• 제목/요약/키워드: reservoir host

검색결과 45건 처리시간 0.027초

Tula 한타바이러스의 분자생물학적 특성분석 및 국내 밭쥐아과 설치류가 매개하는 새로운 한타바이러스 (Microtine Rodent-Borne Hantavirus from Poland and Korea: Molecular Characterization and Phylogenetic Analysis)

  • 송진원;윤재경;김상현;김종헌;이영은;송기준;백락주;;;;이영주
    • 대한바이러스학회지
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    • 제28권3호
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    • pp.275-285
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    • 1998
  • Based on the geographic range and distribution of its rodent reservoir host, the European common vole (Microtus arvalis), Tula virus is likely to be widespread throughout Eurasia. Tula virus-infected voles have been captured in Central Russia, Austria, Czech and Slovak Republics, and the former Yugoslavia. Although serologic evidence for Hantaan (HTN) or Seoul (SEO) virus infection can be found in the vast majority of the more than 300 cases of hemorrhagic fever with renal syndrome (HFRS) occurring annually in Korea, approximately 4% of Korean patients with HFRS show a more than 4-fold higher antibody titer to Puumala (PUU) virus than to HTN or SEO virus by double-sandwich IgM ELISA, suggesting the existence of pathogenic Puumala-related hantaviruses in Korea. To further define the geographic distribution and genetic diversity of Tula virus in Eurasia and to investigate the existence of previously unrecognized Microtus-borne hantavirus in Korea, arvicolid rodents were captured in Lodz, Poland in 1995 and in Yunchon-kun, Kyungki-do during April to May, 1998. In addition, sera from 18 Korean HFRS patients who showed higher (or the same) antibody titer to Tula virus than HTN and SEO viruses were examined for hantavirus RNA by RT-PCR. Hantaviral sequences were not detected in any of the 18 patients or in 35 reed voles (Microtus fortis) in Korea. Alignment and comparison of a 208-nucleotide region of the S segment, amplified from lung tissues of two hantavirus-seropositive Marvalis captured in Poland, revealed $80.8{\sim}83.2%$ sequence similarity, respectively, with Tula virus strains from Central Russia and the Czech and Slovak Republics. Phylogenetic analysis indicated that the newfound Tula virus strains from Poland were closely related to other Tula hantaviruses from Eurasia.

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대청호 하류에서 환경요인과 Anabaena cylindrica 생장억제세균의 계절별 분포 변화 (Seasonal Variations of Environmental Factors and Distribution of Anabaena cylindrica Growth-Inhibiting Bacteria in the Lower Daechung Reservoir)

  • 이정호;김철호
    • 생태와환경
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    • 제33권2호통권90호
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    • pp.128-135
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    • 2000
  • 수화의 소멸과정에서 수계에 분포하는 세균의 역할을 확인하기 위하여 대청호의 주요 정점에서 환경요인과 종속영양세균 군집, Anabaena cylindrica 생장억제세균의 수층별 연중 변화를 조사하였다. 평균수심은 정점 1에서 25.5m, 정점 2에서 15.0m, 정점 3에서는 12.3m였다. 모든 정점에서 수층별 온도는 하절기를 중심으로 하는 온대지방 수계에서의 전형적인 변화를 나타내었다. 용존산소량은 하절기에 불규칙하게 변화하긴 했지만 수온과 비교적 반비례적인 양상으로 변화하였다. 대체적으로 모든 정점에서 5월 초순까지 점차 감소하던 용존산소량은 이후에는 급격한 변화를 나타내다가 9월 중순 이후에는 점차 증가하는 양상을 보였으며, 특히 이러한 변화양상은 표층에서 더욱 뚜렷하였다. 용존산소량이 불규칙적으로 큰 변화를 보이는 하절기에는 다른 수층에 비하여 표층에서 용존산소량이 매우 높았다. 표층에서의 클로로필 a농도는 하절기에 변동폭이 크게 나타났으며, 용존산소량이 높은 시기에 비교적 높은 수치를 나타내었다. 종속영양세균의 분포도는 모든 수층에서 봄부터 가을까지는 대체로 높게 유지되다가 수온이 급격히 하락하는 9월 이후에는 매우 낮은 개체군 크기를 보였다. 특히 모든 표층에서 이러한 변화는 두르러졌다. Anabaena cylindrica 생장억제세균은 6월 이전에는 거의 분포하지 않다가 7월에 분포도가 큰 폭으로 증가하였고, 이후부터는 정점별로 상이한 분포 변화를 보였다. 모든 정점에서 A. cylindrica생장억제세균의 분포값이 높았던 7월과 10월에는 표층보다는 중층과 하층에서 더 많은 생장억제세균이 검출되었는데, 이러한 결과는 숙주인 A. cylindrica의 활력이 상대적으로 떨어질 때 억제세균의 활성이 높아지는 것을 암시한다. 이상의 결과로부터 자연수계에서 세균은 남조세균 분포에 대한 조절자로서의 역할을 하며, 특히 남조세균의 활력이 떨어질 때 그 역할이 더욱 두드러진다는 사실을 알 수 있었다.

