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Report of National Institute of Health
1970 Volume.7 No. 0 p.281 ~ p.306

Studies on the control of ascariasis and hookworm infections by periodic masstreatment

金東燦/Kim, Dong Chan
李溫永/成雨永/金泰雄/韓義正/鄭智澤/方道謙/Lee, On Young/Sung, Woo Young/Kim, Tae Woong/Han, Eui Jung/Chung, Je Teack/Bang, Do Gyum

Abstract

This study was conducted to assess the effects of the periodic mass treatment for the control of ascariasis and hookworm infections in a rural area in Korea. This report covers the results of the first year´s study conducted in Koyang Gun, Kyunggi Do, from April to December 1970.
1. Prevalence of intestinal helminths among inhabitants in Koyang Gun.
1) Prevalence of intestinal helminths by species.
A total of 2,695 persons were examined from sample groups of 2 primary schools and 6 villages both by cellophane thick smear technique and saturated brine floatation technique, and the incidence of the infections was Ascaris lumbricoides 70.2%, Trichuris trichiura 68.9%, hookworm 17.4%, Trichostrongylus orientalis 22.8%, Hymenolepis nana 0.3%.
2) Conditions of Ascaris infection. Incidence of infection in 1,620 children examined in 3 primary schools was 76.0%. On the other hand the incidence of a total of 1,075 inhabitants (all age groups) from the 6 villages was 61.5%. The incidence of infection rose sharply in the group of young children reaching the high level of 75.1% in the age group 5-9, then showed slow decline in infection as the age groups increased in years. The incidence of infection in the female was higher in general than in the male and the difference was more marked in the higher age groups. The intensity of the infection observed in the primary school children showed 4.0 in average Epmg and was considered to be relatively low. No distince seasonal fluctuations were seen in the Ascaris infection.
3) Condition of hookworm infection. The incidence of infection among primary school children was 11.1% on average and that of inhabitants from othe villages was 26.8% on average. The incidence of infection increased gradually by increase in age and was higher in the female than in the male and the difference was more marked in adults. The incidence of infection was considered to be very low with an average Epmg of 0.07 among the hookworm egg positives. The incidence of infection declined approximately to half in the cooler season, i.e., winter, from that shown in late Spring to Autumn.
2. Effects of the 1st mass treament for ascariasis.
Coizumin, Santonin and kainic acid compound, was used in treatment. From the results of total population examined, the incidence of the infection after mass treatment was decreased to 17.5% from 68.7% (pretreatment) showing a decrease of 51.2%. In school children the incidence decreased to 14.7% following treatment from 75.2% (pretreatment) showing a decrease of 60.5%.
On the other hand in the village group the incidence of infection decreased only to 27.7% from 61.5%, results being due to haphazard stool specimen collection and treatment during the course of survey. The intensity of infection by Epmg decreased to 1.0 from 4.0 pretreatment phase.
3. The increase in the prevalence of Ascaris infection in the following 6 month period after the 1st mass treatment.
The infection rate decreased by the 1st mass treatment, increased again gradually and the infection rate of the total population examined reached 58.3%. This means 10.4% drop from that of the pretreatment phase. In the group of school children the infection rate increased to 59.6% which means 15.6% lowered compared with the incidence in the pretreatment phase. Reinfection rate during the 6 months among the cases of egg nagative conversion was 60% on average and the new infection rate among the egg negarive cases at the time of pretreatment was 55% on average.
4. Effect of 2nd mass treatment for ascariasis.
In the 2nd mass treatment carried out 6 months after the 1st mass treatment, the incidence diminished to 30.8%, approximately half of the rate, 63.0%, shown before the treatment in the school children group.
5. Effect of the 1st mass treatment for hookworm control.
Alcopar was used for hookworm treatment. In the total population examined the incidence of the infection decreased in the 1st mass treatment to 6.6% from 18.5% in the pretreatment phase. In the school children group, the incidence dereased to 3.7% from 10.9% in the pretreatment phase on average, and in the village people group the incidence dropped to 17.4% on average from 26.8%. The intensity of infection in hookworm egg positives decreased to a state not detectable by Stoll´s egg counting technique implying maximum Epmg less than 0.01 from average Epmg 0.07 found in the pretreatment phase.
6. Increase of hookworm infection in 6 months after the effects of the 1st mass treatment.
Infection rate decreased by the mass treatment gradually again and reached 8.9% on average after the six month period. This means 9.6% below the original infection rate of 18.5%. In the school children group theincidence of infection increased to 6.2% which showed 4.7% below the original prevalence rate of 10.9%. In the village group, the prevalence rate reached 16.9% which means 9.9% lower than the pretreatment prevalence rate of 26.8%. Hookworm egg positive conversion rate among those converted to negative by mass treatment was 7.7% on average and the positive conversion rate among hookworm egg negatives before treatment showed 7.6%.
7. Effect of 2nd mass treatment for hookworm infection.
The infection rate decreased to 3.0%, i.e., a 4.3% drop, from 7.3% in the pretreatment phase by the 2nd mass treatment, carried out 6 months after the initial mass treatment.
8. Anthelmintic effect and side effects of the drugs used
1) The Ascaris egg negative conversion rate by Coizumin observed in the school children group was 85.3% on average in the 1st mass treatment, and in the 2nd treatment 6 months after the 1st administration was 76.4%. Side effects with Coizumin administration were relatively mild and transient.
2) Egg negative conversion rate of Alcopar for hookworm infection was 93.8% when 2.5gm administered in powder form in each dose (Bephenium salt 1.25gm) and 92% when 1.0gm used (Bephenium salt 0.5gm) in school children.
In addition anthelminthic effect of Alcopar for Trichostrongylus orientalis was 90.9% when 2.5gm administered in powder form and 81.0% when 1.0gm administered of the powder.
It was found that at least for the school children group 1.0gm of Alcopar powder can be used without reducing the efficacy. This also reduces the side effects compared with 2.5gm administration.
9. It was shown that for both ascariasis and hookworm infection in rural areas in Korea, periodic mass treatment, 2 times a year, can gradually reduce the prevalence rate of the infection in the community. Better efficiency could be expected in the mass survey and treatment in Korea by taking possible measures to treat more than one species of common parasite in the same course of treatment.

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