start-ver=1.4 cd-journal=joma no-vol=60 cd-vols= no-issue=4 article-no= start-page=452 end-page=459 dt-received= dt-revised= dt-accepted= dt-pub-year=2011 dt-pub=201112 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Analysis of the effectiveness of control measures against Schistosoma mekongi using an intra- and inter-village model in Champasak Province, Lao PDR en-subtitle= kn-subtitle= en-abstract= kn-abstract=Schistosomiasis mekongi is prevalent in the Khong district of Lao PDR, made up of one big island. Khong, and numerous small islands in the Mekong River. Schistosoma mekongi is spread by Neotricula aperta as the intermediate host along the Mekong River. Therefore, even if an epidemic of S. mekongi were stamped out in a certain village, infection may recur if the source of infection is a village located in the upper reaches of the Mekong River. The purpose of this study was to construct a mathematical model for the transmission of S. mekongi among villages from the upper to lower Mekong River to estimate the effect of control measures against it. The chief characteristic of the present model is competence in dealing with the spread of infection among villages through the Mekong River in consideration of the reduction in longevity of cercariae and miracidia and their diffusion in the river. The model also takes into account seasonal fluctuation in the water level of the Mekong River, which affects human behavior in terms of water contact. The results of simulations indicated that the prevalence of schistosomiasis mekongi would be suppressed to a low level for a long time in a village further downstream when universal mass treatment is performed in villages further upstream simultaneously. en-copyright= kn-copyright= en-aut-name=FukuharaKazuma en-aut-sei=Fukuhara en-aut-mei=Kazuma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=PhompidaSamlane en-aut-sei=Phompida en-aut-mei=Samlane kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=InsisiengmaySithat en-aut-sei=Insisiengmay en-aut-mei=Sithat kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KirinokiMasashi en-aut-sei=Kirinoki en-aut-mei=Masashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=ChigusaYuichi en-aut-sei=Chigusa en-aut-mei=Yuichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NakamuraSatoshi en-aut-sei=Nakamura en-aut-mei=Satoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=MatsudaHajime en-aut-sei=Matsuda en-aut-mei=Hajime kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil= kn-affil=Department Human Ecology, Graduate School of Environmental Science, Okayama University affil-num=2 en-affil= kn-affil=National Centre of Malariology, Parasitology and Entomology, Ministry of Health, Lao PDR affil-num=3 en-affil= kn-affil=Pasteur Institute of Laos, Ministry of Health, Lao PDR affil-num=4 en-affil= kn-affil=Laboratory of Tropical Medicine and Parasitology, Dokkyo Medical University affil-num=5 en-affil= kn-affil=Laboratory of Tropical Medicine and Parasitology, Dokkyo Medical University affil-num=6 en-affil= kn-affil=Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine affil-num=7 en-affil= kn-affil=Institute of International Education and Research, Dokkyo Medical University affil-num=8 en-affil= kn-affil=Department Human Ecology, Graduate School of Environmental Science, Okayama University en-keyword=Schistosoma mekongi kn-keyword=Schistosoma mekongi en-keyword=Khong; Mekong River kn-keyword=Khong; Mekong River en-keyword=Mathematical model kn-keyword=Mathematical model en-keyword=Universal mass treatment (UT) kn-keyword=Universal mass treatment (UT) END start-ver=1.4 cd-journal=joma no-vol=51 cd-vols= no-issue=9 article-no= start-page=823 end-page=832 dt-received= dt-revised= dt-accepted= dt-pub-year=2007 dt-pub=2007 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Mathematical Modeling of Severe Acute Respiratory Syndrome Nosocomial Transmission in Japan: The Dynamics of Incident Cases and Prevalent Cases en-subtitle= kn-subtitle= en-abstract= kn-abstract=An outbreak of Severe Acute Respiratory Syndrome (SARS) occurred in Hong Kong in late February 2003, resulting in 8,096 cumulative cases with 774 deaths. The outbreak was amplified by nosocomial transmission in many hospitals. Using mathematical modeling, we simulated the number of new incident and prevalent cases of SARS after one infected person was admitted to a hospital (index case). The simulation was tested stochastically using the SEIR model based on previously reported Gamma distributions. We estimated the duration time until 10 beds in negative pressure rooms in Chiyoda-ku, one of the 23 wards in Tokyo, were fully occupied with SARS-infected patients. We determined the impact of an increasing number of days on the number of prevalent cases until the index case was isolated. The prevalent cases increase exponentially along with the increase of the non-isolation period of the index case, and all the beds were fully occupied if the index case was not isolated until more than 6 days. However even 2 days non-isolation period of the index case could fill up all the beds when 16% of secondary infections are transmitted outside the hospital. There is a possibility that an epidemic will occur with the isolation of the index case even at early days if the infection is transmitted outside the hospital. The simulation results revealed that it was important to recognize and isolate SARS patients as early as possible and also to prevent the transmission spreading outside the hospital to control an epidemic. en-copyright= kn-copyright= en-aut-name=FukutomeAyako en-aut-sei=Fukutome en-aut-mei=Ayako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=WatashiKoichi en-aut-sei=Watashi en-aut-mei=Koichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawakamiNorito en-aut-sei=Kawakami en-aut-mei=Norito kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Hygiene and Preventive Medicine, Okayama University Graduate School of Medicine, Dentistry & Pharmaceutical Sciences affil-num=2 en-affil= kn-affil=Department of Viral Oncology, Institute for Virus Research, Kyoto University affil-num=3 en-affil= kn-affil=Department of Mental Health, University of Tokyo Graduate School of Medicine affil-num=4 en-affil= kn-affil=Department of Human Ecology, Graduate School of Environmental Science, Okayama University en-keyword=SARS kn-keyword=SARS en-keyword=Nosocomial transmission kn-keyword=Nosocomial transmission en-keyword=Stochastic model kn-keyword=Stochastic model en-keyword=Simulation kn-keyword=Simulation END start-ver=1.4 cd-journal=joma no-vol=55 cd-vols= no-issue=1 article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=20080314 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Modelling the dynamics and control of Schistosoma japonicum transmission on Bohol island, the Philippines en-subtitle= kn-subtitle= en-abstract= kn-abstract=

