Hand, foot, and mouth disease (HFMD), which has led to millions of attacks and several outbreaks across the world and become more predominant in Asia-Pacific Region, especially in Mainland China, is caused by several Human Enteroviruses including new enterovirus, coxsakievirus and echovirus. In recent years, much research has focused on the epidemiological characteristics of HFMD. In this article, multiple characteristics of HFMD such as basic epidemiology, etiology and molecular epidemiology; influencing factors; detection; and surveillance are reviewed, as these can be help protect high risks groups, prevalence prediction and policy making for disease prevention.

Background: Enterovirus 71 (EV71) is the main pathogen that causes severe hand, foot, and mouth disease with fatal neurological complications. However, its neurovirulence mechanism is still unclear. Candidate virulence sites were screened out at structural protein VP1, but the function of these candidate virulence sites remains unclear. Several studies have shown that autophagy is associated with viral replication. However, the relationship between VP1 and autophagy in human neurons has not been studied. Methods: A recombinant virus—SDLY107-VP1, obtained by replacing the VP1 full-length gene of the SDLY107 strain with the VP1 full-length gene of the attenuated strain SDJN2015-01—was constructed and tested for replication and virulence. We then tested the effect of the recombinant virus on autophagy in nerve cells. The effect of autophagy on virus replication was detected by western blot and plaque test. Finally, the changes of mTOR signaling molecules during EV71 infection and the effect of mTOR on virus replication at the RNA level were detected. Results: Viral recombination triggered virulence attenuation. The replication ability of recombinant virus SDLY107-VP1 was significantly weaker than that of the parent strain SDLY107. The SDLY107 strain could inhibit autophagic flux and led to accumulation of autophagosomes, while the SDLY107-VP1 strain could not cause autophagosome accumulation. The synthesis of EV71 RNA was inhibited by inhibiting mTOR. Conclusions: Replacement of VP1 weakened the replication ability of virulent strains and reduced the level of autophagy in nerve cells. This autophagy facilitates the replication of virulent strains in nerve cells. VP1 is an important neurovirulence determinant of EV71, which affects virus replication by regulating cell autophagy. mTOR is a key molecule in this type of autophagy.

Human adenovirus species C (HAdV-C) is frequently detected in China and worldwide. For the first time, 16 HAdV-C strains were isolated from sewage water (14 strains) and hospitalised children with diarrhoea (2 strains,) in Tianjin, China. Nearly complete genome data were successfully obtained for these viruses. Subsequently, genomic and bioinformatics analyses of the 16 HAdV-C strains were performed. A phylogenetic tree of the complete HAdV-C genome divided these strains into three types: HAdV-C1, HAdV-C2, HAdV-C5. Phylogenetic analysis based on the fiber gene showed similar outcomes to analyses of the hexon gene and complete HAdV-C genomes, whereas the penton gene sequences showed more variation than previously reported. Furthermore, analysis of the whole-genome sequencing revealed seven recombination patterns transmitted in Tianjin, of which at least four patterns have not been previously reported. However, the penton base gene sequences of the HAdV-C species had significantly lower heterogeneity than those of the hexon and fiber gene sequences of recombinant isolates; that is, many strains were distinct in origin, but shared hexon and fiber genes. These data illustrate the importance of frequent recombination in the complexity of the HAdV-C epidemic in Tianjin, thus emphasising the necessity for HAdV-C sewage and virological monitoring in China.