American Fancy Rat & Mouse Association

This article is from the WSSF 2009 AFRMA Rat & Mouse Tales news-magazine.


Rat With Mycoplasma or Allergies

By Carmen Jane Booth, D.V.M., Ph.D.

Tracy Petrowski, e-mail
Q I recently purchased the magazine Critters, and I saw your information. I am a concerned rat parent. My rat Cindy has been sneezing off and on since I first got her, almost a year and half ago. I first tried giving her Tetracyline. It didn’t work. She was still sneezing. I then took her to the vet several times. The vet I took Cindy to is recommended by many and is listed in the Critters magazine. He checked her weight, heart and breathing. The vet said she was very healthy. She was eating and drinking. The vet said he didn’t hear her sneeze. He concluded that she may have an allergy, so he prescribed an allergy medicine called Prednisolone. I never heard of a rat with allergies. I gave her this medicine, and she seemed to be sneezing less. I still couldn’t believe that my rat had allergies. But why was she sneezing less with this medicine? When I stopped the medicine, she was sneezing again and also has red porphyrin coming out of her nose. In addition, prior to giving her this and currently, her bowel movement was very soft and light in color. In addition, she was drinking a lot of water. I thought she was drinking too much water.

I had read about mycoplasma, so I took her again to the vet. The vet checked her again and said she seemed healthy. I told him I thought she may have mycoplasma. He said well just in case, he’ll give her a medicine for mycoplasma. He prescribed Tylan. He said to give her 1/8 teaspoon in 8 ounces of water. I gave her this medicine, but she was still sneezing. I then took her back to the vet, again. He said she looked fine and couldn’t find anything wrong with her. He said that she may have a fungus in her nose or food allergies to wheat products. He then prescribed a cat food by Hill’s Prescription Diet called Feline Z/D Low Allergen. She’s been on this ever since, but she still sneezes on and off. I still give her treats; doggy bones, monkey biscuits (wheat products) because a rat needs to eat these as a daily requirement.

Her nose is always wet with red porphyrin stains. She chain sneezes, but then won’t sneeze when she is sleeping or while I’m petting her. She is still eating and drinking well. She doesn’t look horrible, but I’m still concerned. What do you think is wrong with her?

Answer by Karen Robbins
A It sounds like she was sick when you got her. If you got her from a pet shop, then more than likely she was sick when you bought her. Most vets will prescribe Baytril or Doxycycline or a combo of the two or other type of drug for respiratory problems. Tetracycline and Tylan are more for minor respiratory problems. You could try taking her back to the vet and ask for the stronger antibiotics (Baytril/Doxycycline or another drug) and see if that will help. Since she has been sick for so long, nothing may help at this point but you should still try.

Yes, rats can have allergies. If you have her on pine or cedar, you need to get her off of that kind of bedding and change over to to a paper bedding such as CareFRESH™ or aspen shavings.

In the future, you may want to get your rats from a reputable breeder rather than from a pet shop.

Answer by Carmen Jane Booth, D.V.M. Ph.D.
A The most common cause of sneezing in pet rats from pet stores is the bacteria, Mycoplasma pulmonis. Baytril is often the most successful medication in calming things down. However, there is not a long term cure for this bacteria and there are reports of antibiotic resistance of Mycoplasma to various antibiotics including Baytril. In general, the symptoms can be lessened by keeping the cage clean, using a non pine or cedar bedding, and keeping the cage in a draft-free location. A dirty cage causes a build up of ammonia from breakdown of urea by bacteria. Ammonia is very irritating to the respiratory tract. Drafts and large temperature changes also exacerbate the damage caused by Mycoplasma to the respiratory tract.

Regarding Allergies
Although not impossible, they are less than likely in rodents. Most skin problems are due to mites or irritating bedding, and respiratory problems are frequently due to Mycoplasma. Allergy testing is not routinely done in rodents. There are no published reports on rodents with inhalant (pollen) allergies. Rats and mice have their own unique diseases and therapy separate from that of dogs and cats. Many veterinary practitioners have not had sufficient education in rats and mice. Prednisilone is an anti-inflammatory steroid medication that calms down the inflammatory response. It would not be my choice to give this to a rat with Mycoplasma. There are well-known side effects of giving this type of medication to an animal, increased appetite (polyphagia), increased water consumption (polydypsia), and increased urination (polyuria). I use this medication in dogs and cats, but only under very selected circumstances in rodents. *

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Updated March 19, 2014