We have investigated a mathematical model for the transmission of Schistosoma japonicum in the infested region of northeastern Bohol island in the Philippines. The development of transmission models is important for planning control strategies. Since S. japonicum has a complicated mode of transmission, the rates of transmission among its hosts cannot be measured directly by field observation. Instead, they have been estimated through model analysis. The model takes into account the seasonal variations and includes a function of control measures. In 1981, a project to eliminate schistosomiasis started on Bohol island. The prevalence decreased dramatically and has kept low level less than 1%. The simulations based on the model predicted that there is little probability of resurgence of an epidemic in the northeastem endemic villages of Bohol island due to the fact that the project has attained a high coverage of selective mass treatment based oil stool examination accompanied by a successful snail control operation. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

en-copyright= kn-copyright= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OhmaeHiroshi en-aut-sei=Ohmae en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=PangilinanRogelio en-aut-sei=Pangilinan en-aut-mei=Rogelio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=RedullaApolinario en-aut-sei=Redulla en-aut-mei=Apolinario kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MatsudaHajime en-aut-sei=Matsuda en-aut-mei=Hajime kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=National Institute of Infectious Diseases affil-num=3 en-affil= kn-affil=Schistosomiasis Control Team affil-num=4 en-affil= kn-affil=Schistosomiasis Control Team affil-num=5 en-affil= kn-affil=Dokkyo University School of Medicine en-keyword=schistosomiasis japonica kn-keyword=schistosomiasis japonica en-keyword=control kn-keyword=control en-keyword=mathematical model kn-keyword=mathematical model en-keyword=Philippines kn-keyword=Philippines en-keyword=Bohol kn-keyword=Bohol END start-ver=1.4 cd-journal=joma no-vol=57 cd-vols= no-issue=3 article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=20080903 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The evaluation of control measures against Schistosoma mekongi in Cambodia by a mathematical model en-subtitle= kn-subtitle= en-abstract= kn-abstract=

We constructed a mathematical model for the transmission of Schistosoma mekongi in Cambodia. The simulation of the model will be instrumental in planning schistosomiasis control measures. The model includes two definitive hosts, humans and dogs, as animal reservoirs. Dogs are recognized to play an important role in schistosomiasis transmission in Cambodia. For the purpose of dealing with age-specific prevalence and intensity of infection, the human population was classified into eight age categories in the model. To describe the seasonal fluctuation of the intermediate host population of S. mekongi, the "Post-Spate Survival" hypothesis was adopted for the population dynamics of Neotricula aperta present in the Mekong River. We carried out simulations to evaluate the effect of universal treatment (UT) and targeted mass treatment (TT) with praziquantel on the reduction in prevalence of S. mekongi. The simulations indicated that biyearly UT for 8 years or yearly TT for 5 years after three courses of yearly UT could reduce the prevalence to below 5% when a UT or TT coverage of 85% of inhabitants was achieved. The simulation suggested that the suppression of S. mekongi in Cambodia would be possible by UT or TT with a high coverage rate.

en-copyright= kn-copyright= en-aut-name=HisakaneNaoto en-aut-sei=Hisakane en-aut-mei=Naoto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KirinokiMasashi en-aut-sei=Kirinoki en-aut-mei=Masashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=ChigusaYuichi en-aut-sei=Chigusa en-aut-mei=Yuichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SinuonMuth en-aut-sei=Sinuon en-aut-mei=Muth kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SocheatDuong en-aut-sei=Socheat en-aut-mei=Duong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MatsudaHajime en-aut-sei=Matsuda en-aut-mei=Hajime kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil= kn-affil=Department of Human Ecology, Graduate School of Environmental Science, Okayama University affil-num=2 en-affil= kn-affil=Center for Tropical Medicine and Parasitology, Dokkyo Medical University School of Medicine affil-num=3 en-affil= kn-affil=Center for Tropical Medicine and Parasitology, Dokkyo Medical University School of Medicine affil-num=4 en-affil= kn-affil=National Center for Parasitology, Entomology and Malaria Control, Ministry of Health affil-num=5 en-affil= kn-affil=National Center for Parasitology, Entomology and Malaria Control, Ministry of Health affil-num=6 en-affil= kn-affil=Institute of International Education and Research, Dokkyo Medical University School of Medicine affil-num=7 en-affil= kn-affil=Department of Human Ecology, Graduate School of Environmental Science, Okayama University, en-keyword=Schistosoma mekongi kn-keyword=Schistosoma mekongi en-keyword=Cambodia kn-keyword=Cambodia en-keyword=mathematical model kn-keyword=mathematical model en-keyword=Neotricula aperta kn-keyword=Neotricula aperta en-keyword=Mekong River kn-keyword=Mekong River END start-ver=1.4 cd-journal=joma no-vol=91 cd-vols= no-issue=6 article-no= start-page=444 end-page=451 dt-received= dt-revised= dt-accepted= dt-pub-year=2003 dt-pub=20030729 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A model for the transmission of Echinococcus multilocularis in Hokkaido, Japan en-subtitle= kn-subtitle= en-abstract= kn-abstract=

A mathematical model for Echinococcus multilocularis transmission would be useful to estimate its prevalence and manage control strategies. We propose a mathematical model which quantitatively describes the transmission of E. multilocularis in Hokkaido, Japan. The model takes into account the influence of the dynamics of both the definitive and the intermediate host populations, which show large scale seasonal variations as they are wild animals. The simulations based on the model clarify the mechanism for the seasonal transmission of E. multilocularis quantitatively, notwithstanding a lack of seasonal prevalence data. At present, human alveolar echinococcosis is prevalent throughout the mainland of Hokkaido. The risk of being infected with alveolar echinococcosis in the human population has been investigated by analyzing the seasonal fluctuation of parasite egg dispersal in the environment, which should be necessary for planning more suitable preventive measures against E. multilocularis.

