Mutant Strain of Pandemic (H1N1) 2009 Virus | CDC EID

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Volume 16, Number 5–May 2010
Dispatch
Transmission of Hemagglutinin D222G Mutant Strain of Pandemic (H1N1) 2009 Virus
Simona Puzelli, Marzia Facchini, Domenico Spagnolo, Maria A. De Marco, Laura Calzoletti, Alessandro Zanetti, Roberto Fumagalli, Maria L. Tanzi, Antonio Cassone, Giovanni Rezza, Isabella Donatelli, and the Surveillance Group for Pandemic A (H1N1) 2009 Influenza Virus in Italy1
Author affiliations: National Institute of Health, Rome, Italy (S. Puzelli, M. Facchini, D. Spagnolo, M.A. De Marco, L. Calzoletti, A. Cassone, G. Rezza, I. Donatelli); Università degli Studi di Milano, Milan, Italy (A. Zanetti); Università degli Studi di Milano-Bicocca, Milan (R. Fumagalli); and Università degli Studi di Parma, Parma, Italy (M.L. Tanzi)

Suggested citation for this article

Abstract
A pandemic (H1N1) 2009 virus strain carrying the D222G mutation was identified in a severely ill man and was transmitted to a household contact. Only mild illness developed in the contact, despite his obesity and diabetes. The isolated virus reacted fully with an antiserum against the pandemic vaccine strain.
On November 20, 2009, the Norwegian Institute of Public Health reported to the World Health Organization a mutation in the hemagglutinin (HA) of pandemic (H1N1) 2009 virus, consisting in a change of aspartic acid (D) with glycine (G) at aa 222. The mutation had been detected in 3 patients (the first 2 fatal cases in the country and in 1 patient with severe pneumonia) among ≈70 other patients with pandemic (H1N1) 2009, suggesting that it was not widespread in Norway (1). The same mutation has been also detected in Brazil, China, Japan, Mexico, Ukraine, the United States, France, and Spain (1,2).

The D-to-G mutation among the 1918 influenza virus variants (3) correlated with a shift from α2-6–linked sialic acid preference to a dual α2-3/α2-6 specificity. However, whether such a mutation may alter receptor binding specificity in the pandemic (H1N1) 2009 virus is unknown.

Although several pandemic (H1N1) 2009 viral strains sharing this mutation were detected in fatal cases, the same mutation also was detected in some mild cases; conversely, viruses from numerous fatal cases have not shown the same mutation. Thus, the clinical and public health significance of this finding remains unclear. The mutation appears to occur sporadically and spontaneously. No links between the small number of patients infected with the mutated virus have been found, and the mutation did not appear to spread (4). On the basis of results from a retrospective HA1 sequence analysis performed on pandemic (H1N1) 2009 viral isolates in Italy, we report on a transmission event of this virus carrying the D222G mutation.

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Suggested Citation for this Article
Puzelli S, Facchini M, Spagnolo D, De Marco MA, Calzoletti L, Zanetti A, et al. Transmission of hemagglutinin D222G mutant strain of pandemic (H1N1) 2009 virus. Emerg Infect Dis [serial on the Internet]. 2010 May [date cited]. http://www.cdc.gov/EID/content/16/5/863.htm

DOI: 10.3201/eid1605.091858