We sequenced the 29,751-base genome of the severe acute respiratory syndrome (SARS)–associated coronavirus known as the Tor2 isolate. The genome sequence reveals that this coronavirus is only moderately related to other known coronaviruses, including two human coronaviruses, HCoV-OC43 and HCoV-229E. Phylogenetic analysis of the predicted viral proteins indicates that the virus does not closely resemble any of the three previously known groups of coronaviruses. The genome sequence will aid in the diagnosis of SARS virus infection in humans and potential animal hosts (using polymerase chain reaction and immunological tests), in the development of antivirals (including neutralizing antibodies), and in the identification of putative epitopes for vaccine development.

Avian influenza that infects poultry in close proximity to humans is a concern because of its pandemic potential. In 2004, an outbreak of highly pathogenic avian influenza H7N3 occurred in poultry in British Columbia, Canada. Surveillance identified two persons with confirmed avian influenza infection. Symptoms included conjunctivitis and mild influenzalike illness.

The nucleotide sequence of an almost-full-length clone of human parvovirus B19 was determined. Whereas the extreme left and right ends of this genomic clone are incomplete, the sequence clearly indicates that the two ends of viral DNA are related by inverted terminal repeats similar to those of the Dependovirus genus. The coding regions are complete in the cloned DNA, and the two large open reading frames which span almost the entire genome are restricted to one strand, as has been found for all other parvoviruses characterized to date. From the DNA sequence we conclude that the organization of the B19 transcription units is similar although not identical to those of other parvoviruses. In particular, we predict that the B19 genome may utilize a fourth promoter to transcribe mRNA encoding the major structural polypeptide, VP2. Analysis of the putative polypeptides confirms that B19 is only distantly related to the other parvoviruses but reveals that there is a small region in the gene probably enicoding the major nonstructural protein of B19, which is closely conserved between all of the parvovirus genomes for which sequence Information is currently available.

Four virus-specific transcripts have been identified in murine cells infected with Minute-Virus-of-Mice (MVM). These RNAs, 4.8, 3.3, 3.0 and 1.8 kilobases in length, designated R1 to R4 respectively, are all transcribed from the virion (-) strand of DNA and they are all polyadenylated and spliced. The R1 transcript is derived from sequences that reside on the genome between 4.0 and 95 map units (mu). Transcript R2 is composed of exon sequences derived from mu coordinates 4.0-10.0, 40-46 and 48-95. The most abundant RNA, R3, is transcribed from sequences mapping between 40 and 95 mu. All three of these RNAs have a short intron sequence between 46-48 mu removed. The least abundant transcript, R4, has not been mapped precisely, however it hybridizes with all three EcoRI fragments which span the entire 5 kb genome. In vitro transcription of cloned restriction fragments of MVM DNA confirm the existence of functional promoters at map coordinates 4.0 and 39 and sequence analysis of these regions of the viral DNA reveal the characteristic features of RNA polymerase II promoters. These results indicate that MVM DNA encodes two overlapping transcription units with separate promoters near the left end (4.0 mu) and middle (39 mu) of the genome.

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Severe acute respiratory syndrome (SARS) emerged from China as an untreatable and rapidly spreading respiratory illness of unknown etiology. Following point source exposure in February 2003, more than a dozen guests infected at a Hong Kong hotel seeded multi-country outbreaks that persisted through the spring of 2003. The World Health Organization responded by invoking traditional public health measures and advanced technologies to control the illness and contain the cause. A novel coronavirus was implicated and its entire genome was sequenced by mid-April 2003. The urgency of responding to this threat focused scientific endeavor and stimulated global collaboration. Through real-time application of accumulating knowledge, the world proved capable of arresting the first pandemic threat of the twenty-first century, despite early respiratory-borne spread and global susceptibility. This review synthesizes lessons learned from this remarkable achievement. These lessons can be applied to re-emergence of SARS or to the next pandemic threat to arise.

These findings underscore the virulence of human CoV-OC43 in elderly populations and confirm that cross-reactivity to antibody against nucleocapsid proteins from these viruses must be considered when interpreting serological tests for SARS-CoV.

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