en-copyright= kn-copyright= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OhgaYukio en-aut-sei=Ohga en-aut-mei=Yukio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=DoiRikuo en-aut-sei=Doi en-aut-mei=Rikuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Horiba Limited affil-num=3 en-affil= kn-affil=Yokohama City University en-keyword=computer simulation kn-keyword=computer simulation en-keyword=echinococcus multilocularis kn-keyword=echinococcus multilocularis en-keyword=hokkaido kn-keyword=hokkaido en-keyword=japan kn-keyword=japan en-keyword=transmission model kn-keyword=transmission model END start-ver=1.4 cd-journal=joma no-vol=55 cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=20080325 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Mathematical modeling of Echinococcus multilocularis transmission en-subtitle= kn-subtitle= en-abstract= kn-abstract=

A mathematical model for the transmission cycle of Echinococcus multilocularis would be useful for estimating its prevalence, and the model simulation can be instrumental in designing various control strategies. This review focuses on the epidemiological factors in the E. multilocularis transmission cycle and the recent advances of mathematical models for E. multilocularis transmission.

en-copyright= kn-copyright= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=Okayama University en-keyword=Echinococcus multilocularis kn-keyword=Echinococcus multilocularis en-keyword=fox kn-keyword=fox en-keyword=mathematical model kn-keyword=mathematical model en-keyword=vole kn-keyword=vole END start-ver=1.4 cd-journal=joma no-vol=102 cd-vols= no-issue=3 article-no= start-page=465 end-page=479 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=20080201 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A stochastic model of Echinococcus multilocularis transmission in Hokkaido, Japan, focusing on the infection process en-subtitle= kn-subtitle= en-abstract= kn-abstract=

Echinococcus multilocularis causes human alveolar echinococcus. In Japan, high prevalence of E. multilocularis among the fox population has been reported throughout Hokkaido. Accordingly, control measures, such as fox hunting and the distribution of bait containing Praziquantel, have been conducted. This study developed a transmission model for individuals in the fox population and included a stochastic infection process to assess the prevalence of E. multilocularis. To make our model realistic, we used the worm burden for each individual in the fox population. We assumed that the worm burden depends on the number of protoscoleces in a predated vole and the number of infection experiences. We carried out stochastic simulations with 1,000 trials for the situations of Koshimizu and Sapporo, Hokkaido, Japan. The distribution of the worm burden among foxes obtained using the model agreed with dissection data. The simulation indicates that a careful choice of season is necessary for an effective distribution of Praziquantel-containing bait. A stochastic model for E. multilocularis, which can assess the range of the prevalence in the fox population, would be helpful in analyzing their complex life-cycle and also in designing control strategies.

en-copyright= kn-copyright= en-aut-name=NishinaTomohiko en-aut-sei=Nishina en-aut-mei=Tomohiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=Department of Human Ecology, Graduate School of Environmental Science, Okayama University affil-num=2 en-affil= kn-affil=Department of Human Ecology, Graduate School of Environmental Science, Okayama University en-keyword=Echinococcus multilocularis kn-keyword=Echinococcus multilocularis en-keyword=stochastic model kn-keyword=stochastic model en-keyword=control strategy kn-keyword=control strategy en-keyword=Hokkaido kn-keyword=Hokkaido END start-ver=1.4 cd-journal=joma no-vol=14 cd-vols= no-issue=1 article-no= start-page=1 end-page=11 dt-received= dt-revised= dt-accepted= dt-pub-year=2009 dt-pub=20090316 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Evaluation for interventions against influenza of H5N1 in Sapporo-city by using an Individual Based Model en-subtitle= kn-subtitle= en-abstract= kn-abstract=The spread of the highly pathogenic avian influenza (H5N1) among domestic poultry and wild birds has caused global concern over the outbreak of an influenza pandemic of H5N1. The "Pandemic Influenza Preparedness Action Plan" determines the strategy against an influenza pandemic in Japan. Simulations were carried out using an individual based model (IBM). The IBM targeted a virtual area with a population of 100,000 using the demographic data of Sapporo-city, Hokkaido. The effectiveness of targeted antiviral prophylaxis (TAP), geographical targeted antiviral prophylaxis (GTAP), school closure, and pre-pandemic vaccination were explored. Moreover, this study focused on infections among children, who have a high attack rate, and analyzed the effectiveness of interventions for school-age targeted antiviral prophylaxis (STAP). Consequently, TAP, which is recommended by the "Pandemic Influenza Preparedness Action Plan", was found to have high effectiveness in the suppression of the outbreak. Moreover, this study showed the importance of intervention among children, such as STAP and school closure, to prevent the spread of H5N1 influenza. en-copyright= kn-copyright= en-aut-name=MorimotoTomoko en-aut-sei=Morimoto en-aut-mei=Tomoko kn-aut-name=森本智子 kn-aut-sei=森本 kn-aut-mei=智子 aut-affil-num=1 ORCID= en-aut-name=ZenihanaTomohiro en-aut-sei=Zenihana en-aut-mei=Tomohiro kn-aut-name=銭花知弘 kn-aut-sei=銭花 kn-aut-mei=知弘 aut-affil-num=2 ORCID= en-aut-name=MaitaniYusuke en-aut-sei=Maitani en-aut-mei=Yusuke kn-aut-name=米谷祐介 kn-aut-sei=米谷 kn-aut-mei=祐介 aut-affil-num=3 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 affil-num=4 en-affil= kn-affil=岡山大学 en-keyword=Influenza kn-keyword=Influenza en-keyword=Pandemic kn-keyword=Pandemic en-keyword=H5N1 kn-keyword=H5N1 en-keyword=Individual Based Model (IBM) kn-keyword=Individual Based Model (IBM) en-keyword=Sapporo kn-keyword=Sapporo END start-ver=1.4 cd-journal=joma no-vol=13 cd-vols= no-issue=1 article-no= start-page=23 end-page=33 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=200803 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Analysis of the effectiveness of control strategies against bioterrorist smallpox attacks by using Individual Based Model en-subtitle= kn-subtitle= en-abstract= kn-abstract=We carried out simulations of various scenarios for bioterrorist attacks using smallpox occurring in a virtual area set up on the basis of the census of Okayama-city, Japan, which predict the effect of control strategies against bioterrorism and the loss scale. On simulating a smallpox epidemic, we followed the method of the Individual Based Model stochastically, which can treat the population in the virtual area as individuals. Individuals have personal information, behavior patterns, and interactions among social groups. We took into consideration the influence of residual immunity due to past vaccination. We considered Traced Vaccination (TV) and Mass Vaccination (MV) strategies against bioterrorism. We investigated the effect of TV and MV strategies on the suppression of smallpox epidemics. Consequently, the TV strategy was found to have higher effectiveness than the MV strategy. en-copyright= kn-copyright= en-aut-name=ZenihanaTomohiro en-aut-sei=Zenihana en-aut-mei=Tomohiro kn-aut-name=銭花知弘 kn-aut-sei=銭花 kn-aut-mei=知弘 aut-affil-num=1 ORCID= en-aut-name=HisakaneNaoto en-aut-sei=Hisakane en-aut-mei=Naoto kn-aut-name=久兼直人 kn-aut-sei=久兼 kn-aut-mei=直人 aut-affil-num=2 ORCID= en-aut-name=MorimotoTomoko en-aut-sei=Morimoto en-aut-mei=Tomoko kn-aut-name=森本智子 kn-aut-sei=森本 kn-aut-mei=智子 aut-affil-num=3 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 affil-num=4 en-affil= kn-affil=岡山大学 en-keyword=smallpox kn-keyword=smallpox en-keyword=bioterrorism kn-keyword=bioterrorism en-keyword=Individual Based Model kn-keyword=Individual Based Model en-keyword=Traced Vaccination kn-keyword=Traced Vaccination en-keyword=Mass Vaccination kn-keyword=Mass Vaccination END start-ver=1.4 cd-journal=joma no-vol=13 cd-vols= no-issue=1 article-no= start-page=7 end-page=15 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=200803 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Statistical modeling for analysis of malaria epidemic behavior at Ishigaki Island kn-title=石垣島におけるマラリア流行解析のための統計モデリング en-subtitle= kn-subtitle= en-abstract= kn-abstract=It is necessary to consider a stochastic variability in modeling malaria epidemic behavior since the malaria infection cycle essentially depends on stochastic elements. For this requirement, we need to construct an appropriate statistical model from available data in advance. In this report, we provide some statistical models for the analysis of malaria epidemic behavior at Ishigaki Island. These models can be used for recurrence of past malaria epidemic and prediction of future malaria epidemic at Ishigaki Island. en-copyright= kn-copyright= en-aut-name=UekiMasao en-aut-sei=Ueki en-aut-mei=Masao kn-aut-name=植木優夫 kn-aut-sei=植木 kn-aut-mei=優夫 aut-affil-num=1 ORCID= en-aut-name=NakagawaYuuki en-aut-sei=Nakagawa en-aut-mei=Yuuki kn-aut-name=中川祐希 kn-aut-sei=中川 kn-aut-mei=祐希 aut-affil-num=2 ORCID= en-aut-name=FuedaKaoru en-aut-sei=Fueda en-aut-mei=Kaoru kn-aut-name=笛田薫 kn-aut-sei=笛田 kn-aut-mei=薫 aut-affil-num=3 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 affil-num=4 en-affil= kn-affil=岡山大学 en-keyword=Anopheles minimus, kn-keyword=Anopheles minimus, en-keyword=generalized liner model kn-keyword=generalized liner model en-keyword=Ishigaki Island kn-keyword=Ishigaki Island en-keyword=malaria epidemic behavior kn-keyword=malaria epidemic behavior en-keyword=prediction kn-keyword=prediction en-keyword=stochastic model kn-keyword=stochastic model END start-ver=1.4 cd-journal=joma no-vol=1 cd-vols= no-issue=1 article-no= start-page=47 end-page=53 dt-received= dt-revised= dt-accepted= dt-pub-year=1996 dt-pub=199603 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Computational water analysis in an artificial lake: Kojima Lake case en-subtitle= kn-subtitle= en-abstract= kn-abstract=We treat the problem of water pollution by the method of a mathematical model. We illustrate the method of analysis with Kojima Lake. We analyze in-flow and out-flow of the lake, compute numerical solutions of the governing equations of the water flow and the pollutant. The simulation leads to the conclusion concerning the figure of Kojima Lake. en-copyright= kn-copyright= en-aut-name=SasakiToru en-aut-sei=Sasaki en-aut-mei=Toru kn-aut-name=佐々木徹 kn-aut-sei=佐々木 kn-aut-mei=徹 aut-affil-num=1 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=2 ORCID= en-aut-name=KajiwaraTsuyoshi en-aut-sei=Kajiwara en-aut-mei=Tsuyoshi kn-aut-name=梶原毅 kn-aut-sei=梶原 kn-aut-mei=毅 aut-affil-num=3 ORCID= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 affil-num=4 en-affil= kn-affil=岡山大学 en-keyword=Kojima lake kn-keyword=Kojima lake en-keyword=Water analysis kn-keyword=Water analysis en-keyword=Finite element method kn-keyword=Finite element method END start-ver=1.4 cd-journal=joma no-vol=1 cd-vols= no-issue=1 article-no= start-page=27 end-page=41 dt-received= dt-revised= dt-accepted= dt-pub-year=1996 dt-pub=199603 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The determination of small dimensions of the Hilbert Modular Type Cusp forms of Weight Two over Real Quadratic Fields en-subtitle= kn-subtitle= en-abstract= kn-abstract=The author has proved the dimension formula of the space of the Hilbert modular type cusp forms of weight two. We present further refinements of the dimension formula for a real quadratic number field Q(√D), and calculate it effectively. We tabulate the dimensions for square-free natural numbers D below 104 with the computer assistance. We also determine all the spaces of their dimension below 10. en-copyright= kn-copyright= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 