To the Editor: On November 2, 2005, fever, chills, and coughdeveloped in a previously healthy woman who was four monthspregnant. Chickens and ducks in her household had become illand had died during October. From October 25 through October30, the patient had been actively involved in slaughtering anddefeathering sick poultry before they were cooked for familyconsumption. She presented to the hospital in Tongling City,China, on November 7 with dyspnea, cyanosis, a temperature of38.8°C, a pulse of 118 beats per minute, a respiratory rateof 37 breaths per minute, and an oxygen saturation of 69 percent.Her white-cell count was 4050 per cubic millimeter, with a lymphocytecount of 608 per cubic millimeter. A chest radiograph showedbilateral diffuse infiltrates in the lower lobes. Her conditiondeteriorated despite treatment with azithromycin and cefotaxime.She required intubation that evening. The following day, herchest radiograph showed extensive infiltration of both lungs.Despite intensive supportive care, disseminated intravascularcoagulation and multiorgan failure developed, and she died onNovember 10.
Three tracheal aspirates obtained on November 8 tested positivefor the H5 strain of avian influenza A virus and for the genesencoding M protein by reverse-transcriptase–polymerasechain reaction (PCR) and by real-time PCR. Influenza A/Anhui/1/2005virus was isolated from a specimen of tracheal aspirate. Whole-genomesequencing indicated that all segments were of avian origin.The hemagglutinin-receptor–binding site was similar tothose of other avian H5N1 viruses, and a polybasic amino acidcleavage site (LRERRRKRG) was present. Changes in amino acidsrelated to antiviral resistance were not detected in the M-proteinor neuraminidase genes. The hemagglutinin gene sequence wasdifferent from that of other H5N1 human isolates (Figure 1)and was similar to that of influenza A/duck/Fujian/1734/2005(GenBank accession number DQ095629
[GenBank]
), a clade 2 virus. Otherfatal human infections with clade 2 viruses have been identifiedin China and are genetically related to the isolate in thiscase (Anhui/2/2005 and Guangxi/1/2005).
Figure 1. Phylogram Showing the Genetic Relationships among Representative Strains of the Hemagglutinin Gene.
The phylogenic tree displays the genetic relatedness of influenza A (H5N1) strains isolated from animals and humans. The phylogram shows nucleotide positions 29 through 1732 (1704 bp); the scale bar indicates 0.01 nucleotide change per site. Anhui/1/2005 is the virus isolated from the pregnant woman reported here. A/Vietnam/1194/2004 and A/Vietnam/1203/2004 are vaccine strains under development. Clades 1 and 2 designate clusters of genetically related viruses. The absence of a leading animal designation implies human origin of the isolate. The strains discussed here are highlighted in red.
Women in the second and third trimesters of pregnancy are atincreased risk for complications of influenza and should beconsidered for vaccination.1,2 The genetic diversity of H5N1influenza strains causing serious human disease is greater thanpreviously recognized. These observations have important implicationsfor vaccine development, since the vaccine strains being developedinclude A/Vietnam/1194/2004 (in China) and A/Vietnam/1203/2004,3which belongs to clade 1.
Yuelong Shu, Ph.D. State Key Laboratory of Infectious Disease Prevention and Control Beijing 100052, China yshu{at}vip.sina.com
Hongjie Yu, M.D., M.P.H. Chinese Center for Disease Control and Prevention Beijing 100050, China
Dexin Li, M.D. National Institute for Viral Disease Controland Prevention Beijing 100052, China
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