Scrub Typhus: Vector Surveillance and its Control

Abstract

Scrub Typhus is an important emerging vector borne disease being reported now in many parts of the country. This is also known as Chigger Borne Typhus or Tsutsugamushi Fever. Scrub Typhus is caused by bacteria called Orientia tsutsugamushi and is transmitted to people through bites of infected chiggers (larval mites). Recently, it has been reported in the state of Mizoram on wide scale. However, the states of Rajasthan, Jammu & Kashmir, Vellore, Sikkim, Nagaland & Manipur, Mizoram, Tamil Nadu, Maharashtra, Kerala, Himachal Pradesh and Meghalaya have also reported cases of scrub typhus. Scrub typhus is an infectious disease that is transmitted to humans from field mice and rats through the bite of mites that live on the animals. This is a rural disease occurring preferentially in spring and in autumn. Scrub Typhus is an occupational health concern for farmers, park rangers, military personnel, geologist, miners as well as oil palm workers. The life cycle of the trombiculid mite is very complex. The duration of mites’ life cycle depends on species and environment, but normally last 2 to 12 months. Trombiculis mites go through a life cycle of eggs, larva, nymph and adult. Mites have a very patchy distribution over small areas because of their special requirements. The nymphs and adults need certain soil conditions for their survival and development while the larvae require host animals, such as wild rats, other small rodents and birds. Suitable habitats are found in grassy fields, shrubby areas, forests, abandoned rice fields and cleared forests. An attempt has been made to describe the tools for mite surveillance and the possible methods of vector control.