After several years of construction and development, the capability of hospitals in China to deal with PHE, in particular infectious diseases control, has improved greatly [3, 4] . Nevertheless, this research suggests that China has more progress to make before PHE preparedness is satisfactory. To enhance hospital preparation for dealing with PHE, governments at all levels should increase investment in the construction of infrastructure to create and sustain appropriate PHE capacity. On the other hand, hospitals at all levels should enhance their management, including updating and revising of emergency plans; strengthening communication and cooperation with other local agencies; enhancing the capacity of abnormity monitoring and laboratory diagnostic capability for infectious diseases; improving the treatment program for various PHE scenarios; and strengthening psychological intervention and risk communication capabilities. Finally PHE preparedness in relation to terrorism caused by nuclear radiation and biochemical substance was low in this study and should be further assessed for areas of need and improvement. Molecular evidence for the evolution of ichnoviruses from ascoviruses by symbiogenesis BACKGROUND: Female endoparasitic ichneumonid wasps inject virus-like particles into their caterpillar hosts to suppress immunity. These particles are classified as ichnovirus virions and resemble ascovirus virions, which are also transmitted by parasitic wasps and attack caterpillars. Ascoviruses replicate DNA and produce virions. Polydnavirus DNA consists of wasp DNA replicated by the wasp from its genome, which also directs particle synthesis. Structural similarities between ascovirus and ichnovirus particles and the biology of their transmission suggest that ichnoviruses evolved from ascoviruses, although molecular evidence for this hypothesis is lacking. RESULTS: Here we show that a family of unique pox-D5 NTPase proteins in the Glypta fumiferanae ichnovirus are related to three Diadromus pulchellus ascovirus proteins encoded by ORFs 90, 91 and 93. A new alignment technique also shows that two proteins from a related ichnovirus are orthologs of other ascovirus virion proteins. CONCLUSION: Our results provide molecular evidence supporting the origin of ichnoviruses from ascoviruses by lateral transfer of ascoviral genes into ichneumonid wasp genomes, perhaps the first example of symbiogenesis between large DNA viruses and eukaryotic organisms. We also discuss the limits of this evidence through complementary studies, which revealed that passive lateral transfer of viral genes among polydnaviral, bacterial, and wasp genomes may have occurred repeatedly through an intimate coupling of both recombination and replication of viral genomes during evolution. The impact of passive lateral transfers on evolutionary relationships between polydnaviruses and viruses with large double-stranded genomes is considered in the context of the theory of symbiogenesis. Approximately two-thirds of these wasps are endoparasites, meaning that the larval stages develop within the body cavity of their hosts, typically other insects. Among the most successful of these endoparasitic wasps are those that use lepidopteran larvae as hosts. Owing to the economic importance of these insects and the utility of their wasp parasites as biological control agents, the ability of these parasites to develop within lepidopteran hosts without triggering an intense immune response has been the subject of numerous studies over the past forty years.