Lice and Mites in Guinea Pigs: Spotting and Treating an Infestation

In this guide

Skin parasites are common in pet guinea pigs and can range from a mild, manageable nuisance to a severe, distressing condition depending on which parasite is involved. Knowing the difference helps you react with the right level of urgency.

Lice versus mites

Guinea pig lice, sometimes called running lice, live on the surface of the skin and are usually less severe than mites, though still uncomfortable for the animal. Mange mites, particularly the species Trixacarus caviae, burrow into the skin and can cause intense itching severe enough to look like a seizure. Both are typically diagnosed by a vet based on symptoms and sometimes a skin scraping, since mites in particular can be difficult to find directly.

Signs of an infestation

• Excessive scratching, more than the usual occasional itch
• Patchy hair loss, particularly around the shoulders, neck, and back
• Flaky, crusty, or scabbed skin
• Visible small white specks (lice or eggs) in the fur when parted
• With mite infestations specifically, sudden, violent scratching episodes that can look like a seizure or fit

Why infestations flare up

Guinea pigs can carry low-level mites or lice without symptoms for a long time. Stress, such as a new home, pregnancy, illness, or old age, can weaken the immune response enough for a dormant infestation to flare into visible symptoms. This means a guinea pig can develop symptoms even without any recent contact with another animal.

Treatment

Ivermectin, given by a vet either as drops or an injection, is the standard treatment for both lice and mange mites, usually repeated after seven to ten days to catch newly hatched parasites. Newer spot-on treatments are also used in some cases. Because ivermectin dosing must be calculated precisely by body weight, this is not something to attempt with over-the-counter livestock products at home. All guinea pigs living together should be treated at the same time, even if only one shows symptoms, since the others may be carrying a dormant infestation.

Cleaning and preventing reinfestation

• Wash all bedding, fleece liners, and cage accessories thoroughly
• Deep clean the cage itself, including corners and any wooden hideouts, which can harbour eggs
• Quarantine any newly adopted guinea pig for two to three weeks before introducing it to existing pets
• Avoid contact with unfamiliar guinea pigs at pet shops or gatherings without a subsequent quarantine period

A note on humans

Guinea pig mites cannot complete their life cycle on human skin, but Trixacarus caviae can occasionally cause a short-lived, itchy rash on people who have handled an infested guinea pig. Washing hands after handling and treating the infestation promptly resolves this quickly.

With correct veterinary treatment, most lice and mite infestations clear up fully within a few weeks. The key is catching the early scratching and hair loss before it progresses to the more severe, distressing stage.

Part 4

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