[Occurrence of a house-infesting tropical rat mite (Ornithonyssus bacoti) on murides and human beings in Munich: 3 case reports].

In Germany there is little information available about the distribution of the Tropical rat mite (Ornithonyssus bacoti) in rodents. A few case reports show that this hematophagous mite species may also cause dermatitis in man. All developmental stages are exclusively blood feeders. Three children (4, 11 and 15 years old) of a family, a 23-year-old medical student and a 17-year-old dental technician were attacked by the tropical rat mite. Prior to the consultation of our institute, the patients' conditions had been diagnosed as allergic dermatitis and treated by several antiphlogistic agents, however without success. The conclusive diagnosis of tropical rat mite dermatitis, was based on the identification of the arthropod O. bacoti in the flats of the patients (husbandry of gerbils, etc.) and in the dental practice. The diagnosis of rat mite dermatitis requires the detection of the parasite, which is more likely to be found in the environment of its host than on the host's skin itself.