Hepatitis E virus (HEV) is an important public health problem and responsible for both acute and chronic viral hepatitis. The HEV transmission usually occurs through the fecal-oral route, and public health implications of its water-borne and food-borne transmissions along with environmental contamination raise high concerns towards its zoonosis. Apart from affecting developing countries, this virus is causing a rising number of cases in the developed countries. The spread of HEV particles to the environment can pollute surface waters, which could be an HEV infection source for humans and animals. HEV has also been identified in urban sewage samples in various countries. HEV virus quite frequently infects the European community and some animal species and identification of virus in polluted animal products suggest the circulation of HEV from water to food chain. Several studies indicating high seroprevalence and circulation of HEV in pigs as well as in environmental samples warrants to investigate the role of trade in carrier pigs, elucidate HEV virulence maintenance in the environment and meat supply chain to throw light on the possible sources of infection in humans and the degree of occupational risk, and zoonosis. The purpose of this review is to discuss the HEV infections and associated risk factors with an emphasis on pigs, presence in environment, food-borne, water-borne, and zoonotic transmissions.

Objective: To explore the calculation method of dominance degree from biomass, time scale and space scale, so as to provide a reference basis for more realistic reflection of species dominance degree. Methods: Excel was used for statistical analysis of mosquito monitoring data in Wuxi from 2012 to 2021, and t-test was used to test the variability of three calculation methods, namely Time-Space index, Berger Parker index and McNaughton index. Results: The three indices of Culex pipiens pallens and Aedes albopictus were basically consistent, and there was no significant difference between them; Time-Space index of Culex tritaeniorhynchus and Anopheles sinensis was significantly lower than Berger-Parker index (P<0.05), and was close to the significant level (P=0.0762, P=0.0621) lower than McNaughton index; The difference of coefficient of variation among the three calculated results was 4.63%, which was significantly lower than that of the other three mosquitoes (P<0.05). Conclusion: Time-Space index can significantly improve the resolution of species distribution heterogeneity, and better reflect the true state of relative dominance among species.