There is a continous threat to every nation, that some terrorist organization will be capable of using these kinds of weapons. Finding and handling supplies of these materials is getting harder as we progress with international controls on production. Obviously there are possible

Most countries realise it is a no win situation if bio terrorism gets unleashed. Disease would backfire on the users when nations supporting their cause are unable to control or contain epidemics caused by terrorist cells. Fanatics would not be stopped by this threat, but it makes it more likely they would not be supported by rogue states if they threatened using this form of warfare.

As for Al Queda, it is a very fractured organization, and has very little of it's former capability. Most actions are now by uncoordinated wanna be's and splinter groups. Since it has been targeting innocent arabs and stirring up tribal differences in Iraq it has fallen from favour with many. (rather like the Taliban)
Perhaps these fanatics will wake up to the fact that noone will win WW3, at best it will just level the playing field (no pun intended)for WW4.

Yours, Aye. Dave