Clinical observations of scrub typhus on Penghu (the Pescadores Islands)

Between May and September 1973, 68 cases of scrub typhus in Chinese military personnel on the Pescadores Islands were studied. The common symptoms and signs were fever, chills, headache, eschar, myalgia, and lymph node enlargement. Most eschars were located in the axilla, waist, groin and genitals, and neck. These lesions were painless and not noticed by the patients themselves. Regional lymph node enlargement at the site of eschar drainage was common. Relative bradycardia with fever was observed in 40%, a skin rash in 35% of the patients. Leucopenia was noted more frequently in the febrile than in the convalescent stage, but more than half of the patients had a normal count. Lymphocytosis was prominent, especially during the convalescent period. An acceleration of ESR was noted. Instead of depression of the erythroid series in the marrow which was reported previously, 47% of examined patients were found to have erythroid hyperplasia. Two patients showed marked hypocellularity of the marrow in the acute febrile stage; later on became normocellular. Albuminuria was present in 15 and BUN increased in 12 patients. Elevation of serum bilirubin and SGOT was also noted. Biologic false positive VDRL tests were observed in nine patients. In 30 tests elevation of Proteus OX-K titres between 1:160 and 1:640 was noted. A geometric mean OX-K titre rise in the patients is presented; the mean titre reached a peak in the third week of illness, and then fell off. Most of the patients were treated with tetracycline 500 mg every six hours for about nine days. The fever usually subsided within 36 hours. Complications or mortality were not encountered.