• Biomedical Science Letters
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• v.17 no.4
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• pp.367-370
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• 2011

Studies on the relative abundance of potential vectors of scrub typhus was conducted from April to October 2009 at the Jangseong of Jeonnam Province, Korea. Among the total 62 field rodents collected by the Sherman collapsible traps, 56 rodents were $Apodemus$ $agrarius$ (90.3%), 4 were $Crocidura$ $lasiura$ (6.4%) and 2 were $Cricetulus$ $triton$ $nester$ (3.2%). Out of the 62 field rodents, 39 were parasitized by chiggers, showing 62.9% of the infestation rate and 80.0 of the chigger index. Chigger index of $A.$ $agrarius$ and $C.$ $triton$ $nester$ were 79.9, 82.0, respectively. But chigger mite was not collected from $C.$ $lasiura$. From the trapped field rodents, 3,120 chiggers were collected and identified with 6 species of 2 genera. $Leptotrombidium$ $scutellare$, the vector species of tsutsugamushi disease, was the dominant species, showing 2,276 chiggers (72.9%). $L.$ $pallidum$ was the second dominant species showing 346 chiggers (11.0%). The distribution of chigger mites was showed the different dominant species according to seasons. $L.$ $pallidum$ was the predominant chigger collected in April (34.8%), May (77.8%) and Jun (39.3%), whereas $L.$ $scutellare$ was the predominant chigger collected in September (78.78%) and October (76.8%).

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.4
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• pp.547-554
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• 1994

This paper presents the effects of supplementary feeding and internal parasites on the growth rates of female weaner goats raised under improved management. A completely randomized $3{\times}3{\times}2$ factorial design was used. Factors were genotype (Thai native: TN, 75% TN $\times$ 25% Anglo-Nubian: An and 50% TN $\times$ 50% AN), feeding grazing only, low (1.0% BW/d) and high (1.5% BW/d) supplementation and parasite control (undrenched and drenched). It was shown that native goats had significantly (p<0.05) higher growth rates than did the cross-bred goats from 12-24 weeks of the trial. The growth rate of goats grazing improved pasture depended on the amount of concentrate offered as a supplement. There was no significant difference in growth rates between undrenched and drenched goats. There was no interaction effect on growth rates between the treatments. Drenched goats had significantly (p<0.01) lower egg counts per gram of gastro-intestinal nematode than did undrenched goats. There was no significant difference between the treatments for blood constituents (total protein, haemoglobin, packed cell volume, eosinophils, lymphocytes, monocytes and basophils).

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.2
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• pp.181-187
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• 1996

About 8 million tons of straw (dry matter) become rotten during the monsoon(June to August) season in Bangladesh. The possibility of preserving straw with urea, under wet condition during dry period (December to May) and its utilization by cattle has been studied. Five tons of fresh and wet(600g DM/kg material) rice straw were preserved for six months, with 5% urea(W/W) in either dome or rectangular shaped heap without any polythene cover. The preservation quality, acceptability and nutritive value of preserved straw were then comparted with that of dry straw in growing cattle. In both types of heaps, straw was excellently preserved having strong ammonia smell,dark brown in colour with no fungal infestation. Urea preservation of straw increased its CP and ADF content. Preserved straw was readily accepted by the animals and they were healthy throughout the experimental period. Compared to dry straw, urea preserved straw had nonsignificantly higher rumen degradability, straw intgake and growth rate. Similarly, digestibilities of DM(p<0.01), OM(p<0.01) & ADF(p<0.01) were significantly higher in the preserved than the dry straw. It was concluded that wet straw with relatively lower moisture(400 to 500 g/kg straw) content can be readily preserved by using urea without being covered with polythene. Whether the same phenomenon occurs in the preservation of fresh and weet rice straw with relatively higher moisture(600 to 700 g/kg straw) content is yet to be determined.

• The Korean Journal of Zoology
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• v.1 no.1
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• pp.1-6
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• 1958

A rat-fleas survey was carried out in Ducksonm and Kwangnaru areas of Seoul city from Janurary to December 1955 . In this survey, 1,204 redents were trapped alive and 740 of which being Rattus norvegicus, 457 Apodemus agrarius, 5 Eutamiias asiaticus and 2 shrewes ((crocidura rusila). On these rodents 270 fleas were collected and identified thus : Ceratopylidae : Monopsyllus anisus (Rothschild 1908) ···200 Leptosylla segnis(Schonherr, 1832)···1 Hystrichopsyllidae : Ctenophthalmus congener, Rothschild ···43 Neopsylla bidentiformis (Wagner, 1893)···11 Stenoponia sidimi Marikovsky, 1936···9 Pulcidae : Xenopsylla cheopis (Rothschild, 1903)···6 On the average 8.5% of the rodents were infestated with fleas. The infestation rate showed a marked varying degree in a year and three high incidence peaks in Spring (10.3%), Summer (11.4%-11.8%) and Winter (13.7%). The average number of fleas per rat (flea-index) was 0.22 for the whole year with a maximum of 0.41 in December and a minimum of 0.03 in February. Of all, the most prevalent species are Monopsyllus anisus (74.1%) and secondly Ctenophthalmus congener (15.9%). both species occupied 90% of all. Xenopsylla cheopis, a known vector of plague, was found very rare in our survey and only appeared in Winter. The striking lower incidence of flea-index compared with previous data (6.6 by Nagahana, 1931-1936) appears to be due to the nationwide application of DDT and BHC insecticides since 1945.

