Silent geographical spread of the H7N9 virus by online knowledge analysis of the live bird trade with a distributed focused crawler

Chen, Chen; Lu, Shan; Du, Pengcheng; Wang, Haiyin; Yu, Weiwen; Song, Huawen; Xu, Jianguo

In this study, we used online knowledge of the live bird trade in conjunction with distributed focused crawler technology to study the infectious sources, transmission networks, and geographical spread of the newly discovered virus, which has national and international public health significance. This study provides valuable information for the control and prevention of the current H7N9 virus outbreak, and serves as a basis for future outbreak investigations. This method can also be used as a measure of other public interests or concerns about health-related events. This type of information is usually difficult or impossible to obtain by traditional investigation methodology, such as face-to-face or telephone inquiry, especially for infectious diseases or other events with potential significant economic impact. Parts of the virus transmission network that we derived are supported by preliminary epidemiological observations and genome sequence analysis results from virus strains isolated from both patients and poultry. With increasing genome sequences and epidemiological information being published, new technology for infectious disease outbreak investigations will greatly improve. The limitation of this analytical method used here is that we do not know what fraction of total poultry movements could be traced through the Internet. Some information related to trading that was arranged over the phone or performed by integrated poultry companies cannot be obtained from Internet. Because viruses continue to circulate in poultry and cause no clinical signs in birds, it will be important to further improve this method using more surveillance information generated in the coming years.