How's this for a hypothesis - there are maybe as many as 30 different batches. These were collected over the years. As the bacteria is grown and regrown over a long period of time you might get minor variations.
As far as the lab sourcing it would be concerned, it would all be the same thing.
The thieves would deal it as though it were identical. The final users wouldn't know the difference.
Some of it could have been sent in letters. Some of it handcarried to the site by saboteurs otherwise believed to be trustworthy employees.
And, the people buying the stuff may not have been aware that a number of the units they purchased had been sterilized.
Add in these quite reasonable conditions and the results would be dramatically variable.
Me: But Blanco was 74 -- not only did he survive, but he is the only survivor to have fully recovered.
You: I didn't say that everybody over 50 died, just that all who died were over 50.
I understand that -- I wasn't saying you were wrong.
The point was that it's interesting that Blanco not only survived, but he fully recovered, in spite of the fact that he was 74. Everything else being equal, his age would presumably make the illness more severe than it would be in a younger person.
It's natural to ask why Blanco (in FL) recovered fully, while the others who survived inhalation anthrax (in NJ) are still suffering from a variety of symptoms. One conceivable answer in such a situation would be that the patient is young and healthy, with a correspondingly strong immune system. But, in fact, Blanco is 74 years old -- and this makes it even more remarkable that he is the single survivor who has completely recovered.
This really suggests that the FL anthrax is different ("weaker" in some respect) than at least some of the anthrax that passed through the postal system in NJ.
The only hesitation here is the very small sample size. The differences can't be statistically signficant, because of the small sample size; the apparent difference in the FL and NJ anthrax symptoms could be due to chance.