| Project/Area Number |
13576016
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Virology
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| Research Institution | Nagasaki University |
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Principal Investigator |
MORITA Kouichi Nagasaki University, Institute of Tropical Medicine, Professor, 熱帯医学研究所, 教授 (40182240)
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| Co-Investigator(Kenkyū-buntansha) |
HASEBE Futoshi Nagasaki University, Institute of Tropical Medicine, Assistant Professor, 熱帯医学研究所, 講師 (20253693)
TSUDA Yoshio National Institute of Infectious Diseases, Chief, 昆虫医科学部, 室長 (20207393)
INOUE Shingo Nagasaki University, Institute of Tropical Medicine, Research Associate, 熱帯医学研究所, 助手 (00346925)
KUMATORI Atsushi Nagasaki University, Institute of Tropical Medicine, Assistant Professor, 熱帯医学研究所, 講師 (60244092)
TADANO Masayuki Ryukyu University, School of Medicine, Associate Professor, 医学部, 助教授 (80179712)
井上 晋吾 長崎大学, 熱帯医学研究所, 助手
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥9,000,000 (Direct Cost: ¥9,000,000)
Fiscal Year 2002: ¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 2001: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | dengue haemorrhagic fever / Southeast Asia / dengue virus / tropical diseases / デング出血熱 / デングウイルス / チクングニヤウイルス / デング熱 |
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| Research Abstract |
We conducted a study to find out the causes of dengue hemorrhagic fever (DHF) and its emergence in Southeast Asia, by : (a)isolating the dengue virus in many parts of the region ; (b)analyzing patient cells infected by the virus ; and (c)conducting a vector mosquito survey. We then analyzed the following three factors of the disease : 1)pathogen ; 2)host ; and 3)vector. In Thailand, a combination of dengue virus strains and the sensitivity of the mosquito vector was found to be associated with the spread of the virus. In the Philippines, a genotype shift of dengue virus type2 across the country was observed. In Vietnam, a new genotype of dengue type4 virus outbreak was witnessed. Also, Flowcytometry analysis in the Philippines and Vietnam demonstrated multipopulation of dengue virus infected cells in peripheral blood monocytes.
In the past, two hypothesis on DHF were advocated, i.e., 1)virus virulence theory and 2)secondary infection theory. Our conclusion from these series of research is that both factors were concerned with the development, emergence and expansion of DHF in Southeast Asia. The evident physiological characteristic of DHF is its rapid plasma leakage from peripheral vessels. It should be clarified what viral protein(s) and kind of host cytokines are stimulating such rapid leak of plasma. It has also been noted that each population of Aedes aegypti caught from different localities demonstrated a unique susceptibility to dengue virus strains. The genotype shift of dengue 2 virus observed in the Philippines may have been promoted by a higher affinity of the newly introduced genotype of the virus. This indicates the possibility that rapid expansion of DHF during the 1960s may have been promoted by any virus mutation which enhanced virus and vector mosquito affinity. Further genetic analysis of dengue virus strains are necessary to clarify the mechanism of DHF emergence and rapid expansion in Southeast Asia.
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