Rejmanek Daniel, Hosseini Parviez R, Mazet Jonna A K, Daszak Peter, Goldstein Tracey
One Health Institute, School of Veterinary Medicine, University of California, Davis, Davis, California, USA.
EcoHealth Alliance, New York, New York, USA.
J Virol. 2015 Nov;89(21):10993-1001. doi: 10.1128/JVI.01573-15. Epub 2015 Aug 26.
The increasing number of zoonotic infections caused by influenza A virus (IAV) subtypes of avian origin (e.g., H5N1 and H7N9) in recent years underscores the need to better understand the factors driving IAV evolution and diversity. To evaluate the current feasibility of global analyses to contribute to this aim, we evaluated information in the public domain to explore IAV evolutionary dynamics, including nucleotide substitution rates and selection pressures, using 14 IAV subtypes in 32 different countries over a 12-year period (2000 to 2011). Using geospatial information from 39,785 IAV strains, we examined associations between subtype diversity and socioeconomic, biodiversity, and agricultural indices. Our analyses showed that nucleotide substitution rates for 11 of the 14 evaluated subtypes tended to be higher in Asian countries, particularly in East Asia, than in Canada and the United States. Similarly, at a regional level, subtypes H5N1, H5N2, and H6N2 exhibited significantly higher substitution rates in East Asia than in North America. In contrast, the selection pressures (measured as ratios of nonsynonymous to synonymous evolutionary changes [dN/dS ratios]) acting on individual subtypes showed little geographic variation. We found that the strongest predictors for the detected subtype diversity at the country level were reporting effort (i.e., total number of strains reported) and health care spending (an indicator of economic development). Our analyses also identified major global gaps in IAV reporting (including a lack of sequences submitted from large portions of Africa and South America and a lack of geolocation information) and in broad subtype testing which, until addressed, will continue to hinder efforts to track the evolution and diversity of IAV around the world.
In recent years, an increasing number of influenza A virus (IAV) subtypes, including H5N1, H7N9, and H10N8, have been detected in humans. High fatality rates have led to an increased urgency to better understand where and how novel pathogenic influenza virus strains emerge. Our findings showed that mutational rates of 11 commonly encountered subtypes were higher in East Asian countries than in North America, suggesting that there may be a greater risk for the emergence of novel pathogenic strains in East Asia. In assessing the potential drivers of IAV subtype diversity, our analyses confirmed that reporting effort and health care spending were the best predictors of the observed subtype diversity at the country level. These findings underscore the need to increase sampling and reporting efforts for all subtypes in many undersampled countries throughout the world.
近年来，由禽源甲型流感病毒（IAV）亚型（如H5N1和H7N9）引起的人畜共患感染数量不断增加，这突出表明有必要更好地了解推动IAV进化和多样性的因素。为评估全球分析目前对实现这一目标的可行性，我们评估了公共领域的信息，以探索IAV的进化动态，包括核苷酸替换率和选择压力，使用了12年期间（2000年至2011年）32个不同国家的14种IAV亚型。利用来自39785株IAV毒株的地理空间信息，我们研究了亚型多样性与社会经济、生物多样性和农业指数之间的关联。我们的分析表明，在评估的14种亚型中，有11种亚型在亚洲国家，特别是东亚，其核苷酸替换率往往高于加拿大和美国。同样，在区域层面，H5N1、H5N2和H6N2亚型在东亚的替换率明显高于北美。相比之下，作用于各个亚型的选择压力（以非同义进化变化与同义进化变化的比率[dN/dS比率]衡量）几乎没有地理差异。我们发现，在国家层面，检测到的亚型多样性的最强预测因素是报告工作量（即报告的毒株总数）和医疗保健支出（经济发展的一个指标）。我们的分析还确定了IAV报告方面的主要全球差距（包括非洲和南美洲大部分地区缺乏提交的序列以及缺乏地理位置信息）以及广泛的亚型检测方面的差距，在这些差距得到解决之前，将继续阻碍追踪全球IAV进化和多样性的努力。
近年来，包括H5N1、H7N9和H10N8在内的越来越多的甲型流感病毒（IAV）亚型在人类中被检测到。高死亡率使得更迫切需要了解新型致病性流感病毒株出现的地点和方式。我们的研究结果表明，11种常见亚型在东亚国家的突变率高于北美，这表明东亚可能有更大的新型致病株出现风险。在评估IAV亚型多样性的潜在驱动因素时，我们的分析证实，报告工作量和医疗保健支出是国家层面观察到的亚型多样性的最佳预测因素。这些发现强调有必要在全世界许多采样不足的国家增加对所有亚型的采样和报告工作。
