The Geographical and Economical Impact of Scrub Typus, the Fastest-growing Vector-borne Disease in Korea

Scrub typus, or Tsutsugamushi disease is a vector transmitted infectious and febrile illness caused by "Orientia tsutsugamushi" bacteria. It is transmitted to humans through larvae bites of different species of trombiculid mites. The habitat of mites is located in low trees and bushes. However this vector can live in many different areas even in sandy and mountain desert [1]. In 1985, infected people appeared again [2]. Since then Scrub typhus incidences have been reported every year. Now it is considered as one of the most prevalent diseases affecting humans Korea especially in the southwestern provinces of the country [3]. Usually, the larvae of mites feed on wild rats and the human gets infected accidentally in a zone of infected mites. The chance of outbreak of this disease depends on the number of contacts between the human and the mites. Hence the habitats of mites and the human activities are the key factors in the Scrub typus prevalence. Human activities include war, farming, camping, urbanization and so on. A study on the epidemiological characteristic of this disease in Korea supports this general notion [4]. Chigger population densities were great in areas with high relative humidity, low temperature, low incident sunlight and a dense substrate vegetative canopy [5]. The relationship between human incidence of scrub typhus and climate should largely reflect the responses of chiggers to the environment [6]. The occurrence of scrub typhus is also related to land uses such as urbanization and developing cornfield and bio-fuel productions and oil palms [7]. The replacement of natural forests with plantations at forest fringe facilitated the establishment of the disease, providing the best habitats for the mite [8]. Malaysia has seen an