my pet rat died

Question
I just had one of my pet rats die. She was a great friendly pet . We have another one and I don't want her to go as well. She looked like she was gettin ill over the past couple of weeks . She had tiny tufts of hair missing all over his body and she wasn't eating well.  she sneezed occasionally but not alot Last 2 nights she hardly moved . Then she seemed to have a couple of spasms . When I tried to lift her out to make her more comfortable  she was biting on to the cage . It took me several goes to get her out. I put her on a towel but she died no t long after . Can you tell me what it was please I don't want my other one to go the same way . She does look very healthy tho at this point .

Answer
 It really is impossible to tell what caused your rat's death without a necropsy.  If she had missing hair it could have been parasites, though those usually don't cause death.  Since you noticed she was getting ill it was probably something inside her such as an internal tumor, respiratory infection, heart problem, etc.

 If you still have her body and are interested in exactly what caused her death you can take her to a vet for a necropsy.  The cost varies from vet to vet but it is generally around $30 to $50.  The vet will take a look inside her to see if there is anything immediately obvious and if there is nothing obvious you have the option to send tissue samples away for further analysis.  The vet can then stitch her back up and you can bury her at home.

 I'm very sorry to hear about your rat and I hope your other one is okay!  Good luck!