It's not just "dust," birdbrain. It's dust loaded with spores from disturbed soil, such as the alfalfa fields surrounding the prison. You don't find it in Dubai. It's largely confined to the U.S. Southwest. Minorities have less genetic resistance to the disease, which is transmitted through the systems of aphids, so Hawai'ians, with 40% of exported prisoners being natives indigenous to the Islands, are particularly susceptible.