END start-ver=1.4 cd-journal=joma no-vol=2 cd-vols= no-issue=1 article-no= start-page=9 end-page=17 dt-received= dt-revised= dt-accepted= dt-pub-year=1997 dt-pub=19970110 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The Elliptic resolutions for Symmetric Hilbert modular surface and their applications en-subtitle= kn-subtitle= en-abstract= kn-abstract=In this paper, we have calculated the elliptic singularities of the symmetric Hilbert modular group defined over a real quadratic number field. Applying those to the dimension formula, we tabulate the dimensions of the space of symmetric Hilbert modular forms of weight two satisfying certain cusp condition. en-copyright= kn-copyright= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 END start-ver=1.4 cd-journal=joma no-vol=3 cd-vols= no-issue=1 article-no= start-page=31 end-page=36 dt-received= dt-revised= dt-accepted= dt-pub-year=1998 dt-pub=19980114 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Computational analysis of contamination in Kojima Lake using upwind-type finite element method en-subtitle= kn-subtitle= en-abstract= kn-abstract=We have computed the phase of spreading contaminations in Kojima Lake by using the upwind-type finite element method. We have treated the two cases: the pollutant flows from the Sasagase river and from the Kurashiki River. We see that the upwind-type finite element method is effective in both cases, when the diffusion constant is quite small. en-copyright= kn-copyright= en-aut-name=SasakiToru en-aut-sei=Sasaki en-aut-mei=Toru kn-aut-name=佐々木徹 kn-aut-sei=佐々木 kn-aut-mei=徹 aut-affil-num=1 ORCID= en-aut-name=KajiwaraTsuyoshi en-aut-sei=Kajiwara en-aut-mei=Tsuyoshi kn-aut-name=梶原毅 kn-aut-sei=梶原 kn-aut-mei=毅 aut-affil-num=2 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 en-keyword=Upwind-type kn-keyword=Upwind-type en-keyword=Finite element method kn-keyword=Finite element method en-keyword=Kojima Lake kn-keyword=Kojima Lake END start-ver=1.4 cd-journal=joma no-vol=3 cd-vols= no-issue=1 article-no= start-page=5 end-page=9 dt-received= dt-revised= dt-accepted= dt-pub-year=1998 dt-pub=19980114 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The Fourier coefficients of certain Maass wave form for Γ0(2) en-subtitle= kn-subtitle= en-abstract= kn-abstract=We investigate the Maass wave form for Γ(0)(2) whose eigenvalue of Laplacian Δ is 1/4-π(2)/log(2)(√2-1). In this note, we study the methods of calculation of its Fourier coefficients and carry out the numerical calculations. en-copyright= kn-copyright= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 END start-ver=1.4 cd-journal=joma no-vol=5 cd-vols= no-issue=1 article-no= start-page=1 end-page=6 dt-received= dt-revised= dt-accepted= dt-pub-year=2000 dt-pub=20000229 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The prevalence of Plasmodium vivax in Vanuatu Islands: Computer simulation of malaria control trails en-subtitle= kn-subtitle= en-abstract= kn-abstract=We have estimated the degree of transmission of Plasmodium vivax malaria in Vanuatu Islands, eastern Melanesia with the aid of the computer simulations, which has been carried out on the platform of a mathematical transmission model. The malaria caused by Plasmodium vivax has a relapse character, which arises from hypnozoites in the liver. This phenomen makes a malaria control strategy difficult. When the mass drug administration is executed, the prevalence of Plasmodium vivax decreases moderately as compared with that of Plasmodium falciparum, and it recovers before long being affected by the relapses. The simulations suggest that one cannot attain the eradication of Plasmodium vivax malaria without the concentrated execution of the mass drug administration and the vector control that fairly reduces the vactorial capacity. en-copyright= kn-copyright= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=1 ORCID= en-aut-name=IshiiAkira en-aut-sei=Ishii en-aut-mei=Akira kn-aut-name=石井明 kn-aut-sei=石井 kn-aut-mei=明 aut-affil-num=2 ORCID= en-aut-name=KanekoAkira en-aut-sei=Kaneko en-aut-mei=Akira kn-aut-name=金子明 kn-aut-sei=金子 kn-aut-mei=明 aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=Department of Medical Zoology, Jichi Medical School affil-num=3 en-affil= kn-affil=Department of International Affairs and Tropical Medicine, Tokyo Women's Medical University en-keyword=Plasmodium vivax kn-keyword=Plasmodium vivax en-keyword=computer simulation kn-keyword=computer simulation en-keyword=hypnozoite kn-keyword=hypnozoite en-keyword=mass drug administration kn-keyword=mass drug administration en-keyword=relapse kn-keyword=relapse END start-ver=1.4 cd-journal=joma no-vol=7 cd-vols= no-issue=1 article-no= start-page=7 end-page=16 dt-received= dt-revised= dt-accepted= dt-pub-year=2002 dt-pub=20020322 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Mathematical Model for The Transmission of Lymphatic Filariasis and Its Applications en-subtitle= kn-subtitle= en-abstract= kn-abstract=We have constructed a stochastic transmission model for lymphatic filariasis caused by Wuchereria bancrofti, and have analyzed its prevalence using computer simulations. In Pondicherry, India, where Wuchereria bancrofti has been spreading, the Vector Control Research Centre has carried out an integrated vector control strategy against malaria and filariasis for five years (1981~1985) with good results reported. Our study was aimed at evaluating the effect of vector control in the context of Pondicherry, and in particular the continuous effect for the post-control period. In this paper, we have used the LYMFASIM model proposed by Plaisier et al., the carrying capacity model by Rochet and the population dynamics model by us. In the LYMFASIM model and the carrying capacity model, we have modified the quantities of parameters in order to fit the models to the parasitological, entomological and epidemiological data in Pondicherry. We have combined the improved LYMFASIM model with