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Volume 22, Number 1—January 2016

Avian Influenza A(H7N9) Virus Infection in 2 Travelers Returning from China to Canada, January 20151

Danuta SkowronskiComments to Author , Catharine Chambers, Reka Gustafson, Dale B. Purych, Patrick Tang, Nathalie Bastien, Mel Krajden, and Yan Li
Author affiliations: British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada (D.M. Skowronski, C. Chambers, P. Tang, M. Krajden); University of British Columbia, Vancouver (D.M. Skowronski, R. Gustafson, D.B. Purych, P. Tang, M. Krajden); Vancouver Coastal Health Authority, Vancouver (R. Gustafson); LifeLabs Medical Laboratories, Surrey, British Columbia, Canada (D.B. Purych); Public Health Agency of Canada, Winnipeg, Manitoba, Canada (N. Bastien, Y. Li); University of Manitoba, Winnipeg (Y. Li)

Main Article

Table 1

Antibody titers to avian influenza A(H7N9) virus and recent human influenza A(H3N2) and A(H1N1)pdm09 virus strains for 2 persons with virologically confirmed H7N9 virus infection and for an HCW contact, British Columbia, Canada, January 2015*

Person, date of specimen collection Duplicate inverse HI titers and GMT for influenza antibody
A/British Columbia/1/2015(H7N9)†
Titer 1 Titer 2 GMT Titer 1 Titer 2 GMT Titer 1 Titer 2 GMT
Index patient#
January 26 20 20 20 10 10 10 10 10 10
March 5


Second patient#
January 26 20 40 28 10 10 10 10 10 10
March 5


HCW contact**
January 27 <10 <10 <10 40 40 40 20 20 20
May 1 <10 <10 <10 40 40 40 20 20 20

*The 2 H7N9 virus–infected persons were a married couple; the woman was the index patient, and the man was the second patient. GMT, geometric mean titer; HCW, healthcare worker; HI, hemagglutination inhibition.
†Assay was conducted by using homologous H7N9 virus isolated from the index patient (Global Initiative on Sharing Avian Influenza Data accession no. EPI_ISL_171342); the virus was antigenically equivalent to influenza A/Anhui/1/2013(H7N9), which was used in the population serosurvey reported in Table 2. The HI assay was conducted by using horse erythrocytes, as previously described (6).
‡Assay was conducted by using viruses of each human influenza A H1 and H3 subtype to which strains identified globally during the 2014–15 influenza season were considered antigenically related (see Titers were measured according to standard assay protocols of the National Microbiology Laboratory, Canada’s influenza reference laboratory.
§Assay was conducted by using guinea pig erythrocytes and in the presence of oseltamivir carboxylate to address potential neuraminidase-mediated binding of influenza A(H3N2) viruses to erythrocytes.
¶Assay was conducted by using turkey erythrocytes.
#Received neither the 2013–14 nor 2014–15 influenza vaccine nor prior pneumococcal vaccine.
**Received the 2013–14 and the 2014–15 influenza vaccines.

Main Article

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Main Article

1Preliminary results from the population serosurvey were presented at the CACMID-AMMI Canada 2014 Annual Conference, April 3–5, 2014, Victoria, British Columbia, Canada.

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