Smallpox and Season: Reanalysis of Historical Data
Seasonal variation in smallpox transmission is one of the most pressing ecological questions and is relevant to bioterrorism preparedness. The present study reanalyzed 7 historical datasets which recorded monthly cases or deaths. In addition to time series analyses of reported data, an estimation an...
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Formato: | Texto |
Lenguaje: | English |
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Hindawi Publishing Corporation
2009
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2648660/ https://www.ncbi.nlm.nih.gov/pubmed/19266090 http://dx.doi.org/10.1155/2009/591935 |
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author | Nishiura, Hiroshi Kashiwagi, Tomoko |
author_facet | Nishiura, Hiroshi Kashiwagi, Tomoko |
author_sort | Nishiura, Hiroshi |
collection | PubMed |
description | Seasonal variation in smallpox transmission is one of the most pressing ecological questions and is relevant to bioterrorism preparedness. The present study reanalyzed 7 historical datasets which recorded monthly cases or deaths. In addition to time series analyses of reported data, an estimation and spectral analysis of the effective reproduction number at calendar time t, R(t), were made. Meteorological variables were extracted from a report in India from 1890–1921 and compared with smallpox mortality as well as R(t). Annual cycles of smallpox transmission were clearly shown not only in monthly reports but also in the estimates of R(t). Even short-term epidemic data clearly exhibited an annual peak every January. Both mortality and R(t) revealed significant negative association (P < .01) and correlation (P < .01), respectively, with humidity. These findings suggest that smallpox transmission greatly varies with season and is most likely enhanced by dry weather. |
format | Text |
id | pubmed-2648660 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2009 |
publisher | Hindawi Publishing Corporation |
record_format | MEDLINE/PubMed |
spelling | pubmed-26486602009-03-05 Smallpox and Season: Reanalysis of Historical Data Nishiura, Hiroshi Kashiwagi, Tomoko Interdiscip Perspect Infect Dis Research Article Seasonal variation in smallpox transmission is one of the most pressing ecological questions and is relevant to bioterrorism preparedness. The present study reanalyzed 7 historical datasets which recorded monthly cases or deaths. In addition to time series analyses of reported data, an estimation and spectral analysis of the effective reproduction number at calendar time t, R(t), were made. Meteorological variables were extracted from a report in India from 1890–1921 and compared with smallpox mortality as well as R(t). Annual cycles of smallpox transmission were clearly shown not only in monthly reports but also in the estimates of R(t). Even short-term epidemic data clearly exhibited an annual peak every January. Both mortality and R(t) revealed significant negative association (P < .01) and correlation (P < .01), respectively, with humidity. These findings suggest that smallpox transmission greatly varies with season and is most likely enhanced by dry weather. Hindawi Publishing Corporation 2009 2009-01-04 /pmc/articles/PMC2648660/ /pubmed/19266090 http://dx.doi.org/10.1155/2009/591935 Text en Copyright © 2009 H. Nishiura and T. Kashiwagi. https://creativecommons.org/licenses/by/3.0/ This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Article Nishiura, Hiroshi Kashiwagi, Tomoko Smallpox and Season: Reanalysis of Historical Data |
title | Smallpox and Season: Reanalysis of Historical Data |
title_full | Smallpox and Season: Reanalysis of Historical Data |
title_fullStr | Smallpox and Season: Reanalysis of Historical Data |
title_full_unstemmed | Smallpox and Season: Reanalysis of Historical Data |
title_short | Smallpox and Season: Reanalysis of Historical Data |
title_sort | smallpox and season: reanalysis of historical data |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2648660/ https://www.ncbi.nlm.nih.gov/pubmed/19266090 http://dx.doi.org/10.1155/2009/591935 |
work_keys_str_mv | AT nishiurahiroshi smallpoxandseasonreanalysisofhistoricaldata AT kashiwagitomoko smallpoxandseasonreanalysisofhistoricaldata |