• Journal of Nutrition and Health
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• v.7 no.3
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• pp.27-44
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• 1974

A general survey of 82 perschool children and 473 school children (from 1st to 3rd grade) residing in the Dongnae area of Shindong Myun, choonseoung Gun, Kangwon Province was conducted from June 12 to 21, 1973, to obtain information concerning nutritional status, especially the protein and iron nutrition of preschool and school children in a rural area of Korea. A sample of 58 children 2 to 9 years old was selected from these 555 children for hematological, biochemical and parasitological tests. The results of these tests are presented below, 1) Both the mean body height and mean body weight of these children were higher and heavier than the averages in the Korean Physical Standards. About 39 per cent were above the 90 th percentile of the Korean Physical Standards of height and 35 per cent were above the 90th percentile of the Korean Physical Standards of weight. 2) The rate of infestation by helminthes was 67.6 per cent and there were no cases of hookworm infestation Among the ascaris-infected children, 61.6 per cent fell within an Ascaris E.P.G. count range of $501{\sim}2,000$. This was considered a rather mild intensify of ascaris infection. Nutrient loss due to helminthes was also estimated to be low. 3) The mean hemoglobin level was 11.3gm% $({\pm}0.94)$, and 68.4 per cent of the children were anemic (less than 11gm% among those 5 years old or less, less than l2gm% among those 6 years old or more). The average hematocrit value was 36.1% $({\pm}2.36)$, and only 3.5 per cent showed more than 34% on the M.C.H.C. test. These results showed that the incidence of anemia, in these rural children was high, and that in general it displayed hypochromic characteristics. 4) The average serum iron level was $78.2{\mu}g%$\;({\pm}29.8). The Proportion of the children showing less than $50{\mu}g% in the serum iron level was 5.6 per cent, while 41.8 percent revealed $450{\mu}g% or more in the TIBC determination. Transferrin saturation was below 15% in 71.4 percent of the preschool children, and in 28.6 percent of the school children. Those who had a serum iron level of $50{\mu}g% or less and a TIBC of more than $450{\mu}g% constituted 11.9 percent of the children examined. From these results, it was concluded that especially preschool children were low in iron nutrition, and that most of the anemia might be iron-deficiency anemia. 5) The mean values of total serum protein and albumin were 6.98gm% and 4.99gm% respectively. Especially in serum albumin, all children stowed more than 4 gm%. 6) The mean urinary urea nitrogen Per creatinine ratio was 11.5 $({\pm}4.2)$, and 21.8 percent had a ratio of more than 15. Considering these results, it was suggested that protein nutrition in these children was relatively good.

• Korean Journal of Ecology and Environment
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• v.49 no.3
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• pp.215-227
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• 2016

In freshwater ecosystems, the types of fish parasites are diverse and routes of infection are complicated because they maintain the life cycle in a variety of host animals, The present study investigated the infestation characteristics of parasites occurring in abdominal cavity of Zacco platypus in Seom River from February to October 2007. At the same time, four streams (Gam Stream, Daepo Stream, Yangsan Stream, and Yulha Stream) were also surveyed for the reference of fish infection. Aquatic insects and shellfish predominated benthic macroinvertebrate assemblages by 90.4% and 7.7% of relative abundance, respectively. Aquatic insects were composed mostly of Ephemeroptera (46.8%) and Trichoptera (29.8%), and shellfish was Gastropods. Freshwater fish was most abundant Cyprinid and Z. platypus by 85.7% and 48.8%, respectively. Among waterfowl, Anas poecilorhyncha and Egretta garzetta were dominant in August. Fish parasites observed in the abdominal cavity of Z. platypus was classified as Ligula intestinalis, belonging to Phylum Platyhelminthes Cestoda Pseudophyllidae. L. intestinalis was observed from Z. platypus in October, as the number of one individual in the Seom River and fifteen individuals in the Yangsan Stream. Infection rate of plerocercoid ranged 1.4~15.8%. We discussed the relationship between the life cycle of the parasite and the host, and hope our results to be useful for understanding the ecology of the fish abdominal parasites in Korean river ecosystem.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.221-228
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• 2021

The fall armyworm (FAW), Spodoptera frugiperda (Smith), is a notorious invasive migratory pest native to the tropics that has recently invaded South Korea with subsequent damage to cornfields. This study was conducted to evaluate the damage patterns on corn plants caused by the migratory and subsequent generations of FAW. The early migrant generation-related infestation rates reached an average of 13.2%, ranging from a minimum of 4.3% ('Allog-i') to a maximum of 33.0% ('Chodang'), depending on the corn cultivar. The proportion of FAW larvae-infested corn plants, in which the FAW survived until the pupal stage was 19.3%. The subsequent FAW generation caused considerable damage to the ears, resulting in 60% of ears with damaged kernels. This damage was markedly different from the nearly negligible damage caused by the migratory generation. The FAW larval dispersion was the most dynamic during the second instar stage and occurred along the same cornrow in line. In addition, we discuss the development of corn pant damage patterns caused by FAW. In summary, the results of the present study would provide useful basic information for the damage analysis of this pest for future studies.

