Ectoparasitic Infestation of Mites in Rats
Mite infestation is very common in rats. Under normal conditions mites are present in small numbers and do not bother their host. However, they can become an issue when their numbers increase. This typically happens when a rat is stressed, has decreased immunity due to other illnesses, and/or is unable to keep the numbers reduced through normal grooming.
Fortunately, most skin mites are not bloodsuckers and often produce no visible signs. For this reason, the presence of mites, and even an infestation of mites is not really a serious health problem.
Symptoms and Types
Symptoms of excessive mites are generally presented as inflammation of the skin and an increased need to scratch. In rare cases, the irritation and itching can be severe enough that a rat will scratch its skin until there is an abrasion, creating an environment in which a skin infection can occur. Mites appear as white specks under the fur, near the follicle of the hair on the skin -- often on the shoulders, neck, and face of affected rats.
Mites are normally present in small numbers and do not cause any problems, so the mere presence of mites should be of no concern. It becomes a concern when a rat is under stress or is suffering from a diseased condition that lowers its immune system, since it is the immune system -- along with normal self grooming -- that keeps the number of mites within a normal range. When the immune system is low, and/or a rat is weakened from another illness and is unable to self groom as normal, the population of mites is able to grow to a level that can cause some complications of the skin. It is at this point that action needs to be taken to treat the infestation before it leads to further problems.
Your veterinarian will perform a thorough exam on your rat, taking into account the background history and onset of symptoms that you have described for your veterinarian. The clinical symptoms observed and described by you will help your doctor determine how severe the infestation is. Using a magnifying tool, your veterinarian will be able to diagnose mite infestation through a visual inspection of your rat's skin and fur, but it will also be important to differentiate mite infestation from an infestation of other ectoparasites that may be inhabiting your rat's skin -- some of which can be harmful to your rat's health.
A skin scraping may be necessary for differentiating the type of mite that is present. The presence of mites alone is not cause for concern, but a large number or mites and mite eggs on your rat's skin will be a reason to diagnose an infestation and prescribe treatment.