Grave mites

Grave mites (Trixacarus caviae) are a common cause of sarcoptes rue in guinea pigs (see below guinea pig rue)

Trixacarus caviae are 100-200um large mites. The 3rd and 4th pair of legs do not protrude beyond the lateral edge of the body. The development via egg, larva (six-legged), proto- and tritonymph (eight-legged) to the imago takes 21 days. After copulation of adult mites, females lay eggs in the burrows. The animals usually show severe itching with constant scratching, alopecia, skin thickening, hyperkeratosis and scratch erosion.

In close contact with humans, the mites can transfer to the human skin. There, they lead to strongly itchy, not duct-like, but stitch-like, papular or papulo-vesicular skin reactions. The mites dig themselves into the stratum corneum in points, but do not develop any duct structures.
The predilection sites are the arms, neck and abdomen.

Since humans are a false host, the mites remain on the human skin only for a short time (maximum 6 days). Therefore, if there is no renewed skin contact with infected animals, the disease is self-limited.

An antiparasitic therapy is not necessary. A short-term therapy with a glucocorticoid externum is recommended.

1. Beck W (2017) Trixaxarus caviae pathogen of mange in guinea pigs and pseudoskabies in humans. Derm 23: 470-476