I know there are some pretty experienced rat breeders here so I figured I'd ask before hitting the web...


As I have come to understand it, pretty much every rat carries Mycoplasma bacteria in the respiratory tract from birth due to a transfer in the birth canal. I'm not sure if this is directly related or not, but it also seems that almost every rat sneezes to some degree. I think it must be some combination of allergies, sensitivity to dust, and Mycoplasma bacteria that causes them to sneeze a lot more than other animals. Some go into respiratory distress more easily than others and some live healthy lives. The ones in the middle suffer from long term lung scarring that eventually shortens their life.

I've been observing my rats since I got them. There are a couple that sneeze pretty regularly but are not escalating or getting 'better' and there are a couple that don't sneeze at all, despite having 24/7 exposure to the animals that do sneeze. I had one go into distress and die when I first started the colony, but the other animals that were housed with it have stayed the same or even improved since the death.

Question 1: Can you selectively breed for improved respiratory health? What would you actually be controlling there... are specific allergies genetic, like to aspen? Strength of resistance to Mycoplasma bacteria in the respiratory tract? Sensitivity to dust IE overall respiratory heartiness?

Question 2: Short of keeping them on expensive substrate or trying to litter box train them and keep them on fleece, is there anything I can do to reduce the sneezes... it's quite distressing sometimes as I have grown fond of a couple of the little ratties. My sister gave me Baytril and Doxycycline but I am hesitant to medicate when the sneezing is the only symptom that any of them have shown.

I do keep the room as humid as I can (50-65%) to reduce the respiratory stress.

Thanks