Identifying areas with a high risk of human infection with the avian influenza A (H7N9) virus in East Asia

Fuller, Trevon; Havers, Fiona; Xu, Cuiling; Fang, Li‐Qun; Cao, Wu‐Chun; Shu, Yuelong; Widdowson, Marc‐Alain; Smith, Thomas B.

doi:10.1016/j.jinf.2014.03.006

Cited by 22 publications

(40 citation statements)

References 31 publications

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“…In recent years, SDMs have been increasingly used in the public health context [12,13], particularly with respect to infectious diseases that involve vector species such as mosquito-borne diseases [14,15] and tick-borne diseases [16]; these diseases are markedly influenced by subtle changes in climatic conditions which determine vector distribution. In this study we created SDMs using Maxent for both H5N1 and H7N9.A small set of previous studies have used SDMs to identify the set of high risk areas to target for control for both H5N1 [17-23] and H7N9 [24][25][26][27][28][29][30]. However, SDMs alone can only provide estimates of the probability of virus presence.…”

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confidence: 99%

Influenza A H5N1 and H7N9 in China: A spatial risk analysis

et al. 2017

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BackgroundZoonotic avian influenza poses a major risk to China, and other parts of the world. H5N1 has remained endemic in China and globally for nearly two decades, and in 2013, a novel zoonotic influenza A subtype H7N9 emerged in China. This study aimed to improve upon our current understanding of the spreading mechanisms of H7N9 and H5N1 by generating spatial risk profiles for each of the two virus subtypes across mainland China.Methods and findingsIn this study, we (i) developed a refined data set of H5N1 and H7N9 locations with consideration of animal/animal environment case data, as well as spatial accuracy and precision; (ii) used this data set along with environmental variables to build species distribution models (SDMs) for each virus subtype in high resolution spatial units of 1km2 cells using Maxent; (iii) developed a risk modelling framework which integrated the results from the SDMs with human and chicken population variables, which was done to quantify the risk of zoonotic transmission; and (iv) identified areas at high risk of H5N1 and H7N9 transmission. We produced high performing SDMs (6 of 8 models with AUC > 0.9) for both H5N1 and H7N9. In all our SDMs, H7N9 consistently showed higher AUC results compared to H5N1, suggesting H7N9 suitability could be better explained by environmental variables. For both subtypes, high risk areas were primarily located in south-eastern China, with H5N1 distributions found to be more diffuse and extending more inland compared to H7N9.ConclusionsWe provide projections of our risk models to public health policy makers so that specific high risk areas can be targeted for control measures. We recommend comparing H5N1 and H7N9 prevalence rates and survivability in the natural environment to better understand the role of animal and environmental transmission in human infections.

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confidence: 99%

Influenza A H5N1 and H7N9 in China: A spatial risk analysis

et al. 2017

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“…The pattern of cases between the first and second waves may represent varying control efforts, for example, where Shanghai likely implemented stricter closing of LPMs than did Zhejiang. The geographic spread of H7N9 has continued, and if it follows the general pattern of spread of H5N1, then additional provinces and countries, particularly Vietnam, are anticipated to have H7N9 cases (28). A number of cases to date have been attributed to travelers who became infected in one part of China but were diagnosed in another location, notably Beijing, Hong Kong, and Taiwan.…”

Section: Geographic Distributionmentioning

confidence: 99%

H7N9: Preparing for the Unexpected in Influenza

Jernigan

Cox

2015

Annu. Rev. Med.

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In the years prior to 2013, avian influenza A H7 viruses were a cause of significant poultry mortality; however, human illness was generally mild. In March 2013, a novel influenza A(H7N9) virus emerged in China as an unexpected cause of severe human illness with 36% mortality. Chinese and other public health officials responded quickly, characterizing the virus and identifying more than 400 cases through use of new technologies and surveillance tools made possible by past preparedness and response efforts. Genetic sequencing, glycan-array receptor-binding assays, and ferret studies reveal the H7N9 virus to have increased binding to mammalian respiratory cells and to have mutations associated with higher virus replication rates and illness severity. New risk-assessment tools indicate H7N9 has the potential for further mammalian adaptation with possible human-to-human transmission. Vigilant virologic and epidemiologic surveillance is needed to monitor H7N9 and detect other unexpected novel influenza viruses that may emerge.

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“…Thus, we expand on the conclusions of Fuller et al. () that H7N9 will spread from China to Vietnam. Many other places in the world such as the US and Italy have very high betweenness for segments that assort with H7 viruses and thus we expect continued outbreaks of H7 viruses.…”

Section: Resultsmentioning

confidence: 90%

Phylogenetic visualization of the spread of H7 influenza A viruses

et al. 2015

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Viruses of influenza A subtype H7 can be highly pathogenic and periodically infect humans. For example, there have been numerous outbreaks of H7 in the Americas and Europe since 1996. More recently, a reassortant H7N9 has emerged among humans and birds during 2013–2014 in China, Taiwan and Hong Kong. This H7N9 genome consists of genetic segments that assort with H7 and H9 viruses previously circulating in chickens and wild birds in China and ducks in Korea. Epidemic risk modellers have used agricultural, climatic and demographic data to predict that the virus will spread to northern Vietnam via poultry. To shed light on the traffic of H7 viruses in general, we examine genetic segments of influenza that have assorted with many strains of H7 viruses dating back to 1902. We focus on use cases from the United States, Italy and China. We apply a novel metric, betweenness, an associated phylogenetic visualization technique, transmission networks, and compare these with another technique, route mapping. In contrast to traditional views, our results illustrate that segments that assort with H7 viruses are spread frequently between the Americas and Eurasia. In summary, genetic segments that historically assort with H7 influenza viruses have been spread from China to: Australia, Czech Republic, Denmark, Egypt, Germany, Hong Kong, Italy, Japan, Mongolia, the Netherlands, New Zealand, Pakistan, South Africa, South Korea, Spain, Sweden, the UK, the US, and Vietnam.

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Identifying areas with a high risk of human infection with the avian influenza A (H7N9) virus in East Asia

Cited by 22 publications

References 31 publications

Influenza A H5N1 and H7N9 in China: A spatial risk analysis

Influenza A H5N1 and H7N9 in China: A spatial risk analysis

H7N9: Preparing for the Unexpected in Influenza

Phylogenetic visualization of the spread of H7 influenza A viruses

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