The nomenclature of hepatitis E virus (HEV) subtypes is inconsistent and makes comparison of different studies problematic. We have provided a table of proposed complete genome reference sequences for each subtype. The criteria for subtype assignment vary between different genotypes and methodologies, and so a conservative pragmatic approach has been favoured. Updates to this table will be posted on the International Committee on Taxonomy of Viruses website (http://talk.ictvonline.org/r.ashx?C). The use of common reference sequences will facilitate communication between researchers and help clarify the epidemiology of this important human pathogen. This subtyping procedure might be adopted for other taxa of the genus Orthohepevirus.The current literature contains several inconsistencies in the naming of hepatitis E virus (HEV) subtypes, which often creates confusion in the scientific community. HEV is a member of the family Hepeviridae within the genus Orthohepevirus. The genus has three species that infect birds (Orthohepevirus B), rodents, soricomorphs and carnivores (Orthohepevirus C) or bats (Orthohepevirus D), and one species, Orthohepevirus A, comprising seven genotypes that infect humans (HEV-1, -2, -3, -4 and -7), pigs (HEV-3 and -4), rabbit (HEV-3), wild boar (HEV-3, -4, -5 and -6), 3Members of the ICTV Hepeviridae study group.

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Perfusion CT not only allows early detection of cerebral ischemia but also yields valuable information about the extent of perfusion disturbances.

Background and Purpose-Besides the delineation of hypoperfused brain tissue, the characterization of ischemia with respect to severity is of major clinical relevance, because the degree of hypoperfusion is the most critical factor in determining whether an ischemic lesion becomes an infarct or represents viable brain tissue. CT perfusion imaging yields a set of perfusion related parameters which might be useful to describe the hemodynamic status of the ischemic brain. Our objective was to determine whether measurements of the relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), and relative time to peak (rTP) can be used to differentiate areas undergoing infarction from reversible ischemic tissue. Methods-In 34 patients with acute hemispheric ischemic stroke Ͻ6 hours after onset, perfusion CT was used to calculate rCBF, rCBV, and rTP values from areas of ischemic cortical and subcortical gray matter. Results were obtained separately from areas of infarction and noninfarction, according to the findings on follow-up imaging studies. The efficiency of each parameter to predict tissue outcome was tested. Results-There was a significant difference between infarct and peri-infarct tissue for both rCBF and rCBV but not for rTP.Threshold values of 0.48 and 0.60 for rCBF and rCBV, respectively, were found to discriminate best between areas of infarction and noninfarction, with the efficiency of the rCBV being slightly superior to that of rCBF. The prediction of tissue outcome could not be increased by using a combination of various perfusion parameters. Conclusions-The assessment of cerebral ischemia by means of perfusion parameters derived from perfusion CT provides valuable information to predict tissue outcome. Quantitative analyses of the severity of ischemic lesions should be implemented into the diagnostic management of stroke patients.