In Chatham County, North Carolina, the discovery of a rare tick-borne bacteria in local dogs has opened a quiet but urgent question about the boundaries between animal and human health. Ticks, indifferent to species, carry pathogens across the invisible lines we draw between the wild and the domestic — and what circulates in a dog today may reach a person tomorrow. Health officials are now tracing the contours of an ecological reality that was present long before it was named, asking how far it extends and what it means for the people who share this landscape.