We evaluated the status of Clonorchis sinensis infection and potential risk factors among residents of riverside areas (Geumgang) in Muju-gun, Jeollabuk-do (Province), Korea. From January to February 2010, a total of 349 (171 males, 178 females) stool samples were collected and examined by the formalin-ether concentration technique. Also, village residents were interviewed using questionnaires to obtain information about C. sinensis infection-related risk factors. Overall egg-positive rate of C. sinensis was 13.2%. Egg-positive rates were significantly higher in males, farmers, and residents who had lived there more than 20 years, and in residents who had eaten raw freshwater fish than in opposite groups, respectively. However, there was no significant difference between age groups, education levels, cigarette smoking, alcohol drinking, health status, past history of infection, and experience of clonorchiasis medication and examination. Logistic regression analysis was performed to determine risk factors for clonorchiasis. On univariate analysis, the odds ratios for males, farmers, those who had lived there more than 20 years, and who had eaten raw freshwater fish were 2.41, 4.44, 3.16, and 4.88 times higher than those of the opposites, respectively. On multivariate analysis, the odds ratio of residents who had eaten raw freshwater fish was 3.2-fold higher than that of those who had not. These results indicate that residents living in Muju-gun, along the Geum River, Korea, have relatively high C. sinensis egg-positive rates, and the habit of eating raw freshwater fish was the major factor for the maintenance of clonorchiasis.

Changes in the Leydig cell from pre-puberty to adulthood were studied in Korean native cattle. Eight groups of male cattle aged 14, 17, 20, 25, 30, 35, 40 and 104 weeks (n=7 cattle per group) after birth were used. The purpose of this study was to obtain quantitative information on the Leydig cell of the Korean native cattle during postnatal development. Testes of cattle were fixed by perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using 1 m section stained with methylene blue-azure II, qualitative and quantitative (stereological) morphological studies were performed. The average diameter of seminiferous tubules gradually increased with age from 14 (75.56 m) to 104 weeks (298.9 m). The volume density of the seminiferous tubules increased with age from 54.2% at week 14 to 76.9% at week 104. The volume density of the interstitium represents 45.52% at week 14. This proportion progressively diminishes during development to reach a value of 23.14% at week 104. The volume density of Leydig cells decreased almost linearly from 14 (20.71%) to 104 weeks (5.28%). The absolute volume of Leydig cells per testis increased significantly from 14 to 104 weeks. The number of Leydig per testis have almost linearly increased from 14 to 104 weeks. The average volume of a Leydig cell reached maximum size by 104 weeks (2553 m 3). These data suggested development of Leydig cell can be classified as the fetal and immature adult Leydig cells (14∼35 weeks), and the adult Leydig cells (40∼104 weeks).