Invasive species in Hawaii and health-related problems. The introduction of mosquitoes to Hawaii has resulted in the spread of avian malaria, and increases the risk of dengue and west Nile virus (not known to be in Hawaii yet). Other native species can be affected by invasive species diseases as well, such as the once-dominant koa tree being killed by koa wilt, which is believed to have been brought into Hawaii on an ornamental acacia plant, and the 'ohi'a tree, now being affected by Rapid Ohia Death. Invasive predators can severely reduce the population sizes of native species, or even drive them extinct, because native
Acacia koaia It can be seen on ranch land in North Kohala, and at a small fenced exclosure outside of Waimea known as the "koaia" sanctuary. "Koaia" is one of the species being used to revegetate the island of Kahoolawe, which lost most of its plant life to overgrazing and ordnance testing. Native Hawaiians ground "koaia" leaves and bark with "auaukoi" ("Senna occidentalis") and "kikānia pipili" ("Desmodium sandwicense") stalks. The mixture was then hydrated and used in a steam bath to treat diseased skin. The wood of "koaia" is harder and more dense than that of "koa". It was used to make