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Volume 8, Number 2—February 2002


Lack of Evidence for Human-to-Human Transmission of Avian Influenza A (H9N2) Viruses in Hong Kong, China 19991

Timothy M. Uyeki*Comments to Author , Yu-Hoi Chong†, Jacqueline M. Katz*, Wilina Lim†, Yuk-Yin Ho†, Sophia S. Wang*, Thomas H.F. Tsang*, Winnie Wan-Yee Au†, Shuk-Chi Chan†, Thomas Rowe*, Jean Hu-Primmer*, Jensa C. Bell*, William W. Thompson*, Carolyn Buxton Bridges*, Nancy J. Cox*, Kwok-Hang Mak†, and Keiji Fukuda*
Author affiliations: *Centers for Disease Control and Prevention, Atlanta, Georgia, USA; †Department of Health, Hong Kong Special Administrative Region of China;

Main Article

Table 2

Serologic responses of two patients from Hong Kong infected with influenza A (H9N2) virus

Patient Age (years) Sex Serologic anti-H9 response
Days post symptom onset Neutralizing antibody titera Western blotb ELISA IgGc ELISA IgMc
1 4 female 39 135 Positive 51200 18100
2 1 female 35 40 Positive 6400 1600

aTiters expressed as the geometric mean of four replicate titers; titers ≥80 were considered positive for anti-H9 antibodies.
bWestern blots were performed by using a purified baculovirus-expressed recombinant HK/1073 HA as antigen.
cEnzyme-linked immunosorbent assay (ELISA) immunoglobulin (Ig) G and IgM antibodies were detected on plates coated with purified baculovirus-expressed recombinant HK/1073 HA (1 μg/mL). Titers are expressed as the geometric mean of duplicate endpoint titers estimated as described in Methods. A titer ≥1,600 was considered positive for anti-H9 antibodies.

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1Presented in part at the International Conference on Emerging Infectious Diseases 2000, Atlanta, Georgia, July 2000 (Poster #55), Session 7, July 16-19, 2000.

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