FC‐45 Mites as newly emerging disease pathogens in rodents and human beings

Abstract

Different mite species generally found on animals may temporarily also infest humans. Consequently, these arthropods may be responsible for pruritic skin reactions that are often misdiagnosed. Mite dermatitis caused by the tropical rat mite Ornithonyssus bacoti occurs in several small mammals and rodents under tropical and temperate climatic conditions. According to various observations in Germany, O. bacoti appears in wild rodents more frequently than previously thought. In most cases, symptoms of mites are recognized only when they attack humans, but the diagnosis of rat mite dermatitis requires identification of the parasite, which is more likely to be found in the environment than on the hosts’ skin itself. Here, five different outbreaks from Bavaria are reported. A clinical example is the case of a 23‐year‐old medical student and several other residents inhabiting a rat‐ and mouse‐infested house in Munich. The arthropods originally came from an Italian restaurant and surrounding facilities. Mites were found in large numbers in the students’ flat. The patient was suffering from severe itching and papular urticaria. He consulted a dermatology clinic complaining of a pruritic dermatitis of 2‐weeks duration. Dermatitis was misdiagnosed as allergy and treatment with an anti‐inflammatory agent was unsuccessful. Eradication of rodents and treatment of the house with a pyrethroid were performed to prevent reinfestation. Ornithonyssus bacoti is a periodic haematophageous parasite and spends a relatively short time on the host. Causal therapy with antiparasitic agents on human patients is not necessary. If indicated, treatment should be symptomatic. Funding: Self‐funded.