Scrub Typhus, also known as Tsutsugamushi Disease, is caused by Orienta tsutsugamushi bacteria. It is a zoonosis (an animal disease that can spread to humans) primarily affecting rodents, rabbits, and marsupials. This rickettsial infection is transmitted to humans through the bite of infected Leptotombidium mite larvae (chiggers). The mites are found in grasslands, forests, bush areas, wood piles, gardens, and beaches. Scrub Typhus can also be transmitted through unscreened blood transfusions and unhygienic needles. It does not spread from person to person.
The infection is endemic in Central Asia, southeast Asia, and northern Australia. Travellers undertaking outdoor activities such as visiting farms, camping, backpacking, hunting, archeological digs, or participating in ecotourism are at risk of getting bitten by chiggers. Scrub Typhus is an occupational health concern for farmers, park rangers, military personnel, geologist, miners, as well as oil palm workers. The presence of Scrub Typhus is related to increasing deforestation and urbanization. Scrub Typhus typically occurs during the rainy season, but can be present throughout the year.
Usually symptoms appear 6 to 20 days after exposure to the bacteria and include fever, headache, chills, sweating, muscle pain, eye infection, skin rash, and lymph node swelling. Often the bite area becomes red and a black scab, also known as an ‘eschar’, forms at the center. If untreated, the infection can progress to more severe symptoms including pneumonia, jaundice, hemorrhaging, multi-organ failure, and paralysis which can lead to death. Treatment includes a course of antibiotics and supportive care of symptoms.
Travellers who engage in hiking, camping, or similar outdoor activities in endemic regions should take measures to prevent mite bites. There is no vaccine or preventive medication against Scrub Typhus.
Scrub Typhus images, life cycle, and distribution maps:
Information last updated: December 10, 2019