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

First wave of H7N9 spreading Online knowledge analysis revealed that the live birds in Shanghai were traded from Jiangsu, Zhejiang, and Anhui provinces with 84% Spread of H7N9 by online knowledge analysis C Chen et al 2 (571) of 682 live bird trade queries linked to Shanghai authorities stated that approximately 80% of live birds in this city were from the three aforementioned provinces. 13 Therefore, the live birds from these three provinces and Shanghai are potential sources of new infection. The date of illness onset for the first patient in Shanghai was February 18, followed by March 7, 15, and 19 for Zhejiang, Jiangsu, and Anhui provinces, respectively. Therefore, we propose that the H7N9 outbreak in China occurred in two waves separated by April 5 (Figure 1) , the date when Shanghai authorities announced the suspension of FMLBs and told the public that live birds carried the newly discovered H7N9 virus and that people in FMLBs were infected. This information can significantly change the trading designations and activities for live birds that carry the virus as well as public behavior to avoid the live birds during the outbreak. In the first wave, 11 prefecture cities and 106 people were infected. In the second wave, the number of infected prefecture cities increased to 28, covering 11 county level cities, but the number of infected people was reduced to 24. The first-wave was characterized by more infected people, while the second wave featured more infected cities, indicating that the live bird trade contributed to the geographical spread of the disease. 3 Estimating the infection risk to first-wave provinces at the province level We drew a topological provincial map of the spread of the H7N9 virus based on live bird trade information linked with first-wave provinces. The risk of H7N9 virus infection was estimated by the live bird trade links to Shanghai, Zhejiang, Jiangsu, and Anhui Provinces (Figure 2 ). Only seven provinces and one municipality were linked to one of the first-wave provinces, indicating that they had a very low risk of H7N9 infection from live bird trade. They are Jilin, Gansu, Qinghai, Inner Mongolia, Hainan, Yunnan, and Heilongjiang Provinces and the municipality of Chongqing cities (Figure 2 ). Among these provinces, Qinghai only had context information and we did not find any connection in the crawling pages. Of the 18 provinces suggested to be at high risk, 10 had confirmed cases of infection ( Figure 2 ). In this group, Guangdong Province had poultry specimens that tested positive for Therefore, based on our analysis, no risk associated with the live bird trade in these provinces could be detected using our method.