Avian Influenza Redux
Avian Influenza Redux
Abstract & Commentary
Synopsis: Avian influenza virus has reemerged in Hong Kong and, independently, in The Netherlands, where it has caused conjunctivitis in poultry workers.
Source: Promed archives at http://www.promedmail.org.
A 33-year-old Hong Kong resident developed respiratory symptoms on February 7, 2002, while visiting Fujian Province, China, with his family. He returned to Hong Kong the following day and was admitted to a hospital on February 11, where he died 6 days later. The man’s 9-year-old son, who also became ill while in Fujian, was admitted to the Hong Kong hospital on February 12 with pneumonia but survived. The boy’s 8-year-old sister died while in Fujian on February 4. The mother is recovering from a respiratory tract infection. Influenza A virus (H5N1) was isolated from nasopharyngeal isolates from the boy and from postmortem specimens of the father. The etiology of the mother’s illness was thought to have been parainfluenza virus infection, while the etiology of the girl’s death has not yet been determined.
At least 65 poultry workers in The Netherlands, where an outbreak of influenza A (H7N7) is affecting poultry plants, have developed infection due to this virus. Most patients had conjunctivitis as the main manifestation of infection. There has been 1 instance of human-to-human transmission identified. The viral strain is susceptible to oseltamivir, and it has been recommended that this drug be prophylactically administered to workers at affected sites.
Comment by Stan Deresinski, MD, FACP
Eighteen people, 6 of whom died, were infected with avian influenza A virus (H5N1) in Hong Kong in 1997.1 The etiologic pathogen in that outbreak is not, however, related to the current influenza A strain. Sequencing of the recently isolated virus has demonstrated it to be genetically distinct from the earlier strain.
Avian influenza A virus subtype H9N2 was isolated from 5 humans on mainland China in August 1998, and in March of 1999 influenza A virus (H9N2) was isolated from 2 children in Hong Kong with flu-like illnesses.2
While these infections caused a typical influenza-like illness, avian influenza may also cause conjunctivitis in humans, as illustrated by the experience in The Netherlands. This is not the first report of this phenomenon: An H7N7 influenza virus of avian origin was isolated from a woman with a self-limited conjunctivitis in 1996.
These viruses have limited capacity for human-to-human transmission. A major concern is the possibility that genetic reassortment could occur with emergence of a virus capable of spread through a human population immunologically naïve to the viral antigens.3
Dr. Derenski is Clinical Professor of Medicine, Stanford; Associate Chief of Infectious Diseases, Santa Clara Valley Medical Center.
References
1. Deresinski S. The bird flu—Drifting, shifting, and jumping species. Infectious Disease Alert. 1998;17: 57-59.
2. Hatta M, Kawaoka Y. The continued pandemic threat posed by avian influenza viruses in Hong Kong. Trends Microbiol. 2002;10:340-344.
3. Capua I, et al. The 1999-2000 avian influenza (H7N1) epidemic in Italy: Veterinary and human health implications. Acta Trop. 2002;83:7-11.
Dr. Derenski is Clinical Professor of Medicine, Stanford; Associate Chief of Infectious Diseases, Santa Clara Valley Medical Center.
Avian influenza virus has reemerged in Hong Kong and, independently, in The Netherlands, where it has caused conjunctivitis in poultry workers.Subscribe Now for Access
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