A panel of the Health, Labor and Welfare Ministry said it is unlikely that a teenage girl in a Tokyo area hospital has contracted new variant Creutzfeldt-Jakob disease (nvCJD), a fatal brain-wasting illness linked to mad cow disease.

Last week, hospital reports surfaced that the girls' symptoms are consistent with nvCJD.

The panel said Thursday it made a provisional judgment based on the account of a doctor in charge of the girl.

Takeshi Sato, head of Konodai Hospital of the National Center of Neurology and Psychiatry in Ichikawa, Chiba Prefecture, said the girl did not show any symptoms typical of those suffering from CJD, such as involuntary flexing of muscles.

"I would say there would be a very low possibility of her suffering from any type of CJD," said Sato.

But the panel will continue to monitor reports from the patient's doctor on her condition, they said. According to Sato, the girl was first hospitalized in early July after feeling numbness in her feet. About 10 days later, she was transferred to a different hospital and began experiencing convulsions and memory lapses, symptoms typical of CJD. In September, the hospital contacted the expert panel, saying it feared that the girl could be suffering from CJD. But Sato, who diagnosed the patient on Sept. 20, said that her memory loss was a side effect stemming from the medication she was receiving to reduce her convulsions.

A second diagnosis of the girl Wednesday showed that the symptoms, which would have worsened if she was suffering CJD, had "remained at the same levels, or in some cases had eased," Sato said.

Magnetic resonance imaging of her brain also showed nothing abnormal, he said.

Classic CJD is a fatal brain disorder that causes rapid, progressive dementia and associated neuromuscular problems and usually affects older people. New variant CJD, however, hits younger people and is believed to be caused by eating food containing a protein linked to mad cow disease.

The revelation that the teen could be suffering from nvCJD shocked much of the country.

It came just as the government launched a new beef inspection system after the first case of mad cow disease -- formally known as bovine spongiform encephalopathy -- was confirmed in late September.

There are four main causes of CJD -- hereditary transmission, transplants of dura mater, the fibrous membrane surrounding the brain and spinal cord, sporadic outbreaks without known causes and the new variation.

Medical experts say that about six months is needed to make a final diagnosis on whether a patient has contracted nvCJD.

Also Thursday, the expert panel said the two other reports of suspected CJD that surfaced last October were caused by a dura mater transplant in one case and a sporadic outbreak of the disease in the other.