There is nothing linking the sudden deaths from infectious diseases of four toddlers at two hospitals during the past three weeks or the serious brain condition of two other children, the Health Ministry said. Officials do not believe the infections were spread in the hospitals but were contracted in the community. But the ministry has contacted the pediatric departments and intensive care units of all the hospitals, asking staff to be alert for any additional cases beyond those at Schneider Children's Medical Center in Petah Tikva and at the Dana Children's Hospital of the Tel Aviv Soursky Medical Center. A few years ago there was a similar situation in Jerusalem. The ministry said that in an average year, 10 children aged one to four die from infectious diseases. The cause of these latest infections is not known. One 14-month-old girl who suddenly went into clinical death at her day care center, was resuscitated by Magen David Adom medics and hospitalized with a severe neurological condition, was found to have Cocksackie B virus in her stools that damaged her heart and caused her death. Ten days ago, an 18-month boy with fever went into cardiac arrest; an autopsy showed myocarditis (inflammation of the heart muscle) was the cause of his death. Two other cases are a 15-month-old girl who died of an infectious condition at Dana and an 18-month-old girl from Rechasim who died suddenly in her home. In addition, two children aged 18 months and three years are being treated at Schneider for serious neurological damage, one of them after going into cardiac arrest. Dr. Yechiel Schlesinger, head of the infectious disease unit at Jerusalem's Shaare Zedek Medical Center, said he was not at all familiar with the cases. However, he did hear that the toddlers had developed myocarditis and encephalitis (acute inflammation of the brain caused by a bacterial infection or a complication of another disease, usually viral). "Such deaths have always happened; what has to be fully investigated is whether the cases are linked and what caused them. We do not have cases in Shaare Zedek," he said. "It is hard to calm down frightened parents when there is not enough data. Not everything that looks like an outbreak really is one. One can't quickly rule it out, but it can easily be a coincidence," the infectious disease expert said. Parents should be alert when their young children have a high fever, fast pulse, difficulty breathing and weakness, as these could be symptoms of myocarditis - though it is more likely to be the flu, said Schlesinger. Encephalitis presents itself with apathy, reduced consciousness, vomiting and fever, but those symptoms usually mean something else. "There is a thin line between very serious conditions and those that pass by themselves," said Schlesinger.