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간흡충증(肝吸虫症)의 역학(疫學) - I. 고도유행지(高度流行地) 김해지방(金海地方)에 있어서의 간흡충감염(肝吸虫感染)의 현황(現況)과 자연추이(自然推移) (Epidemiological Studies of Clonorchiasis. - I. Current Status and Natural Transition of the Endemicity of Clonorchis sinensis in Gimhae Gun and Delta, a High Endemic area in Korea)

  • 김동찬;이온영;이종수;안장수;장영미;손성창;문익상
    • 농촌의학ㆍ지역보건
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    • 제8권1호
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    • pp.44-65
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    • 1983
  • As a part of the epidemiological studies of clonorchiasis, this study was conducted to evaluate the current endemicity and the natural transition of the Clonorchis infection in Gimhae Gun and delta area a high endemic area in Korea in recent years, prior to the introduction of praziquantel which will eventually influence the status of the prevalence. The data obtained in this study in 1983 were evaluated for natural transition of the infection in comparison with those obtained 16 years ago in 1967 by the author(Kim, 1974). The areas of investigation, villages and schools surveyed, methods and techniques used in this study were the same as in 1967, except for the contents of the questionnaire for raw freshwater fish consumption by the local inhabitants. 1) The prevalence rate of clonorchiasis in the general population of the villages was 48.1% on the average out of a total of 484 persons examined. The average of those of the riverside-delta area was 65.2% and 43.0% in the inland area. Among the schoolchildren, the prevalence rate was 8.2% on the average out of a total of 1,423 examined. By area, the prevalence rate was 10.8% in the riverside delta area and 2.8% in the inland area. By sex, difference in the prevalence was seen only in the inhabitants of the inland area showing 52.4% in the male and 33.5% in the female. 2) In the natural transition of the infection, the prevalence rate among the inhabitants has decreased from 68.8% in 1967 to 48.1% in 1983, and in the schoolchildren from 56.4% in 1967 to 8.2% in 1983. The reduction rate was higher in the riverside-delta area than in the inland area. 3) In the prevalence rate by age, 11.9% was first seen in the 5-9 age group and the rate gradually increased up to 75.0% in the 50-59 age group. By sex, the rate was higher in the male than in the female in the 20-29 age group and over. 4) In the natural transition of the prevalence rate by age, the reduction rate of the infection during the past 16 years was greater in the younger age groups up to the 40-49 age group and reached the same level in the age group 50-59. Reduction was seen again in the age group over 60s. By sex, the reduction rate was greater in the female than in the male in the 20-29 age group and over. By area, the reduction rate was greater in the riverside delta area than in the inland area, particularly in the young age groups. 5) In the intensity of the infection among the cases, the mean egg out-put per mg feces per infected cases(EPmg) in the inhabitants was 6.3. EPmg of those of the river-side-delta area was 15.4 and that of the in-land was 2.8. On the other hand, in the schoolchildren, EPmg was 3.2, and no difference was seen between the two areas, the river-side-delta area and the inland area. 6) In the transition of the intensity of the infection by area, EPmg among the inhabitants inexplically increased from 7.8 in 1967 to 15.4 in 1983. This was probably caused by uneven specimen collection in the process of sampling the population. EPmg of the inhabitants in the inland area and those of the schoolchildren of both riverside delta and inland areas showed a similar decrease in the past 16 years. 7) The intensity of the infection by age showed a relatively low level in the 20-29 age group and below, and EPmg 5.1-9.5 was seen in the 30-39 age group and over. Sex, Epmg was 5.8 in the male and 4.7 the female. By in 8) In the transition of the intensity of the infection, EPmg decreased from 6.2 in 1967 to 5.4 in 1983. By age, in contrast to the figures of 1967 in which EPmg gradually increased with some fluctuation from 1.1 in the 0-4 age group to peak 10.5 in the 50-59 age group, in 1983 lower intensity of the infection was seen in the age group from 10-14 to 20-29 with the EPmg range of 0.6-2.7. 9) In the distribution of the clonorchiasis cases by the range of EPmg value, 43.2% of the cases were in 0.1 0.9 and 34.6% in 1.0-4.9. As a whole by cumulative percent, 44.6% of them were under 0.9 as light infection and 86.1% of them under 9.9 up to moderate infection. By sex, no difference was seen in Epmg. 10) In the transition of the distribution by the range of Epmg, the cases were distributed up to the range 80.0-99.9 in 1967 and to 60.0-79.9 in 1983. By cumulative percent, in the range of 0.1-0.9 and less, light infection, 34.3% of them were distributed in 1967 and 44.6% in 1983 with about 10% increase. In the range of 5.0-9.9 and less, up to moderate infection, 83.2% in 1967 and 86.1% in 1983 of the cases were seen, respectively. 11) The practice of raw freshwater fish consumption among the inhabitants seems to have decreased in recent years. Those who admitted to raw freshwater fish consumption in the last two years among the infected inhabitants were 59.3%, although 86.8% of them professed to have experience with raw freshwater fish consumption. 31.7% of those who have had experience of the raw freshwater fish consumption denied any further consumption in recent years. From an interview of 543 school-children, 24.1% of them admitted to an experience of raw freshwater fish consumption. However, those who have practised in the past two years comprized 17.9%. Those who denied raw freshwater fish consumption in recent years among those who had such experience were 26.0% out of 131 interviewed. The rate of raw freshwater fish consumption in both inhabitants and schoolchildren were higher in the male than in the female. On the contrary, the rate of those who did not practise in recent years among those who had experience of raw freshwater fish consumption was higher in the female than in the male. 12) The major reason for the reduction of raw freshwater fish consumption among the local inhabitants was the risk of the fluke infection. However, it has become apparent that such change of taste has resulted from water pollution impact which has affected throughout the areas of the freshwater systems in this locality since last several years. 13) In animal survey, Clonorchis infection was seen in 14.8% of 88 dogs examined and 3.7% of 27 house rats examined. It was noted that populations of dogs and cats have increased in the villages surveyed. Although the prevalence rate was lower in the present survey than those of 1967, the significance of the animals as the reservoir host has not changed. 14) Prevalence rate of Clonorchis infection by cercariae in the first intermediate host, Parafossarulus manchouricus, was 0.6% out of 517 snails examined. The infection rate was lower in comparison with 2.3% out of 2,124 examined in 1967. Moreover, sharp decreases in number and distribution of the intermediate host snails in many watershed areas of the huge freshwater systems in this locality seemed to reduce transmission of Clonorchis in connection with the intermediate host stage of its life cycle. 15) Clonorchis infection in the second intermediate fish hosts was relatively low. The mean number of Clonorchis metacercaria per fish in Pseudorasbora parva was 517 in 1983, whereas it was 1943 in 1968 through 1969. Environmental water pollution has also caused the decreased fish population density in these areas, and this has also apparently affected to the practice of raw freshwater fish consumption among the local inhabitants. 16) In conclusion, endemicity of Clonorchis infection in Gimhae Gum and delta area of the Nagdong River has sharply decreased during the past 16 years. The major cause of the regressive transition of the infection was the water pollution of the land water systems of this locality. The pollution has upset the ecosystems comprizing of the intermediate hosts of Clonorchis in many areas, and also affected to a significant extent to the discontinuance of the local inhabitants for raw freshwater fish consumption.

