The Risk of Borrelia burgdorferi Infection Is Not Increased in Pet Owners

To the Editor. —  The possibility that cat owners may be at risk of infection by the spirochete Borrelia burgdorferi, the etiologic agent of Lyme disease, has been suggested by Steere and coworkers¹ in their early studies on the disease. They have reported that significantly more patients are cat owners than unaffected neighbors.¹ More recently, the association between dog ownership and risk of human Lyme disease has been denied by Eng and coworkers² in a small pilot study. Although pets may represent a spirochete reservoir,³ it is unlikely that human beings can be infected directly by them. However, in areas of endemic Lyme disease, both adult and nymphal ticks, carried into the household by dogs and cats, may infest humans.⁴

Study. —  We have evaluated the relationship between pet ownership and B burgdorferi infection in 238 subjects living in north Italy, in a rural area endemic