UCバークレー校の研究者が、カリフォルニア州におけるバレー熱の増加は、同州の旱魃と気温の上昇に関連していることを明らかにした。 UC Berkeley researchers show that Valley fever’s rise in California is linked to drought and warming temperatures in the state
2022-10-05 カリフォルニア大学バークレー校(UCB)
研究者らは、州および地方機関が20年間にわたって収集した81,000件以上のコクシジオイデス症監視記録を分析しました。研究者らは、複雑な非線形統計モデルを適用して、気温、降水量、コクシジオイデス真菌症発生率の関係を調査した。その結果,数年周期で乾燥した状態が続き,その後,雨の多い冬が訪れると,コクシジオイデス真菌症の感染が増幅されることが判明した。
<関連情報>
- https://publichealth.berkeley.edu/news-media/research-highlights/drought-exacerbates-emerging-infectious-disease-in-california/
- https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(22)00202-9/fulltext
米国西部におけるコクシジオイデス真菌症の発生および拡大に対する降水・暑熱・旱魃の影響:縦断的監視研究 Effects of precipitation, heat, and drought on incidence and expansion of coccidioidomycosis in western USA: a longitudinal surveillance study
Jennifer R Head,Gail Sondermeyer-Cooksey,Alexandra K Heaney,Alexander T Yu,Isabel Jones,Abinash Bhattachan,Simon K Campo,Robert Wagner,Whitney Mgbara,Sophie Phillips,Nicole Keeney,Prof John Taylor,Prof Ellen Eisen,Prof Dennis P Lettenmaier,Prof Alan Hubbard,Prof Gregory S Okin, Duc J Vugia,Seema Jain,Prof Justin V Remais
Lancet Planetary Health Published:October, 2022
DOI:https://doi.org/10.1016/S2542-5196(22)00202-9
Summary
Background
Drought is an understudied driver of infectious disease dynamics. Amidst the ongoing southwestern North American megadrought, California (USA) is having the driest multi-decadal period since 800 CE, exacerbated by anthropogenic warming. In this study, we aimed to examine the influence of drought on coccidioidomycosis, an emerging infectious disease in southwestern USA.
Methods
We analysed California census tract-level surveillance data from 2000 to 2020 using generalised additive models and distributed monthly lags on precipitation and temperature. We then developed an ensemble prediction algorithm of incident cases of coccidioidomycosis per census tract to estimate the counterfactual incidence that would have occurred in the absence of drought.
Findings
Between April 1, 2000, and March 31, 2020, there were 81 448 reported cases of coccidioidomycosis throughout California. An estimated 1467 excess cases of coccidioidomycosis were observed in California in the 2 years following the drought that occurred between 2007 and 2009, and an excess 2649 drought-attributable cases of coccidioidomycosis were observed in the 2 years following the drought that occurred between 2012 and 2015. These increased numbers of cases more than offset the declines in cases that occurred during drought. An IQR increase in summer temperatures was associated with 2·02 (95% CI 1·84–2·22) times higher incidence in the following autumn (September to November), and an IQR increase in precipitation in the winter was associated with 1·45 (1·36–1·55) times higher incidence in the autumn. The effect of winter precipitation was 36% (25–48) stronger when preceded by two dry, rather than average, winters. Incidence in arid counties was most sensitive to precipitation fluctuations, while incidence in wetter counties was most sensitive to temperature.
Interpretation
In California, multi-year cycles of dry conditions followed by a wet winter increases transmission of coccidioidomycosis, especially in historically wetter areas. With anticipated increasing frequency of drought in southwestern USA, continued expansion of coccidioidomycosis, along with more intense seasons, is expected. Our results motivate the need for heightened precautions against coccidioidomycosis in seasons that follow major droughts.
Funding
National Institutes of Health.