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간모세선충(Capillaria hepatica) 표피의 미세구조 (Ultrastructure of the Integument of Capillaria hepatica (syn. Calodium hepatica))

  • 김수진;민병훈;이행숙;이병욱;주경환
    • Applied Microscopy
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    • 제39권2호
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    • pp.167-173
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    • 2009
  • 간모세선충(Capillaria hepatica)은 설치류와 인간을 포함한 포유류의 간에 모세선충증(capillariasis)을 일으키는 기생선충이다. 성충은 모세관과 같이 대단히 가늘고 길며, 충체의 앞부분에는 stichosome (염주체) 및 bacillary band 등의 구조가 있다. 간모세선충은 설치류를 주숙주로 하며, 여러 지역에서 채집된 야생 설치류에 거의 100% 감염률이 보고되었다. 자연계에 존재하는 감염형 자충포장란은 물과 음식에 포함되어 포유류에 감염된다. 감염된 성충은 충란을 배출한 뒤 간 조직 내에서 사멸하고, 죽은 충체와 충란은 간 조직에서 숙주 면역반응을 유발시킨다. 본 연구에서는 집쥐로부터 충란을 수집하여 마우스에 감염형 자충포장란을 감염시키고. 감염 7주 후에 간 조직에 포함되어 있는 성충을 손상되지 않게 분리하였다. 분리된 간모세선충은 주사전자현미경과 투과전자현미경을 이용하여 충체 표피의 미세구조를 관찰하였다. 분리된 간모세선충은 길이가 약 99mm로 확인되었으며, 충체의 표피에는 cuticle, bacillary band 등의 구조물이 관찰되었다. Bacillary band에는 여러 형태의 pore가 분포하였고, pore는 cuticle을 가로질러 존재하며, cap material의 존재 유무에 따라 bacillary pore의 형태적 차이가 나타났다. 간모세선충은 간 조직내에서 성장하는 특성을 가지고 있으므로 손상되지 않도록 성충을 분리해 내기 어렵고, 이에 따라 충체 외부형태에 대한 연구가 용이하지 않았던 것으로 생각한다. 이러한 간모세선충의 성충을 손상없이 분리하고, 표피의 미세구조를 확인함으로써 아직까지 연구가 이루어지지 않은 간모세선충을 포함한 선충류의 형태에 관한 연구에 중요한 기초자료가 될 것으로 생각한다.

