Scrub Typhus : Variations in Clinical Symptoms and Strains

The object of this short paper is to point out certain symptoms peculiar to certain places and present laboratory evidence of the variation of the rickettsial strains which one considers to be the cause of difference in the severity and symptoms of the disease. The entry of the forces in large numbers in the eastern zone of war not only brought to light the presence of scrub typhus in unrecorded areas, but also interesting information about its clinical variations in different countries and in different parts of the same country. The local population in endemic areas generally acquires immunity by mild attacks during childhood and does not provide evidence of the disease. It is also well known that the disease in children is mild and has low mortality rate and reverse is the case in older people. Lewthwaite and Savoor (1940) in Malaya have recorded two deaths out of twenty-five in patients under eighteen and 4 out of 20 in those over forty years of age. The experience in this war was that the fatalities were higher in the age group thirty-five years and over as compared to the age group below it. The information obtained during this war is important, for it is based on the incidence of the disease in a non-immune population more or less of the same age group in different areas.