

NHS Greater Glasgow and Clyde (NHSGGC), Police Scotland and Health Protection Scotland say they are investigating the cause of the two cases, with the focus on intravenous drug use.

Addicts were urged to seek medical attention if they noticed any symptoms.

Botulism, which is caused by botulinum toxin, can progress to a paralysis of the arms, legs, and eventually the muscles that control breathing.

Dr Catriona Milošević, NHS Greater Glasgow Consultant in Public Heath Medicine, said: "I urge all drug injecting heroin users to be extremely alert and to seek urgent medical attention from Accident and Emergency if they experience any early symptoms such as blurred or double vision, difficulty in swallowing and speaking and/or inflammation at the injection site.

"It is important for injecting drug users to engage with the wide range of services we offer designed to help them tackle their addictions.

"However for those who continue to inject it is extremely important that they seek urgent medical help if they show these early symptoms.

"Heroin users should avoid injecting heroin into their muscles.

"Injecting heroin into a vein or smoking can reduce the risk of botulism, although not using heroin at all is by far the best course of action."

Officials said they were not aware of any other cases in Scotland.