Epidemiological study of Paragonimus westermani in Wiseong County, Kyungpook Province, Korea

This survey was undertaken to determine the recent prevalence of lung fluke, Paragonimus westermani, in the three localities of Wiseong county, Kyungpook Province, Korea and to compare the prevalence among the residents in the same areas between 1924 and 1980. The three localities, Ku-seong, Sam-chun, and Um-ji villages (dong) have been known as the endemic areas of Paragonimus westermani. The surveys were made on the general population. They were examined using intradermal test with Paragonimus westermani antigen, and the diagnosis of paragonimiasis was made depending on the positive intradermal reaction. The sputum examination could not be performed beacause the residents were inaccessible. The prevalence of Paragonimus westermani among the residents in the three communities varied from 1.4 percent to 7.9 per cent, with an average of 4.0 per cent. Whereas, the average reported by Ichinomiya in 1924 was 4.7 percent. There are no significant differences in the sex and age specific rates of infection between 1924 and 1980. With the abundant density of Semisulcospira snails and crayfish in Sam-chun stream and the high rate of infection with Paragonimus westermani among the residents in the village, it is found that Sam-chun village, one of the three localitied in Wiseong county, where Ichinomiya (1924) surveyed, was still the endemic focus of Paragonimus westermani.

Demonstration of Entamoeba histolytica cyst from urban and rural school children

School children between 6 to 12 years of age were studied for the presence of Entamoeba histolytica cysts in a period of 6 months, form March to August 1980. Fecal specimens collected form urban and rural children were examined first by the Lugol stained technique and then by the Faust's iron alum hematoxylin method. A total of 731 specimens were examined. Of these 26.9 per cent, 197 specimens, harbored the cysts. The demonstration rate for the cysts by age group varied from 19.6 to 43.5 per cent. The demonstration rate in boys was 24.4 per cent and in girls 29.8 per cent. Similarily, the rate in urban and rural area was 32.4 and 24.1 per cent, respectively. It was found in the present study that there were no significant differences in the age and sex rates of demonstration between urban and rural children but there was a predominance of the small race of Entamoeba histolytica over the large race.

Metacercarial density of Metagonimus yokogawai in Plecoglossus altivelis in Kyungpook province, Korea

In order to determine the intensity of infection with the encysted larvae of Metagonimus yokogawai among Plecoglossus altivelis, sweetfish, caught at the rivers in Kyungpook Province, Korea were examined in the period from July to October, 1976. The data were compared with the results obtained from Tribolodon hakonensis, the sea-run dace, caught at the river Hyungsan in the Province. A total of 128 Plecoglossus altivelis were examined. All the fish were infected with the metacercaria of Metagonimus yokogawai. The metacercarial rate for the fluke in the flesh was higher than the rates in the fins and scales. The average number of larvae per sweetfish was 4,333, compared with the average of 1,541 from the sea-run dace. It was found that the highest number of encysted larvae was found in the flesh of sweetfish, whereas it was encountered on the scales of sea-run dace. In the distribution pattern of the cysts, there was no relationship between the size of fish and the intensity of infection.