집단치료사업에 따른 간흡충증의 역학적 변동에 관한 조사 (Studies on the Epidemiological Change of Clonorchiasis After Mass Chemotherapy in Highly endemic Areas)

  • 주경환;주봉덕;임한종;이준상
    • 농촌의학ㆍ지역보건
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    • 제12권1호
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    • pp.80-93
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    • 1987
  • Mass chemotherapy of Clonorchis sinensis infection in Korea was started in 1982 with 40mg/kg body weight single dose administration scheme of praziquantel. The purpose of this study was to investigate the efficiency of current mass chemotherapy project and compare the epidemiological changes in endemic area of Ckmorchis sinensis. This study was performed at Kimhae-city and Samrangjin-eup of Miryang-gun, Kyongnam province, highly endemic area of C. sinensis located southeastern part of Korea from July to October of 1986. The therapy project of Kimhae area was performed in 1984, whereas that of Samrangjin was done in 1985 by stool examination of the Korea Association for Parasite Eradication(KAPE) and drug administration of local health centre. The results obtained were as follows; 1) As a results of stool examination from 234 specimens obtained in Kimhae area, the infection rate has decreased to 34.2%from 45.6p in 1983, but the infection rate of C. sinensis from 341 specimens obtained in Samrangjin area did not decrease (58.1%in 1986 490%in 1983). 2) The study in Kimhae area showed that the average EPG decreased remarkably from 4,858 to 1,340 and those classified above the category of heavy infection decreased also from 14.0pp to 1.7%. The study in Samrangjin area showed that the average EPG did decrease drastically from 9,597 to 6,498 and those classified above the category of heavy infection did not go down drastically from 25.2% to 14.2%. 3) The study in Kimhae area showed decrease of Cs.$D._{50}$ in comparison to that in 1983, wheareas Cs.$D._{50}$ in Samrangjin area showed no much difference compared to that in 1983. The intensities of endemicity were represented with the regression equation calculated with the cumulative percentages of EPG count. Regression equation was Y=4.49+1.19 log x in Kimhae area and Y=3.66+127 log x in Samrangjin area. 4) The two stage catalytic model was applied and the calculation lead to the equation $Y=5.33(e^{-0.018t}-e^{-0.016t})$ in Kimhae area and $Y=1.25(e^{-0.010t}-e^{-0.018t})$ in Kimhae area and $Y=125(e^{-0.010t}-e^{-0.050t})$ in Samrangjin area 5) The infection rate of cercaria in P.manchouric-us studied in Kimhae area showed 1.25% which is not much different from that in previous years, wheareas the infection rate of metacercaria in P. parva studied in the same area this year showed 2.5-20.2/gm of flesh in comparison to 64/gm of flesh in 1983. 6) Data of C. sinensis infection on the reservoir host in Kimhae area showed 4 out of 18 dogs, 1 out of 18 rats and that in Samrangjin area showed 2 out of 18 dogs respectively. 7) Among the inhabitants who were under mass chemotherapy in Kimhae area, 71out of them, upon stool examination, showed infection rate of 66.2% and those classified above the category of heavy infection, 2.4%. In comparison to infection rate of 33.7% and those classified above the category of heavy infection, which is 1.0%, obtained from those not under mass chemotherapy showed higher infection rate and somewhat equal distribution of intensity of infection. The above statements reflect the fact that individual therapy besides mass chemotherapy was prevalent in that area. 8) On the other side, the studies in Samrangjin area showed infection rate of 68.7% and those above the category of heavy infection, which is 6.1%, in comparison to infection rate of 58.3% and those above the category of heavy infection, which is 16.5%, in those not under mass chemotherapy. the above reflects that although a good deal of inhabit-ants were classified under light or moderate infection category, those above the category of heavy infection, yet, numbered a lot, and individual chemotherapy has not been going on. In conclusion, it was suggested that the number of reinfected inhabitants among those under mass chemotherapy were numerous. Accordingly, the reinforcement of health education should be followed with mass chemotherapy. The facts of high infection rate exemplified by 65% and high number of those above the category of heavy infection in Samrangjin area say that reevaluation of dosage, number of medication and intervals should be necessarily made.

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