Anaplasma phagocytophilum (Ap) is the agent of human granulocytic anaplasmosis, an emerging infectious disease and a common tick-borne disease in the US and Europe. Ap is transmitted by the blacklegged tick (Ixodes scapularis), and small and medium-sized mammals are the typical reservoir species. Birds are also exposed to Ap and it has been hypothesized that birds aid in the dispersal of the pathogen and vector during migration. We exposed wild-caught gray catbirds (Dumetella carolinensis) and American robins (Turdus migratorius; n=10/species) to Ap-infected I. scapularis nymphs (day 0) and observed changes to temperature and mass during the exposure period. Four BALB/c mice (Mus musculus) served as controls throughout the experiment. Uninfected larvae were attached to each bird and mouse on days 7, 14, 42 and 77 to assess transmission rate and duration, blood samples were taken on days 3, 5, 7, 9, 14 for bacteremia and days 14 and 28 for serology. None of the birds were found to be bacteremic, transmit at appreciable levels, nor develop Ap-specific antibodies. All mice, however, were bacteremic on day 7 and transmitted through day 42 and developed Ap-specific antibodies. Exposed catbirds may have developed a fever due to exposure, though no other signs of disease were detected. Our results show that catbirds and robins are unlikely to play a significant role in the maintenance and transmission of Ap.
Read
