Mites and Lice in Guinea Pigs

By Gregory Rich, DVM; Laurie Hess, DVM; Rick Axelson, DVM

Mites are arachnid parasites and are related to ticks and spiders. Mites can cause serious skin problems for your guinea pig. The two common guinea pig fur mites are Trixacarus caviae (sarcoptic mange mite) and Chirodiscoides caviae.

Lice are small insect parasites. Lice are visible to the naked eye and are seen crawling along the hair shafts in affected guinea pigs. Lice lay eggs on the hairs of affected animals. These eggs are called nits. Lice are “species specific”, so they will not cause infections in humans or the family dog or cat. There are two common lice that may affect guinea pigs: Gliracola porcelli and Gyropus ovalisInfections with Gliracola are more common.

Your guinea pig may acquire these fur mites or lice from other infested guinea pigs that they come in contact with, or from previously contaminated bedding. Mites and lice can affect a guinea pig of any age or sex.

What kinds of problems can mites cause in my guinea pig?

Early in the infection, your guinea pig may not show any signs. Your pet may or may not be itchy. It all depends on the type of mite or lice and if your guinea pig is hypersensitive to bites from either parasite.

Chirodiscoides caviae mites may cause mild to no clinical signs and are generally not life-threatening.

Trixacarus caviae mites (sarcoptic mange mite) can cause extreme clinical signs because they cause extreme itchiness. These mites cause such itchiness that your guinea pig may even go into seizures and die. With sarcoptic mange mites, the following signs may occur:

  • Affected skin will get thick and sometimes yellowish and crusty.
  • There is generally hair loss in the affected area.
  • Secondary bacterial skin infection commonly occurs.
  • Your guinea pig may become debilitated, lethargic, depressed, and may lose weight.
  • Seizures are often noted when the itching becomes intense.

Guinea pigs with lice may show limited to no signs of itching or scratching. Live lice may be noted on close observation of the base of hair shafts. Nits look like tiny white to tan specs stuck to the sides of hair shafts.

How will my veterinarian diagnose mites in my guinea pig?

Your veterinarian should examine your guinea pig regularly (at least once a year) to identify mites as early as possible and provide treatment.

  • First, your veterinarian will examine your pet's hair and skin for evidence of mites, lice, and other external parasites. 
  • Trixacarus mites bury into the skin and are microscopic, so a skin scraping may be taken and examined under the microscope to provide an accurate diagnosis. (Photo at right shows a guinea pig with Trixacarus caviae infection; photo credit Gregory Rich, DVM.)
  • If your veterinarian sees evidence of skin disease, cultures for bacteria and fungus may be taken as well.
  • Your veterinarian also may run diagnostic tests to make sure the itching and scratching are not caused by other diseases.

How are guinea pigs with mites treated?

If your guinea pig is badly debilitated, your veterinarian may suggest hospitalization for supportive care to build up the animal's strength.

There are no specific drugs specifically formulated for managing mites or lice in guinea pigs, so it is likely your veterinarian will suggest an “off-label” use of products designed for dogs and cats. These may include topical cat medications such as Advantage®, Senergy®, Revolution®, or an injectable anti-parasitic medication. These drugs are safe in guinea pigs but should only be used under the guidance of a veterinarian familiar with guinea pigs. All medications require an accurate weight in grams to dose the medication safely.

Your veterinarian may also recommend topical flea powders, premise sprays, or even professional pest exterminators. Before considering any of these treatments, be sure to ask your veterinarian about using them safely.

"Be sure to clean and treat your home and other areas where the animal resides, plays, and visits."

Since adult mites and lice can survive off your guinea pig for short periods of time (e.g., in carpets, bedding, and other fabrics), be sure to clean and treat your home and other areas where the animal resides, plays, and visits. Mite or lice eggs or adults may have fallen off the animal in those areas. This treatment must be long enough to get the adult from the last mite egg that hatches. Your veterinarian can advise you about how to do this.

Certain products should never be used on guinea pigs, including mite collars, organophosphates, straight permethrin sprays, and permethrin spot-on treatments, as these may be toxic to your pet.

Should I be concerned about mites affecting my family?

Guinea pig mites do not like living on people, so most people living in a home with a mite-infected guinea pig do not develop infection. However, Trixacarus caviae mites are contagious to people, so if someone in your family is sensitive to mites, they may develop a mild and likely temporary dermatitis (skin infection) from encountering an infected guinea pig. Individuals living in a household with a mite-infected guinea pig and who develop skin problems should seek the advice of their physicians.

Lice are species-specific, so there is no danger to humans in the household or dogs and cats in the house.

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