Prevalence and zoonotic risk of tropical rat mite (Ornithonyssus bacoti) in exotic companion mammals in southern Italy.

BACKGROUND: Exotic companion mammals are popular pets worldwide. They are a potential source of zoonotic infections transmissible to their owners. HYPOTHESIS/OBJECTIVES: To determine the prevalence and zoonotic risks of tropical rat mite (Ornithonyssus bacoti) in exotic companion mammals in Italy. ANIMALS: The records of 782 exotic pet mammals seen in multiple veterinary clinics (n = 20), pet shops (n = 10) and private breeders (n = 2) around Naples (Italy) were searched. METHODS AND RESULTS: The isolation of O. bacoti was the only inclusion criterion. Relative (in the subgroups) and absolute prevalence (in the entire population sampled) of clinical signs in pets and owners were calculated. The prevalence of clinical signs in pets and their owners was also calculated based on their housing (pet shops versus private housing) using Fisher's exact test. A P-value < 0.05 was considered significant. Seventy seven records (9.8%) of animals infested were identified. Of those, 33.8% (26 of 77) were hamsters, 25.9% (20 of 77) gerbils, 11.7% (nine of 77) guinea pigs, 7.8% (six of 77) rabbits, 7.8% (six of 77) degus, 5.2% (four of 77) kangaroo mice, 2.6% (two of 77) hedgehogs, 2.6% (two of 77) squirrels and 2.6% (two of 77) were sugar gliders. The frequency of owners affected by the rat mite dermatitis was very high in gerbils (20 of 20), hamsters (21 of 26) and guinea pigs (seven of nine). CONCLUSIONS AND CLINICAL IMPORTANCE: The results of the present survey indicate that exotic pet mammals may serve as an active reservoir for O. bacoti infestation. The results of this study also suggest a lack of species specificity for O. bacoti when favourable conditions are present (overcrowding).