• Journal of agricultural medicine and community health
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• v.7 no.1
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• pp.80-89
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• 1982

In order to observe the endemic status of Clonrchis sinensis infection in Samrangjin eup, Milyang gun, Kyongsang nam do, a total number of 294 stool specimens were collected from the inhabitants who lived in the basin of the Nakdong river. The specimens were examined by cellophane thick smear technique and Stoll's egg dilution technique during the period from May to June 1983. The epidemiological status was analysed statistically by the regression equation and catalytic curv with the results obtained from this area. The results are as follows : 1) The infestation rate of Clonorchis sinensis in 294 was 49.0%. 2) No remarkable difference was observed between male (52.5%) and female (44.8%). 3) Average E.P.G. by Stoll's egg dilution technique in this area was 9,597. 4) The degree of the intensity of Clonorchis infection by E.P.G. count was distributed as 10.5% in very heavy infection, 14.7% in heavy infection, 47.4% in moderate infection, and 29.3% in light infection. 5) The intensity of endemicity in this area was represented with the regression equation calculated with the cumulative percentages of E.P.G. counts. Regression equation was y=3.40+1.23 log x and Cs. $D._{50}$ was 19.99. 6) The two stage catalytic model was applied and the calculation lead to the equation $y=1296(e^{-0.008t}-e^{-0.035t})$ ; a=0.035 > b=0.008 in this surveyed area. 7) Other helminthic infection rate in this area was 7.1% in A. lumbricoides, 9.5% in T. trichiura and 4.1% in E. vermicularis respectively.

• Parasites, Hosts and Diseases
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• v.50 no.4
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• pp.327-331
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• 2012

Monthly surveys were conducted to investigate the occurrence of chigger mites and seroprevalence of scrub typhus among small mammals in Jeollanam-do, the southwestern part of Korea, from November 2006 through October 2007. Fifty-eight small mammals, including 57 Apodemus agrarius (98.3%) and 1 Crocidura lasiura (1.7%), were captured, and a total of 4,675 chigger mites representing 4 genera and 8 species were collected from them. The chigger infestation rate among small mammals was 69.0%. The most predominant species in A. agrarius was Leptotrombidium scutellare (54.0%), followed by Leptotrombidium pallidum (39.4%), Leptotrombidium orientale (4.4%), Leptotrombidium palpale (1.1%), Neotrombicula tamiyai (0.6%), Eushoengastia koreaensis (0.3%), Neotrombicula gardellai (0.3%), and Cheladonta ikaoensis (<0.1%). The chigger index of A. agrarius was the highest in October (740.0), followed by November (242.0), September (134.6), March (98.3), February (38.2), January (35.3), December (34.5), April (30.8), and May (1.7). The average antibody positive rate of scrub typhus in wild rodents was 50.0%. The seropositive rates were high in October (100.0%) and November (83.3%), whereas those in other months were relatively low (28.6-57.1%). The chigger index of L. scutellare rapidly increased in September to form an acuminate peak in October, followed by a gradual decline. These results suggest that the outbreak of scrub typhus in the southwestern part of Korean peninsula is mostly due to L. scutellare.

• Current Research on Agriculture and Life Sciences
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• v.2
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• pp.42-55
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• 1984

The direction of scientific researches on tree improvement and forest management in several universities and research institutes in Japan can be summarized as follows: They put a great emphasis on sugi, Cryptomeria japonica and cypress, Chamaecyparus oblusa which are two major conifer species largerly planted in the Japanese forestry. In the research of sugi, a great concern has been made in evaluating inheritance of forest tree, quantitative characters and genetic parameter of growth, and in breeding for resistance to diseases and insects and to all the natural calamities. Interaction between environmental conditions and genetic nature of tree can be concerned factors in relation with forest damage, together with silvicultural conditions and pest infestation. Selfing hybrids of $F_1$ made from crossing twisted-leaf sugi, defomity leaf type and midori sugi, normal leaf type segregated the normal needle, twisted needle, green leaf and albino leaf type. It seemed that separation of many defomity individuals can be governed by two dominant complementary genes and from the near loci of which it was detected lethal genes. 52% of Japanese forestry is occupied by the small forest landowners like Korean forestry. This made difficulty for forest improvement such as progressive afforestation and for capital accumulation form forestry. The Forest Corporation was established at first in 1959 to aming at productive forestry structure and forest management, and afforestation. For these purpose, 35 Forest Corporations are at moment operating throughout Japan. However, investment in forestry business becomes less attractive since the wage in forest production duction increased in higher trend. than timber price. Therefore, an artifical afforestation becomes yearly decreased. At present. the self-sufficient rate of timber production in Japan is about 35%, and so a great effort is being made to increase self-sufficient rate of timber production.