the other models. Through simulations of our combinated model, we have compared the prevalence rate in the human population as well as the mean number of L3-larvae in the mosquito population, with and without vector control. As a result, the simulations show that the prevalence rate would be restrained for a long time even if only a small continuous effect of the vector control remains in the post-control period. However, the mean number of L3-larvae would recovered within a short time comparatively. This is because of the differences in life spans between human and mosquito as well as the incubation periods between the adult worm in the human host and L3-larvae in the mosquito vector. en-copyright= kn-copyright= en-aut-name=IshiiHiroyuki en-aut-sei=Ishii en-aut-mei=Hiroyuki kn-aut-name=石井裕之 kn-aut-sei=石井 kn-aut-mei=裕之 aut-affil-num=1 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=2 ORCID= en-aut-name=OhgaYukio en-aut-sei=Ohga en-aut-mei=Yukio kn-aut-name=大賀潔生 kn-aut-sei=大賀 kn-aut-mei=潔生 aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 en-keyword=Lymphatic filariasis kn-keyword=Lymphatic filariasis en-keyword=mathematical model kn-keyword=mathematical model en-keyword=Pondicherry kn-keyword=Pondicherry en-keyword=vector control kn-keyword=vector control en-keyword=Wuchereria bancrofti kn-keyword=Wuchereria bancrofti END start-ver=1.4 cd-journal=joma no-vol=7 cd-vols= no-issue=1 article-no= start-page=1 end-page=5 dt-received= dt-revised= dt-accepted= dt-pub-year=2002 dt-pub=20020322 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Simulations on Prevalence of Echinococcus multilocularis in Hokkaido on the Basis of Vole Population Dynamics en-subtitle= kn-subtitle= en-abstract= kn-abstract=In our study, we have investigated the influence of the intermediate host population density on the prevalence of Echinococcus multilocularis in the definitive host using a mathematical model of transmission. For the vole population (intermediate host) in Hokkaido, a model of population dynamics has been constructed in this paper which follows the seasonal and annual fluctuations. In the northeastern area, the vole density appears to fluctuate periodically with a 4 year cycle. The prevalence of Echinococcus multilocularis in the fox population (definitive host) can be affected by the density of vole through the fox ingesting infectious voles. Therefore we have prepared a food habit function of foxes and the logistic distribution has been proposed. The simulations which have been carried out using the mathematical model for transmission of Echinococcus multilocularis together with the vole dynamics have indicated that the prevalence in foxes is correlated and synchronized with the population dynamics of vole. In addition they have also made us recognize that it is necessary to introduce a suitable food habit function into the transmission model. en-copyright= kn-copyright= en-aut-name=OhgaYukio en-aut-sei=Ohga en-aut-mei=Yukio kn-aut-name=大賀潔生 kn-aut-sei=大賀 kn-aut-mei=潔生 aut-affil-num=1 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=2 ORCID= en-aut-name=DoiRikuo en-aut-sei=Doi en-aut-mei=Rikuo kn-aut-name=土井陸雄 kn-aut-sei=土井 kn-aut-mei=陸雄 aut-affil-num=3 ORCID= en-aut-name=IshiiHiroyuki en-aut-sei=Ishii en-aut-mei=Hiroyuki kn-aut-name=石井裕之 kn-aut-sei=石井 kn-aut-mei=裕之 aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=Department of Hygiene, School of Medicine, Yokohama City University affil-num=4 en-affil= kn-affil=岡山大学 en-keyword=Echinococcus multilocularis kn-keyword=Echinococcus multilocularis en-keyword=food habit of foxes kn-keyword=food habit of foxes en-keyword=Hokkaido kn-keyword=Hokkaido en-keyword=population dynamics kn-keyword=population dynamics en-keyword=vole kn-keyword=vole END start-ver=1.4 cd-journal=joma no-vol=8 cd-vols= no-issue=1 article-no= start-page=1 end-page=7 dt-received= dt-revised= dt-accepted= dt-pub-year=2003 dt-pub=200303 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Studies on the transmission model of HIV/AIDS among commercial sex workers in Thailand en-subtitle= kn-subtitle= en-abstract= kn-abstract=In 1990s, there were rapid increases in the number of HIV epidemics and AIDS cases in Thailand, Southeast Asia. In particular the risk of HIV infection was very high among female prostitutes who played a large part in the transmission of HIV infection. We formulated a mathematical model for the transmission of HIV in prostitutes. We carried out the model simulations to analyze the incipient spread of HIV infection and the effect of AIDS prevention methods in prostitutes. The simulation of our model indicates that even if the effect of AIDS prevention methods such as the recommendation of condom use for commercial sex workers would block the transmission at rate by 70%, the elimination of the HIV epidemic is still beyond attainment. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=TsunekuniYasuhiro kn-aut-sei=Tsunekuni kn-aut-mei=Yasuhiro aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=OhgaYukio kn-aut-sei=Ohga kn-aut-mei=Yukio aut-affil-num=2 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 en-keyword=AIDS kn-keyword=AIDS en-keyword=HIV kn-keyword=HIV en-keyword=prostitution kn-keyword=prostitution en-keyword=Thailand kn-keyword=Thailand en-keyword=transmission model kn-keyword=transmission model END start-ver=1.4 cd-journal=joma no-vol=10 cd-vols= no-issue=1 article-no= start-page=1 end-page=7 dt-received= dt-revised= dt-accepted= dt-pub-year=2005 dt-pub=20050228 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Linear and Differential Cryptanalysis of SHA-256 en-subtitle= kn-subtitle= en-abstract= kn-abstract=The one-way hash function plays an important role in digital signatures and message authentication from the viewpoint of security. No effective attacking method has been discovered to the algorithm of hash function standard. In this study, we tried to attack SHA-256 in encryption mode using linear and differential cryptanalysis to solve a private key. We deduced that an estimate of the private key would require huge known and chosen plaintexts in both linear and differential cryptanalysis, and that it would be difficult to decipher SHA-256 in view of the required computation. