{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,10]],"date-time":"2026-10-10T04:53:50Z","timestamp":1791608030002,"version":"4.3.4"},"reference-count":31,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,1,13]],"date-time":"2022-01-13T00:00:00Z","timestamp":1642032000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>Aiming to identify the potentially reduced malaria cases by stagnation of international traffic after the COVID-19 pandemic, a longitudinal analysis of malaria cases as well as entries of Japanese and foreigners was conducted using data from 5 April 1999 to 30 September 2021 in Japan. Multivariable risk ratios were calculated with the Poison regression model as a predictive model of malaria cases by the number of entries for Japanese and foreigners. A generalized regression model was used to examine an association of time trend with entries for Japanese and foreigners using data before 2019, to estimate the potentially reduced number of entries after 2020. The potentially reduced number of malaria cases was estimated by the potentially reduced number of entries for Japanese and foreigners after 2020 using a multivariable Poison regression model. The multivariable risk ratio (95% confidence intervals) of malaria case numbers per 100,000 persons increment of entries per day was 3.41 (1.50\u20137.77) for Japanese and 1.47 (0.92\u20132.35) for foreigners. During 2020, a potential reduction of 28 (95% confidence limit: 22\u201334) malaria cases was estimated, which accounted for 58% (52\u201363%) of malaria cases in Japan. These finding suggest that the stagnation of international traffic during the COVID-19 pandemic reduced the number of malaria cases in Japan. This model may be helpful for countries without indigenous malaria to predict future trends of imported malaria cases.<\/jats:p>","DOI":"10.3390\/ijerph19020880","type":"journal-article","created":{"date-parts":[[2022,1,13]],"date-time":"2022-01-13T10:57:37Z","timestamp":1642071457000},"page":"880","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["A Model to Estimate the Effect of International Traffic on Malaria Cases: The Case of Japan from 1999 to 2021"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9086-3771","authenticated-orcid":false,"given":"Hiroyuki","family":"Noda","sequence":"first","affiliation":[{"name":"Public Health, Department of Social Medicine, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan"},{"name":"Cabinet Secretariat, Tokyo 100-8968, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,13]]},"reference":[{"key":"ref_1","unstructured":"World Health Organization (2016). International Health Regulations (2005), World Health Organization. [3rd ed.]."},{"key":"ref_2","unstructured":"Nagata, N. (2010). The International Control of Epidemic Disease: The Study of the International Sanitary Conferences, 1851\u20131938, Kokusai Shoin. (In Japanese)."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"340","DOI":"10.1080\/17441692.2020.1805786","article-title":"Travel restrictions as a disease control measure: Lessons from yellow fever","volume":"16","author":"Vanderslott","year":"2021","journal-title":"Glob. Public Health"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1186\/s12992-021-00677-5","article-title":"How does globalization affect COVID-19 responses?","volume":"17","author":"Bickley","year":"2021","journal-title":"Glob. Health"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"555","DOI":"10.1016\/j.jiac.2020.12.022","article-title":"Progress of public health policy regarding global infectious diseases over the past decade in Japan","volume":"27","author":"Noda","year":"2021","journal-title":"J. Infect. Chemother."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1436","DOI":"10.1126\/science.abb6950","article-title":"Travel restrictions violate international law","volume":"367","author":"Meier","year":"2020","journal-title":"Science"},{"key":"ref_7","unstructured":"Meghan, B., Batalova, J., Davidoff-Gore, S., and Schmidt, T. (2021). COVID-19 and the State of Global Mobility in 2020, Migration Policy Institute and International Organization for Migration."},{"key":"ref_8","unstructured":"UNWTO (2021). Tourism suffers its deepest crisis with a drop of 74% in 2020 in international arrivals. World Tour. Barom., 19, 1."},{"key":"ref_9","unstructured":"Immigration Services Agency of Japan (2021). Annual Report of Statistics on Legal Migrants 2020."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"UNWTO (2021). International travel largely on hold despite uptick in May 2021. World Tour. Barom., 19, 1.","DOI":"10.18111\/wtobarometereng.2021.19.1.3"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1265\/jjh.64.3","article-title":"Two types of malaria epidemics during the postwar occupation period in Japan","volume":"64","author":"Tanaka","year":"2009","journal-title":"Jpn. J. Hyg."