Family Clustering of Avian Influenza A (H5N1)

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作者：

SJ Olsen，K Ungchusak，L Sovann，TM Uyeki，SF Dowell，NJ Cox，W Aldis，S Chunsuttiwat

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摘要：

To the Editor: The unprecedented epizootic of avian influenza A (H5N1) in Asia poses a serious threat of causing the next global influenza pandemic. H5N1 viruses, to which humans have little or no immunity, have demonstrated the capacity to infect humans and cause severe illness and death (1-4). Fortunately, these viruses have not yet demonstrated the capacity for efficient and sustained person-to-person transmission, although limited person-to-person transmission was the cause of at least 1 family cluster of cases (5). Since family clusters of H5N1 illness may be the first suggestion of a viral or epidemiologic change, we have been monitoring them with great interest. Through our regional contacts and public sources, we have monitored family clusters and other aspects of H5N1 in Southeast Asia. A cluster was defined as [greater than or equal to] 2 family members with laboratory-confirmed H5N1 or [greater than or equal to] 2 family members with severe pneumonia or respiratory death, at least one of which had confirmed H5N1. To determine if family cluster events had increased over time, we divided the number of cluster events by the total number of days in 2 discrete periods and calculated rate ratios (RR) and 95% confidence intervals (CI). To determine whether the increase in family clustering was attributable to an increase in the number of cases, we divided the number of family units with [greater than or equal to] 2 laboratory-confirmed cases by the total number of family units in the period. Percentage of deaths was also compared. From January 2004 to July 2005, 109 cases of avian influenza A (H5N1) were officially reported to the World Health Organization (WHO) (6). During this time, 15 family clusters were identified (Table). Of the 11 (73%) clusters that occurred in Vietnam, 7 were in northern Vietnam....

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关键词：

avian influenza H5N1 letter family clusters

DOI：

10.3201/eid1111.050646

被引量：

1119

年份：

2005