It has been rats in all ages, from a 3 week old baby to rats over 2 years old. All ages in between.
It started monday the 20th of August, with Myrina (the other breeder) losing 5 rats within a day, they basicly died between her hands, they were both young and older rats.
She told me on msn, that she had lost 5 rats, so I went to check on mine, and found Avalon with pneumonia.
We warned everyone who had been in contact with her, she had just send a couple of rats to me, which Bati had transported, and she had brought some rats for another person as well, as brought a guinea pig from me to yet another breeder. Those 2 haven't got any sickness though.
Thuesday, Bati lost her first rat, a male over 2 years old. She had 2 more with illness, she lost one of them, but the other one got over it.
The signs has been like pneumonia. Myrina has had a single one with swollen glands. They got sick from one day to another. Myrina got an autopsy on the first 5 she lost, and all showed signs of pneumonia.
Both Myrina and Bati kept losing rats. It seemed to have slow down at Myrina's, while it got more aggressive at Bati's. Bati lost 7 on the 29th of August, I don't know the age of all of them, but 2 of them were 1½ year old females. I can't remember when Myrina lost the last one, but it was the 3 week old baby. The last entry I've been able to find of Bati's lost rats is a single one on the 30th of August, that was so ill, that the vet had to put him down, he had nose bleed (not phorpyrin, but real blood).
2 days later Bati went to London, and I don't think she has lost any while she is away.
I don't know if this is important, but when Myrina handed over the rats, that Bati transported to me and when the illness broke out, both she and her family were ill with the flu. A few days after Bati lost the first one, she got ill too. So we have thought about the possibility of a streptococcus infection, but we don't know how that works.
I don't know if any of this helps.