S of HFMD epidemics mostly occurred in April to July in Zhejiang Province due to the subtropical monsoon climate of warm weather, plentiful rainfall and low sunshine. Previously, researchers had found that the weather factors were associated with the incidence of HFMD [64, 65]. Furthermore, Deng et al. found that sunshine was negatively correlated with the incidence rate of HFMD [25] and Xing et al. associated the spring sunshine with the annual amplitude of epidemics [4]. We also showed that the clustered regions of Zhejiang Province had rather lower levels of sunshine than non-clustered regions (Table 6). Furthermore, Wenzhou, the district that had a great outbreak of severe cases in 2010, had quite low sunshine in that year according to the recent history (S10 Fig). Since the levels of other meteorological factors such as temperature and rainfall are similar in different regions of Zhejiang Province, sunshine may be the important meteorological factor for the reproduction or transmissibility of EV71 as well as for the early warning of epidemics of HFMD. It was widely known that EV71 was the major cause of the severe cases of HFMD and our analysis found that the proportion of EV71 among all isolated viruses was correlated with the case-severity rate. When the proportions of EV71 reach 50 during April and July, the caseseverity rate also reached their peaks for the year (Fig 4 and S5 Fig). Furthermore, the proportions of EV71 were much higher in the clustered regions than non-clustered regions (Table 5). Thus, the ecology of the enteroviruses may be important for the outbreaks of HFMD epidemics and the serological distribution of the enteroviruses can be a predictable factor for the early warning of epidemics of severe cases. In reality, the serotypes of the enteroviruses were measured only for the enteroviruses routinely isolated from most severe cases and a small part of mild cases. Therefore, it was an indirect index and biased estimate for investigating the serological distribution of the enteroviruses in the susceptible population and the clusters. Targeted sampling and serotyping may improve the accuracy of estimating the pathogens’ composition. Phylogenetic analysis provides an essential way to track the variation and the evolution of the genomes of the enteroviruses and determine the phylogenetic relationships between the enteroviruses isolated from different regions. The MG-132MedChemExpress MG-132 genotypes of EV71 can be divided into A, BPLOS ONE | DOI:10.1371/journal.pone.0139109 September 30,14 /HFMD Epidemics in Zhejiang Province, journal.pone.0158910 China, 2008-and C groups according to the phylogenetic tree of the VP1 gene [15]. Group B has five sublineages: B1 5; and Group C also has five sublineages: C1 5. C4 was originally detected in Japan in 1997 and then circulated in the Asia-Pacific regions, especially in mainland China [23, 66, 67]. Almost all EV71 LY294002 solubility strains isolated from China belonged to C4 while other genotypes such as B3, B4, B5, C3 and C5 had circulated in the Asia-Pacific region, and the exact reason is still unknown (S1 File and S11 Fig). From S11 Fig, we can conclude that the sequences of EV71 isolated from China were highly homologous and all Zhejiang strains originated from the country and were mixed with the strains from j.neuron.2016.04.018 other provinces in the phylogenetic tree. Thus, the epidemics that occurred in Zhejiang Province were tightly related to those which occurred in other provinces. No sequence from Wenzhou was deposited in the NCBI database; however,.S of HFMD epidemics mostly occurred in April to July in Zhejiang Province due to the subtropical monsoon climate of warm weather, plentiful rainfall and low sunshine. Previously, researchers had found that the weather factors were associated with the incidence of HFMD [64, 65]. Furthermore, Deng et al. found that sunshine was negatively correlated with the incidence rate of HFMD [25] and Xing et al. associated the spring sunshine with the annual amplitude of epidemics [4]. We also showed that the clustered regions of Zhejiang Province had rather lower levels of sunshine than non-clustered regions (Table 6). Furthermore, Wenzhou, the district that had a great outbreak of severe cases in 2010, had quite low sunshine in that year according to the recent history (S10 Fig). Since the levels of other meteorological factors such as temperature and rainfall are similar in different regions of Zhejiang Province, sunshine may be the important meteorological factor for the reproduction or transmissibility of EV71 as well as for the early warning of epidemics of HFMD. It was widely known that EV71 was the major cause of the severe cases of HFMD and our analysis found that the proportion of EV71 among all isolated viruses was correlated with the case-severity rate. When the proportions of EV71 reach 50 during April and July, the caseseverity rate also reached their peaks for the year (Fig 4 and S5 Fig). Furthermore, the proportions of EV71 were much higher in the clustered regions than non-clustered regions (Table 5). Thus, the ecology of the enteroviruses may be important for the outbreaks of HFMD epidemics and the serological distribution of the enteroviruses can be a predictable factor for the early warning of epidemics of severe cases. In reality, the serotypes of the enteroviruses were measured only for the enteroviruses routinely isolated from most severe cases and a small part of mild cases. Therefore, it was an indirect index and biased estimate for investigating the serological distribution of the enteroviruses in the susceptible population and the clusters. Targeted sampling and serotyping may improve the accuracy of estimating the pathogens’ composition. Phylogenetic analysis provides an essential way to track the variation and the evolution of the genomes of the enteroviruses and determine the phylogenetic relationships between the enteroviruses isolated from different regions. The genotypes of EV71 can be divided into A, BPLOS ONE | DOI:10.1371/journal.pone.0139109 September 30,14 /HFMD Epidemics in Zhejiang Province, journal.pone.0158910 China, 2008-and C groups according to the phylogenetic tree of the VP1 gene [15]. Group B has five sublineages: B1 5; and Group C also has five sublineages: C1 5. C4 was originally detected in Japan in 1997 and then circulated in the Asia-Pacific regions, especially in mainland China [23, 66, 67]. Almost all EV71 strains isolated from China belonged to C4 while other genotypes such as B3, B4, B5, C3 and C5 had circulated in the Asia-Pacific region, and the exact reason is still unknown (S1 File and S11 Fig). From S11 Fig, we can conclude that the sequences of EV71 isolated from China were highly homologous and all Zhejiang strains originated from the country and were mixed with the strains from j.neuron.2016.04.018 other provinces in the phylogenetic tree. Thus, the epidemics that occurred in Zhejiang Province were tightly related to those which occurred in other provinces. No sequence from Wenzhou was deposited in the NCBI database; however,.
