Hello and thanks for researching this important question...I am so sorry that you are having this difficult experience with your tiny pets.
There are a number of viral illnesses that can cause high fever and subsequent neurological damage in ferrets. These viruses are unfortunately common in breeder's facilities and pet stores. Some viruses reproduce and express themselves quickly in a sudden fever, but some can incubate and cause damage over a great deal of time. Other illnesses that cause fevers in adult ferrets (intestinal blockage, for instance) have additional symptoms.
Here are some links to things to consider:
http://www.miamiferret.org/fhc/aleutian.htm This illness can take up to 2 years to fully express itself, and so new pets can seem completely normal indefinitely...unfortunately, fatalities are to be expected in the majority of cases. High globulin levels are pretty much diagnostic for Aleutian Ferret Fever. Paralysis starts from the back-end-forward.
http://www.veterinarypartner.com/Content.plx?P=A&A=674&S=1&SourceID=43
http://www.cvm.uiuc.edu/ope/enotes/showarticle.cfm?id=181
http://www.texasferret.org/news/200208.shtml
I am going to also include these links to sites that have vet-search indexes...if you are to succeed with a viral condition, support is best found earlier rather than later:
http://www.quincyweb.net/quincy/vet.html http://www.ferret-universe.com/vets/vetlist.asp http://www.ferretclub.com/vets/ http://www.rabbitrodentferret.org/rabbitrodentferret.org/vets.asp?animal=3
In the meantime, do continue nursing this little one, and be sure that she can urinate and pass stool. Since her appetite is poor, you can offer jars of baby food meats and fruits to supplement regular food (when using baby food meats, make sure that there is NO garlic or onions listed on the ingredient panel).
Provide a thick plastic bottle filled with warm water (or similar, hard-shell heat source) in case she has trouble keeping her body temperature regulated. Ferrets should always be able to roll away from heat sources to avoid burns or overheating, so don't close her into a very small container with heat bottles.
If you need additional support at this time, please click "Reply", otherwise I thank you in advance for your "Accept" and will hold a Good Thought for you all.
Retired Veterinary Technician
Dog, Guinea Pig, Hamster, Gerbil breeder / Reptile Keeper / Bunny-Ferret-Exotic Specialist