|This article is from the Fall 1998
AFRMA Rat & Mouse Tales news-magazine.
Q When rats abort or absorb the
litter at 2 weeks gestation, is this caused by a bacteria,
virus, or something else?
A The abortions could be caused by
any number of things including bacteria, fungi, microscopic
parasites, viruses, nutritional problems, and environmental
What do the dead pups look like? This is key. If they are
very smelly and look rotten, then it is probably a bacterial
infection. If they look pretty normal, just immature, than
virus, nutritional, or environmental factors would be more
likely than bacteria.
How are the moms? Do they have a bad smelling vaginal
discharge? If they do, what color is it?
What I would suggest is that if these females are rebred,
that the following be implemented:
What is really needed for viruses is to have a blood sample
tested from the mom. Most veterinarians cannot get a sample
from the tail vein of a rat. It only takes 300 microliters
of serum (½–1 cc whole blood) to do a full viral
- Make sure that the environment is as stress
free as possible, i.e., no drafts, but good ventilation.
Keep the cages clean with fresh bedding. What type of
bedding is being used? Feed good quality rodent blocks and
no fresh food (avoid any potential food born bacterial
problems). Provide clean fresh water (not tap, get bottled)
every 3 days if using bottles. Keep the environmental noises
to a minimum.
- Once they look pregnant, around day 15–17
post breeding, do not disturb them other than to a provide
food and water. I would change the cage one more time, with
lots of bedding and nesting material and then leave them
alone except for food and water until they deliver.
- If they abort, immediately put all the dead
pups in a clean plastic container and try not to touch them
with your hands. I would use gloves or clean tongs. This
might sound strange, but you do not want to contaminate them
with the normal bacteria on your skin. I would take them to
the vet and have some of them cultured for bacteria
(external, placental, and liver and lung if the vet can find
them) and have some or all the bodies submitted for
I would also do a vaginal smear to look for bacteria,
microscopic parasites, and bacterial culture on the mom.
Getting some of the small placentas cultured and submitted
for histopathology is also very important. In other animal
species, we can frequently diagnose the most likely cause by
looking at the placenta.
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