Dengue fever is threatening to become established in Easter Island, leading to fears the disease could be carried to mainland Chile, where tropical infections are unusual.
Scientists think the disease could have been carried to Easter Island in recent years by tourists from French Polynesia or Brazil.
The newspaper La Nacion reports flies which destroy vegetation are also threatening to become established in the island, also known as Rapa Nui.
The mayor, Petero Edmonds Paoa, is concerned these flies, originally from the United States and Hawaii, could reach mainland Chile and destroy agricultural areas in the central zone.
Mr Paoa also says growing tourism on Easter Island has meant more rubbish and tensions over electricity distribution.