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=WangXiao Dong kn-aut-sei=Wang kn-aut-mei=Xiao Dong aut-affil-num=1 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 en-keyword=differential cryptanalysis kn-keyword=differential cryptanalysis en-keyword=encryption mode kn-keyword=encryption mode en-keyword=hash function kn-keyword=hash function en-keyword=linear cryptanalysis kn-keyword=linear cryptanalysis en-keyword=SHA-256 kn-keyword=SHA-256 END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue=1 article-no= start-page=19 end-page=26 dt-received= dt-revised= dt-accepted= dt-pub-year=2004 dt-pub=20040227 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Study on the Linear Cryptanalysis of AES Cipher en-subtitle= kn-subtitle= en-abstract= kn-abstract=We have investigated the linear cryptanalysis of AES cipher in this article. As the previous encryption standard DES could be broken by the linear cryptanalysis, NIST decided a new encryption standard AES in 2000. We try to analyze one and two rounds AES cipher by the method of the linear cryptanalysis and learn the limits of this mehtod. AES cipher provides a conspicuous difficulty in breaking its keys because of small bias of its S-box. We report the experimental results of success rate and are led to conclusion that this method would not work well on more than 3 rounds to break keys. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=SakamuraKenichi kn-aut-sei=Sakamura kn-aut-mei=Kenichi aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=DongWang Xiao kn-aut-sei=Dong kn-aut-mei=Wang Xiao aut-affil-num=2 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 en-keyword=AES kn-keyword=AES en-keyword=Chosen plaintext attack kn-keyword=Chosen plaintext attack en-keyword=Linear cryptanalysis kn-keyword=Linear cryptanalysis END start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue=1 article-no= start-page=19 end-page=27 dt-received= dt-revised= dt-accepted= dt-pub-year=2007 dt-pub=20070315 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=A mathematical model of Plasmodium falciparum transmission incorporating drug resistance: Simulations of the Solomon Islands situation kn-title=クロロキシン薬剤耐性に関する熱帯熱マラリア数理モデル解析 ―ソロモン諸島を対象としたシミュレーション en-subtitle= kn-subtitle= en-abstract= kn-abstract=The Solomon Islands are known as a high endemic region of malaria. The resistance of Plasmodium falciparum to chloroquine has been confirmed since 1980 in the Solomon Islands, and the spread of chloroquine resistance is a big hurdle to malaria control. We have constructured the model for P. falciparum making allowance of chloroquine resistance. We distinguish the infection of resistance strains from that of sensitive strains in both the human and the vector populations. Since the overall parasite rate and the parasite rate of gametocytes for P. falciparum are strongly dependent on age, the human population is divided into 7 age groups in the model. The epidemiological parameters are determined by malariological survey in northeastern Guadalcanal (Ishii et al.) and the sporozoite rate in vector population is assumed as 0.1% based on the entomological study (Harada et al.) Our study aims at estimating the effect of mass drug administration under the presence of drug-resistance and also analyzing the escalation of drug-resistance through the transmission model for P. falciparum which can deal with chloroquine resistance. en-copyright= kn-copyright= en-aut-name=ChenTiantian en-aut-sei=Chen en-aut-mei=Tiantian kn-aut-name=陳甜甜 kn-aut-sei=陳 kn-aut-mei=甜甜 aut-affil-num=1 ORCID= en-aut-name=NishinaTomohiko en-aut-sei=Nishina en-aut-mei=Tomohiko kn-aut-name=仁科朝彦 kn-aut-sei=仁科 kn-aut-mei=朝彦 aut-affil-num=2 ORCID= en-aut-name=HisakaneNaoto en-aut-sei=Hisakane en-aut-mei=Naoto kn-aut-name=久兼直人 kn-aut-sei=久兼 kn-aut-mei=直人 aut-affil-num=3 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 affil-num=4 en-affil= kn-affil=岡山大学 en-keyword=Solomon Islands kn-keyword=Solomon Islands en-keyword=Plasmodium falciparum kn-keyword=Plasmodium falciparum en-keyword=drug resistance kn-keyword=drug resistance en-keyword=model kn-keyword=model END start-ver=1.4 cd-journal=joma no-vol=11 cd-vols= no-issue=1 article-no= start-page=9 end-page=14 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=20060315 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A stochastic model of Echinococcus multilocularis focusing on protoscoleces en-subtitle= kn-subtitle= en-abstract= kn-abstract=The red fox (Vulpes vulepes) and the vole ( Clethrionomys refocanus) are principal hosts of Echinococcus multilocularis in Hokkaido, Japan. How protoscoleces increases in voles and the level of immunity in foxes remain unknown because of the lack of survey data, so that it is important to clarify these mecahnisms in order to develop control strategies against E. multilocularis. In this study, the growth of protoscoleces in the infected voles was approximated as the logistic curve, the level of immunity in the fox was assumed to depend on the experience of the infection with E. multilocularis, and the worm burden in the fox was assumed to be governed by the amount of protoscoleces in the vole. Our model showed that the population densities of the hosts and the level of immunity influenced the prevalence of the E. multilocularis. