Well that was sort of what I was thinking.
I'd love to read the full text when it is free, otherwise it is a bit of a puzzle.
My first thought was about the actual conditions that preceded the seizures in all of those patients to cause the fever in the first place.

Interesting too, is that there was another article on that same page suggesting that low iron and low serum ferritin may be risk factors for febrile seizures in children.

Association between iron status and febrile seizures in children
Soheila Zareifar, Hamid Reza Hosseinzadeh, Nader Cohan

http://neurotalk.psychcentral.com/post1041370-86.html
older articles re: ferritin, iron

anyway...