Risk of tick-borne pathogen spillover into urban yards in New York City

BACKGROUND: The incidence of tick-borne disease has increased dramatically in recent decades, with urban areas increasingly recognised as high risk for exposure to infected ticks. Green spaces may play a key role in facilitating the invasion of ticks, hosts and pathogens into residential areas, particularly where they connect residential yards with larger natural areas (e.g. parks). However the factors mediating tick distribution across heterogeneous urban landscapes remains poorly characterized. METHODS: Using generalized linear models in a multimodel inference framework with model averaging, we determined the residential yard- and local landscape-level features associated with the presence of three tick species of current and growing public health importance in residential yards across Staten Island, NY. RESULTS: We found that the amount and configuration of canopy cover immediately surrounding residential yards strongly predicted the presence of Ixodes scapularis and Amblyomma americanum , but not that of Haemaphysalis longicornis . Within yards, we found limited evidence for a protective effect of fencing against I. scapularis and A. americanum, but not H. longicornis . For all species, the presence of log and brush piles strongly increased the odds of finding ticks in yards. CONCLUSIONS: We highlight considerable risk of tick exposure in residential yards in Staten Island and identify both yard- and landscape-level features associated with their distribution. In particular, the significance of log and brush piles for all three species supports recommendations for yard management as a means of reducing contact with ticks.