著者

重藤 えり子 佐藤 裕恵 重藤 紀和 鎌田 達 阿部 千代治 高橋 光良 森 亨

出版者

JAPANESE SOCIETY FOR TUBERCULOSIS

雑誌

結核 (ISSN:00229776)

巻号頁・発行日

vol.70, no.5, pp.347-354, 1995

被引用文献数

6

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A twenty-four year old male Peruvian of Japanese origin, who came to Japan in September 1990 and had been working in a minor factory in a rural area, was admitted to a hospital in March '91 with severe cough. Smear examination of his sputum smear was positive for acid-fast bacilli and his chest X-ray showed multiple cavities (Index case). Subsequent contact examination identified further four patients with pulmonary tuber culosis among his colleagues in the factory, all of whom lived in the same house with the index case.<BR>During following three years, further six patients with mycobacteriosis, two Peruvians and four Japanese, were found among the employee of that factory. M. tuberculosis was cultured from the sputa obtained from seven of these eleven patients. Another patient was diagnosed as non-tuberculous mycobacteriosis.<BR>Restriction fragment length polymorphism (RFLP) analysis carried out with five strains of M. tuberculosis isolated from these patients revealed the identical RFLP pattern which is uncommon in Japan. Still more, an isolate from another patient was subjected to RFLP analysis by chance, and was found to show the same RFLP pattern. Later epidemiological study revealed that the last patient, a 53 year-old saleswoman of boxlunch, might have some contact with the index case at her booth.<BR>Though RFLP analysis was not done for the isolate from the index case, from the identity of RFLP patterns of other isolates, clinical course and epidemiological study, it is considered that six patients were certainly, and two others were probably infected from the index case. One of the patients had a history of surgical treatment for pulmonary tuberculosis and, as RFLP analysis could not be carried out, it is not possible to determine whether his disease was due to reactivation or re-infection.<BR>Tuberculin skin test survey of 133 workers in the factory was carried out in March '91. The diameter of erythema showed bimodal distribution pattern for the Japanese workers. Considering that most of the young Japanese have been vaccinated with BCG, it is assumed that at least 40% (10/23) of Japanese workers younger than thirty years old were infected in this epidemic. All the Peruvians, who had not been vaccinated with BCG, showed positive reaction to PPD (mean diameter was 41.9mm) and were assumed to had been infected newly in this epidemics or in the past. Chemoprophylaxis were indicated for two young Peruvians only. Subsequent patients were diagnosed among the strong tuberculin reactors (For Japanese ≥50 mm, for Peruvians ≥30mm in diameter).<BR>Total delay in the diagnosis of the index case was considered to be about six months. Though he was coughing on his entrance to Japan on September '90, no reliable medical checkup was done until he was pointed out the abnormal findings on his chest X-ray image at a routine medical checkup in November '90. At that time he was recommended to go to some hospital or clinics, but he did not obey this recommendation promptly. Such a delay may cause this outbreak.