Small Mammals Q&A 08

This question was provided by Manson Publishing as part of the OVAL Project. See more

An adult male rat in a pet shop has what appears to be blood coming from his eyes. Two other adult males in the same cage are sneezing and sitting hunched in the corner with rough appearing hair coats. There is a total of six large rats in the 75- litre glass tank with fresh pine shavings for bedding.

Question	Answer		Article
What is the red staining around the rat’s eyes?	Porphyria. It occurs when the rat’s Harderian gland becomes inflamed and secretes porphyrin-pigmented tears.		[[|Link to Article]]
What is the likely etiology for the rats’ condition?	A common viral agent, SDAV, is frequently responsible for this highly contagious condition, which is called sialodacryoadenitis. SDAV is an RNA virus that replicates in the epithelial cytoplasm of the respiratory tract and travels along the ducts into the glands of the head. It has a special predilection for the Harderian gland. Younger animals are more severely affected and the virus usually resolves in a week. Other causes of poryphyria include infections caused by Sendai virus, P3 virus and corona virus. Organisms such as Pasteurella pneumotropica and Mycoplasma pulmonis can act as common bacterial secondary invaders. It is advisable to treat most cases with antibiotics following appropriate cultures and sensitivities. In some cases the porphyria persists due to permanent damage to the Harderian gland.		[[|Link to Article]]
What predisposing factors are associated with rat respiratory diseases?	Bedding, such as cedar or pine shavings or cypress mulch, can predispose rats to respiratory disease. They contain the volatile oil thujone. Thujone is a respiratory irritant and may be tumorogenic. Thujone can cause convulsions and cortical brain lesions if there is prolonged exposure. In addition, volatile oils are strongly scented and may mask feces and urine odors in the cage. In an aquarium or other enclosed environment, ammonia and other toxic gases, which are heavier than oxygen, sink to the floor where the animals are living. This disastrous situation may cause respiratory conditions to deteriorate rapidly. Hardwood shavings or pellets are a much better choice for cage litter, with no sanitary compromise. Other predisposing factors include overcrowding, high environmental temperatures and inadequate nutrition.		[[|Link to Article]]