after the abolishment of slavery in 1850, brazil opened its doors to european, asian and middle-eastern immigrants in order to satisfy labor demand - work and prices were not sufficient in keeping the viability of the plantations, as a result many closed and resulted the the economic collapse of many of the towns in the greater region.

in the eighteen hundreds, to handle the influx of immigrant arrivals, two hospitals were built on the island as quarantine stations - epidemics of cholera led brazilian emperor dom pedro ii to build quarantine hospitals in 1886, as well as an aqueduct for clean water supplies three years later.

thus, part of the hospitals became leper colonies and, at the turn of the twentieth century, a prison was built in dois rios, on the island's south side - the ruins of these historical structures are still visible today from praia preta (black beach).