Mites: Ecto-Parasites


Mites are 8-legged parasites (arachnids). They are the same parasites that cause sarcoptic mange in cats and dogs, which can be quite difficult, although not impossible, to treat. They are ecto-parasites, an external parasite which all living creatures are infested with.


You need to know the life cycle of the parasite in order to be able to get on top of the problem. First you have the egg. It then develops into larvae, then into an adult. They have to be killed in the adult or larvae stage. Most of the insecticides used are a 3-4 week course.


There are in fact three types of mites, the fur mite (Radfordia ensifera), the burrowing mite (Notoedres muris) and the bloodsucking mite (ornithonyssus bacoti).


The fur mite doesn't seem to cause many problems unless there is a heavy infestation, or if the rats immune system is compromised, as in old or debilitated, or under-nourished and stressed. Clinical signs include lesions, intense itching (puritis), alopecia and skin ulcerations. Treatment is Ivormectin orally, injected or topical solution. We recommend topical application, in which a small amount is dropped onto the scruff of the neck. Dosage is one drop a week for three weeks.


The burrowing mite is the ear mange mite, which attack the external ear, tail and nose. Clinical signs include intense scratching and alopecia, especially over the dorsum. Crusty sores will occur behind the ears and over the face. The rat will make it worse by 
scratching, causing inflammation and scabs to form. It is highly contagious. Treatment again is with Ivormectin, orally or injected, or by topical solution. Affected rats can also be dipped in a solution containing amitraz - it should be used for at least six weeks.


The bloodsucking mite is the most dangerous. They are related to ticks. The mite will feed on the rats blood and when it has had enough, it will drop off and hide in crevices and cracks, particularly in wood. It is a good idea to remove all wooden materials, as they are impossible to clean. The mite can actually drain so much blood from the rat that it becomes anaemic. You can visibly see the mite hiding in and around the rats bedding. It is 
extremely highly contagious and will also attack humans. Treatment is orally, topically or injected Ivormectin.