Epidemiological study on paragonimus westermani in Hae-nam district, Cholla-nam-do, Korea
Many Studies on paragonimiasis in Korea have been reported since Muta(1912) Kobayashi(1926) examined 353,729 samples of sputum from endemic area of Paragonimus westermani in Korea and found 7.9% positive rate. Walton and Chyu (1959) reported 1,229 (13%) positive skin reactions but of 9,771 peoples in various areas of South Korea Chyu(1961) reported 60 cases(11.8%) with paragonimus positive skin reaction from 510 patients who were diagnosed as tuberculosis, and Soh et al. (1961) found 73 cases (7.0%) of paragonimus positive eputa from 1,050 patients who
visited the Severance Hospital With the suspicion of phthisis.
It was found that in Korea the endemic areas an correlated with the distribution of Semisulco spira libertina, the first intermediate host of Paragonimus westermani. It inhabits mainly mountainous infestation The second intermediate hosts which have been reported to inhabit in Korea are Eriocheir sinesis, Cambaroidas similis and Sesarma dehaani. The main causes of paragonimus infestation in Korea have been the habit of consuming raw crape-fish juide for measles treatment and eating improperly cooked crabs(Yun, 1960; Chyu and Lee. 1963; Loh, 1966).
Yokogawa ct al.. (1961) attempted the administration of bithionol (bithin) for paragonimiasis and recommended it as an excellent anthelminthic. Kim et al. (1964) reported that out of 19 patients who were given bithionol, 17 cases were recognized
with negative conversion of paragonimus eggs.
However, there have been no report concerning the mass survey and control of paragonimiasis in Korea.
This study was designed epidemiologically to estimate the infection status of p. westermani in Haenam Gun, Cholla Nam-Do area.
Materials and metheds
Areas, objects and duration of the study: The inhabitants in talc river-side areas of Haenam Gun, Cholla Nam-Do province were surveyed for this study during the period of April, 1965 to January, 1970.
Antigens for intradermal test of paragonimiasis and clonorchiasis: Two purified antigens from adult worm extract wish veronal buffered solution were prepared by Chaffee'a method.
Examination of paragonimus eggs in sputum : The egg concentration was prepared from the sputa collected from the various areas. The sputa were dissolved in 5% NaOH solution, and centrifugated at 2,500 r.p.m. for 2 minutes.
Examination of paragonimus metacercariae from the second intermediate host: The metacercariac of P. westerstomani were collected from the clay-fish (Cambaroides similis) and crabs (Eriochirsinsis). The infection rate of metacercariae was
calculated and checked the weight and infection site in the 2nd intermediate heat.
Environmental survey for paragonimus patients: A questionaire was used to determine the eating habits and past history of the 110 paragonimiasis canes.
Survey for the reservoir host of p. westermani: The wild rats were caught in the surveyed areas The adults and eggs of p. westermani, were examined in the lunes of rats. Feces from dogs, a domestic animal, was colleted and examined the eggs of paragonimus by AMS Ⅲ concentration technic.
Determination of therapeutic effects of bithionol for paragonimiasis cases: 157 paragonimiasis cases were selected and administered with 40mg of bithionol per kg of body weight emery other day for 70 days After the administration, the egg conversion rates and the sixte-effects were continuously checked
Routine check of the complement fixation test was also carried out wish the sera collected and V.A S. antigen of the lung fluke.
The positive rate of the skin teat was 40.6% from 13,282 examinees(male, 45.5% , female, 33.2%). The rate was the highest in the 40 to 59-year age group (56.0%).Among 4,130 skin test positives, p. westermani eggs were found in 33.97% (make, 37.8% ;female, 24.5%). The rate was the highest in the 40 to 49-year group and the lowest in below the 10-year age group. In the surveyed areas, the highest rates were 41.2% at Bukpyung-Myun, 37.9% at Songji-Myun and the lowest rate was 5.0% at Munnac-Myun. Metacercarial incidences were 44.1% in the crayfish (Cambaroidss similis) caught in Spring 1965 and 31.3$, 49.6% in those caught in Autumns, 1968 and 1969, respectively. The order of the infected portion in the caryfish was decreasing from the cephalothorax, abdomen and legs
Metacercarial rates in the crabs (Eriorhir sinensis 5.5%) was lower than the crayfish.
Among the 110 egg positives in the sputum, 76.4% had history of the ingestion of improperly cooked crafts and 40.9% ate cray fish.
Neither the adults nor the eggs were detecter in the wild rats and dogs, which have been considered as the reservoir hosts.
The nagative conversion rate in the egg-positive cases after bithionol administration, was 73.2% (115 out of 157). Side effcets of the drug were observed in the administration cases (157 cases). The side effects were dizziness 31.2%, diarrhea 25.4%, abdominal pain 17.8%, headache 15.2%, fatigue 13.3% anorexia 10.1% and vomitting 5.7%.
The positive rates by complement fixation test wan 59.2% in the patients's sera, and 28.5 to 40.0% in the group treated with bithionol.
An epidemiological study on the paragonimus westermani infestation in Korea was done in the Haenam area, Cholla Nam-Do from April,1965 to January, 1970, The results are summarited as follows:
1. The skin-test positive rate of P. westermani among the resident in Haenam Gun was 40.6% (5,394 out of 13,282).
2. The paragonimus eggs were found in 33.9% from the sputa of 4,130 skin test positives.
3. Sensitivity and specificity of the skin test using the paragonimus antigen were 33.9% and 98.6%, respectively.
4. The metacercarial incidences of p. westermani in crape fish were 31.3∼49.6% and 5.5% in crabs.
5. A majority of paragenimiasis had a past history of eating improperly cooked crayfish or crabs.
6. Among rats and dogs, no paragonimus was found.
7. The egg positive cases converted to negative 73.2% by bithionol administration.
The present studs indicates that the paragonimiasis still exists in Haenam area, though the incidence shows declination by year and age. The combination of health education and marts treatment will be the expected mean to 디iminate the endemic
disease from the urea,