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=NishinaTomohiko kn-aut-sei=Nishina kn-aut-mei=Tomohiko aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=Tian TianChen kn-aut-sei=Tian Tian kn-aut-mei=Chen aut-affil-num=2 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=FujitaKazutoshi kn-aut-sei=Fujita kn-aut-mei=Kazutoshi aut-affil-num=3 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 affil-num=4 en-affil= kn-affil=岡山大学 en-keyword=Echinococcus multilocularis kn-keyword=Echinococcus multilocularis en-keyword=protoscoleces kn-keyword=protoscoleces en-keyword=immunity kn-keyword=immunity en-keyword=worm burden kn-keyword=worm burden en-keyword=stochastic model kn-keyword=stochastic model END start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue=1 article-no= start-page=7 end-page=18 dt-received= dt-revised= dt-accepted= dt-pub-year=2007 dt-pub=20070315 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The order elliptic curves over finite fields of characteristic two using the Schoof algorithm en-subtitle= kn-subtitle= en-abstract= kn-abstract=The elliptic curve cryptosystem is a popular cryptosystem. Its safety depends on the difficulty of the elliptic curve discrete logarithm problem (ECDLP). From the viewpoint of ECDLP, it is very interesting to determine the order of elliptic curves. We tabulate the order of elliptic curves on the finite field of characteristic two using the Schoof algorithm, which is an efficient algorithm to decide orders. The Schoof algorithm is carried out by O(log(8)q). Because the calculation of y(q2) occupies most of the time used to execute the Schoof algorithm, it is necessary to reduce the amount of y(q2) calculations. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=ImuraKeigo kn-aut-sei=Imura kn-aut-mei=Keigo aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=XiaoDongWang kn-aut-sei=XiaoDong kn-aut-mei=Wang aut-affil-num=2 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 en-keyword=elliptic curve kn-keyword=elliptic curve en-keyword=order kn-keyword=order en-keyword=division polynomial kn-keyword=division polynomial en-keyword=Schoof algorithm kn-keyword=Schoof algorithm en-keyword=finite field of characteristic two kn-keyword=finite field of characteristic two END start-ver=1.4 cd-journal=joma no-vol=11 cd-vols= no-issue=1 article-no= start-page=1 end-page=7 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=20060315 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Modeling of re-emerging Plasmodium vivax in the Northern Area of the Republic of Korea Based on a Mathematical Model en-subtitle= kn-subtitle= en-abstract= kn-abstract=Plasmodium vivax re-emerged in 1993 near the demilitarized zone (DMZ) in South Korea, although P. vivax malaria disappeared in South Korea in 1979. The re-emergence of malaria in South Korea is believed to have originated from infection by mosquitoes from North Korea across the DMZ. The principal vector of P. vivax in the Korean Peninsula is Anopheles sinensis. The density of An. sinensis has a peak during the second week of July. The North Korean strain of P. vivax has 2 characteristics: a wide distribution of the terms of relapse and a high rate of relapse. Therefore, we may well wonder why the incidence of malaria is concentrated in summer, especially in August. Mathematical models in North Korea and South Korea were constructed in which the South Korean model was affected unidirectionally by the North Korean model. We carried out simulations of the model for the Paju-shi and Yonchon-gun situations near the DMZ region. The simulation results followed the time-course of the re-emergence of P. vivax there, and revealed the mechanism of the elevation of the incidence of P. vivax in summer. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=FujitaKazutoshi kn-aut-sei=Fujita kn-aut-mei=Kazutoshi aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=Tian TianChen kn-aut-sei=Tian Tian kn-aut-mei=Chen aut-affil-num=2 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=NishinaTomohiko kn-aut-sei=Nishina kn-aut-mei=Tomohiko aut-affil-num=3 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 affil-num=4 en-affil= kn-affil=岡山大学 en-keyword=DMZ kn-keyword=DMZ en-keyword=Korea kn-keyword=Korea en-keyword=model kn-keyword=model en-keyword=Plasmodium vivax kn-keyword=Plasmodium vivax en-keyword=re-emergence kn-keyword=re-emergence END start-ver=1.4 cd-journal=joma no-vol=54 cd-vols= no-issue=4 article-no= start-page=165 end-page=171 dt-received= dt-revised= dt-accepted= dt-pub-year=2000 dt-pub=200008 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Estimation of the sporozoite rate of malaria vectors using the polymerase chain reaction and a mathematical model. en-subtitle= kn-subtitle= en-abstract= kn-abstract=

We developed a sensitive polymerase chain reaction (PCR) method for the detection of Plasmodium falciparum DNA from mosquitoes collected in the field. Plasmodium falciparum was detected from 15.2% of 1-parous mosquitoes, Anopheles farauti, in the Solomon Islands through use of the PCR method. A novel mathematical model was developed to estimate the sporozoite rate based on the malaria-positive rate of 1-parous mosquitoes. Using this model, the sporozoite rate of Anopheles farauti in the Solomon Islands was calculated to be 0.09%. This method enables estimation of the sporozoite rate based on a relatively small number (100-200) of mosquitoes compared with the number needed for the ELISA method.

en-copyright= kn-copyright= en-aut-name=HaradaMasakazu en-aut-sei=Harada en-aut-mei=Masakazu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MatsuokaHiroyuki en-aut-sei=Matsuoka en-aut-mei=Hiroyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=IshiiAkira en-aut-sei=Ishii en-aut-mei=Akira kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SuguriSetsuo en-aut-sei=Suguri en-aut-mei=Setsuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Kagawa Medical University, Kagawa affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Jichi Medical School affil-num=4 en-affil= kn-affil=Jichi Medical School affil-num=5 en-affil= kn-affil=Kagawa Medical University en-keyword=sporozoite rate kn-keyword=sporozoite rate en-keyword= polymerase chain reaction (PCR) kn-keyword= polymerase chain reaction (PCR) en-keyword=mathematical model kn-keyword=mathematical model en-keyword=Anopheles kn-keyword=Anopheles en-keyword=Plasmodium kn-keyword=Plasmodium END