We have surveyed the incidence of adult T-cell leukemia/lymphoma (ATLL) in an endemic area of 290,464 inhabitants for 7 years. We now revise our previous results on the basis of additional findings and estimate the age- and sex-specific cumulative rate for HTLV-I carriers, the adoption of which is recommended by current cancer epidemiology as a new age-standardized incidence rate. An unequivocal age-dependent increase in seroprevalence was observed for both sexes with a characteristic predominance in females. The age-dependent seroconversion in females may be partly explained by additional infection from infected husbands to their wives but the reason for men remains obscure. The mean annual number of incident cases of ATLL was 11.4, giving 3.9 ATLL patients annually per 10(5) inhabitants, 6.1 per 10(5) inhabitants aged over 30, and 85.0 per 10(5) seropositives aged over 30. Crude annual incidence rate of ATLL among 10(5) male seropositives aged over 30 was 145.3 and that for females was 55.2 and 95% confidence intervals of ATLL incidence rates were 34.8 to 255.7 for males and 6.4 to 104.1 for females, respectively. Although the sex ratio of 80 ATLL patients was 1.35, males are more prone to the disease (46 male patients among 4,522 male seropositives aged over 30 vs 34 female patients among 8,801 female seropositives aged over 30; p less than 0.001) for unknown reason(s). Morbidity in male seropositives aged over 30 is 2.6 times as high as that of females. Decennial incidence rates in males in their fifties and sixties were significantly higher than those in females. The remarkable male preponderance in oncogenicity of HTLV-I may be due to the fact that men are more prone to the disease and the number of female carriers in the denominator used to calculate the incidence rate is larger than that of males. The whole life span (0-79) cumulative risk for males was 6.9% and significantly higher than that of females (2.95%).

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We report a case of tsutsugamushi disease found in south western Shikoku. A 64-year-old male who lived in Towa Village in Kochi, developed a fever and headache on April 6, 1994, and was admitted to Uwajima City Hospital on April 15, with a ten-day history of illness. He had an eschar on the right anterior side of the breast and an enlargement of the right axillary lymph node, without a rash. Laboratory data showed mild liver injury and atypical lymphocytes with 6% in peripheral blood. After his blood was drawn for rickettsial isolation, the minocycline was administered. His symptoms improved rapidly and was discharged in good condition. We successfully isolated the causative agent, Rickettsia tsutugamushi, and designated it as the Shiba strain. High antibody titer against the Kato, Karp and Gilliam strains was detected in serum on admission and increased during the course of the disease. In Shikoku, tsutsugamushi disease is rare and only 13 cases were reported during last ten years. Especially in south western district of Shikoku, there have been no case reported since 1960. This case is important epidemiologically and suggests that we should pay attention to this disease.

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