Identification and Treatment of a Storage Mite Infestation in Rats (Rattus norvegicus)

Storage mites are environmental pests that commonly invade hay, grain, or stored food. While generally regarded as harmless, they have been reported to elicit allergic reactions in both humans and animals. Although storage mites are considered environmental contaminants, this case report describes an infestation of storage mites on rats (Rattus norvegicus) in a laboratory animal facility. Despite traditional diagnostic methods initially revealing negative results, mites were consistently observed under repeated direct microscopic examinations of the animals. Eventual positive pelage tapes confirmed the presence of the ectoparasites and identified them as mold or cheese mites (Tyrophagus brevicrinatus or Tyrophagus putrescentiae) via Sanger sequencing. To our knowledge, this report is the first to implement permethrin-soaked cotton balls for the successful treatment of mold mites in an entire rat colony. Furthermore, considering the initial negative diagnostic results, this report emphasizes the pelage tape method as highly susceptible to false negatives.