The Diagnosis of Schistosomiasis Japonica

I. The Symptoms, Signs and Physical Findings Characteristic of Schistosomiasis Japonica at Different Stages in the Development of the Disease

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  • Commission on Schistosomiasis, Commission on Tropical Diseases, Army Epidemiological Board, Preventive Medicine Service, Office of the Surgeon General, Washington 25, D. C.


Schistosomiasis japonica is a disease which has been known clinically for a century and its etiology has been understood for nearly half a century. Its present importance has resulted from exposure of several hundred American and Australian troops on Leyte, Philippine Islands from October 20, 1944 through the winter and early spring of 1945.

Three stages of the disease are recognized, incubation, acute and chronic. There has been a paucity of observations on patients during the incubation period because in native populations in endemic areas the infected individuals seldom see physicians until the disease is well advanced. Each of the three stages is considered; native and military case histories are utilized to provide a relatively full picture of the clinical progress of the disease from the time of exposure until the late chronic condition has been attained. A special report is included on this infection in a family group of eight, from a newly discovered endemic focus on Mindanao, P. I.

The differential diagnosis of schistosomiasis japonica is discussed for each of its three stages of development. While there are certain relatively characteristic symptoms, signs and physical findings at each stage of the disease, it is frequently hazardous to depend on these findings alone. Recovery of the eggs of the etiological agent, Schistosoma japonicum, constitutes the only method known of specific diagnosis. Since the eggs are not deposited until the worms mature, only tentative diagnosis can be made during the incubation period. They are easily recovered in moderate to heavy infections during the acute stage, but as the chronic stage progresses they are discharged into the lumen of the bowel in increasingly smaller numbers. During this later period considerable diligence may be required to obtain egg confirmation of the clinical diagnosis. The intradermal test or formol-gel test add strength to a presumptive diagnosis.

Author Notes

Dept. of Tropical Medicine, Tulane University of Louisiana, New Orleans, La.

Colonel (Sanitarian Director (R)), U. S. Public Health Service, Bethesda, Md.

Dept. of Preventive Medicine and Public Health, University of Oklahoma School of Medicine, Oklahoma City, Okla.

Major, Sn.C., A.U.S., Army Medical School, Washington, D. C.