},{"key":"ref_12","first-page":"31","article-title":"History of vector control in Okinawa islands, 1945\u20131998","volume":"33","author":"Kishimoto","year":"1999","journal-title":"Annu. Rep. Okinawa Prefect. Inst. Health Environ."},{"key":"ref_13","first-page":"15","article-title":"How was endemic malaria eradicated? Community-based action in postwar Hikone. Nihon Ishigaku Zasshi","volume":"55","author":"Tanaka","year":"2009","journal-title":"Jpn. Hist. Med."},{"key":"ref_14","unstructured":"National Institute of Infectious Diseases (2018). Malaria 2006\u20132017, IASR, (In Japanese)."},{"key":"ref_15","unstructured":"The Ministry of Health, Labour and Welfare, National Institute of Infectious Diseases (2020). Data of the 53rd Week, IDWR, (In Japanese)."},{"key":"ref_16","first-page":"151","article-title":"Report of 2 cases of falciparum malaria within the same group after traveling to Kenya and an adult case of cerebral malaria","volume":"35","author":"Yamamoto","year":"2014","journal-title":"IASR"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"e00104-19","DOI":"10.1128\/CMR.00104-19","article-title":"Imported Malaria in Countries where Malaria Is Not Endemic: A Comparison of Semi-immune and Nonimmune Travelers","volume":"33","author":"Mischlinger","year":"2020","journal-title":"Clin. Microbiol. Rev."},{"key":"ref_18","unstructured":"World Health Organization (2021). World Malaria Report 2021, World Health Organization."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1381","DOI":"10.1016\/S0140-6736(21)02235-2","article-title":"Malaria vaccine approval: A step change for global health","volume":"398","author":"Lancet","year":"2021","journal-title":"Lancet"},{"key":"ref_20","unstructured":"Tuberculosis and Infectious Diseases Control Division, Health Service Bureau, Ministry of Health, and Labour and Welfare (2016). Act on the Prevention of Infectious Diseases and Medical Care for Patients with Infectious Diseases, (In Japanese)."},{"key":"ref_21","unstructured":"World Health Organization (2020). World Malaria Report 2020: 20 Years of Global Progress and Challenges, World Health Organization."},{"key":"ref_22","unstructured":"Gujarati, D.N. (2009). Basic Econometrics, McGraw-Hill. [4th ed.]."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1007\/s11135-006-9018-6","article-title":"A Caution Regarding Rules of Thumb for Variance Inflation Factors","volume":"41","year":"2007","journal-title":"Qual. Quant. Int. J. Methodol."},{"key":"ref_24","unstructured":"Government of Japan (2017). Tourism Nation Promotion Basic Plan, (In Japanese)."},{"key":"ref_25","first-page":"107","article-title":"Recent trend in global infectious disease control","volume":"31","author":"Noda","year":"2019","journal-title":"J. Biomed. Sci. Biosaf."},{"key":"ref_26","first-page":"54","article-title":"Bootstrap Methods for Standard Errors, Confidence Intervals, and Other Measures of Statistical Accuracy","volume":"1","author":"Efron","year":"1986","journal-title":"Stat. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"e2116","DOI":"10.1136\/bmj.e2116","article-title":"Risk factors for mortality from imported falciparum malaria in the United Kingdom over 20 years: An observational study","volume":"344","author":"Checkley","year":"2012","journal-title":"BMJ"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1190","DOI":"10.1016\/S0140-6736(20)30755-8","article-title":"Dementia care during COVID-19","volume":"395","author":"Wang","year":"2020","journal-title":"Lancet"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1016\/S2215-0366(20)30141-3","article-title":"COVID-19, unemployment, and suicide","volume":"7","author":"Kawohl","year":"2020","journal-title":"Lancet Psychiatry"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"m4352","DOI":"10.1136\/bmj.m4352","article-title":"Trends in suicide during the covid-19 pandemic","volume":"371","author":"John","year":"2020","journal-title":"BMJ"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"2196","DOI":"10.1093\/cid\/ciaa1328","article-title":"Impact of Social Distancing and Travel Restrictions on Non-Coronavirus Disease 2019 (Non-COVID-19) Respiratory Hospital Admissions in Young Children in Rural Alaska","volume":"72","author":"Nolen","year":"2021","journal-title":"Clin. Infect. Dis."}],"container-title":["International Journal of Environmental Research and Public Health"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1660-4601\/19\/2\/880\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T14:14:57Z","timestamp":1760364897000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1660-4601\/19\/2\/880"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,1,13]]},"references-count":31,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2022,1]]}},"alternative-id":["ijerph19020880"],"URL":"https:\/\/doi.org\/10.3390\/ijerph19020880","relation":{},"ISSN":["1660-4601"],"issn-type":[{"value":"1660-4601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,1,13]]}}}