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Human Avian H7N2 Reassortant in New York Patient
Recombinomics Commentary 14:44
April 28, 2008
Sequences from a 2003 H7N2 case in New York, A/New York/107/2003(H7N2), were released at Genbank. These sequences clearly show that the isolate was a reassortant with avian H7, N2, and NP genes and human H3N2 genes for PB1, PA, MP, NS (PB2 sequences were not released).
The case was originally hospitalized in late 2003, but was not diagnosed as H7N2 until the spring of 2004. The H7N2 isolate was confirmed with antibodies from the patient. The origin of the infection was not determined.
However, the avian sequences are most closely related to sequences from the eastern US and the NP sequence is most closely related to H7N2 sequences from New York. Similarly, the human internal genes are most closely related to 2003 human H3N2 isolates from New York. Thus, it would appear that the patient was co-infected with avian H7N2 flu as well as H3N2 seasonal flu in 2003.
This is the first report of an H7N2 reassortant with human and avian flu genes and raises concerns of further genetic exchanges in an avian population since the H and N genes are avian. H7 is also readily transmitted human to human, but usually produces mild symptoms, including conjunctivitis. This patient however had respiratory symptoms and was hospitalized. The delay in the discovery of the H7N2 infection in this patient was because it was initially thought to be an H1N1 infection, and testing was slow because of a low frequency of cases in 2003/2004. However, it remains unclear why it took four years to release the sequence data.
Surveillance of H7 in wild birds is poor. There have been H7 outbreaks in Canada in British Columbia and Saskatchewan, but no H7 was detected in wild birds prior to the poultry outbreaks. A recent report on H7 surveillance indicated that the primers, designed to detect H7 in poultry, were mismatched for H7 in wild birds.
Recombinomics Paper at Nature Precedings