Epidemiological Studies On A Breast Disease Of Unknown Etiology

This paper reports epidemiological studies on a breast disease of unknown etiology. In April, 1989, Anti-Epidemic Center of Zhalute Banner, Inner Mongolia Autonomous Region, reported that an epidemic of breast enlargement of unknown etiology occurred in the local population of two villages in northern mountain area of the Banner. In May, 1989, Zhelimu League Anti-Epidemic Center and Norman Bethune Medical University co-investigated the epidemic in the field. Then, follow-up studies and relevant experimental studies were carried out.There are five villages in the plain with an area of 40 km~2 surrounded by mountains. Household survey showed that the cases of the breast disease with unknown etiology occurred only in Harinaoer village and Beiaqilangtu village. There were 81 households with 429 persons in Harinaoer village with a prevalence of 13.5% (58/429), and the households with the cases accounted for 53.1% (43/81) of the total. And there were 59 households with 282 persons in Beiaqilontu village with a prevalence of 12.1% (34/282) , and the households with the cases accounted for 45.8% (27/59) of the total.There were altogether 140 households with 711 persons in the two villages with a prevalence of 12.9% (92/711), and the households with the cases accounted for 50% (70/140) of the total. No case was found in the other three villages with 84 households and 447 persons in total.The first two cases with breast enlargement in Harinaoer and Beiaqilangtu villages occurred in March and April of 1989, respectively, and afterwards, the similar cases gradually increased and reached the peak in March of 1989.